What are the common causes of hypercalcemia. How is high blood calcium diagnosed. What are the symptoms of elevated calcium levels. When should you seek medical attention for hypercalcemia. How is high blood calcium treated. Can hypercalcemia be prevented. What are the long-term effects of untreated hypercalcemia.

Understanding Hypercalcemia: An Overview of High Blood Calcium

Hypercalcemia, a condition characterized by elevated levels of calcium in the blood, is a common medical finding that affects millions of Americans annually. While a single high calcium reading may be due to laboratory error or dehydration, persistent elevation often indicates an underlying health issue that requires further investigation.

The normal range for blood calcium typically falls between 8.5 to 10.5 mg/dL (milligrams per deciliter). Levels above this range are considered hypercalcemia and can have various causes, ranging from benign conditions to more serious health concerns.

Primary Hyperparathyroidism: The Leading Cause of Hypercalcemia

Primary hyperparathyroidism is the most prevalent cause of chronically elevated blood calcium levels. This condition occurs when one or more of the parathyroid glands, small endocrine glands located in the neck, produce excessive amounts of parathyroid hormone (PTH).

In primary hyperparathyroidism, a benign tumor (adenoma) typically develops in one of the parathyroid glands, leading to overproduction of PTH. This excess hormone causes increased calcium release from bones and enhanced calcium absorption in the intestines, resulting in elevated blood calcium levels.

Diagnosis of Primary Hyperparathyroidism

Classical primary hyperparathyroidism is diagnosed when both calcium and PTH levels are above the normal range:

• Calcium > 10.5 mg/dL
• PTH > 65 pg/mL (picograms per milliliter)

However, it’s important to note that non-classical forms of primary hyperparathyroidism can occur with calcium levels in the high-normal range and varying PTH levels.

Malignancy: The Second Most Common Cause of Hypercalcemia

Cancer is the second leading cause of high blood calcium levels, unrelated to parathyroid gland dysfunction. Various types of cancer can lead to hypercalcemia, including:

• Lung cancer
• Breast cancer
• Esophageal cancer
• Oral cancers (mouth, tongue, lip)
• Kidney cancer
• Ovarian cancer
• Uterine cancer
• Cervical cancer
• Blood-borne cancers (lymphoma, multiple myeloma)

It’s crucial to emphasize that hypercalcemia of malignancy is relatively uncommon and generally not a concern for most healthy individuals. However, persistent hypercalcemia in the absence of other explanations may warrant further investigation to rule out underlying malignancies.

Medication-Induced Hypercalcemia: The Role of Thiazide Diuretics

Certain medications, particularly thiazide diuretics, can contribute to elevated blood calcium levels. Thiazide diuretics are commonly prescribed to treat hypertension (high blood pressure) and work by increasing calcium retention in the kidneys.

Examples of thiazide diuretics include:

• Hydrochlorothiazide (HCTZ)
• Chlorothiazide
• Chlorothalidone
• Indapamide
• Metolazone

These medications can cause a slight increase in blood calcium levels by preventing calcium excretion through urine. Patients taking thiazide diuretics should have their calcium levels monitored regularly and discuss any concerns with their healthcare provider.

Kidney Disease and Its Impact on Calcium Levels

Chronic kidney disease (CKD) or renal failure can significantly affect calcium homeostasis in the body. As kidney function declines, the ability to regulate calcium levels becomes impaired, potentially leading to hypercalcemia.

Individuals with the following conditions may experience elevated blood calcium levels:

• Chronic renal failure
• End-stage renal disease requiring dialysis
• Kidney transplant recipients

The relationship between kidney disease and calcium imbalance is complex, often involving factors such as altered vitamin D metabolism, secondary hyperparathyroidism, and impaired calcium excretion.

Rare Causes of Hypercalcemia: Beyond Common Culprits

While primary hyperparathyroidism, malignancy, medications, and kidney disease account for the majority of hypercalcemia cases, several rare conditions can also lead to elevated blood calcium levels:

Familial Hypocalciuric Hypercalcemia (FHH)

Also known as benign familial hypocalciuric hypercalcemia (BFHH), this rare inherited condition is characterized by slightly elevated blood calcium levels without associated health complications. FHH is caused by a genetic mutation affecting calcium-sensing receptors in the kidneys and parathyroid glands.

Milk-Alkali Syndrome

This condition results from excessive oral calcium intake, often in combination with absorbable alkali. Historically, it was common among individuals self-treating peptic ulcers with large quantities of milk and calcium-based antacids. While rare today due to the availability of more effective ulcer treatments, it can still occur in people consuming high doses of calcium supplements.

Thyroid Disorders

Severe thyroid dysfunction can occasionally lead to calcium imbalances:

• Hypothyroidism (insufficient thyroid hormone production)
• Hyperthyroidism (excessive thyroid hormone production)

Although the thyroid gland is anatomically close to the parathyroid glands, its primary function is regulating metabolism. In rare cases of severe thyroid disease, calcium homeostasis can be disrupted.

Hypervitaminosis D

Excessive intake or production of vitamin D can lead to hypercalcemia. This condition can occur due to:

• Overdosing on vitamin D supplements
• Errors in food fortification (e.g., milk)
• Certain granulomatous diseases that cause increased vitamin D production

While vitamin D is essential for calcium absorption and bone health, toxic levels can disrupt calcium homeostasis and lead to hypercalcemia.

Symptoms and Clinical Manifestations of Hypercalcemia

The symptoms of hypercalcemia can vary widely depending on the severity and duration of elevated calcium levels. Some individuals may remain asymptomatic, especially in cases of mild hypercalcemia, while others may experience a range of symptoms affecting multiple organ systems.

Common Symptoms of Hypercalcemia

• Fatigue and weakness
• Confusion or difficulty concentrating
• Increased thirst and frequent urination
• Nausea and vomiting
• Constipation
• Abdominal pain
• Bone pain or fractures
• Kidney stones
• Depression or mood changes
• Heart rhythm abnormalities

In severe cases, hypercalcemia can lead to more serious complications such as kidney failure, severe dehydration, or even coma. It’s crucial to seek medical attention if you experience persistent symptoms or have risk factors for hypercalcemia.

Diagnosis and Evaluation of Hypercalcemia

Diagnosing hypercalcemia involves a combination of clinical assessment, laboratory tests, and sometimes imaging studies. The first step is typically a blood test to measure serum calcium levels.

Key Diagnostic Steps

1. Serum calcium measurement: Total and ionized calcium levels are assessed.
2. Parathyroid hormone (PTH) test: To evaluate parathyroid gland function.
3. 25-hydroxyvitamin D test: To check for vitamin D status.
4. Kidney function tests: Including blood urea nitrogen (BUN) and creatinine.
5. 24-hour urine calcium collection: To assess calcium excretion.
6. Bone density scan: To evaluate the impact on bone health.
7. Imaging studies: Such as ultrasound or sestamibi scan for parathyroid glands.

Additional tests may be necessary depending on the suspected underlying cause, such as cancer markers or genetic testing for familial conditions.

Treatment Approaches for Hypercalcemia

The treatment of hypercalcemia depends on its severity, underlying cause, and associated symptoms. Management strategies can range from simple observation to aggressive medical interventions.

Conservative Management

For mild, asymptomatic hypercalcemia:

• Increased fluid intake to promote calcium excretion
• Limiting dietary calcium and vitamin D intake
• Regular monitoring of calcium levels
• Addressing underlying causes (e.g., medication adjustment)

Medical Treatment

For moderate to severe hypercalcemia or symptomatic cases:

• Intravenous fluids for rehydration
• Bisphosphonates to reduce bone calcium release
• Calcitonin to decrease bone resorption and increase calcium excretion
• Glucocorticoids for certain conditions (e.g., vitamin D intoxication)
• Loop diuretics to enhance calcium excretion (used cautiously)

Surgical Intervention

In cases of primary hyperparathyroidism:

• Parathyroidectomy: Surgical removal of overactive parathyroid gland(s)

For hypercalcemia due to malignancy:

• Treatment of the underlying cancer

The choice of treatment depends on the individual patient’s condition, overall health status, and the expertise of the medical team. Close monitoring and follow-up are essential for all patients with hypercalcemia.

Long-Term Management and Prognosis of Hypercalcemia

The long-term outlook for individuals with hypercalcemia varies depending on the underlying cause and the effectiveness of treatment. Proper management can significantly improve quality of life and prevent complications.

Follow-up Care

• Regular blood tests to monitor calcium and PTH levels
• Bone density scans to assess bone health
• Kidney function monitoring
• Dietary and lifestyle modifications

Potential Complications

Untreated or poorly managed hypercalcemia can lead to:

• Osteoporosis and increased fracture risk
• Kidney stones and renal dysfunction
• Cardiovascular issues (hypertension, arrhythmias)
• Neurological symptoms (confusion, memory problems)
• Gastrointestinal disorders

Early detection and appropriate treatment can significantly reduce the risk of these complications and improve overall prognosis.

Prevention and Risk Reduction for Hypercalcemia

While not all cases of hypercalcemia can be prevented, certain measures can help reduce the risk or catch the condition early:

• Regular health check-ups and blood tests
• Maintaining adequate hydration
• Balanced calcium and vitamin D intake
• Monitoring medication side effects
• Addressing underlying health conditions
• Genetic counseling for familial forms of hypercalcemia

Understanding personal risk factors and maintaining open communication with healthcare providers are key to prevention and early intervention.

Emerging Research and Future Directions in Hypercalcemia Management

The field of hypercalcemia research continues to evolve, with ongoing studies focusing on improving diagnosis, treatment, and long-term management strategies.

Areas of Active Research

• Genetic factors influencing calcium metabolism
• Novel therapeutic targets for resistant hypercalcemia
• Improved imaging techniques for parathyroid gland localization
• Personalized treatment approaches based on molecular profiling
• Long-term outcomes of various management strategies

As our understanding of calcium homeostasis and its dysregulation deepens, we can expect more targeted and effective treatments for hypercalcemia in the future.

Hypercalcemia, while common, remains a complex condition with diverse causes and manifestations. From primary hyperparathyroidism to rare genetic disorders, the spectrum of conditions leading to elevated blood calcium levels highlights the importance of thorough evaluation and personalized management. By understanding the underlying mechanisms, recognizing symptoms early, and adhering to appropriate treatment plans, individuals with hypercalcemia can maintain their health and quality of life. As research progresses, we anticipate further advancements in the diagnosis, treatment, and prevention of this important metabolic disorder.

High Calcium – Endocrine Surgery

High calcium levels or high blood calcium levels

What to do if your blood calcium level is high
The finding of a high blood calcium level is very common, occurring in millions of Americans each year.  Sometimes, this will just be a single event related to a laboratory error or being dehydrated on the day the lab was drawn. 

However, quite frequently a high blood calcium level will mean that there is an important underlying problem.  In general, the first thing to do is re-check the level to confirm it.

Primary hyperparathyroidism is the most common cause of high blood calcium levels >

This is common sense.  For example, if you heard a strange noise in your car, you would certainly listen for it again the next time you drove to double check if it was a real problem, right?  You will see that in these pages we will frequently ask that you use common sense, as using your instincts or “gut feeling” is a good way to avoid being misled by biased or inaccurate information on the web. See Getting started: a word of caution regarding medical information on the internet.

If your blood calcium level is high on more than one occasion, then it is probably time to get more serious about finding out why this is happening.

Causes of high blood calcium levels include:

1. Primary hyperparathyroidism.  This is the most common cause of high blood calcium levels.  People with primary hyperparathyroidism usually have a benign tumor of the parathyroid glands (see What are the parathyroid glands?  Regulation of calcium in the human body) causing excessive amounts of calcium to leave the bone and enter the blood.
2. Malignancy (cancer).  This is the second most common cause of high blood calcium levels, and has nothing to do with the parathyroid glands.  Types of cancer that cause hypercalcemia of malignancy include cancers of the lung, breast, esophagus, mouth, tongue, lip, kidney, ovary, uterus, and cervix.   Blood-borne cancers such as lymphoma and multiple myeloma can also cause high calcium levels.  Thankfully, hypercalcemia of malignancy is uncommon and generally not worth worrying about in most healthy people.  (Really, please don’t worry.  Kindly read on.)
3. Thiazide diuretics.  Thiazide diuretics are a class of medicines that are commonly used to treat hypertension (high blood pressure).  They cause the kidney to “hold on” to calcium, preventing it from exiting in the urine and thereby increasing the blood calcium level slightly.  Examples of thiazide diuretics are: hydrochlorothiazide (HCTZ), chlorothiazide, chlorothalidone, indapamide, and metolazone.
4. Kidney disease, also known as renal failure or chronic renal failure.  High blood calcium levels can be found in people with slow or reduced kidney function, including those on dialysis and those who have had a kidney transplant.
5. Other rare causes, such as:

• Familial hypocalciuric hypercalcemia (FHH), also known as benign familial hypocalciuric hypercalcemia (BFHH) since it is associated with normal health.   This is a rare inherited trait characterized by a slightly high blood calcium level.
• Milk-alkali syndrome, or taking too much calcium by mouth.  Many antacids are calcium salts.  In the past, people with stomach ulcers would treat themselves by drinking lots of milk and taking lots (fistfuls) of calcium salt antacids, thereby raising the blood calcium level.  This is very rare now, since powerful non-calcium-based antacids have become available over the counter.
• Thyroid disease, such as hypothyroidism (too little thyroid hormone) and hyperthyroidism (too much thyroid hormone).  The thyroid gland is a neighbor to the parathyroid glands but has a completely separate function.  The thyroid gland governs metabolism, or how fast the cells in your body work.  In rare cases of severe thyroid disease, blood calcium levels can become imbalanced.
• Hypervitaminosis D, or too much vitamin D (See Vitamin D).  In rare circumstances, people can receive toxic levels of vitamin D leading to high blood calcium.   There have been a few interesting outbreaks of this related to errors in fortifying milk (see references below).
• There are a few more rare causes of high blood calcium levels but we have decided to leave them out because they are so very rare as to barely be worth mentioning.  So please note that this is not a complete list.

Primary hyperparathyroidism is the most common cause of high blood calcium levels (Figure 1). 

This pie chart shows the most common causes of chronically elevated blood calcium levels, meaning when the calcium test is high more than once over several months. 

Classical primary hyperparathyroidism is diagnosed when both the calcium level and the parathyroid hormone (PTH) level are above the normal range (calcium >10.5 mg/dL and PTH >65 pg/mL). 

Non-classical primary hyperparathyroidism is diagnosed when the calcium level is elevated and the PTH level remains higher than it should be, given what the calcium level is (calcium >10. 5 mg/dL and PTH 21-65 pg/mL, this is also known as an inappropriately normal PTH level – see Establishing the diagnosis of primary hyperparathyroidism).  Other causes of high blood calcium are listed above and most commonly refer to hypercalcemia of malignancy (high blood calcium levels due to cancer elsewhere in the body as described above) and use of thiazide diuretics.  Patients with “possible primary hyperparathyroidism” in the pie chart are those in whom the PTH level was never checked; however all of the other causes of high calcium were ruled out.  Please note that renal failure (chronic kidney disease) can also cause high blood calcium levels but those patients were excluded from this analysis.

To summarize, about 90% of patients whose blood calcium levels are found to be high more than once have some form of primary hyperparathyroidism.  If this has happened to you or a family member, you may wish to have the parathyroid hormone (PTH) level checked.  A high or inappropriately normal PTH level will frequently establish the diagnosis of primary hyperparathyroidism (see Establishing the diagnosis of primary hyperparathyroidism).   A low PTH level will suggest other causes of high blood calcium levels.

Where does this information come from?

The pie chart contains data derived from approximately 3.5 million Americans who receive care from a vertically-integrated health maintenance organization in California.  The population studied is similar in size to the population of the state of Ohio.  Through this unique research collaboration, UCLA Endocrine Surgery has been able to study both high blood calcium levels and primary hyperparathyroidism in a completely new way, looking at large, racially diverse populations in great detail with respect to their health outcomes (see How successful is parathyroid surgery?).

References

1. Lafferty FW. Differential diagnosis of hypercalcemia. J Bone Miner Res. 1991 Oct;6 Suppl 2:S51-9; discussion S61. Review. PubMed PMID: 1763670.
2. Stewart AF. Clinical practice. Hypercalcemia associated with cancer. N Engl J Med. 2005 Jan 27;352(4):373-9. Review. PubMed PMID: 15673803.
3. Varghese J, Rich T, Jimenez C. Benign familial hypocalciuric hypercalcemia.Endocr Pract. 2011 Mar-Apr;17 Suppl 1:13-7. Review. PubMed PMID: 21478088.
4. Blank S, Scanlon KS, Sinks TH, Lett S, Falk H. An outbreak of hypervitaminosis D associated with the overfortification of milk from a home-delivery dairy. Am J Public Health. 1995 May;85(5):656-9. PubMed PMID: 7733425; PubMed Central PMCID: PMC1615443.
5. Yeh MW, Haigh PI, Ituarte PH, Liu IL, Zhou H, Nishimoto S, Dell RM, Adams AL. Incidence and prevalence of primary hyperparathyroidism in a racially mixed population. Manuscript in preparation.

What Causes Hypercalcemia? Here Are 6 Known Causes

Written by Keri Wiginton

Medically Reviewed by Poonam Sachdev on April 30, 2022

• Overactive Parathyroid Glands (Hyperparathyroidism)
• Cancer
• Supplements
• Medication
• Genetics
• Less Common Causes
• More

If your doctor tells you that you have hypercalcemia, it means you have too much calcium in your blood. Some medical conditions can cause it. So can the kind of lifestyle you have, your genes, and certain medications.

You may not notice any symptoms if you have a mild case of hypercalcemia. But as your body tries to get rid of the extra calcium, you might pee a lot and get really thirsty. If your calcium levels are very high, you could get nervous system problems, including becoming confused and eventually unconscious.

You’ll usually find out that you have hypercalcemia through a blood test. If you don’t get it treated, high levels of calcium in your blood can lead to bone loss, kidney stones, kidney failure, and heart problems.

Your doctor can help you get your calcium levels back to normal and figure out why they’re out of whack in the first place.

Overactive parathyroid glands are the most common cause of hypercalcemia. When these glands are working right, they release parathyroid hormone (PTH) when your blood calcium levels get low. The release of this hormone helps your body absorb more calcium and lessens the amount you lose when you pee. It also pulls calcium from your bones and puts it into your blood.

But if you have overactive parathyroid glands, your body pumps out more PTH than you need. This can happen if they grow too big or a noncancerous tumor forms on one or more of your glands.

If hyperparathyroidism is the cause of your high calcium, you may also get:

• Depression
• Memory loss
• Heartburn
• Sleep trouble
• Bone and muscle pain
• Fatigue

You may not need treatment if you have mild hypercalcemia. But your doctor will monitor your health. Most likely, they’ll check your blood calcium and blood pressure every 6 months. And they’ll run tests on your kidneys once a year. You may need to get a bone density test every 1-3 years.

They may also tell you to:

• Drink more fluids
• Exercise
• Stop taking thiazide diuretics or lithium

You may need to take drugs called calcimimetics. They lower your PTH levels. In more serious cases, a surgeon may take out your parathyroid gland (or glands).

If your calcium levels are very high, you’ll need to go to the hospital to get fluids and medicine called diuretics through your veins. This can treat hypercalcemia fast.

Around 10%-30% of people with cancer may get hypercalcemia. That’s because cancer can:

• Cause your bones to break down and send calcium into your blood
• Mimic your parathyroid hormone, which triggers the release of calcium from your bones
• Affect your kidneys, which can lower the amount of calcium you get rid of when you pee

The most common cancer types that cause hypercalcemia include:

• Lung cancer
• Kidney cancer
• Breast cancer
• Multiple myeloma (a blood cancer that starts in bone marrow)

Your cancer or the treatment you get for it can share symptoms with hypercalcemia, such as feeling sick or throwing up. If you get dehydrated, your kidneys can’t get rid of calcium very well. Your doctor may give you fluids through your vein.

Hypercalcemia from cancer can be hard to manage. It helps to treat your cancer. But you may need drugs to slow the release of calcium from your bones, including:

• Bisphosphonates — given through your veins
• Denosumab (Prolia, Xgeva) — as an injection

If you take really high doses of vitamin A or D, you may absorb too much calcium. Overuse of calcium-containing antacids can also lead to hypercalcemia.

Your doctor will probably ask you to stop taking these supplements. If your vitamin D levels are really high, you may need to take steroid pills, like prednisone, for a short time.

Blood pressure drugs like thiazide diuretics can lower the amount of calcium that leaves your body when you pee. They may also make your parathyroid problems worse.

More than 20% of people who take lithium get hypercalcemia. Experts aren’t sure why this happens. They think it’s because the drug affects your parathyroid glands and the amount of PTH they make.

Your doctor may switch your medicine. If you need to stay on these drugs, they may give you medication to lower the amount of calcium in your blood.

If you inherit a certain gene, your body misjudges how much calcium is in your blood. You’ll send out more PTH than you need. It happens if you have a condition called familial hypocalciuric hypercalcemia (FHH). But in most cases, you won’t have any symptoms or need treatment.

Your doctor may want to monitor your health. It’s not common, but FHH can cause inflammation in your pancreas or calcium to build up in other parts of your body.

Health conditions. Lung diseases like tuberculosis and sarcoidosis can raise your blood levels of vitamin D. In turn, your gut will absorb more calcium. Paget’s disease and an overactive thyroid are also linked to hypercalcemia.

Inactivity. Your bones release calcium if you don’t put your body weight on them. This can happen if you’re paralyzed or you have another illness that keeps you in bed for a long time. Not getting enough exercise may also make hyperparathyroidism worse.

Serious dehydration. Your kidneys can’t get rid of calcium if you don’t have enough fluid in your body. An easy way to know if you’re dehydrated is to look at your urine. You want it to be light yellow, not a shade of dark orange. You should drink fluids until you’re not thirsty. Call a doctor if you have diarrhea or you throw up for a long time and can’t keep liquids down.

Top Picks

Serum calcium

Calcium is one of the main intracellular cations found mainly in bone tissue. Physiologically, it is active only in the ionized form, in which it is present in large quantities in the blood plasma.

Test method

Colorimetric photometric method.

Units

mmol/l (millimoles per litre).

Russian synonyms

Total calcium.

Synonyms English

Calcium total, Ca.

What biomaterial can be used for research?

Venous, capillary blood.

How to properly prepare for an examination?

• Do not eat for 12 hours before the test.
• Exclude physical and emotional overexertion 30 minutes prior to the study.
• Do not smoke for 30 minutes before the test.

General information about the study

Calcium is one of the most important minerals for humans. It is necessary for the contraction of skeletal muscles and the heart, for the transmission of a nerve impulse, as well as for normal blood clotting (promotes the transition of prothrombin to thrombin), to build the framework of bones and teeth.

Approximately 99% of this mineral is found in the bones and less than 1% circulates in the blood. Almost half of the calcium in the blood is metabolically active (ionized), the rest is bound to proteins (mainly albumin) and anions (lactate, phosphate, bicarbonate, citrate) and is inactive.

Total calcium in the blood is the concentration of its free (ionized) and bound forms. Only free calcium can be used by the body.

Part of the calcium leaves the body every day, being filtered from the blood by the kidneys and excreted in the urine. To maintain equality between the allocation and use of this mineral, it should be about 1 g per day.

When the concentration of calcium in the blood increases, the level of phosphate decreases, when the content of phosphate increases, the proportion of calcium decreases.

Mechanisms of phosphorus-calcium metabolism:

• parathyroid glands with a high phosphate content (at a low level of calcium) secrete parathormone, which destroys bone tissue, thereby increasing the concentration of calcium,
• When calcium levels in the blood are high, the thyroid gland produces calcitonin, which causes calcium to move from the blood to the bones,
• parathyroid hormone activates vitamin D, increasing calcium absorption in the gastrointestinal tract and cation reabsorption in the kidneys.

What is research used for?

First of all, it is worth noting that the results of this test indicate the amount of calcium not in the bones, but in the blood.

• For the diagnosis and control of certain pathological conditions associated with the bone, heart, nervous system, as well as with the kidneys and teeth.
• As part of a biochemical analysis at a routine examination. If the obtained indicators are outside the normal range, it is necessary to do additional tests – for ionized calcium, calcium in the urine, phosphorus, magnesium, vitamin D, parathyroid hormone. Often the balance between these substances is much more important than just their concentrations separately. These indicators help to determine the cause of the disturbed level of calcium in the body: a lack of its intake or excessive excretion by the kidneys.
• In the control of nephrolithiasis, bone disease and neurological disorders.
• For preliminary assessment of calcium metabolism.

When is the examination scheduled?

• During a scheduled preventive medical examination.
• In kidney disease (because calcium levels are low in people with kidney failure).
• In diseases associated with disorders of calcium metabolism, such as pathology of the thyroid gland, small intestine, cancer.
• With certain changes in the electrocardiogram (shortened ST segment with low calcium levels, lengthening of the ST segment and QT interval).
• When a patient has symptoms of elevated calcium levels – hypercalcemia: loss of appetite, nausea, vomiting, lack of stool, abdominal pain, frequent urination, intense thirst, bone pain, fatigue, weakness, headaches, apathy, depression of consciousness up to coma.
• With symptoms of low calcium levels – hypocalcemia: spastic pain in the abdomen, tremor of the fingers, numbness around the mouth, carpopedal spasm, arrhythmias, spasms of the mimic muscle, numbness, tingling, muscle cramps.
• For certain malignant neoplasms (especially lung, breast, brain, throat, kidney and multiple myeloma).
• In case of kidney disease or after transplantation of one of them.
• If it is necessary to monitor the effectiveness of calcium metabolism therapy with calcium and / or vitamin D preparations.

What do the results mean?

Reference values ​​

Usually, the level of total calcium in the blood is measured to assess calcium metabolism. The level of total calcium in the blood is a good indicator of the content of free and bound calcium – each of them accounts for half of the total calcium. However, since about half of the calcium in the blood is associated with proteins, the amount of total calcium changes when protein metabolism is disturbed. In such cases, it is better to measure the level of free (ionized) calcium. The absorption, use and excretion of calcium is regulated by parathyroid hormone and vitamin D by a feedback mechanism. Diseases leading to calcium dysregulation can cause sudden or slow increases in calcium levels, accompanied by symptoms of hypo- and hypercalcemia.

The normal level of total and ionized calcium most likely indicates the absence of disorders of calcium metabolism.

Causes of high calcium levels

An increase in total calcium is hypercalcemia. Its two most common causes are hyperparathyroidism (enlargement of the parathyroid glands) and malignancy.

Hyperparathyroidism is usually caused by a benign tumor of the parathyroid glands.

Cancer formation leads to hypercalcemia after damage to the skeletal system. They secrete a substance similar to parathyroid hormone, and thereby lead to the release of calcium into the bloodstream.

Some other causes of hypercalcemia:

• hyperthyroidism,
• sarcoidosis,
• tuberculosis,
• prolonged immobility,
• vitamin D excess,
• diseases of the blood system (lymphoma, leukemia, multiple myeloma, polycythemia vera),
• kidney transplant,
• dehydration,
• Addison’s disease,
• Paget’s disease.

Causes of low calcium levels

The most common cause of hypocalcemia, a decrease in the amount of total calcium, is a decrease in the content of proteins in the blood, especially albumins. At the same time, only the level of bound calcium is reduced, ionized calcium remains normal and calcium metabolism continues to be regulated by parathyroid hormone and calcitonin.

Some other causes of hypocalcemia:

• hypoparathyroidism (decreased function of the parathyroid glands),
• congenital resistance to the effects of parathyroid hormone (parathyroid hormone has no effect, or it is significantly reduced),
• lack of calcium in the diet,
• magnesium deficiency (hypomagnesemia),
• vitamin D deficiency,
• increasing the concentration of phosphorus,
• sprue, acute pancreatitis, alcoholism (malabsorption of nutrients and, as a result, lack of enzymes and substrates for many types of metabolism),
• chronic renal failure.

What can influence the result?

Some people have high calcium levels due to certain drugs: alkaline antacids, androgens, thiazide diuretics (most common cause), ergocalciferol, lithium salts, progesterone, parathyroid hormone, tamoxifen, vitamins D and A.

Other drugs On the contrary, they can cause a decrease in the concentration of calcium in the blood: gentamicin, calcitonin, anticonvulsants (carbamazepine), glucocorticoids, laxatives, magnesium salts.

In addition, the following factors influence the results of this analysis:

• false values ​​due to dehydration or hyperproteinemia,
• false-low values ​​due to hypervolemia (excessive blood dilution) after intravenous saline.

Important Notes

• Newborns, especially preterm and underweight newborns, have daily blood tests for ionized calcium in the first days of life for early detection of hypocalcemia. It can occur due to underdevelopment of the parathyroid glands, often asymptomatic.
• The concentration of calcium in the blood and urine does not indicate the total content of calcium in the bones – for this there is a special technique for determining bone mineral density, called densitometry.
• Blood calcium levels are usually higher in children and lower in the elderly and pregnant women.
• The level of total calcium in the blood increases with an increase in the concentration of albumin and decreases with its decrease, while the content of ionized calcium does not depend on their concentration.

Also recommended

• Ionized calcium
• Daily urine calcium
• Sulkovich test
• Microalbumin in urine
• Serum magnesium
• Serum albumin
• Total protein in whey
• Vitamin D, 25-hydroxy (calciferol)
• Serum calcitonin
• Thyroid Stimulating Hormone (TSH)
• Thyroxine free (T4 free)
• General thyroxine (T4)
• Triiodothyronine total (T3)
• Triiodothyronine free (T3 free)
• Parathyroid hormone, intact

Who orders the examination?

Therapist, nephrologist, endocrinologist, gastroenterologist, nutritionist, traumatologist.

Endocrinologist told why high blood calcium is dangerous – Moscow 24, 09/13/2022

September 13, 2022, 09:09

Society

The level of calcium in the blood can rise above normal for a variety of reasons. Including with a serious endocrine pathology – hyperparathyroidism. We tell you why it is dangerous, what symptoms it accompanies and how to diagnose it in time.

Frequent pathology

Photo: Moscow 24/Anton Velikzhanin

Calcium is necessary for our body, without it, none of the basic life processes can proceed normally. This microelement is especially important for the health and strength of bones, endocrinologist Marina Berkovskaya told Moscow.

“As a rule, patients are pleased with elevated levels of calcium in the biochemical blood test. They believe that fractures and bone diseases can not be afraid. In fact, the opposite is true,” the doctor said.

The most common cause of elevated blood calcium is primary hyperparathyroidism (excess parathyroid hormone). Among the problems with the endocrine system, it ranks third after diabetes and thyroid disease.

Women suffer from hyperparathyroidism three times more often than men. People over 50 are also at risk. Although pathology can develop at any age.

Marina Berkovskaya

endocrinologist

Excess production of parathormone is bad because it leads to leaching of calcium from the bones, increased excretion with urine, as well as deposition in the internal organs. Therefore, there is a lot of this substance in the blood, vessels, kidneys. In the bones, on the contrary, there is little.

Dangerous complications

Photo: depositphotos/stevanovicigor

In hyperparathyroidism, pathological changes occur primarily in bone tissue and kidneys. If we talk about pronounced manifestations of pathology, then a person may be disturbed by chronic pain in the body, aggravated by pressure, the doctor noted.

Even without injuries, fractures begin to appear, especially in the ribs, pelvic bones and lower extremities. And then they heal long and hard.

Osteoporosis (decrease in bone density) and skeletal deformity develop due to lack of calcium. A “keeled” chest may appear, the shape of the pelvic region may change with the formation of a “duck” gait, and bone tissue growth may begin.

Marina Berkovskaya

endocrinologist

In hyperparathyroidism, excess calcium is removed from the body through the kidneys, so stones form in the excretory tract. As a result, urolithiasis develops. Often it has a aggravated character: colic and the development of renal failure.

In addition, excess calcium in the blood can lead to pathologies of the gastrointestinal tract: peptic ulcer of the stomach or duodenum, cholecystitis (inflammation of the walls of the gallbladder) and pancreatitis (inflammation of the pancreas).

Hyperparathyroidism affects all body systems. Therefore, among the symptoms of the disease may be muscle weakness, arrhythmia, depression, obesity and insulin resistance (impaired metabolic response to insulin).