Etiological spectrum of hypokalemic periodic paralysis: A prospective study at tertiary care hospital

 

 

Abstract              Background: Hypokalemic periodic paralysis (HPP) can occur due to various causes which can be either primary or secondary. Identification of these secondary causes is important so that specific therapy can be instituted and long term complications prevented. Aim: To analyze the common etiological factors in our setup. Identification of these factors will help us to institute a specific therapy that will prevent future complications. Material and Methods: A total of 32 patients admitted in the Medical and Nephrology wards with acute onset of flaccid weakness and documented serum potassium of <3.5 mEq/L during the episode were included in the study. Relevant laboratory and other investigations were done to find out the cause. Results: In the group with normal acid base, none of them had evidence of renal potassium loss. Those with biochemical evidence of thyrotoxicosis were diagnosed as Thyrotoxic Periodic Paralysis (TPP) and those without were diagnosed as Sporadic Periodic Paralysis (SPP). In the group with metabolic acidosis all of them had evidence of renal potassium loss. In the third group with metabolic alkalosis and renal potassium loss after carefully excluding diuretic use those with urinary chloride loss (>40 mEq/L) and hypocalciuria (<2 mg/kg) were diagnosed to have Gitelman’s syndrome. In the absence of hypocalciuria Classic Bartter syndrome was diagnosed. Conclusion: Among the patients with Hypokalemic Periodic Paralysis two thirds of them are due to secondary causes. In our study the common causes are Idiopathic or sporadic periodic paralysis, Gitelman’s / Bartter syndrome and Distal Renal Tubular Acidosis.

Key Words: Hypokalemic periodic paralysis, metabolic acidosis, metabolic alkalosis, Gitelman’s syndrome, Classic Bartter syndrome