Case Report: Lithium-induced bradycardia triggered by cecal volvulus: a case of obstruction-associated drug accumulation.

Background: Lithium toxicity can rarely manifest as cardiac arrhythmias, often initially presenting as bradycardia. Bowel obstruction is a rare cause of acute lithium toxicity. We present a case of lithium-induced symptomatic bradycardia induced by cecal volvulus. Case report: An 84-year-old female with a history of bipolar 1 disorder on chronic lithium therapy was admitted for symptomatic bradycardia and abdominal pain. She also presented with myoclonus, polydipsia, and encephalopathy. Laboratory evaluation revealed lithium toxicity in the setting of renal impairment, and abdominal imaging findings indicated large bowel obstruction secondary to cecal volvulus. Lithium was discontinued, and the patient was managed supportively. Despite declining lithium levels, the patient's symptomatic bradycardia persisted until surgical correction of the volvulus, after which cardiac and neurological function markedly improved. Significance: This case highlights the potential role of gastrointestinal obstruction in exacerbating lithium-induced bradycardia by impairing its clearance and inducing a vagal response triggered by abdominal distension.