Introduction: The thyroid is an essential organ of the endocrine system and produces thyroid hormones which regulate multiple physiologic processes. Dysfunction can cause various clinical presentations with diagnosis relying heavily on laboratory testing. Hypothyroidism is a condition in which the thyroid fails to produce adequate amounts of thyroid hormone. This case highlights a severe form of hypothyroidism that is uncommonly encountered. Case Description: A 64 year old woman with a history of arthritis and hypothyroidism presented to the hospital after two months duration of progressive weakness, excessive fatigue, and increased confusion. Vital signs showed bradycardia (30s), hypotension, and hypothermia with exam positive for altered mental status, garbled speech, dry mucous membranes, bradycardia, cool extremities, and non-pitting bilateral lower extremity edema. Pertinent labs revealed TSH of 127 and free T4 of 0. The family reported she had been unwilling to see a physician, and had not taken her levothyroxine for two years. Due to clinical instability, she was intubated and started on dobutamine infusion for bradycardia. She received a bolus of levothyroxine and hydrocortisone followed by daily intravenous levothyroxine. The patient showed improvement but failed extubation on two separate occasions leading to tracheostomy. One day following tracheostomy, she developed PEA arrest due to hypoxia and later passed away. Discussion: Myxedema coma is a severe form of hypothyroidism, which is rarely seen due to availability of thyroid function tests. It is a medical emergency with a high mortality rate. Clinical presentation is highly variable but often includes altered mental status and hypothermia. Other findings can include bradycardia, periorbital and perioral swelling, macroglossia, hyporeflexia, and xeroderma. Early identification is paramount for improving outcomes. Patients should be managed in the ICU with attention to ventilation, hypotension, and hypothermia. Aggressive measures should be taken to identify precipitating factors, with early administration of intravenous steroids and thyroid hormones.