Sudden night palsy in a young man: thyrotoxic periodic paralysis as a first manifestation of hyperthyroidism

A 19-year-old Caucasian man presented to the emergency department with acute onset of tetraparesis with preserved consciousness He reported having a similar episode of generalized, but self-limited and much less pronounced muscle weakness several months ago. Any use of medications or illicit drugs was denied, as well as excessive alcohol intake or extraordinary physical exertion in the last days. The personal and family history was negative for muscular or neurologic diseases. On examination, the patient appeared to be fully conscious and oriented with normal vital signs and a predominantly proximal tetraparesis, but not involving the sensory system or bladder and bowel function.