LAUSR

Introduction Diarrhea is a common complaint in lung transplant recipients but has significant consequences with increased morbidity from dehydration, medication toxicity and allograft dysfunction. Etiologies range from side effects to infection, malignancy, and graft-versus-host disease. The most common causes of infectious diarrhea in this population are Clostridium difficile, cytomegalovirus (CMV), and norovirus. Norovirus is well known to cause prolonged viral shedding and chronic diarrhea in lung transplant recipients and limited case reports in renal transplant recipients suggest that sapovirus may present similarly. Case Report A 53-year-old woman with excellent allograft function at seven months following right single lung transplant was admitted with gastroenteritis and acute kidney injury. She reported diffuse abdominal cramps and distension, nausea, vomiting, watery diarrhea, and headache for five days prior to presentation. Notable home medications included tacrolimus, prednisone, azithromycin, itraconazole, atovaquone, and valganciclovir. Examination revealed normal vital signs, dry mucus membranes and a distended abdomen with diffuse tenderness. Laboratory studies showed a white blood cell count of 3.7 K/μL with 56% lymphocytes and elevated creatinine of 1.65 mg/dL. Tacrolimus level was 9.8 ng/mL. Non-contrasted CT of the abdomen and pelvis did not show any acute intraabdominal pathology. The patient was treated with intravenous fluids and broad-spectrum antibiotics while awaiting additional workup including an undetectable CMV DNA viral load and negative testing for COVID-19, serum cryptococcal antigen, stool Giardia antigen, ova and parasites, Shigatoxin and Clostridium difficile antigen and toxin. A multiplex PCR gastrointestinal panel detected the presence of sapovirus. Antibiotics were discontinued and the patient experienced progressive improvement in symptoms and renal function by day 3. Summary To our knowledge, this is the only case report of sapovirus-related gastroenteritis in a lung transplant recipient, emphasizing the need to maintain a high index of suspicion for both common and uncommon etiologies of diarrhea in transplant recipients. Though sapovirus is not an uncommon cause of self-limited viral gastroenteritis in healthy individuals, it may present with a severe and prolonged course in transplant patients and can result in significant morbidity.