Background & Objectives: Hypokalemic paralysis is a relatively uncommon syndrome which is potentially dangerous. If it is diagnosed and treated timely, the patients will be saved without any side effects. Various diseases can lead to this syndrome which is characterized with decreasing of serum potassium and acute systemic paralysis. In hypokalemic paralysis, the serum level of potassium reaches to less than 3.5 Mmol/lit. This may be caused by transferrence of K to intracellular department, (periodic hypokalemic paralysis and periodic thyrotoxic paralysis). The aim of this study was to determine sex and age prevalence of these patients as well as other features of the patients suffering from periodic hypokalemic paralysis.

  Methods: 55 patients participated in this prospective, descriptive and cross-sectional study which was conducted from 1999 to 2003. These patients were referred to the neurological department with hypokalemic diagnosis on the basis of laboratory and clinical examinations. The data were collected using a questionnaire. Also the serum level of K was measured. The data were analyzed by SPSS software.

  Results: from 50 patients, 46 (92%) were male and others were female. The patients were in 19-60 age range (Mean=33.16 SD=9.1). Mean serum level of K⁺ was 2.37 Mmol/lit (SD= 0.49) in the first hospitalization. The incidence of hypokalemia increased with aging , but majority of the patients (76%) were in age range 20-40. In 86% of the patients the time of hypokalemia crisis was at night and early morning. 11 patients had a high consumption of rich carbohydrate foods previously and 11 others had consumed corticosteroids. There was relapse of disease in 21 patients. 40 patients had paralysis in 4 extremities and 12 patients in 2 extremities. 4% of the patients were hypertensive and 4 patients were hyperthyroid. EKG was normal in 8 patients but in other cases there were abnormal changes.

  Conclusion: Despite the international references, the incidence ratio of male to female is high but the decreasing of K is more severe in female. Asetazolamide and oral KCL therapy not only decrease the period of hospitalization, but also are more effective in treatment of the disease.