Secondary hypokalemic periodic paralysis: A study of a case series

Background: Periodic paralysis is a group of heterogeneous disorders of different etiologies, with episodic, short-lived, and hyporeflexic skeletal muscle weakness, with or without myotonia. There is neither sensory deficit nor loss of consciousness. They can be familial (primary) or acquired (secondary). Secondary periodic paralysis is due to demonstrably known causes. The interictal potassium level is abnormal in these cases. Hypokalemic paralysis is more common than hyperkalemic. Materials and Methods: This is a prospective observational study elucidating the clinical profile of the cases of secondary hypokalaemic periodic paralysis seen in our care over a period of 14 months. Results: In this study, we present nine patients with hypokalemic periodic paralysis, in which four were diagnosed with thyrotoxicosis and five with dengue. They were given potassium correction under judicious cardiac monitoring. Antithyroid drugs and beta-blockers were used in thyrotoxicosis. Dengue patient received adequate fluid and antipyretic cover. All the patients made complete recovery, without any neurological sequelae. Conclusion: Secondary hypokalemic periodic paralysis should always be kept in mind as a differential in the setting of acute, painless, flaccid motor paralysis, especially in young patients with no significant family history or risk factors for stroke or Guillain–Barre Syndrome. A clinician must be aware of causes of secondary periodic paralysis as recognition and diagnosis can completely prevent further attacks of periodic paralysis. Routine estimation of thyroid levels should be the initial line of investigation even if features of thyrotoxicosis are absent. In the presence of acute febrile illness, ordering serology for dengue, after ruling out thyrotoxicosis, is the preferred approach in India.