Thyrotoxicosis hypokalemic periodic paralysis is a rare autosomal recessive condition most commonly seen in Asian populations. 1,2 The disease shows a marked male predominance 2,3 and is characterized by periodic episodes of paralysis and weakness. The authors present a rare case of a fatal cardiac dysrhythmia secondary to the disease.
Case PresentationA 24-year-old white male presented to the emergency department with acute weakness of the legs. Upon waking, the patient was unable to move his legs, although he noted no sensory loss to the legs. He stated that he had mild weakness with some cramping of the legs for 1 week prior without sensory decrease. The cramping was particularly noticeable at rest. The patient also complained of weakness of the left arm and an inability to void urine.A review of the patient's clinical history showed a similar episode a year previous to the current episode. At that time, the episode lasted 2 to 3 days and resolved spontaneously. A family relative, who was a physician, made a diagnosis of dehydration. It was suggested that the patient try Pedialyte or bananas to relieve the symptoms. At this point, the patient began eating 2 bananas per day.The patient also reported occasional blurring of his vision. No loss of memory or consciousness was noted. The patient had no history of seizures. A history of hyperthyroidism, hypertension, and a possible herniated disc 6-years previously were noted. The herniated disc was treated and resolved with a cortisone injection. The patient's family and social history were negative for drug use and smoking. The patient had a recent travel history to Colorado for 3 months from which the patient had returned 2 weeks prior to presentation.On physical examination, the patient was a well-developed and well-nourished white male who was alert and anxious. The patient's blood pressure was 134/69 with a pulse of 150. The patient's temperature was 97.9°F. The patient's respirations were 28/min. His thyroid was reported as palpably enlarged.While a neurologic examination of the patient showed flaccid lower extremities with an absence of ankle and knee reflexes, the patient retained sensation within the affected limbs. After 3 hours, the patient's leg strength had significantly improved and his deeptendon reflects had returned. The patient was alert and fully oriented, there was no alteration of speech, and the patient followed commands without difficulty. The patient's pupils were equal round and reactive to light. No nystagmus or alteration in extraocular movements was noted. No facial asymmetry was noted.Initial laboratory values in the emergency department were as follows: potassium = 2.9 mM/L, sodium = 140 mM/L, total CO 2 = 25 mM/L, serum glucose = 122 mg/dL, ESR = 15 mm/hour, TSH = 0.05 uIU/mL, WBC = 9.0 K/uL with a normal differential count, Hct = 42.5%, Hgb = 13.9g/dL, MCV = 78 fL, PLT = 229 K/dL.Magnetic resonance images (MRIs) of the cervical and thoracic spine were performed, with and without contrast. These showed a small left paramedial disc her...