Ciprofloxacin-associated seizures in a patient with underlying thyrotoxicosis: case report and literature review.

BACKGROUND: Ciprofloxacin-associated seizures (CAS) occur most commonly in patients with special risk factors that may cause accumulation of drug (high doses of the drug, old age, renal insufficiency, drug interactions) or that may decrease the threshold of epileptogenic activity (electrolyte abnormalities, history of seizures, electroconvulsive therapy).
OBJECTIVE: To report thyrotoxicosis as a risk factor previously not heralded for the development of CAS. CASE
SUMMARY: A 24-year-old woman was admitted to the hospital because of convulsions, severe myopathy, and acute renal failure after taking ciprofloxacin for sinusitis, and urinary tract infections. Prior to ciprofloxacin ingestion, she had no seizure history, was not receiving any other medication, and her routine laboratory results including creatinine and electrolytes were within normal ranges. Electroencephalogram suggested epileptiform waves. Cranial magnetic resonance imaging was normal. Further laboratory examinations documented thyrotoxicosis in association with postpartum thyroiditis. DISCUSSION: In the reviewed literature, all cases of CAS occurred in the presence of at least one risk factor for CAS.
CONCLUSIONS: CAS appear to be restricted to individuals with predisposing risk factors, therefore it is always necessary to search such fact. When a physician encounters the possibility of CAS, in addition to previously described risk factors, thyrotoxicosis should also be considered in the differential diagnosis. Further, in patients with untreated thyrotoxicosis, antibiotics other than ciprofloxacin might be preferable for therapy.