Iodoform induced thyrotoxicosis in the elderly: case report and review of literature

Background. Drug-induced hyperthyroidism is a rare condition linked to dietary supplements, iodine-containingmedications and intentional or unintentional over ingestion of levothyroxine; its detection is importantsince, if left untreated, thyroid storm can develop, carrying a mortality rate of 20-50%.Case presentation. Here we describe the case of an oldest old (84 years) woman, with severe cognitiveimpairment and immobilization syndrome attending our geriatric ward for aspiration pneumonia. During thefifth day of hospitalization, while pneumonia and respiratory symptoms were improving, tachycardia persisted(heart rate 130 bpm), associated with tremors and lack of sleep. The patient was affected by multinodulargoiter and, a diagnosis of thyrotoxicosis was documented by elevated serum free thyroxine and free triiodothyroninelevels (4.7 ng/dL and 6.6 ng/L, respectively), associated with undetectable thyroid-stimulating hormone(TSH 0.04 mIU/L), elevated urinary iodine excretion (849 μg/L) and normal serum thyroglobulin levels (10 ng/mL).131I thyroid scan showed diffuse low uptake, suggesting iatrogenic thyrotoxicosis. The patient sufferedfrom immobilization syndrome with bedsores that had been medicated twice a week with iodoform gauzes forone year. Prior to starting the use of iodoform dressings the patient was documented euthyroid.Conclusions. Over the past century, few cases have been described regarding possible severe toxicity causedby the use of iodoform gauzes, all of them presenting with neurovegetative symptoms as vomiting, alteredsensor, which disappeared after withdrawn of the medication, but iatrogenic thyrotoxicosis was never demonstrated.Thus, to our knowledge, this is the first report documenting the onset of thyrotoxicosis induced bylasting use of iodoform gauzes.