What are the symptoms of hypercalcemia?

Symptoms of Hypercalcemia

The symptoms of hypercalcemia vary by severity: mild hypercalcemia (calcium <12 mg/dL) is often asymptomatic but may cause fatigue and constipation in 20% of patients, while moderate hypercalcemia (11-12 mg/dL) presents with polyuria, polydipsia, nausea, vomiting, confusion, and abdominal pain, and severe hypercalcemia (>14 mg/dL) causes mental status changes, dehydration, bradycardia, hypotension, acute renal failure, somnolence, and potentially coma. 1, 2, 3

Mild Hypercalcemia (Calcium <12 mg/dL or <3 mmol/L)

• Constitutional symptoms occur in approximately 20% of patients, including fatigue, constipation, and generalized weakness 3
• Many patients remain completely asymptomatic, with hypercalcemia discovered incidentally on routine laboratory testing 4
• Muscle weakness and lethargy may be present but are often subtle 5, 4

Moderate Hypercalcemia (Calcium 11-12 mg/dL)

Renal Manifestations

• Polyuria and polydipsia are prominent symptoms due to impaired renal concentrating ability 1, 2, 3
• Excessive thirst develops as a compensatory mechanism 5

Gastrointestinal Symptoms

• Nausea and vomiting are common presenting complaints 1, 2, 3
• Abdominal pain may occur, sometimes mimicking acute abdominal conditions 1, 5, 4
• Constipation can be a persistent problem 3
• Pancreatitis may develop in some cases 6

Neuromuscular Effects

• Confusion and impaired cognitive function are frequently observed 1, 3
• Muscle weakness and myalgia (muscle pain) are characteristic 7, 4
• Fatigue becomes more pronounced than in mild cases 6

Severe Hypercalcemia (Calcium >14 mg/dL or >3.5 mmol/L)

Neurological Manifestations

• Mental status changes ranging from confusion to lethargy are hallmark features 1, 2, 8
• Somnolence (excessive drowsiness) progresses as calcium levels rise 3, 8
• Coma can develop in untreated severe cases 3, 8, 6
• Loss of consciousness may occur 9

Cardiovascular Effects

• Bradycardia (slow heart rate) is a concerning sign 1, 2
• Hypotension develops due to severe dehydration and cardiovascular depression 1, 8
• Cardiac arrhythmias may occur, with electrocardiographic changes including prolonged QT interval 9

Renal Complications

• Severe dehydration results from ongoing polyuria and decreased oral intake 1, 8, 6
• Acute renal failure (prerenal renal failure) develops from volume depletion 9, 1
• Renal insufficiency worsens as hypercalcemia persists 8, 4

Special Population Considerations

Pediatric Presentations

• In infants with Williams syndrome, hypercalcemia manifests as extreme irritability, vomiting, constipation, and muscle cramps 7
• Hypoglycemia may occur in children with acute adrenal crisis and concurrent mild hypercalcemia 9

Context-Dependent Symptoms

• Seizures may occur in patients with underlying parathyroid dysfunction, particularly in 22q11.2 deletion syndrome, though these typically resolve with calcium normalization 9
• Emotional irritability and abnormal involuntary movements can be associated with hypocalcemia in certain genetic syndromes, but the inverse relationship should be monitored 9

Important Clinical Caveats

• Symptom severity correlates more with the rapidity of calcium elevation than absolute levels—hypercalcemia developing over days to weeks causes more severe symptoms than chronic elevation 3
• Symptoms may be confused with psychiatric conditions or other medical disorders, particularly in patients with underlying genetic syndromes 9
• The classic mnemonic "stones, bones, groans, and psychiatric overtones" captures the renal (stones), skeletal (bones), gastrointestinal (groans), and neuropsychiatric manifestations 4