A bulimic adolescent with a low potassium level is at risk for which medical problem?

• A. Anemia.
• B. Cardiac arrhythmias.
• C. Gastrointestinal reflux.
• D. Heightened neurologic reflexes.

Answer: (B)

Potassium is essential for normal cardiac electrical activity. When potassium is low, myocardial cells become more exotically excitable and repolarization is disturbed, which can show up as ECG changes like prolonged repolarization and U waves and, more importantly, creates a substrate for dangerous heart rhythms. In bulimia, repeated vomiting leads to loss of potassium and chloride, along with volume depletion; the body’s response includes increased aldosterone, which drives further renal potassium loss. This combination raises the risk of cardiac arrhythmias, including potentially life-threatening ones.

Anemia, while it can occur with poor nutrition, is not a direct or immediate result of low potassium. Gastroesophageal reflux can be associated with bulimia due to vomiting, but it’s not caused by the potassium level itself. Heightened neurologic reflexes are not typical of potassium deficiency, which more commonly causes weakness and decreased reflexes in more severe cases.