Hyperkalemic Paralysis Due to Addison’s Disease

A 60-year-old woman with type 1 diabetes mellitus, past history of breast cancer, degenerative disc disease, hypothyroidism and asthma gave a 5-day history of flaccid paralysis and a 5-month history of back pain and worsening mobility. Investigations revealed hypercalcemia, hyperkalemia and hyponatremia which were initially thought to be due to hypercalcemia of malignancy on the assumption that her breast cancer had recurred. Imaging of the spine did not reveal cauda equina syndrome. There was no clinical and biochemical improvement in spite of fluid resuscitation. Hypoadrenalism was suspected and confirmed three days later. Adrenal replacement therapy fully resolved her paralysis within 24 hours. Addison’s disease is a rare clinical entity that requires a high index of suspicion. It may rarely present with weakness and/or back pain. Early recognition and treatment of Addison’s disease adequately resolves hyperkalemic paralysis. It is good clinical practice to keep an open-ended differential list to help reduce diagnostic suspicion bias.