Severe adenovirus-associated pneumonia complicated by biopsy-evaluated acute kidney injury in an immunocompetent adult: a case report

BACKGROUND: Adenovirus infection is typically self-limited in immunocompetent individuals. Severe adenovirus-associated pneumonia with renal involvement is uncommon and has been predominantly reported in immunocompromised hosts. Acute kidney injury (AKI) during viral infections may occur through inflammatory or tubular mechanisms even in the absence of immune-complex-mediated glomerular disease. CASE PRESENTATION: An 18-year-old previously healthy immunocompetent woman presented with severe pneumonia. Upper respiratory tract PCR was positive for adenovirus, while blood and urine cultures were negative. Laboratory findings showed marked systemic inflammation (CRP 256 mg/L; procalcitonin 15 ng/mL). Serum creatinine was elevated to 4.0 mg/dL prior to antibiotic therapy. Urinalysis revealed leukocyturia, microscopic hematuria, and proteinuria below the nephrotic range. Due to severe acute kidney injury at presentation and diagnostic uncertainty, a kidney biopsy was performed. Light microscopy demonstrated preserved glomerular architecture without proliferative or crescentic changes. Immunofluorescence staining was negative for IgG, IgA, IgM, C3, and C1q. Mild tubular alterations, including focal granular-hyaline casts, were observed, without specific vascular pathology. Overall findings were compatible with infection-associated acute kidney injury. Mini-pulse corticosteroid therapy and empirical broad-spectrum antibiotics were administered. Renal function subsequently improved, with complete recovery during hospitalization. CONCLUSION: Severe adenovirus-associated pneumonia may be complicated by acute kidney injury even in immunocompetent adults. In the absence of immune-complex deposition or overt glomerular pathology, renal dysfunction may reflect infection-associated tubular injury or systemic inflammatory mechanisms.