There is little relationship between symptoms of hypercalcemia and the actual level of calcium in the blood. Symptoms of hypercalcemia resemble symptoms of other illnesses, making an early and rapid diagnosis difficult. The severity of the symptoms may depend on other factors, such as previous cancer treatment, reactions to drugs, or other illnesses a patient may have.
Most patients do not experience all of the symptoms of hypercalcemia, and some patients may not have any symptoms at all. However, most patients with high calcium levels in the blood do have symptoms. Some patients develop signs of hypercalcemia when calcium levels are only slightly high, while patients who have had higher calcium levels for a long time may show few symptoms.
Symptoms may be classified by the affected body part:
Calcium plays a major role in the normal functioning of the central nervous system (the brain and spinal cord). Symptoms of hypercalcemia may include weakness, loss of reflexes in the muscles, and decreased stamina. Patients with central nervous system symptoms may have changes in personality, difficulty thinking or speaking clearly, disorientation, or hallucinations. Eventually, coma may result. Headaches can also occur, which can be made worse by vomiting and dehydration.
Hypercalcemia affects normal heart rhythms and increases sensitivity to some heart medications (such as digoxin). As calcium levels increase, irregular heartbeats may develop, and may lead to a heart attack.
Increased stomach acid often is produced with hypercalcemia and may intensify loss of appetite, nausea, and vomiting. Constipation may result from the dehydration associated with hypercalcemia.
Hypercalcemia causes the kidneys to not function correctly, leading to the production of large volumes of urine. The large amount of urine combined with less liquid intake leads to symptoms of dehydration, including thirst, dry mouth, little or no sweating, and concentrated urine. Patients with myeloma often have kidney problems due to hypercalcemia. Kidney stones may result from long-term hypercalcemia.
Hypercalcemia of cancer can result from bone metastases or bone loss, and may contribute to broken bones, bone disfigurement, and pain.