Correspondence

Hypokalemic Myopathy Induced by Giardia lamblia

N Engl J Med 1994; 330:66-67January 6, 1994

Article

To the Editor:

Cervello and colleagues (July 15 issue)1 reported a case of hypokalemic myopathy associated with Giardia lamblia infection. To determine the frequency of hypokalemia and rhabdomyolysis in patients with severe giardiasis, we analyzed hospital-discharge data from two sources.

The National Hospital Discharge Survey is a sample of approximately 0.1 percent of patients discharged from short-stay hospitals in the United States2. Data from 1979 through 1988 indicate that approximately 4600 patients are hospitalized for giardiasis annually in the United States,3 which is similar to the number hospitalized for shigellosis (Centers for Disease Control and Prevention: unpublished data). During this period, an estimated 3.8 percent of all patients discharged with a first-listed diagnosis of giardiasis (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM] code 007.1) and 23.6 percent of those at least 65 years old had been given a diagnosis of hypokalemia (ICD-9-CM code 276.8); none had been given a diagnosis of myopathy or rhabdomyolysis (ICD-9-CM codes 359.8, 359.9, and 728.89).

Small numbers limited the precision of these national estimates, particularly for the elderly. Therefore, we analyzed hospital-discharge data collected from 1984 to 1991 by the Health Care Financing Administration on all Medicare beneficiaries in Wisconsin who were 65 years of age or older4. Of these patients, 70 had a first-listed diagnosis of giardiasis, 13 of whom also had a diagnosis of hypokalemia. Hypokalemia was not associated with age, race (95.7 percent of the beneficiaries were white), a diagnosis of hypertension, the length of the hospital stay, or death during hospitalization. Thirteen of 56 women (23.2 percent) had been given a diagnosis of hypokalemia, as compared with none of 14 men (P = 0.06 by two-tailed Fisher's exact test). None of the 70 patients had been given a diagnosis of myopathy or rhabdomyolysis.

Two of 22 Medicare beneficiaries hospitalized with a first-listed diagnosis of shigellosis (ICD-9-CM codes 004.0 to 004.9) and 40 of 248 with salmonellosis (ICD-9-CM code 003.0) had hypokalemia. Among the patients with salmonellosis or shigellosis, hypokalemia was not associated with sex, and none of these patients with hypokalemia had been given a diagnosis of myopathy or rhabdomyolysis.

Hospitalization for giardiasis is more common in the United States than is generally recognized. These data suggest that hypokalemia occurs in a substantial proportion of elderly persons, particularly women, who are hospitalized for giardiasis. The causes and clinical consequences of giardia-associated hypokalemia are unclear. We found no instances of giardia-associated myopathy in these hospital-discharge data. If G. lamblia is a cause of myopathy or rhabdomyolysis, it appears to be an unusual one.

David G. Addiss, M.D., M.P.H.
Eugene J. Lengerich, V.M.D., M.S.
Centers for Disease Control and Prevention, Atlanta, GA 30341

4 References

1. 1

   Cervello A, Alfaro A, Chumillas MJ. Hypokalemic myopathy induced by Giardia lamblia. N Engl J Med 1993;329:210-211
   Full Text | Web of Science | Medline

2. 2

   National Center for Health Statistics. National Hospital Discharge Survey [machine-readable data files]. Hyattsville, Md.: Department of Health and Human Services, 1979-1988.
   

3. 3

   Warhurst DC, Smith H. Getting to the guts of the problem. Parasitol Today 1992;8:292-293
   CrossRef

4. 4

   Health Care Financing Administration. Medicare provider analysis and review file [machine-readable data files]. Baltimore: Department of Health and Human Services, 1984-1990.
   

Author/Editor Response

The authors reply:

To the Editor: The data of Drs. Addiss and Lengerich confirm the rarity of myopathy and rhabdomyolysis in patients with hypokalemia induced by G. lamblia. The high incidence of hypokalemia in elderly patients with giardiasis, particularly women, is remarkable.

To address this question further, we reviewed the medical records of patients older than 14 years with a first-listed diagnosis of giardiasis who were admitted to the University Hospital La Fe of Valencia, Spain, between 1984 and 1992. There were 10 men and 3 women ranging from 18 to 74 years of age. Seven patients were admitted for suspected malabsorption or chronic diarrhea, three for acute diarrhea, two for chronic abdominal symptoms without diarrhea, and one for an acute febrile illness probably not related to giardiasis. All three patients who were older than 65 years had malabsorption. The only patient with hypokalemia was a 50-year-old woman with chronic diarrhea and severe hypogammaglobulinemia. There were two homosexual men with AIDS. Three patients had a peripheral neuropathy, one of whom had AIDS and two of whom had chronic alcoholism. Creatine kinase levels were normal in all patients. None of the patients had myopathy or rhabdomyolysis.

Severe neuromuscular symptoms do not seem to result from acute hypokalemia, unless there is preexisting potassium depletion1. Thus, chronic diarrhea or malabsorption may be crucial for the development of hypokalemic myopathy in giardiasis. In a prospective study, malabsorption was present in 29 of 40 adults with symptomatic giardiasis2. Magnesium depletion also has an important role in the development of hypokalemia. Patients with malabsorption tend to have both potassium and magnesium depletion, and it is not possible to correct hypokalemia without concomitantly treating the magnesium deficit3. Potassium depletion in chronic giardiasis may also be related to the duration of symptoms, the dietary intake of potassium, and the use of laxatives. Although hypokalemic myopathy with rhabdomyolysis appears to be an extremely unusual complication of gastrointestinal loss of potassium, the prevalence of electrolyte-related neuromuscular symptoms in elderly patients with chronic diarrhea and malabsorption may be underestimated.

Alberto Alfaro, M.D., Ph.D.
University Hospital La Fe, 46009 Valencia, Spain

Angeles Cervello, M.D.
University General Hospital, 46008 Valencia, Spain

Maria Jose Chumillas, M.D.
University Hospital La Fe, 46009 Valencia, Spain

3 References

1. 1

   Mineral and electrolyte disorders. In: Layzer RB. Neuromuscular manifestations of systemic disease. Contemporary neurology series. Vol. 25. Philadelphia: F.A. Davis, 1985:47-77.
   

2. 2

   Wright SG, Tomkins AM, Ridley DS. Giardiasis: clinical and therapeutic aspects. Gut 1977;18:343-350
   CrossRef | Web of Science | Medline

3. 3

   Harvey AM, Johns RJ, McKusick VA, Owens AH Jr, Ross RS, eds. The principles and practice of medicine. 22nd ed. Norwalk, Conn.: Appleton & Lange, 1988:701.
   

Citing Articles (2)

Citing Articles

1. 1

   D WILLIAMS, R SMITH, W MALLON. (2008) Severe hypokalemia, paralysis, and AIDS-associated Isospora Belli diarrhea. Journal of Emergency Medicine
   CrossRef

2. 2

   A. Geovese, G. Spadaro, L. Santoro, P. Gasparo Rippa, A. M. Onorati, G. Marone. (1996) Giardiasis as a cause of hypokalemic myopathy in congenital immunodeficiency. International Journal of Clinical & Laboratory Research 26:2, 132-135
   CrossRef