Background: Severe acute myxedematous psychosis, or myxedema madness, is a rare and serious psychiatric complication of hypothyroidism. It is most often misdiagnosed, but it remains reversible after treatment with thyroid hormones. Case Presentation: We report a case of a patient without a known past medical history who underwent total thyroidectomy for papillary thyroid carcinoma. During her withdrawal from thyroid hormone therapy to perform a diagnostic radioiodine wholebody scintigraphy, she presented with anxiety, delirium, and hallucinations, culminating in a suicide attempt. Laboratory testing revealed a high sensible-thyroid stimulating hormone (TSH) value of 35 µIU/ml. The patient was hospitalized in a psychiatric unit, where she received antipsychotic medication and was started on thyroid hormones. After a week, there was a dramatic improvement. Psychiatric symptoms were completely gone a month later justifying the discontinuation of antipsychotics. Recombinant human TSH (rh-TSH) was necessary injected before radioiodine therapy to avoid thyroid hormone therapy suppression and to prevent a second episode of acute psychosis. Conclusion: rh-TSH interest is both in the pre Ira therapy stimulation and for the post-treatment monitoring of patients with thyroid cancer, and helps avoiding hormonal treatment suppression.

Keywords: Myxedema, psychosis, hypothyroidism, carcinoma, rhTSH.