Rationale

In patients with hypocalcemia, tetany and/or seizures may develop, particularly if the onset is acute. Severe or prolonged hypercalcemia may cause irreversible end-organ damage and may be life-threatening.

Causal Conditions

(list not exhaustive)

1. Hypocalcemia

   1. Loss of calcium from the circulation

      • Hyperphosphatemia (e.g., renal insufficiency)

      • Pancreatitis

      • Osteoblastic metastases

      • Drugs (e.g., ethylenediaminetetraacetic acid [EDTA])

      • Rhabdomyolysis

   2. Decreased vitamin D production or action

      • Kidney injury

      • Rickets

      • Malabsorption

      • Neonatal

   3. Decreased parathyroid hormone production or action

      • Postoperative (e.g., postparathyroidectomy)

      • Autoimmune

      • Diminished response

   4. Low magnesium

2. Hypercalcemia

   1. Increased intestinal absorption

      • Increased intake (e.g., milk-alkali syndrome)

      • Vitamin D mediated (e.g., sarcoidosis)

   2. Increased bone resorption

      • Malignancy

      • Hyperparathyroidism

      • Hyperthyroidism

      • Immobilization

   3. Diminished excretion (e.g., diuretics)

Key Objectives

Given a patient with either hypocalcemia or hypercalcemia, the candidate will diagnose the cause, severity, and complications and will initiate an appropriate management plan.

Enabling Objectives

Given a patient with hypocalcemia, the candidate will

1. list and interpret critical clinical findings, including

   1. differentiation between hypocalcemia related to renal disease and hypocalcemia due to other causes; and

   2. signs and symptoms of tetany;

2. list and interpret critical clinical investigations, including

   1. ionized calcium and/or total calcium levels corrected for albumin to assess severity; and

   2. phosphate, magnesium, parathyroid hormone, and vitamin D levels and renal function assessment; and

3. construct an effective initial management plan, including

   1. administering intravenous calcium if the patient has symptomatic hypocalcemia; and

   2. determining whether the patient needs specialized care.