Giardia lamblia mimicking acute graft versus host disease after allogeneic hematopoietic stem cell transplantation

Abstract

Rationale: As the major complications post allogeneic hematopoietic stem cell transplantation (allo-HSCT), gastrointestinal disorders were most commonly ascribed to acute graft-versus-host disease (aGVHD) and opportunistic infections. Though Giardia lamblia ( G lamblia ) is the most common waterborne parasite of intestinal infection worldwide, seldom has it been reported in a patient with acute severe aplastic anemia after allo-HSCT. Patient concerns: A 23-year-old male with severe aplastic anemia developed diarrhea, abdominal cramps, bloating, nausea, vomiting, fever, weight loss, and fatigue after allo-HSCT. Diagnosis: Stool examinations for ova and parasites showed Giardia trophozoites and cysts. Interventions: Methylprednisolone was stopped and the patient was intravenously treated with a 7-day course of metronidazole (500 mg, tid.). Simultaneously, cyclosporine (5 mg/kg) was continually utilized for suspicious gut GVHD. Outcomes: The Giardia lamblia in stool turned negative and his symptoms were resolved after the 7-day course. Lessons: Incorporating non-invasive monitoring of stool examination for ova and parasites in the follow-up algorithm for post-HSCT patients can expedite clinical decision-making in the differential diagnoses for aGVHD even in the non-endemic area. Metronidazole therapy can be well-tolerated in HSCT patients with giardiasis.

Parasitic infections in hematopoietic stem cell transplant recipients

“…Despite this, there have been no reports of reactivation of latent giardia or donor transmission of giardia in HSCT patients, with all reported cases occurring as de novo infection. [8][9][10][11] There are many factors that contribute to the variation of clinical manifestations seen in Giardiasis infection including the virulence of the Giardia strain, the number of cysts ingested, the age of the host, and the state of the host immune system at the time of infection. 12 While there is some data available on giardiasis in children with HSCT, 13,14 people with human immunodeficiency virus (HIV), 15 and patients with solid organ transplant (SOT), 16 there are few studies to date on the prevalence of giardiasis in adult HSCT patients.…”

“…12 While there is some data available on giardiasis in children with HSCT, 13,14 people with human immunodeficiency virus (HIV), 15 and patients with solid organ transplant (SOT), 16 there are few studies to date on the prevalence of giardiasis in adult HSCT patients. [8][9][10][11] Since diarrhea is a symptom present in both GVHD and giardiasis, it is important to distinguish between them as they can be mistaken for one another. 8 Unlike in immunocompetent patients, microscopic detection of parasites in stool has low sensitivity in immunocompromised patients.…”

“…[8][9][10][11] Since diarrhea is a symptom present in both GVHD and giardiasis, it is important to distinguish between them as they can be mistaken for one another. 8 Unlike in immunocompetent patients, microscopic detection of parasites in stool has low sensitivity in immunocompromised patients. 17 Furthermore, the fact that cysts are often excreted intermittently or sometimes released in numbers too small to be detected also decreases the sensitivity of this test.…”

“…18 In all reported cases of giardia seen in HSCT patients that elucidated treatment outcomes, metronidazole was effective in resolving symptoms. [8][9][10] With all reported cases of giardia in HSCT patients being de novo infections, patients with HSCT should practice strict hygiene practices and ensure they use safe drinking water. Given the low prevalence and limited severity, there is no chemoprophylaxis indicated for giardia in this patient population.…”

“…Considering the significant prevalence of asymptomatic carriers of Giardia, it is reasonable to speculate that such individuals exist amongst candidates for HSCT. Despite this, there have been no reports of reactivation of latent giardia or donor transmission of giardia in HSCT patients, with all reported cases occurring as de novo infection 8–11 …”