title: Aetiological, clinical and metabolic profile of hypokalaemic periodic paralysis in adults: a single-centre experience.
abstract: BACKGROUND
  Hypokalaemic periodic paralysis constitutes a heterogeneous group of disorders that present with acute muscular weakness. In this analysis, we discuss the aetiological factors that appear to be more common in the Indian population.
  
  
  METHODS
  From 1995 to 2001, 31 patients presented with periodic paralysis (mean age 34.5 years, range 11-68 years). Of the 31 patients, 19 were men. The clinical and laboratory data of these patients were analysed. Patients were investigated for possible secondary causes of hypokalaemla.
  
  
  RESULTS
  There were 13 patients (42%) with renal tubular acidosis, 13 with primary hyperaldosteronism (42%), 2 each with thyrotoxic periodic paralysis and sporadic periodic paralysis, and I with Gitelman syndrome. Of the 13 patients with renal tubular acidosis, 10 had proximal and 3 distal renal tubular acidosis. Three of these patients with renal tubular acidosis had Sjogren syndrome. The patients diagnosed to have renal tubular acidosis had significantly lower serum bicarbonate (18.7 [14.6] v. 29.6 [5.0] mEq/L; p < 0.05) and higher levels of chloride (107.5 [6.0] v. 99.5 [3.4] mEq/L; p < 0.05) compared with those who had primary hyperaldosteronism, although the potassium values were similar (2.4 [0.65] v. 2.26 [0.48] mEq/L; p = 0.43). All patients with primary hyperaldosteronism had hypertension at presentation and were proven to have adrenal adenomas.
  
  
  CONCLUSIONS
  A significant number of patients in this study had secondary and potentially reversible causes of hypokalaemic periodic paralysis. The common causes were renal tubular acidosis and primary hyperaldosteronism. A detailed work-up for secondary causes should be undertaken in Indian patients with hypokalaemic periodic paralysis.
authors.affiliation: Department of Endocrinology, Diabetes and Metabolism, Christian Medical College, Ida Scudder Road, Vellore 632004, Tamil Nadu, India.
authors.forename: Narsing
authors.initials: N
authors.lastname: Rao
authors.forename: Mathew
authors.initials: M
authors.lastname: John
authors.forename: Nihal
authors.initials: N
authors.lastname: Thomas
authors.forename: Simon
authors.initials: S
authors.lastname: Rajaratnam
authors.forename: Mandalam Subramaniam
authors.initials: MS
authors.lastname: Seshadri
mesh_terms: D000141:Acidosis, Renal Tubular / Q000150:complications*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D005260:Female; D006801:Humans; D006929:Hyperaldosteronism / Q000150:complications*; D020514:Hypokalemic Periodic Paralysis / Q000175:diagnosis* / Q000209:etiology; D007194:India; D008297:Male; D008875:Middle Aged; D010245:Paralyses, Familial Periodic / Q000175:diagnosis / Q000209:etiology; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors