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. The most common symptoms of hypercalcemia are feeling tired, difficulty thinking clearly, lack of appetite, pain, frequent urination, increased thirst, constipation, nausea, and vomiting. 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.
As calcium levels increase, irregular heartbeats may develop, and may lead to a heart attack. Gastrointestinal 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. Kidney 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.