title: Severe hypokalemia, paralysis, and AIDS-associated isospora belli diarrhea.
abstract: BACKGROUND
  Hypokalemia of clinical significance, severe enough to cause paralysis and cardiac dysrhythmias, is an uncommon life-threatening medical disorder. Hypokalemic periodic paralysis (HPP), where an abrupt intracellular shift of potassium has occurred, must be distinguished from hypokalemic non-periodic paralysis (non-HPP), where a total body potassium deficit exists. The challenge for emergency physicians is to swiftly and accurately differentiate disease etiology and institute prompt treatment. Aggressive potassium repletion, required in non-HPP etiologies, may predispose HPP patients to dangerous and potentially fatal rebound hyperkalemia as the intracellular potassium shift resolves.
  
  
  OBJECTIVE
  Describe the process by which HPP and non-HPP can be differentiated on clinical and laboratory grounds leading to appropriate resuscitation from severe and clinically relevant hypokalemia. Chronic diarrhea syndromes and possibly normal alkaline phosphatase levels alert the clinician to the potential for non-HPP.
  
  
  METHODS
  A case of HIV/AIDS-associated isospora belli diarrheal illness with severe hypokalemia of the non-HPP type is presented. Historical, laboratory, and clinical findings, which assisted in the differentiation from HPP, are emphasized. Clinical progression and treatment strategies, as well as electrocardiogram findings with T-U-P fusion waves, are described in detail.
  
  
  CONCLUSIONS
  The history, especially the time course of disease, is essential in differentiating HPP and non-HPP, allowing treatment to proceed without overcorrection and rebound hyperkalemia. Although other infectious diseases have been linked to non-HPP, to our knowledge this is the first report linking non-HPP to isospora belli diarrheal illness.
authors.affiliation: Department of Emergency Medicine, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Williams
authors.forename: Ryan S
authors.initials: RS
authors.lastname: Smith
authors.forename: William K
authors.initials: WK
authors.lastname: Mallon
mesh_terms: D017088:AIDS-Related Opportunistic Infections / Q000469:parasitology*; D000328:Adult; D003937:Diagnosis, Differential; D003967:Diarrhea / Q000469:parasitology*; D006801:Humans; D007008:Hypokalemia / Q000175:diagnosis*; D020514:Hypokalemic Periodic Paralysis / Q000175:diagnosis*; D007549:Isospora / Q000302:isolation & purification*; D021865:Isosporiasis / Q000175:diagnosis*; D008297:Male