Calcium disorders

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
      1. Hyperphosphatemia (e.g., renal insufficiency)
      2. Pancreatitis
      3. Osteoblastic metastases
      4. Drugs (e.g., ethylenediaminetetraacetic acid [EDTA])
      5. Rhabdomyolysis
   2. Decreased vitamin D production or action
      1. Kidney injury
      2. Rickets
      3. Malabsorption
      4. Neonatal
   3. Decreased parathyroid hormone production or action
      1. Postoperative (e.g., postparathyroidectomy)
      2. Autoimmune
      3. Diminished response
   4. Low magnesium
2. Hypercalcemia
   1. Increased intestinal absorption
      1. Increased intake (e.g., milk-alkali syndrome)
      2. Vitamin D mediated (e.g., sarcoidosis)
   2. Increased bone resorption
      1. Malignancy
      2. Hyperparathyroidism
      3. Hyperthyroidism
      4. 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.

Given a patient with hypercalcemia, the candidate will

1. list and interpret critical clinical findings, including
   1. differentiation between hypercalcemia caused by malignancy and hypercalcemia due to other causes;
   2. volume status of the patient; and
   3. common physical examination findings associated with hypercalcemia;
2. list and interpret critical clinical investigations, including
   1. ionized calcium and/or total calcium levels corrected for albumin to assess severity; and
   2. laboratory and imaging investigations to determine the causal condition(s); and
3. construct an effective initial management plan, including
   1. administering fluid resuscitation with or without medications if the patient has severe hypercalcemia; and
   2. determining whether the patient needs specialized care.