Correspondence

Hypokalemic Myopathy Induced by Giardia Lamblia

N Engl J Med 1993; 329:210-211July 15, 1993

Article

To the Editor:

Giardiasis is the leading cause of waterborne outbreaks of diarrhea in the United States,1 yet its role as a potential cause of malabsorption in elderly patients may be underestimated2. We report a case of severe hypokalemic myopathy induced by chronic intestinal infection with Giardia lamblia.

A 69-year-old man with a one-month history of progressive muscular weakness, diarrhea, and weight loss was hospitalized. Intermittent bouts of diarrhea had begun 10 years before, when G. lamblia cysts were found on a stool examination and metronidazole was given. The patient was a heterosexual industrial manager who had never traveled outside Spain. On physical examination, abnormal findings were limited to the neurologic examination. There was an intense and symmetrical muscular weakness of all four extremities and the neck. Muscle stretch reflexes were absent. Mentation, cranial nerves, and the results of sensory examination were normal. The erythrocyte sedimentation rate was 60 mm per hour. The hematologic findings were normal. Blood-chemical findings on admission and during the hospital course are presented in Table 1Table 1Laboratory-Test Results.. Tests for urinary myoglobin were positive. An electrocardiogram and an electroencephalogram were normal. Motor- and sensory-nerve conduction studies were normal, except for a moderately decreased amplitude of the compound muscle action potentials. Electromyography revealed fibrillation potentials, positive sharp waves, and low-amplitude, short-duration polyphasic motor-unit action potentials in proximal muscles. Repetitive stimulation at slow rates was normal, but facilitation of 30 percent appeared after 20 seconds of tetanization. Jitter measurement in the extensor digitorum communis muscle after axonal stimulus was normal (18.2 microsec).

These findings were consistent with impairment of muscle excitability and denervation due to muscle necrosis. Stools contained G. lamblia cysts. Treatment with gradual intravenous electrolyte supplementation and oral metronidazole was followed by steady clinical improvement. After three months, the patient had resumed work and gained 15 kg. He has remained asymptomatic for 15 months.

Symptomatic hypokalemia caused by diarrhea is uncommon in adults. Isolated cases of hypokalemic myopathy have been described in salmonella, strongyloides, and yersinia infections3. Giardiasis has been associated with a peripheral neuropathy of obscure origin4. Infestation with G. lamblia should be considered as a potential cause of malabsorption-induced hypokalemia and rhabdomyolysis in elderly patients.

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

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

4 References

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   Bassett ML, Danta G, Cook TA. Giardiasis and peripheral neuropathy. BMJ 1978;2:19-19
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Citing Articles (7)

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   Cabot, Richard C.Harris, Nancy Lee, Shepard, Jo-Anne O., Rosenberg, Eric S., Cort, Alice M., Ebeling, Sally H.Peters, Christine C., Ryan, Edward T., Cronin, Carmel G., Branda, John A., . (2011) Case 38-2011. New England Journal of Medicine 365:24, 2306-2316
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   D WILLIAMS, R SMITH, W MALLON. (2008) Severe hypokalemia, paralysis, and AIDS-associated Isospora Belli diarrhea. Journal of Emergency Medicine
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   Valeria Rossi, Simone Saibeni, Luigi Sinigaglia, Maddalena Peracchi, Antonina Parafioriti, Maurizio Vecchi. (2006) Hypokalemic Rhabdomyolysis without Watery Diarrhea: An Unexpected Presentation of a Pancreatic Neuro-Endocrine Tumor. The American Journal of Gastroenterology 101:3, 669-672
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   Joern P. Sieb, Thomas Gillessen. (2003) Iatrogenic and toxic myopathies. Muscle & Nerve 27:2, 142-156
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   Sibel Tulgar Kinik, GÜLten SeÇMeer, Guler Kanra, Mehmet Ceyhan, Zafer Ecevit Khalil Halit, Nuray ÖKsÜZ. (1998) Hypokalemic paralysis in association with acute gastroenteritis: A report of a sporadic case. Pediatrics International 40:2, 143-145
   CrossRef

6. 6

   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

7. 7

   (1994) Hypokalemic Myopathy Induced by Giardia lamblia. New England Journal of Medicine 330:1, 66-67
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