[Reactive arthritis caused by Giardia lamblia in a patient with secretory IgA deficiency]. / Artrite reactiva por Giardia lamblia num doente com défice de IgA secretora.

The authors report a case of seronegative polyarthritis resistant to the anti-inflammatory therapy in a 16-year-old male with intermittent diarrhea. A stool examination showed the presence of cysts of Giardia lamblia and an immunological study detected a partial serum IgA deficiency, including its secretory fraction. Based on clinical, analytical and radiological findings and the clinical improvement after treatment with metronidazole, a diagnosis of reactive arthritis associated to chronic giardiasis was made. Authors make a brief review of the literature the regarding this case.