What are the three stages of pertussis. How long does each stage of whooping cough last. What are the main symptoms of pertussis in infants. How is pertussis diagnosed and treated. Why are pertussis cases increasing despite vaccination.

The Origins and Resurgence of Pertussis

Pertussis, commonly known as whooping cough, has a long and complex history in human health. First described during a Paris epidemic in 1578, this highly contagious respiratory disease has been a significant cause of infant morbidity and mortality for centuries. The causative organism, Bordetella pertussis, was identified in 1906, leading to the development of a vaccine in the 1940s. This breakthrough drastically reduced pertussis cases, but recent decades have seen a concerning resurgence.

Why is pertussis making a comeback despite widespread vaccination? Several factors contribute to this trend:

• Waning immunity in adolescents and adults
• Increased awareness and improved diagnostic techniques
• Possible genetic changes in the Bordetella bacteria
• Gaps in vaccination coverage

The Centers for Disease Control and Prevention (CDC) reported over 48,000 cases in the United States in 2012, though experts believe this number is likely underreported due to diagnostic challenges. Globally, pertussis continues to be a significant health concern, with an estimated 24 million cases and 160,000 deaths annually.

Understanding the Causative Agents of Pertussis

Pertussis is primarily caused by two closely related bacteria: Bordetella pertussis and Bordetella parapertussis. These gram-negative coccobacilli are highly adapted to the human respiratory tract, making humans their sole reservoir. How do these bacteria cause infection?

1. Attachment to ciliated respiratory epithelial cells
2. Release of various toxins (pertussis toxin, dermonecrotic toxin, adenylate cyclase toxin, and tracheal cytotoxin)
3. Local inflammatory changes in the respiratory tract mucosal lining
4. Systemic effects from toxin circulation

Interestingly, while the bacteria cause significant local damage, they rarely invade the bloodstream, making blood cultures typically negative for Bordetella species.

Transmission and Risk Factors

Pertussis spreads through aerosolized droplets produced during coughing. Its high contagiousness can lead to infection in up to 100% of non-immune household contacts. What factors increase the risk of contracting pertussis?

• Pregnancy
• Exposure during an epidemic
• Lack of immunization or waning immunity
• Close contact with an infected individual
• Being an infant, especially under 6 months old

It’s worth noting that while pertussis remains predominantly a pediatric disease, with 71% of cases occurring in children under 5 years old, adolescents and adults can also contract and spread the infection, often with milder symptoms that may go unrecognized.

The Three Stages of Pertussis Infection

Pertussis infection typically progresses through three distinct stages, each with its own characteristic symptoms and duration. Understanding these stages is crucial for accurate diagnosis and appropriate management of the disease.

1. The Catarrhal Stage

How does pertussis initially present? The catarrhal stage mimics a common cold or upper respiratory infection, making early diagnosis challenging. Key features include:

• Duration: 1 to 2 weeks
• Symptoms: Fever, fatigue, rhinorrhea (runny nose), and conjunctival injection
• Infectiousness: This is the most contagious phase of the disease

2. The Paroxysmal Stage

What characterizes the paroxysmal stage of pertussis? This phase is marked by the classic “whooping cough” symptoms:

• Duration: Can last 1 to 6 weeks or longer
• Key symptom: Paroxysms of staccato coughing followed by a forceful inspiration (the “whoop”)
• Associated features: Cyanosis, diaphoresis, or apnea during coughing episodes
• Post-paroxysm effects: Vomiting, syncope, or apnea

Notably, patients typically appear well between coughing episodes, which can be triggered by cold air or noise and often worsen at night.

3. The Convalescent Stage

How long does recovery from pertussis take? The convalescent stage can be prolonged:

• Duration: Weeks to months
• Main feature: Persistent cough that gradually decreases in frequency and severity
• Other symptoms: Generally resolve, but fatigue may persist

Diagnosing Pertussis: Challenges and Techniques

Accurate diagnosis of pertussis can be challenging, especially in its early stages or in partially immunized individuals. What methods are used to diagnose whooping cough?

• Clinical presentation: Characteristic cough and progression of symptoms
• Nasopharyngeal swab for PCR testing: Highly sensitive and specific, especially early in the disease
• Culture: Less sensitive than PCR but useful for antibiotic susceptibility testing
• Serologic testing: More useful for late diagnosis or epidemiological studies
• Chest X-ray: May show perihilar infiltrates or atelectasis, but often normal

Why is early diagnosis crucial? Prompt identification allows for timely treatment, which can reduce symptom severity and duration, as well as limit transmission to others, especially vulnerable infants.

Treatment Strategies for Pertussis

How is pertussis managed once diagnosed? The treatment approach depends on the stage of illness and severity of symptoms:

Antibiotic Therapy

What antibiotics are effective against Bordetella pertussis?

• Macrolides: Azithromycin, clarithromycin, or erythromycin
• Alternative: Trimethoprim-sulfamethoxazole for patients allergic to macrolides

Antibiotic treatment is most effective when initiated early in the disease course, ideally during the catarrhal stage. While it may not significantly alter the course of illness if started later, it can still reduce infectiousness.

Supportive Care

What supportive measures can help manage pertussis symptoms?

• Oxygen therapy for cyanosis or respiratory distress
• Intravenous fluids if oral intake is compromised
• Suctioning of secretions to maintain airway patency
• Avoidance of cough suppressants, which can be counterproductive
• Close monitoring for complications, especially in infants

Hospital Admission Criteria

When should patients with pertussis be hospitalized?

• Infants younger than 6 months
• Patients with severe respiratory distress or cyanosis
• Those with significant comorbidities or complications
• Cases where adequate home care cannot be ensured

Pertussis Prevention: Vaccination Strategies

Vaccination remains the cornerstone of pertussis prevention. How has the vaccination strategy evolved to address the resurgence of pertussis?

Current Vaccination Recommendations

• DTaP vaccine: 5-dose series for children at 2, 4, 6, 15-18 months, and 4-6 years
• Tdap booster: Recommended for adolescents and adults, including pregnant women
• Cocooning strategy: Vaccinating close contacts of newborns

Why is pertussis vaccination particularly important for pregnant women? Maternal antibodies can provide some protection to newborns in their first months of life, before they can receive their own vaccinations.

Addressing Waning Immunity

How is the issue of waning immunity being tackled?

• More frequent booster doses for adolescents and adults
• Research into more effective and longer-lasting vaccines
• Increased emphasis on timely vaccination and catch-up schedules

Complications and Special Considerations in Pertussis

While pertussis can be serious for anyone, certain groups face higher risks of complications. Who is most vulnerable to severe pertussis, and what complications can occur?

High-Risk Groups

• Infants under 6 months: Highest risk of severe disease and death
• Unvaccinated or incompletely vaccinated children
• Pregnant women: Risk of preterm labor and transmission to newborn
• Elderly individuals: Increased risk of complications due to comorbidities
• Immunocompromised patients: May have atypical presentation and prolonged course

Potential Complications

What are the most serious complications of pertussis?

• Pneumonia: Both primary and secondary bacterial
• Respiratory failure: Particularly in young infants
• Seizures and encephalopathy: Due to hypoxia or direct effects of pertussis toxin
• Subconjunctival hemorrhage: From violent coughing
• Rib fractures: In severe cases, especially in adults
• Hernias or pneumothorax: From increased intra-abdominal and intrathoracic pressure

How does pertussis affect infants differently? Infants may present with apnea or cyanosis as the primary symptom, often without the characteristic whoop. They are also at higher risk for life-threatening complications like pneumonia and encephalopathy.

The Role of Public Health in Pertussis Control

Effective control of pertussis requires a coordinated public health approach. What strategies are employed to prevent outbreaks and manage cases?

Surveillance and Reporting

• Mandatory reporting of confirmed and suspected cases
• Active surveillance during outbreaks
• Molecular typing to track strain changes and transmission patterns

Contact Tracing and Prophylaxis

How are pertussis exposures managed?

• Identification and notification of close contacts
• Antibiotic prophylaxis for high-risk contacts, especially household members
• Vaccination status assessment and catch-up immunization as needed

Public Education

What key messages are important in pertussis prevention?

• Importance of timely vaccination for all age groups
• Recognition of pertussis symptoms, especially in adults
• Proper cough etiquette and hand hygiene
• Importance of seeking medical care for prolonged cough illnesses

By combining robust vaccination programs, vigilant surveillance, prompt case management, and public education, public health efforts aim to reduce the burden of pertussis and protect vulnerable populations.

Future Directions in Pertussis Research and Management

As pertussis continues to pose challenges worldwide, ongoing research and innovation are crucial. What areas are scientists and healthcare professionals focusing on to improve pertussis control?

Vaccine Development

• Research into more effective and longer-lasting vaccines
• Exploration of novel antigen combinations to broaden immune response
• Development of mucosal vaccines for enhanced local immunity

Diagnostic Improvements

How can pertussis diagnosis be enhanced?

• Development of rapid, point-of-care tests for early diagnosis
• Refinement of PCR techniques to increase sensitivity and specificity
• Exploration of biomarkers for disease severity and prognosis

Treatment Innovations

What new approaches are being investigated for pertussis treatment?

• Research into antitoxin therapies to neutralize pertussis toxin
• Exploration of immunomodulatory treatments to reduce inflammation
• Investigation of combination therapies for enhanced efficacy

Epidemiological Studies

Ongoing epidemiological research aims to:

• Better understand transmission dynamics, especially in partially vaccinated populations
• Identify factors contributing to waning immunity
• Assess the impact of different vaccination strategies on disease burden

As research progresses, the hope is to develop more effective strategies for preventing, diagnosing, and treating pertussis, ultimately reducing its global impact on public health.

The management of pertussis requires a multifaceted approach involving healthcare providers, public health officials, researchers, and the general public. By continuing to improve our understanding of the disease, refining prevention strategies, and developing new diagnostic and treatment tools, we can work towards better control of this challenging respiratory infection. As always, vaccination remains a cornerstone of pertussis prevention, and ongoing efforts to optimize immunization strategies will be crucial in reducing the burden of this disease worldwide.

Pertussis – StatPearls – NCBI Bookshelf

Continuing Education Activity

Pertussis, literally meaning “a violent cough,” also known as whooping cough or “the cough of 100 days,” was first described in the Paris epidemic of 1578. Bordetella pertussis, the causative organism, was discovered in 1906, and a vaccine was developed in the 1940s. Before the pertussis vaccine was developed, pertussis was a major cause of infant morbidity and mortality. This activity describes the presentation and management of pertussis and highlights the role of the interprofessional team in the treatment of affected patients and families.

Objectives:

• Identify the etiology of pertussis.

• Describe the typical presentation of a patient with pertussis.

• Outline the treatment and management options available for pertussis.

• Summarize interprofessional team strategies for improving care coordination and communication to enhance the care of patients with pertussis and improve patient outcomes.

Access free multiple choice questions on this topic.

Introduction

Pertussis, literally meaning “a violent cough,” also known as whooping cough or “the cough of 100 days,” was first described in the Paris epidemic of 1578. Bordetella pertussis, the causative organism, was discovered in 1906, and a vaccine was developed in the 1940s. Before the pertussis vaccine was developed, pertussis was a major cause of infant morbidity and mortality.[1][2][3] Pertussis is a serious illness with very high morbidity and mortality.

Etiology

The causative organisms of pertussis are Bordetella pertussis and Bordetella parapertussis. Bordetella is spread by airborne droplets and is highly contagious. Pertussis often affects 100% of non-immune household contacts. Immunity wanes to 50% 12 years after completing a vaccination series. Immunocompromised persons can also contract Bordetella bronchiseptica, which typically affects animals and is commonly known as “a kennel cough. ”[4][5][6]

Humans are the sole reservoir for Bordetella; the organism is spread via aerosolized droplets produced during a cough. The organism is highly contagious, with the majority of cases occurring during summer.

Risk factors for acquiring pertussis include:

• Pregnancy

• Epidemic exposure

• Lack of immunization

• Close contact with an infected individual

Epidemiology

Reported pertussis cases are increasing in the United States and worldwide. The prevalence of pertussis in the United States sharply declined from 150,000 to 250,000 cases per year in the prevaccination era to 1010 cases reported in 1976. Since then, pertussis has been on the rise, which is partially attributed to waning adolescent and adult immunity. Although pertussis largely remains a pediatric disease, with 38% of cases occurring in infants younger than 6 months and 71% of cases occurring in children younger than 5 years, adolescents and adults can also contract the disease and are likely contributing to the increasing number of both adult and pediatric cases seen over the past three decades. Worldwide, there are over 24 million cases annually, with greater than 160,000 deaths. The Center for Disease Control and Prevention (CDC) reported over 48,000 cases in the United States in 2012, the most recent year for which this data is available. Due to difficulty in diagnosis, the CDC estimates likely underreporting.[7]

Pathophysiology

Bordetella is a gram-negative coccobacillus that adheres to ciliated respiratory epithelial cells. Local inflammatory changes occur in the mucosal lining of the respiratory tract. Released toxins (pertussis toxin, dermonecrotic toxin, adenylate cyclase toxin, and tracheal cytotoxin) act locally and systemically, although the organism itself does not fully penetrate the respiratory tract, and almost never is found in blood cultures.

History and Physical

After an incubation period of 1 to 3 weeks, pertussis infection typically progresses through three distinct stages: the catarrhal phase, the paroxysmal phase, and the convalescent phase.

The catarrhal phase presents similarly to other upper respiratory tract infections, with fever, fatigue, rhinorrhea, and conjunctival injection. The catarrhal phase lasts 1 to 2 weeks and is the most infectious stage of the disease.

The paroxysmal phase follows the catarrhal phase and is characterized by paroxysms of a staccato cough and the resolution of fever. The patient typically coughs repeatedly, followed by forceful inspiration, which creates the characteristic “whoop.” These episodes may be triggered by cold or noise and are more common at night. Patients are nontoxic-appearing in between paroxysms, but during coughing episodes, may exhibit cyanosis, diaphoresis, or apnea. Immediately following a paroxysm, patients may develop post-tussive emesis, syncope, or apnea.

Finally, during the convalescent phase, a residual cough persists for weeks to months, usually triggered by exposure to another upper respiratory infection or irritant.

Atypical presentations are common in infants, and fever may not occur. Rather, tachypnea, apnea, cyanosis, and episodic bradycardia may be the presenting features.

Increased intrathoracic pressure from coughing may result in petechiae above the nipple line, subconjunctival hemorrhage, and epistaxis.

Breath sounds are variable; auscultation may reveal clear lungs or rhonchi, while rales suggest superimposed pneumonia. The inspiratory whoop or gasp is usually heard in children between 6 months to 5 years.

Evaluation

Testing for pertussis is not readily available in the emergency department. Nasopharyngeal culture and polymerase chain reaction (PCR) may yield laboratory confirmation, but the fastidious and slow-growing Bordetella organisms require specialized media, and cultures are typically not positive for 3 to 7 days. In adults, by the time the diagnosis is suspected, cultures are typically negative (96%), and overall culture sensitivity is only 20% to 40%. PCR is more sensitive and specific than culture, but testing is not widely available. [8][9][10]

In the emergency department, pertussis should be considered in patients with prolonged cough, especially occurring in paroxysms or with whoops or post-tussive emesis. During the late catarrhal and early paroxysmal phases, leukocytosis (often 25,000 to 60,000 per mL) with lymphocytosis may raise suspicion for pertussis. In a study of 100 infants less than 120 days old and admitted to a pediatric intensive care unit, there was a significantly higher leukocytosis in the five fatal cases. Unfortunately, leukocytosis may be the only laboratory finding useful in the emergency department. Chest x-ray findings are nonspecific and may show peribronchial thickening, atelectasis, or infiltrates. The classic association, though not often seen, is a “shaggy” right heart border.

Treatment / Management

Treatment of pertussis is largely supportive, including oxygen, suctioning, hydration, and avoidance of respiratory irritants. Parenteral nutrition may be necessary as the disease tends to have a prolonged course.

Hospitalization is indicated for patients with superimposed pneumonia, hypoxia, central nervous system (CNS) complications, or who are unable to tolerate nutrition and hydration by mouth. Patients less than 1-year-old are not fully vaccinated and carry the greatest risk of morbidity and mortality; they should be hospitalized regardless of symptoms. Neonates should be admitted to an intensive care setting as life-threatening cardiopulmonary complications and arrest can occur unexpectedly.

Antibiotic effect on the duration or severity of the disease is minimal when started in the catarrhal phase and not proven effective when started in the paroxysmal phase. Rather, the primary goal of antibiotic treatment is to decrease the carriage and spread of disease. Erythromycin (40 to 50 mg/kg per day, maximum 2 g per day, in 2 to 3 divided doses) is the first-line treatment for pertussis. Azithromycin (10 mg/kg per day on day 1 followed by 5 mg/kg on days 2 to 5) and clarithromycin (15 mg/kg per day in two divided doses) are alternative treatments. Trimethoprim-sulfamethoxazole (8 mg/kg per day of trimethoprim) has been used as an alternative in macrolide-allergic patients, but its efficacy has not been proven.

The macrolides are not recommended for infants less than 4 weeks old for fear that this may lead to infantile hypertrophic pyloric stenosis.

Strict isolation is important while the patient remains infectious. Pertussis is contagious throughout the catarrhal phase and for 3 weeks after the onset of the paroxysmal phase. In patients treated with antibiotics, isolation should be continued for at least 5 days after treatment is initiated. Postexposure prophylaxis with erythromycin is recommended for all household contacts.

Corticosteroids have not shown definite benefit in reducing the severity and course of illness but are sometimes given to critically ill infants. Beta2-agonists, pertussis immune globulin, cough suppressants, and antihistamines are not effective. Exchange blood transfusion therapy for leukocytosis with lymphocytosis may be considered.

Close contacts should be treated with azithromycin or erythromycin.

Vaccination is recommended with the acellular vaccine at ages 2,4,6, 15-18 months, and at ages 4 to 6 years. In addition, the CDC recommends a single dose of Tdap for all adults to reduce transmission to children. Adverse effects of the vaccine include crying and febrile seizures, but severe neurological effects are rare. The vaccine can also be administered during the third trimester to pregnant women without causing harm to the fetus. 

DTaP is approved during the last 3 months of pregnancy to prevent pertussis in infants under 2 months old.

Differential Diagnosis

Pertussis initially presents similarly to other respiratory infections, such as viral upper respiratory infection, bronchiolitis, pneumonia, and tuberculosis. Key differentiating factors of pertussis include typical progression through the three phases and persistent cough without fever. Foreign body aspiration should be considered in younger patients, and exacerbation of chronic obstructive pulmonary disease should be considered in older patients with the appropriate history. The striking leukocytosis may also be confused with leukemia.

Prognosis

Most people infected with pertussis will fully recover, albeit usually after a prolonged illness of months. Infants and older adults tend to have the highest mortality and morbidity, respectively. The infant death rate is about 2% of cases and accounts for 96% of deaths related to pertussis. Older adults tend to have increased morbidity due to other chronic medical conditions, as well as an increased rate of complications, such as pneumonia.[11][12][13]

Secondary complications like pneumonia, seizures, and encephalopathy may occur in some patients.

Complications

Secondary pneumonia or otitis media may occur. Superimposed pneumonia is a major cause of mortality in infants and young children and may be caused by aspiration of gastric contents during paroxysms of cough or because of decreased respiratory clearance of pathogens. Fever should subside during the catarrhal phase, and its presence during the paroxysmal phase should raise suspicion for pneumonia. The most common causes of secondary bacterial pneumonia are Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Staphylococcus aureus; although viral infections with the respiratory syncytial virus, cytomegalovirus, and adenovirus superinfections are also common.

Rarely (less than 2% of cases), CNS complications such as seizures and encephalopathy can occur, likely secondary to hypoxia, hypoglycemia, toxins, secondary infections, or cerebral bleeding from increased pressure during coughing. Sudden increases in intrathoracic and intraabdominal pressures can also result in periorbital edema, pneumothorax, pneumomediastinum, subcutaneous emphysema, diaphragmatic rupture, umbilical and inguinal hernias, and rectal prolapse.

Pertussis toxin also causes histamine hypersensitivity and increased insulin secretion.

Infants are particularly prone to bradycardia, hypotension, and cardiac arrest from pertussis. The development of pulmonary hypertension has been increasingly recognized as a factor contributing to infantile mortality, as it may lead to worsening systemic hypotension and hypoxia.

Deterrence and Patient Education

Pertussis vaccine exists in both whole-cell (DPT) and acellular (DTaP) forms. In 1991, the acellular formulation largely replaced the whole-cell vaccine, which had been associated with acute encephalopathy and prolonged seizures. The acellular form has fewer adverse effects and is as effective as the whole-cell formulation. As a result, the whole-cell preparation is only recommended when the acellular form is not available. Common adverse effects are mild and include fever, irritability, behavioral changes, and pain at the injection site. Less commonly, moderately severe reactions, including fever over 40 C, persistent and high-pitched crying, and seizures may occur. A recent study of over 50,000 patients vaccinated from 1981 to 2016 did not detect any new or unexpected adverse effects.

Pearls and Other Issues

Laboratory and radiographic confirmation of pertussis is a challenge in the emergency department setting. It is important to maintain a low threshold of suspicion for pertussis in any patient presenting with prolonged cough, regardless of immunization status. A complete blood count with attention to leukocytosis and lymphocytosis may be the best diagnostic screening tool in the emergency department.

Enhancing Healthcare Team Outcomes

The management of pertussis is best done with an interprofessional team that includes the pharmacist and nurses. With a strong anti-vaccine movement, patient education is key. Parents and caregivers have to be informed that the adverse effects of the vaccine are rare. In an era of anti-vaccination sentiments, clinicians should educate the public that the vaccine is safe and effective.

Pertussis immunity wanes significantly about seven years after vaccination and about 15 years after natural infection. As a result, the CDC Advisory Committee on Immunization Practices recommends routine booster immunization, starting at ages 11 to 18 years. A study of almost 70,000 patients showed no significant adverse effects for patients receiving Tdap instead of Td as a tetanus booster; in patients requiring a tetanus booster in the emergency department, adding the acellular pertussis component could be considered, especially in pregnant women. Mothers are often identified as the source of pertussis infection in newborns who have not completed their vaccination series, and preliminary data suggest that infants of mothers vaccinated against both influenza and pertussis may be at lower risk for contracting pertussis.

Pertussis is a reportable infection in the US, and even one case must be reported immediately, and control measures to prevent transmission should be in place. Open communication between the interprofessional team is vital to ensure that patients are treated with optimal care and that vaccination protocols are in place.

Review Questions

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References

1.

Leong RNF, Wood JG, Turner RM, Newall AT. Estimating seasonal variation in Australian pertussis notifications from 1991 to 2016: evidence of spring to summer peaks. Epidemiol Infect. 2019 Jan;147:e155. [PMC free article: PMC6518527] [PubMed: 31063086]

2.

Hotez PJ. Immunizations and vaccines: a decade of successes and reversals, and a call for ‘vaccine diplomacy’. Int Health. 2019 Sep 02;11(5):331-333. [PubMed: 31034023]

3.

Xu J, Liu S, Liu Q, Rong R, Tang W, Wang Q, Kuang S, Zhou C. The effectiveness and safety of pertussis booster vaccination for adolescents and adults: A systematic review and meta-analysis. Medicine (Baltimore). 2019 Apr;98(16):e15281. [PMC free article: PMC6494346] [PubMed: 31008974]

4.

Dou M, Macias N, Shen F, Bard JD, Domínguez DC, Li X. Rapid and Accurate Diagnosis of the Respiratory Disease Pertussis on a Point-of-Care Biochip. EClinicalMedicine. 2019 Feb;8:72-77. [PMC free article: PMC6469871] [PubMed: 31008450]

5.

Dou M, Sanchez J, Tavakoli H, Gonzalez JE, Sun J, Dien Bard J, Li X. A low-cost microfluidic platform for rapid and instrument-free detection of whooping cough. Anal Chim Acta. 2019 Aug 13;1065:71-78. [PMC free article: PMC6481316] [PubMed: 31005153]

6.

Etskovitz H, Anastasio N, Green E, May M. Role of Evolutionary Selection Acting on Vaccine Antigens in the Re-Emergence of Bordetella Pertussis. Diseases. 2019 Apr 16;7(2) [PMC free article: PMC6630436] [PubMed: 30995764]

7.

Jenkinson D. Pertussis (whooping cough) is common in teens and adults. BMJ. 2019 Apr 09;365:l1623. [PubMed: 30967372]

8.

Toubiana J, Azarnoush S, Bouchez V, Landier A, Guillot S, Matczak S, Bonacorsi S, Brisse S. Bordetella parapertussis Bacteremia: Clinical Expression and Bacterial Genomics. Open Forum Infect Dis. 2019 Apr;6(4):ofz122. [PMC free article: PMC6453521] [PubMed: 30976607]

9.

Kandeil W, Atanasov P, Avramioti D, Fu J, Demarteau N, Li X. The burden of pertussis in older adults: what is the role of vaccination? A systematic literature review. Expert Rev Vaccines. 2019 May;18(5):439-455. [PubMed: 30887849]

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Argondizo-Correia C, Rodrigues AKS, de Brito CA. Neonatal Immunity to Bordetella pertussis Infection and Current Prevention Strategies. J Immunol Res. 2019;2019:7134168. [PMC free article: PMC6387735] [PubMed: 30882004]

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Forsyth KD, Tan T, von König CW, Heininger U, Chitkara AJ, Plotkin S. Recommendations to control pertussis prioritized relative to economies: A Global Pertussis Initiative update. Vaccine. 2018 Nov 19;36(48):7270-7275. [PubMed: 30337176]

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Campbell H, Gupta S, Dolan GP, Kapadia SJ, Kumar Singh A, Andrews N, Amirthalingam G. Review of vaccination in pregnancy to prevent pertussis in early infancy. J Med Microbiol. 2018 Oct;67(10):1426-1456. [PubMed: 30222536]

13.

Lumbreras Areta M, Martinez De Tejada B. [Preventing whooping cough in infants : vaccinated mother, protected newborn]. Rev Med Suisse. 2018 Oct 24;14(624):1884-1886. [PubMed: 30375788]

Disclosure: Ashley Lauria declares no relevant financial relationships with ineligible companies.

Disclosure: Christopher Zabbo declares no relevant financial relationships with ineligible companies.

Pertussis – StatPearls – NCBI Bookshelf

Continuing Education Activity

Pertussis, literally meaning “a violent cough,” also known as whooping cough or “the cough of 100 days,” was first described in the Paris epidemic of 1578. Bordetella pertussis, the causative organism, was discovered in 1906, and a vaccine was developed in the 1940s. Before the pertussis vaccine was developed, pertussis was a major cause of infant morbidity and mortality. This activity describes the presentation and management of pertussis and highlights the role of the interprofessional team in the treatment of affected patients and families.

Objectives:

• Identify the etiology of pertussis.

• Describe the typical presentation of a patient with pertussis.

• Outline the treatment and management options available for pertussis.

• Summarize interprofessional team strategies for improving care coordination and communication to enhance the care of patients with pertussis and improve patient outcomes.

Access free multiple choice questions on this topic.

Introduction

Pertussis, literally meaning “a violent cough,” also known as whooping cough or “the cough of 100 days,” was first described in the Paris epidemic of 1578. Bordetella pertussis, the causative organism, was discovered in 1906, and a vaccine was developed in the 1940s. Before the pertussis vaccine was developed, pertussis was a major cause of infant morbidity and mortality.[1][2][3] Pertussis is a serious illness with very high morbidity and mortality.

Etiology

The causative organisms of pertussis are Bordetella pertussis and Bordetella parapertussis. Bordetella is spread by airborne droplets and is highly contagious. Pertussis often affects 100% of non-immune household contacts. Immunity wanes to 50% 12 years after completing a vaccination series. Immunocompromised persons can also contract Bordetella bronchiseptica, which typically affects animals and is commonly known as “a kennel cough.”[4][5][6]

Humans are the sole reservoir for Bordetella; the organism is spread via aerosolized droplets produced during a cough. The organism is highly contagious, with the majority of cases occurring during summer.

Risk factors for acquiring pertussis include:

• Pregnancy

• Epidemic exposure

• Lack of immunization

• Close contact with an infected individual

Epidemiology

Reported pertussis cases are increasing in the United States and worldwide. The prevalence of pertussis in the United States sharply declined from 150,000 to 250,000 cases per year in the prevaccination era to 1010 cases reported in 1976. Since then, pertussis has been on the rise, which is partially attributed to waning adolescent and adult immunity. Although pertussis largely remains a pediatric disease, with 38% of cases occurring in infants younger than 6 months and 71% of cases occurring in children younger than 5 years, adolescents and adults can also contract the disease and are likely contributing to the increasing number of both adult and pediatric cases seen over the past three decades. Worldwide, there are over 24 million cases annually, with greater than 160,000 deaths. The Center for Disease Control and Prevention (CDC) reported over 48,000 cases in the United States in 2012, the most recent year for which this data is available. Due to difficulty in diagnosis, the CDC estimates likely underreporting.[7]

Pathophysiology

Bordetella is a gram-negative coccobacillus that adheres to ciliated respiratory epithelial cells. Local inflammatory changes occur in the mucosal lining of the respiratory tract. Released toxins (pertussis toxin, dermonecrotic toxin, adenylate cyclase toxin, and tracheal cytotoxin) act locally and systemically, although the organism itself does not fully penetrate the respiratory tract, and almost never is found in blood cultures.

History and Physical

After an incubation period of 1 to 3 weeks, pertussis infection typically progresses through three distinct stages: the catarrhal phase, the paroxysmal phase, and the convalescent phase.

The catarrhal phase presents similarly to other upper respiratory tract infections, with fever, fatigue, rhinorrhea, and conjunctival injection. The catarrhal phase lasts 1 to 2 weeks and is the most infectious stage of the disease.

The paroxysmal phase follows the catarrhal phase and is characterized by paroxysms of a staccato cough and the resolution of fever. The patient typically coughs repeatedly, followed by forceful inspiration, which creates the characteristic “whoop.” These episodes may be triggered by cold or noise and are more common at night. Patients are nontoxic-appearing in between paroxysms, but during coughing episodes, may exhibit cyanosis, diaphoresis, or apnea. Immediately following a paroxysm, patients may develop post-tussive emesis, syncope, or apnea.

Finally, during the convalescent phase, a residual cough persists for weeks to months, usually triggered by exposure to another upper respiratory infection or irritant.

Atypical presentations are common in infants, and fever may not occur. Rather, tachypnea, apnea, cyanosis, and episodic bradycardia may be the presenting features.

Increased intrathoracic pressure from coughing may result in petechiae above the nipple line, subconjunctival hemorrhage, and epistaxis.

Breath sounds are variable; auscultation may reveal clear lungs or rhonchi, while rales suggest superimposed pneumonia. The inspiratory whoop or gasp is usually heard in children between 6 months to 5 years.

Evaluation

Testing for pertussis is not readily available in the emergency department. Nasopharyngeal culture and polymerase chain reaction (PCR) may yield laboratory confirmation, but the fastidious and slow-growing Bordetella organisms require specialized media, and cultures are typically not positive for 3 to 7 days. In adults, by the time the diagnosis is suspected, cultures are typically negative (96%), and overall culture sensitivity is only 20% to 40%. PCR is more sensitive and specific than culture, but testing is not widely available.[8][9][10]

In the emergency department, pertussis should be considered in patients with prolonged cough, especially occurring in paroxysms or with whoops or post-tussive emesis. During the late catarrhal and early paroxysmal phases, leukocytosis (often 25,000 to 60,000 per mL) with lymphocytosis may raise suspicion for pertussis. In a study of 100 infants less than 120 days old and admitted to a pediatric intensive care unit, there was a significantly higher leukocytosis in the five fatal cases. Unfortunately, leukocytosis may be the only laboratory finding useful in the emergency department. Chest x-ray findings are nonspecific and may show peribronchial thickening, atelectasis, or infiltrates. The classic association, though not often seen, is a “shaggy” right heart border.

Treatment / Management

Treatment of pertussis is largely supportive, including oxygen, suctioning, hydration, and avoidance of respiratory irritants. Parenteral nutrition may be necessary as the disease tends to have a prolonged course.

Hospitalization is indicated for patients with superimposed pneumonia, hypoxia, central nervous system (CNS) complications, or who are unable to tolerate nutrition and hydration by mouth. Patients less than 1-year-old are not fully vaccinated and carry the greatest risk of morbidity and mortality; they should be hospitalized regardless of symptoms. Neonates should be admitted to an intensive care setting as life-threatening cardiopulmonary complications and arrest can occur unexpectedly.

Antibiotic effect on the duration or severity of the disease is minimal when started in the catarrhal phase and not proven effective when started in the paroxysmal phase. Rather, the primary goal of antibiotic treatment is to decrease the carriage and spread of disease. Erythromycin (40 to 50 mg/kg per day, maximum 2 g per day, in 2 to 3 divided doses) is the first-line treatment for pertussis. Azithromycin (10 mg/kg per day on day 1 followed by 5 mg/kg on days 2 to 5) and clarithromycin (15 mg/kg per day in two divided doses) are alternative treatments. Trimethoprim-sulfamethoxazole (8 mg/kg per day of trimethoprim) has been used as an alternative in macrolide-allergic patients, but its efficacy has not been proven.

The macrolides are not recommended for infants less than 4 weeks old for fear that this may lead to infantile hypertrophic pyloric stenosis.

Strict isolation is important while the patient remains infectious. Pertussis is contagious throughout the catarrhal phase and for 3 weeks after the onset of the paroxysmal phase. In patients treated with antibiotics, isolation should be continued for at least 5 days after treatment is initiated. Postexposure prophylaxis with erythromycin is recommended for all household contacts.

Corticosteroids have not shown definite benefit in reducing the severity and course of illness but are sometimes given to critically ill infants. Beta2-agonists, pertussis immune globulin, cough suppressants, and antihistamines are not effective. Exchange blood transfusion therapy for leukocytosis with lymphocytosis may be considered.

Close contacts should be treated with azithromycin or erythromycin.

Vaccination is recommended with the acellular vaccine at ages 2,4,6, 15-18 months, and at ages 4 to 6 years. In addition, the CDC recommends a single dose of Tdap for all adults to reduce transmission to children. Adverse effects of the vaccine include crying and febrile seizures, but severe neurological effects are rare. The vaccine can also be administered during the third trimester to pregnant women without causing harm to the fetus. 

DTaP is approved during the last 3 months of pregnancy to prevent pertussis in infants under 2 months old.

Differential Diagnosis

Pertussis initially presents similarly to other respiratory infections, such as viral upper respiratory infection, bronchiolitis, pneumonia, and tuberculosis. Key differentiating factors of pertussis include typical progression through the three phases and persistent cough without fever. Foreign body aspiration should be considered in younger patients, and exacerbation of chronic obstructive pulmonary disease should be considered in older patients with the appropriate history. The striking leukocytosis may also be confused with leukemia.

Prognosis

Most people infected with pertussis will fully recover, albeit usually after a prolonged illness of months. Infants and older adults tend to have the highest mortality and morbidity, respectively. The infant death rate is about 2% of cases and accounts for 96% of deaths related to pertussis. Older adults tend to have increased morbidity due to other chronic medical conditions, as well as an increased rate of complications, such as pneumonia.[11][12][13]

Secondary complications like pneumonia, seizures, and encephalopathy may occur in some patients.

Complications

Secondary pneumonia or otitis media may occur. Superimposed pneumonia is a major cause of mortality in infants and young children and may be caused by aspiration of gastric contents during paroxysms of cough or because of decreased respiratory clearance of pathogens. Fever should subside during the catarrhal phase, and its presence during the paroxysmal phase should raise suspicion for pneumonia. The most common causes of secondary bacterial pneumonia are Streptococcus pneumoniae, Streptococcus pyogenes, Haemophilus influenzae, and Staphylococcus aureus; although viral infections with the respiratory syncytial virus, cytomegalovirus, and adenovirus superinfections are also common.

Rarely (less than 2% of cases), CNS complications such as seizures and encephalopathy can occur, likely secondary to hypoxia, hypoglycemia, toxins, secondary infections, or cerebral bleeding from increased pressure during coughing. Sudden increases in intrathoracic and intraabdominal pressures can also result in periorbital edema, pneumothorax, pneumomediastinum, subcutaneous emphysema, diaphragmatic rupture, umbilical and inguinal hernias, and rectal prolapse.

Pertussis toxin also causes histamine hypersensitivity and increased insulin secretion.

Infants are particularly prone to bradycardia, hypotension, and cardiac arrest from pertussis. The development of pulmonary hypertension has been increasingly recognized as a factor contributing to infantile mortality, as it may lead to worsening systemic hypotension and hypoxia.

Deterrence and Patient Education

Pertussis vaccine exists in both whole-cell (DPT) and acellular (DTaP) forms. In 1991, the acellular formulation largely replaced the whole-cell vaccine, which had been associated with acute encephalopathy and prolonged seizures. The acellular form has fewer adverse effects and is as effective as the whole-cell formulation. As a result, the whole-cell preparation is only recommended when the acellular form is not available. Common adverse effects are mild and include fever, irritability, behavioral changes, and pain at the injection site. Less commonly, moderately severe reactions, including fever over 40 C, persistent and high-pitched crying, and seizures may occur. A recent study of over 50,000 patients vaccinated from 1981 to 2016 did not detect any new or unexpected adverse effects.

Pearls and Other Issues

Laboratory and radiographic confirmation of pertussis is a challenge in the emergency department setting. It is important to maintain a low threshold of suspicion for pertussis in any patient presenting with prolonged cough, regardless of immunization status. A complete blood count with attention to leukocytosis and lymphocytosis may be the best diagnostic screening tool in the emergency department.

Enhancing Healthcare Team Outcomes

The management of pertussis is best done with an interprofessional team that includes the pharmacist and nurses. With a strong anti-vaccine movement, patient education is key. Parents and caregivers have to be informed that the adverse effects of the vaccine are rare. In an era of anti-vaccination sentiments, clinicians should educate the public that the vaccine is safe and effective.

Pertussis immunity wanes significantly about seven years after vaccination and about 15 years after natural infection. As a result, the CDC Advisory Committee on Immunization Practices recommends routine booster immunization, starting at ages 11 to 18 years. A study of almost 70,000 patients showed no significant adverse effects for patients receiving Tdap instead of Td as a tetanus booster; in patients requiring a tetanus booster in the emergency department, adding the acellular pertussis component could be considered, especially in pregnant women. Mothers are often identified as the source of pertussis infection in newborns who have not completed their vaccination series, and preliminary data suggest that infants of mothers vaccinated against both influenza and pertussis may be at lower risk for contracting pertussis.

Pertussis is a reportable infection in the US, and even one case must be reported immediately, and control measures to prevent transmission should be in place. Open communication between the interprofessional team is vital to ensure that patients are treated with optimal care and that vaccination protocols are in place.

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References

1.

Leong RNF, Wood JG, Turner RM, Newall AT. Estimating seasonal variation in Australian pertussis notifications from 1991 to 2016: evidence of spring to summer peaks. Epidemiol Infect. 2019 Jan;147:e155. [PMC free article: PMC6518527] [PubMed: 31063086]

2.

Hotez PJ. Immunizations and vaccines: a decade of successes and reversals, and a call for ‘vaccine diplomacy’. Int Health. 2019 Sep 02;11(5):331-333. [PubMed: 31034023]

3.

Xu J, Liu S, Liu Q, Rong R, Tang W, Wang Q, Kuang S, Zhou C. The effectiveness and safety of pertussis booster vaccination for adolescents and adults: A systematic review and meta-analysis. Medicine (Baltimore). 2019 Apr;98(16):e15281. [PMC free article: PMC6494346] [PubMed: 31008974]

4.

Dou M, Macias N, Shen F, Bard JD, Domínguez DC, Li X. Rapid and Accurate Diagnosis of the Respiratory Disease Pertussis on a Point-of-Care Biochip. EClinicalMedicine. 2019 Feb;8:72-77. [PMC free article: PMC6469871] [PubMed: 31008450]

5.

Dou M, Sanchez J, Tavakoli H, Gonzalez JE, Sun J, Dien Bard J, Li X. A low-cost microfluidic platform for rapid and instrument-free detection of whooping cough. Anal Chim Acta. 2019 Aug 13;1065:71-78. [PMC free article: PMC6481316] [PubMed: 31005153]

6.

Etskovitz H, Anastasio N, Green E, May M. Role of Evolutionary Selection Acting on Vaccine Antigens in the Re-Emergence of Bordetella Pertussis. Diseases. 2019 Apr 16;7(2) [PMC free article: PMC6630436] [PubMed: 30995764]

7.

Jenkinson D. Pertussis (whooping cough) is common in teens and adults. BMJ. 2019 Apr 09;365:l1623. [PubMed: 30967372]

8.

Toubiana J, Azarnoush S, Bouchez V, Landier A, Guillot S, Matczak S, Bonacorsi S, Brisse S. Bordetella parapertussis Bacteremia: Clinical Expression and Bacterial Genomics. Open Forum Infect Dis. 2019 Apr;6(4):ofz122. [PMC free article: PMC6453521] [PubMed: 30976607]

9.

Kandeil W, Atanasov P, Avramioti D, Fu J, Demarteau N, Li X. The burden of pertussis in older adults: what is the role of vaccination? A systematic literature review. Expert Rev Vaccines. 2019 May;18(5):439-455. [PubMed: 30887849]

10.

Argondizo-Correia C, Rodrigues AKS, de Brito CA. Neonatal Immunity to Bordetella pertussis Infection and Current Prevention Strategies. J Immunol Res. 2019;2019:7134168. [PMC free article: PMC6387735] [PubMed: 30882004]

11.

Forsyth KD, Tan T, von König CW, Heininger U, Chitkara AJ, Plotkin S. Recommendations to control pertussis prioritized relative to economies: A Global Pertussis Initiative update. Vaccine. 2018 Nov 19;36(48):7270-7275. [PubMed: 30337176]

12.

Campbell H, Gupta S, Dolan GP, Kapadia SJ, Kumar Singh A, Andrews N, Amirthalingam G. Review of vaccination in pregnancy to prevent pertussis in early infancy. J Med Microbiol. 2018 Oct;67(10):1426-1456. [PubMed: 30222536]

13.

Lumbreras Areta M, Martinez De Tejada B. [Preventing whooping cough in infants : vaccinated mother, protected newborn]. Rev Med Suisse. 2018 Oct 24;14(624):1884-1886. [PubMed: 30375788]

Disclosure: Ashley Lauria declares no relevant financial relationships with ineligible companies.

Disclosure: Christopher Zabbo declares no relevant financial relationships with ineligible companies.

Whooping cough

Whooping cough is a pathology of infectious origin, which is more common in children. The disease has specific symptoms and requires appropriate treatment.

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Bacteriological examination for whooping cough (Bordetella pertussis) in any sample

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The pathogenesis of the disease is a violation of the respiratory function, and in the process of the development of the disease, the mucous membrane of the respiratory tract is damaged. The disease is quite complex and, before the invention of a vaccine and treatment, was a significant cause in the structure of infant mortality.

Today, the disease is also quite dangerous. Every year, about 300,000 people die from this pathology. Fatal are the complications of the disease, which are more often observed in patients of childhood and old age, due to anatomical, physiological and immune characteristics. This indicates how important it is to know the symptoms of the disease and the features of treatment.

Features of symptoms depend on the period of the disease. They are as follows:

Incubation period lasts from the moment the pathogen enters the body until the first symptoms appear. As a rule, it is from 3 to 20 days. During this time, the respiratory tract is so affected by the pathogen that the body ceases to compensate for the condition and the clinical picture of the disease begins.

Catarrhal period corresponds to the degree of damage to the body by a pathogenic agent, which means it develops gradually. The patient cannot even immediately determine the onset of the disease, the first symptoms are so vague. The first sign is a dry cough or even a slight cough. There may be a runny nose, in which mucus is secreted from the nasal passages in a small amount. Younger patients are more difficult to tolerate this period, since their anatomical structure of the respiratory tract contributes to the more rapid development of the disease. In general, the onset of the disease resembles SARS, which often confuses both patients and specialists. The cough gradually becomes stronger, irritability and restlessness of the patient join it.

Then develops a period of spasmodic cough, which usually coincides with the 2nd week of the catarrhal period. The duration of this segment of the disease is several weeks, 3-4. At this time, the most striking manifestations of the disease are observed, namely a spasmodic cough that occurs in attacks. Before an attack, its harbingers appear – discomfort and sore throat, a feeling of squeezing in the chest, panic and anxiety. The time of onset of seizures can be different, often they disturb at night. How to recognize a coughing fit? It consists of strong shocks that are replaced by convulsive breaths. Such a breath is accompanied by a weak moan and whistle and is called a reprise. This sound is produced when air passes through a severely constricted airway. At the end of the attack, the patient begins to leave a viscous transparent sputum.

If the disease reaches a severe degree, vomiting, convulsions, tachycardia, and respiratory failure may occur. Outwardly, such an attack is accompanied by swelling of facial tissues, cyanosis, and swelling of the vessels of the neck. Redness of the eyes may be observed, saliva and lacrimal fluid are discharged in an increased amount. Between coughing fits, the child is in a normal state, plays, eats with appetite, does not experience any discomfort. Of the characteristic symptoms that occur with whooping cough: a white ulcer on the frenulum of the tongue, which occurs when it is damaged by teeth, hemorrhages in the conjunctiva, a tendency to nosebleeds.

The disease resolution stage gradually replaces the previous stage. Cough occurs less and less, becomes less specific, seizures and reprises disappear. The patient becomes weak, asthenic, feels irritable and tired. This state of exhaustion may persist for some time after the illness.

The period of recovery or convalescence takes about half a year. The patient gets tired during physical exertion, lessons are difficult for children, capriciousness and emotional lability are observed. During this period, the body’s immune function is somewhat reduced and the patient becomes more prone to SARS, during which the typical cough for whooping cough again occurs.

Such periods are characteristic of the typical clinical picture of whooping cough. But there are also atypical forms of the disease. This is an abortive and erased form. They can occur in those who are vaccinated, as well as in adults whose immunity is more developed than in children and the elderly. The erased form is accompanied by the usual dry cough, which does not go away while taking antitussives. There are no characteristic seizures. such a cough can disturb the patient from several weeks to several months, but the condition remains stable, complications do not appear. Abortive form is characterized by a fulminant course in which the symptoms appear suddenly and just as suddenly disappear after a few days.

When is it necessary to diagnose whooping cough?

Indications for the diagnosis of whooping cough are the clinical manifestations of the disease, which must be confirmed or refuted. Since the pathology is infectious in nature, a diagnosis based on clinical data is not possible – laboratory results are required. If the patient has characteristic coughing fits, an analysis is required.

There are also epidemic indications for diagnosis. It is necessary to take tests for all persons who visit or were in childcare facilities, hospitals, maternity wards, where patients with whooping cough were found and there is a risk of infection. In addition, diagnostics is required for a differential diagnosis in conditions such as cystic fibrosis, a foreign body in the respiratory tract, asthma, acute bronchitis, lymphogranulomatosis, measles, pneumonia, acute respiratory infections.

Modern methods of pathology diagnostics

Bacteriological method

The study is carried out on the 5th-7th day of the disease, it is at this time that it has the greatest information content. It should also be taken into account that it is best to take the material before starting antibiotic therapy, otherwise the result may be false negative. Before taking the test, you can not eat, rinse your mouth, drink, brush your teeth. The material is taken from the posterior pharyngeal wall using a special swab. Sometimes a dish with a nutrient medium is brought to the patient during a cough. The resulting material is sown on nutrient media that are suitable for the life and growth of the microorganism. A few days after receiving the material, a preliminary conclusion can be made, and a week later – the exact result of the analysis.

Serological method

This technique is used at a later stage of the disease, a few weeks after the onset of characteristic symptoms. By this time, the bacteriological method loses its effectiveness, since the pathogen practically disappears from the respiratory tract, but antibodies to it circulate throughout the body. The titers of antibodies to the pathogen and their type are determined. There are three classes of immunoglobulins, M, A and G. Antibodies of class M appear at 2 weeks of illness, immunoglobulins A indicate that the disease develops more than 2-3 weeks, and immunoglobulins G can be detected after 4 weeks of illness.

ELISA method

This is the main method of serological diagnosis. The study requires venous blood. The resulting material is combined with a laboratory reagent that contains the pathogen. If there are antibodies in the blood, an immune complex occurs, which indicates the presence of the disease. Before taking the tests, the patient should not eat, take medications, or be subjected to physical exertion. A study of paired sera is carried out, the interval between which is from 10 to 14 days. The results are obtained on the basis of an increase in the antibody titer, which indicates the further development of the pathology and makes it possible to exclude the fact that the antibodies appeared as a result of a vaccine or a previous illness.

PCR

The polymerase chain reaction method is the most modern and high-quality way to confirm or exclude a diagnosis. For the reaction, you need to donate blood. In laboratory conditions, it is being studied for amino acid fragments of the genetic material of the pathogen. Further, the belonging of the obtained structure to the type of pathogen that causes whooping cough is confirmed or excluded. The analysis requires specific expensive reagents and appropriate laboratory equipment, as well as staff skills.

Hematological analysis

This refers to a routine blood test that does not have specific results. Based on it, one can only confidently say about the presence of an inflammatory process of bacterial origin, since leukocytosis is observed with a typical shift in the leukocyte formula. Such a result can be the beginning of laboratory diagnostics, on the basis of which the doctor will make the following appointments.

Diagnosis scheme

The diagnostic scheme differs by the age of the patient, as well as by the presence of vaccination against the disease.

Diagnosis scheme for those who have not been vaccinated:

• in the first two weeks of the disease, bacteriological examination or PCR is effective;
• at 3-4 weeks of illness, PCR or serological testing is used;
• more than 4 weeks of illness – an indication for a serological examination.

Against the background of taking antibiotics, PCR is used.

D For vaccinated persons, the following examination scheme is used:

• at 1-2 weeks of illness – PCR method, bacteriological analysis;
• at 3-4 weeks, PCR is used;
• disease duration of more than 4 weeks requires serological diagnosis.

Interpretation of results

The results of the bacteriological method are unambiguous: the presence of microorganisms in the material indicates that they are the cause of the pathology.

The hematological method is non-specific; an increase in leukocytes of more than 9 109/l has a diagnostic value.

PCR results are positive if there are fragments of the bacterial genetic material in the body.

The results of serological diagnostics are decoded as follows:

• less than 10.0 – a negative result, the absence of antibodies. Such a result can be in a healthy person or in a patient who fell ill less than three weeks ago;
• from 10.0 to 50.0 – a weakly positive reaction, an unreliable result that requires re-diagnosis;
• more than 50.0 – the reaction is positive, antibodies are detected. Such a result indicates that the person is sick or has recently had whooping cough.

Basic aspects of disease prevention and treatment

Prevention of whooping cough is through routine vaccination. The DTP vaccine is used, which contains components against whooping cough, diphtheria and tetanus and is used at the age of 3, 4, 5, 6 months, and after that at 1.5 and 6 years. There is also emergency prophylaxis, which consists in the introduction of a specific immunoglobulin after contact of an unvaccinated child or a child under one year old with a carrier of the bacterium.

The vaccine is highly effective, but it does not exclude a possible disease. Please note that the disease in this case will be of a milder form, will not bring complications, and will not lead to serious consequences, limiting itself to only erased symptoms of the disease. The vaccine is needed not so much to prevent the disease itself, but to prevent its severe course and fatal complications. Non-specific prevention consists in observing epidemic measures in a team where there are cases of the disease, limiting contact with carriers of the microorganism, and sanitary and hygienic measures.

Treatment is carried out on an outpatient basis for patients with a mild course of the disease, and those who are severely ill, young children are hospitalized. Antibacterial therapy, glucocorticoids, antihistamines, vitamins, drugs that affect respiratory function are used. In severe cases, additional administration of oxygen, nootropics, psychostimulant drugs is required.

Reasons to get diagnosed at the SZTSDM

The laboratory of the center is equipped with the latest diagnostic equipment. Analyzes are performed quickly and efficiently. The staff of medical centers employs highly qualified specialists, which allows us to make diagnostics versatile and effective. The patient can not only establish the fact of the disease, but also undergo an extended check of the body, as well as treatment. For our doctors, there is no disease of a separate system – they assess the full condition of the patient and treat him, not pathology. It is possible to receive the results of the study by personal e-mail or receive them in printed form at the medical center.

Laboratory diagnosis of whooping cough and parapertussis

A comprehensive study aimed at diagnosing whooping cough and parapertussis, as well as evaluating the effectiveness of pertussis vaccination.

Synonyms Russian

Pertussis, parapertussis pathogens; comprehensive examination.

Synonyms English

Bordetella pertussis, Bordetella parapertussis; comprehensive examination.

What biomaterial can be used for research?

Venous blood, nasopharyngeal swab, throat swab (oropharynx).

How to properly prepare for the examination?

• Do not eat, drink, brush your teeth, gargle your mouth/throat, chew gum, or smoke 3-4 hours before taking oral oropharyngeal (pharyngeal) swabs. 3-4 hours before taking swabs from the nose, do not instill drops / sprays and do not rinse the nose. Taking smears is best done in the morning, immediately after a night’s sleep.

General information about the study

Whooping cough is an acute anthroponotic bacterial infection. The causative agent is Bordetella pertussis (Bordet-Jongou stick), a small immobile gram-negative coccobacillus, a strict aerobe. The infection is transmitted by airborne droplets. The source of infection is a sick person with any form of infectious process.

During the course of the disease, the following periods are distinguished: incubation period (lasting from several days to two weeks), catarrhal (from 5-8 to 11-14 days), paroxysmal or spasmodic (2-8 weeks), resolution (2-4 weeks) and convalescence (2-6 months). The most characteristic of whooping cough are manifestations that characterize the paroxysmal period of the disease. These include dry spastic cough, cyanosis of the nasolabial triangle, acrocyanosis, possible vomiting, fever, weakness, leukocytosis, lymphocytosis in the hemogram. It should be noted that the disease is most severe in young children, complications from the bronchopulmonary and nervous systems are possible. In adults and individuals after vaccination, whooping cough often occurs in a mild, atypical form, as a rule, without complications.

Parapertussis is an acute bacterial infection of the respiratory tract that affects children and adults. The causative agent of the infection is the aerobic bacillus Bordetella parapertussis. The clinical manifestations of this disease are similar to the picture of whooping cough, characterized by a more erased change of periods, a mild course, a rare development of complications, mainly in children.

Diagnosis of whooping cough and parapertussis is based on clinical and epidemiological data, the results of changes in the clinical analysis of blood and is confirmed by laboratory methods. In the clinical laboratory diagnosis of these diseases, several methods are used: bacteriological method to detect the growth of colonies of whooping cough / parapertussis pathogens; serological method aimed at determining total antibodies to these pathogens; polymerase chain reaction (PCR) method – to identify the genetic material of the whooping cough pathogen.

Bacteriological examination is the first stage of diagnosis, but it allows to identify pathogens only in the early stages of the disease, in the first 2-3 weeks.

The PCR method is highly effective in the diagnosis of whooping cough, allows the detection of DNA fragments of the pathogen B. pertussis in the studied biomaterial, and has a high diagnostic specificity, reaching 100%. The use of this method is recommended in the first three weeks from the onset of the clinical manifestations of the disease, that is, in the catarrhal and early paroxysmal period. In the later stages of the disease, the diagnostic sensitivity of the method falls. It should be noted that, unlike other laboratory methods, PCR is effective against the background of treatment with antibacterial drugs. It is also used in young children, as opposed to older children and adults, where an increase in false positives is possible. In individuals vaccinated against whooping cough, a positive result of this method may indicate a transient carriage of the pathogen, and not an active form of the disease.

Serological examination allows the detection of specific antibodies in the blood serum directed to the antigens of the pathogens B. pertussis and B. parapertussis. They can be detected using an indirect hemagglutination test (IHA).

When choosing RIGA as a diagnostic test for suspected whooping cough and parapertussis, the clinical period of the disease, the age of the patient and the presence of previous vaccination should be taken into account. To confirm the diagnosis, it is necessary to determine the increase in antibody titer by four or more times in paired sera taken at intervals of 10-14 days. The reaction is placed in parallel with pertussis and parapertussis antigen. Serological examination is recommended to be used within 3-6 weeks from the onset of the first clinical symptoms of the disease, which characterizes the paroxysmal period of whooping cough. This method is not recommended for children under 3 months of age, since the immune system of newborns at this time is still immature and low titers of maternal antibodies can be detected. It is also not recommended to perform serological testing in individuals within 1 year after pertussis vaccination due to the inability to distinguish between the immune response to vaccination or to primary infection. Anti-B. pertussis titer can be measured to evaluate the effectiveness of pertussis vaccination in children.

What is research used for?

• For comprehensive laboratory diagnosis of pertussis and parapertussis.
• For the diagnosis of whooping cough in the first three weeks from the onset of the disease, characterizing the catarrhal and early paroxysmal period, as well as against the background of treatment with antibacterial drugs.
• For the diagnosis of whooping cough and parapertussis in the spasmodic (paroxysmal) period of the disease.
• To evaluate the effectiveness of pertussis vaccination.

When is the examination scheduled?

• With clinical manifestations of whooping cough / parapertussis: dry spastic cough, accompanied by deep wheezing, vomiting, cyanosis of the nasolabial triangle, acrocyanosis, fever, weakness, runny nose, lacrimation.
• When examining persons who were in close contact with patients with whooping cough / parapertussis.
• When evaluating the effectiveness of pertussis vaccination.

What do the results mean?

Reference values ​​

1. anti-Bordetella pertussis

Result: negative.

Titer: 1:80 – conditionally protective titer in unvaccinated individuals; 1:160 – conditionally protective titer of post-vaccination immunity.

2. anti-Bordetella parapertussis

Result: negative.

Title:

3. Bordetella pertussis, DNA

Result: not found.

Reason for positive result:

• whooping cough;
• parapertussis;
• transient carrier;
• immune response after vaccination.

Reason for negative result:

• no pertussis/parapertussis;
• ineffective pertussis vaccination;
• decreased immunological response after vaccination;
• false negative results.

What can influence the result?

• Clinical period of the disease, age of the patient, previous vaccination;
• the use of antibacterial drugs depending on the stage (period) of the disease and the method of laboratory diagnostics used;
• features of the immune response in newborns;
• previous vaccination.

Important notes

• When interpreting the results of the examination, it is necessary to take into account diagnostic methods, age of patients, clinical stage (period) of the disease, previous vaccination.
• For a comprehensive assessment of the results obtained, they must be compared with epidemiological, clinical and other laboratory data.

Also recommended

• Bordetella pertussis/parapertussis inoculation
• Clinical blood test: general analysis, leukocyte formula, ESR (with microscopy of a blood smear in case of pathological changes)

Who orders the examination?

Infectionist, pediatrician, pulmonologist, otorhinolaryngologist, internist, general practitioner.

Literature

1. Ghanaie RM, Karimi A, Sadeghi H, Esteghamti A, Falah F, Armin S, Fahimzad A, Shamshiri A, Kahbazi M, Shiva F. Sensitivity and specificity of the World Health Organization pertussis clinical case definition / Int J Infect Dis. 2010 Dec;14(12):e1072-5.
2. Przegl Epidemiol. 2014;68(4):633-6.
3. Piekarska K, Rzeczkowska M, Rastawicki W, Dąbrowska-Iwanicka A, Paradowska-Stankiewicz I.