Hyperkalemia

Rationale

Elevated serum potassium levels may be life-threatening and may also be indicative of the presence of other serious associated medical conditions.

Causal Conditions

(list not exhaustive)

1. Redistribution
   1. Decreased entry into cells (e.g., insulin deficiency, β-2 blockade)
   2. Increased exit from cells (e.g., metabolic acidosis, insulin deficiency, use of β-blockers, exercise, rhabdomyolysis)
2. Reduced urinary excretion
   1. Decreased glomerular filtration rate (e.g., acute or chronic kidney injury)
   2. Decreased secretion (e.g., aldosterone deficiency, drugs)
3. Increased intake (usually associated with low excretion)

Key Objectives

Given a patient with hyperkalemia, the candidate will diagnose the cause, severity, and complications, and initiate an appropriate management plan that includes indications for specialized care. In particular, the candidate will recognize the urgency of hyperkalemia associated with electrocardiogram abnormalities.

Enabling Objectives

Given a patient with hyperkalemia, the candidate will

1. list and interpret critical clinical findings, including those based on a history and physical examination aimed at determining the underlying cause (e.g., potassium-sparing medications, signs of kidney injury);
2. list and interpret critical investigations, including
   1. those that can help in distinguishing between life-threatening hyperkalemia and pseudohyperkalemia,
   2. electrocardiography to determine the severity of the case, and
   3. tests to distinguish between causes of hyperkalemia (e.g., serum creatinine level, urine electrolytes);
3. construct an effective initial management plan, including
   1. initiating emergency measures (e.g., intravenous calcium, insulin and glucose, prescription of potassium binders, dialysis) in the case of hyperkalemia with electrocardiogram changes, and
   2. referring the patient for specialized care (e.g., nephrology) if necessary.