Lithium Intoxication-Induced Myxedema Coma in a Schizophrenic Patient: A Case Report

Lithium intoxication-induced myxedema coma, is a rare, life threatening & emergency presentation of severe hypothyroidism, it can be easily misdiagnosed in patients with unknown history of hypothyroidism. Studies have shown that Lithium mechanism on thyroid is that it inhibits synthesis & release of thyroid hormones. This case report describes a 59-year old patient with schizophrenia admitted with lithium intoxication & myxedema crisis. This case emphasizes the fact that severe & dangerous hypothyroidism can develop in some patients who take lithium for prolonged period. A 59-year-old female was admitted to our institution with history of tremors & a decrease in level of consciousness. Patient was a known case of Type 2 Diabetes Mellitus & Schizophrenia, on Insulin, Olanzapine & Lithium. On examination patient is hypothermic, bradycardic, with periorbital puffiness, non-pitting edema on lower extremities & tremors on all extremities. Thyroid function tests showed primary hypothyroidism. The serum lithium level was moderately elevated. She was initially managed with Levothyroxine started 100 mcg/tab once a day before breakfast & was increased to 150 mcg/tab daily as home medication. Liothyronine 25 mcg/tab, ½ tab Q8, Hydrocortisone 50 mg/IV Q8, IV antibiotics & IV fluids were also given. Lithium was discontinued. On the fourth hospital day patient was transferred to ICU due to a decrease in sensorium & close monitoring. From day ten, patient started showing progressive improvement & by day fourteen, patient was discharged. In conclusion lithium-induced hypothyroidism may be life-threatening, if myxedema crisis is suspected treatment should be initiated even without the laboratory tests. It is recommended that periodic thyroid function should be monitored before & during lithium therapy & drug should be discontinued & appropriate therapy instituted if hypothyroidism develops.