Drug induced hyperthermia is a rare presentation which can rapidly lead to gross metabolic abnormality and death. These presentations are further complicated by the wide range of potentially causative agents. We present a case of rigidity and hyperthermia, following overdose of an initially unknown substance leading to challenging management decisions in the Emergency Department. This case was later identified as Serotonin Syndrome. The patient presented with trismus which was managed with rapid sequence induction of anaesthesia to allow airway protection. On extubation a significant degree of laryngeal oedema complicated weaning, a possible complication of Serotonin Syndrome not previously described in the literature. We discuss the pathophysiology of Serotonin Syndrome, important differentials and practical considerations in managing hypertonicity of unknown origin in a young person.

A man with past lithium use for more than 15 years, but off lithium for two years and not carrying the diagnosis of diabetes mellitus or nephrogenic diabetes insipidus (NDI), presented with coma and hyperglycemic hyperosmolar state (HHS). Following correction of HHS, he developed persistent hypernatremia accompanied by large volumes of urine with low osmolality and no response to desmopressin injections. Urine osmolality remained < 300 mOsm/kg after injection of vasopressin. Improvement in serum sodium concentration followed the intake of large volumes of water plus administration of amiloride and hydrochlorothiazide. Severe hyperglycemia may trigger symptomatic lithium-induced NDI years after cessation of lithium therapy. Patients with new-onset diabetes mellitus who had been on prolonged lithium therapy in the past require monitoring of their serum sodium concentration after hyperglycemic episodes regardless of whether they do or do not carry the diagnosis of NDI.