title: Granulomatous interstitial nephritis associated with influenza A: H1N1 infection--A case report.
abstract: BACKGROUND
  The causes of acute tubulointerstitial nephritis can be grouped into four broad categories: medications, infections, immunologic diseases, or idiopathic processes. Here we report a 17-year-old female who developed acute kidney injury (AKI) due to granulomatous interstitial nephritis (GIN) associated with influenza A: H1N1 infection.
  
  
  METHODS
  The illness presented after two weeks of respiratory tract infection, skin rash and hypermenorrhea. On admission the patient was febrile, with bilateral pedal edema, macular skin rash, and auscultatory finding that suggested pneumonia. Laboratory investigations showed normocytic anemia, azotemia, hematuria and proteinuria. Renal ultrasound was normal. Antinuclear antibodies, antineutrophil cytoplasmic antibodies, lupus anticoagulant, antiphospholipid antibodies were negative with normal complement. Urine cultures including analysis for Mycobacterium tuberculosis were negative. The diagnosis of influenza A: H1N1 infection was made by positive serology. A kidney biopsy showed interstitial nephritis with peritubular granulomas. Glomeruli were normal. Staining for immunoglobulins A, M, G, and F was negative. The girl was treated with oseltamivir phosphate (Tamiflu; Genentech, Inc., South San Francisco, CA, USA) for five days, as well as with tapered prednisone after a starting dose of 2 mg/kg. The treatment resulted in a complete remission during two years of follow-up.
  
  
  CONCLUSIONS
  We present a severe but reversible case of GIN and AKI associated with influenza A: H1N1 infection. Although a causal effect cannot be confirmed, this case suggests that influenza A: H1N1 should be considered in the differential diagnosis of GIN manifested with AKI in children.
authors.forename: Gordana
authors.initials: G
authors.lastname: Milosevski-Lomić
authors.forename: Jasmina
authors.initials: J
authors.lastname: Marković-Lipkovski
authors.forename: Mirjana
authors.initials: M
authors.lastname: Kostić
authors.lastname: Dusan Paripović
authors.forename: Brankica
authors.initials: B
authors.lastname: Spasojević-Dimitrijeva
authors.forename: Amira
authors.initials: A
authors.lastname: Peco-Antić
mesh_terms: D058186:Acute Kidney Injury / Q000188:drug therapy / Q000209:etiology* / Q000473:pathology; D000293:Adolescent; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000998:Antiviral Agents / Q000627:therapeutic use; D053099:Azotemia / Q000209:etiology; D005260:Female; D006417:Hematuria / Q000209:etiology; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications* / Q000188:drug therapy; D009395:Nephritis, Interstitial / Q000150:complications* / Q000188:drug therapy / Q000473:pathology; D053139:Oseltamivir / Q000627:therapeutic use; D011241:Prednisone / Q000627:therapeutic use; D011507:Proteinuria / Q000209:etiology
chemical_list: D000893:Anti-Inflammatory Agents; D000998:Antiviral Agents; D053139:Oseltamivir; D011241:Prednisone