What are the signs and symptoms of hypercalcemia?

Signs and Symptoms of Hypercalcemia

The clinical presentation of hypercalcemia varies by severity and rapidity of onset, ranging from asymptomatic in mild cases to life-threatening manifestations including confusion, coma, and cardiovascular collapse in severe cases.

Severity-Based Clinical Presentation

Mild Hypercalcemia (10-11 mg/dL or >5.0 to <5.5 mEq/L)

• Most patients are asymptomatic, though approximately 20% experience constitutional symptoms 1
• Fatigue and constipation are the most common complaints when symptoms occur 1
• Hypercalcemia tends to be chronic (>6 months duration) and symptoms are subtle, particularly in primary hyperparathyroidism 2

Moderate Hypercalcemia (11-12 mg/dL or 5.5 to 6.0 mEq/L)

Gastrointestinal manifestations:

• Nausea and vomiting 3, 4
• Abdominal pain 3, 4
• Constipation 5

Renal manifestations:

• Polyuria (excessive urination) 6, 3, 1
• Polydipsia (excessive thirst) 3, 4
• Progressive dehydration 6

Neurologic manifestations:

• Confusion 3, 4, 1

Severe Hypercalcemia (>14 mg/dL or >6.0 mEq/L)

When hypercalcemia is severe or develops rapidly over days to weeks, life-threatening symptoms emerge 1:

Neurologic crisis:

• Mental status changes and altered consciousness 3, 4
• Somnolence (excessive drowsiness) 1
• Coma 1, 7

Cardiovascular manifestations:

• Bradycardia (slow heart rate) 3
• Hypotension 3

Renal manifestations:

• Severe dehydration 1, 7
• Acute renal failure 3
• Decreased glomerular filtration rate 6

Gastrointestinal manifestations:

• Severe nausea and vomiting 1, 7

System-Specific Manifestations

Neuromuscular System

• Constitutional symptoms including fatigue 1, 5
• Neurologic symptoms ranging from confusion to coma depending on severity 5, 8

Cardiovascular System

• Bradycardia and hypotension in severe cases 3
• Cardiovascular system involvement is a recognized complication 5

Renal System

• Polyuria leading to dehydration 6, 7
• Kidney calculi (stones), particularly in primary hyperparathyroidism 2
• Renal impairment and decreased glomerular filtration 6, 7

Gastrointestinal System

• Nausea, vomiting, abdominal pain, and constipation 3, 5
• Gastrointestinal disturbances are prominent features 6

Skeletal System

• Bone pain and pathologic fractures in chronic cases 6
• Metabolic bone disease (osteitis fibrosa cystica) in hyperparathyroidism 2

Critical Clinical Distinctions

Primary hyperparathyroidism typically presents with:

• Lower calcium levels (<12 mg/dL) 2
• Longer duration (>6 months) 2
• Fewer and more subtle symptoms 2
• Kidney calculi and hyperchloremic metabolic acidosis 2
• No anemia 2

Malignancy-associated hypercalcemia typically presents with:

• Rapid onset over days to weeks 1, 2
• Higher calcium levels 2
• More severe symptoms 2
• Marked anemia 2
• No kidney calculi or metabolic acidosis 2

Common Pitfall

The acuity of symptom development matters as much as the absolute calcium level 8. A patient with rapidly rising calcium may be severely symptomatic at 12 mg/dL, while someone with chronic primary hyperparathyroidism may tolerate 12 mg/dL with minimal symptoms 2. The clinical presentation depends on the rapidity of development, degree of hypercalcemia, and underlying cause 8.