Hypercalcemia is the term used when the blood calcium levels are higher than normal. Calcium is an important mineral for the body. Ninety-nine percent of the calcium is stored in the bones and about one percent circulates in the blood. Calcium is crucial for bone formation and also for the brain, the nerves, and the muscles to function properly. When calcium levels are too high or too low it causes problems in many parts of the body. The causes, symptoms, diagnosis, treatment, and prevention of hypercalcemia will all be addressed here. The word hypercalcemia literally means too much calcium in the blood. That is the simple definition.
The reality of diagnosing and treating hypercalcemia is much more complicated. There are many possible causes for hypercalcemia, so the diagnosis and treatment, of not just the elevated calcium, but also the disorder that caused it can be a critical challenge. Twenty to forty percent of cancer patients will develop hypercalcemia at some point. About fifty thousand new cases of hypercalcemia due to parathyroid disfunction are also diagnosed each year. Left untreated, hypercalcemia can cause havoc with many organ systems. It can cause osteoporosis, bone fractures and spinal column curvature in the skeletal system.
In the renal system it can cause kidney stones and kidney failure. In the cardio-vascular systems it can interfere with the electrical impulses that regulate heart beat and cause arrhythmia. In the nervous system it can cause confusion, lethargy, dementia, coma and even death. The symptoms for hypercalcemia can vary greatly. Sometimes there are no observable symptoms. Symptoms often are slow to develop. Younger patients will show fewer symptoms than older patients. Some common symptoms are excessive thirst, dehydration, loss of appetite and fatigue. Digestive symptoms can include nausea, vomiting and constipation.
Bone pain, abdominal pain, and muscle weakness can also occur. Confusion and lethargy can also occur and are also indicators of severe hypercalcemia. Heart arrhythmia is another sypmtom associated with severe hypercalcemia. The most predominant cause of hypercalcemia is an overactive parathyroid gland. The kidneys filter the blood and keep the calcium concentration correct. Hormones from the parathyroid control the absorption of calcium by the kidneys. When they do no function properly, too much calcium will remain in the blood. This condition is referred to as primary hyperparathyroidism.
The second most likely cause is the spread of cancer. One way that cancer causes hypercalcemia is that when it spreads to the bone it destroys the bone. When the bone breaks down it releases the stored calcium back into the blood stream. There are several other ways that cancer causes hypercalcemia. Some tumors can produce a protein that mimics the hormone that the parathyroid produces and prevent the absorption of calcium by the kidney. Other cancers interfere with kidney function. Nausea and vomiting associated with cancer can cause dehydration which causes elevated calcium. Inactivity is another factor.
Sadly, when hypercalcemia occurs in cancer patients, it can be an indicator that the kidneys are failing and that they are in the final stage of the disease. Other diseases that can cause hypercalcemia include tuberculosis, sarcoidosis, berylliosis,leprosy, coccidioidomycosis, and histoplasmosis. Some drugs can cause hypercalcemia. Three examples are lithium, tamoxifen and thiazide diuretics. Incorrect use of calcium supplements or vitamin D supplements can also cause elevated calcium. Immobilization can cause hypercalcemia. Dehydration can also cause temporary hypercalcemia. Heredity can also be a factor.
Familial hypocalciuric hypercalcemeia is a rare genetic disorder that causes defective calcium receptors that in turn do not properly regulate the blood calcium levels. Hypercalcemia can be diagnosed with a routine blood serum test. The normal range for calcium is 8. 7-10. 4 mg/dL. Any result over 10. 4 mg/dL is considered elevated. A result over 14 mg/dL is considered an acute metabolic emergency. Once hypercalcemia is determined, further testing is often required to determine the underlying cause. A second blood test will often be run to determine if the parathyroid hormone level is high.
If cancer or sarcoidosis is suspected the doctor will often also order images of the lungs or bones. If other diseases are suspected even further testing will be required for diagnosis. These could include collection of cultures for bacterial or fungal testing or an examination of the patients history to determine possible exposure to pathogens. An interesting note on the diagnosis of hypercalcemia is that when it causes a heart arrhythmia, that it makes a distinctive pattern on the EKG electrocardiogram test. The treatment for hypercalcemia is often dependent on the severity and the underlying cause.
In mild cases, the best option is often to just monitor the bones and kidneys and wait for the body to correct itself. In acute cases, IV fluids and diuretics can quickly lower the calcium levels. Several classes of drugs are also often used to treat hypercalcemia. Calcimimetics imitate calcium circulating in the blood and aid in regulating an overactive parathyroid. Biophosphonates can be given intravenously. These help rebuid bone. Calcitonin can help lower calcium levels. Both calcitonin and biophoshonates are also known to have an analgesic effect and can help alleviate bone pain in cancer patients.
The steroid prednisone is helpful if the hypercalcemia caused by high levels of vitamin D. Dialysis is another treatment that can help when calcium levels are elevated. Dialysis mechanically removes waste from the blood and restores the correct concentration of electrolytes and minerals, including calcium. When the cause of hypercalcemia is an overactive thyroid gland, surgerical removal is also an option. There are four parathyroid glands. A test using a small amount of radioactive material can isolate which gland is not working properly and it can be removed.
Prevention of hypercalcemia is not always possible due to the fact that it is often directly caused by an underlying cancer or illness. Staying hydrated will prevent dehydration related cases. A general healthy lifestyle and diet can boost the immune system and may help prevent some of the diseases that can cause elevated calcium. Patients taking medication that is known to elevate calcium levels, and those diagnosed with conditions that cause hypercalcemia can be monitered with routine blood testing. In some instances these patients can be treated before the elevated calcium levels become critical.
