IgA-dominant post-infectious glomerulonephritis presenting as a fatal pulmonary-renal syndrome

Abstract

Over the last decades, post-infectious glomerulonephritis underwent major changes in its epidemiology, pathophysiology, and outcomes. We are reporting a case of IgA-dominant post-infectious glomerulonephritis (IgA-PIGN) presenting as a fatal pulmonary-renal syndrome. An 86-year-old Filipino man presented with worsening dyspnea, hemoptysis, and decreased urine output over 2 weeks. Past medical history is significant for hypertension, chronic kidney disease stage III, and pneumonia 3 weeks prior treated with intravenous cefazolin for methicillin-sensitive Staphylococcus aureus bacteremia. Physical examination was remarkable for heart rate of 109/min and respiratory rate of 25/min saturating 99% on 3 liters via nasal cannula. There were bibasilar rales in the lungs and bilateral ankle edema. A chest radiograph showed bibasilar opacifications. Blood work was significant for hemoglobin of 8.3 g/dL and creatinine of 9.2 mg/dL (baseline of 1.67). TTE showed EF 55%. Urinalysis revealed large blood and red blood cell casts. Kidney ultrasound showed bilateral echogenicity compatible with renal disease. Pulse methylprednisolone therapy and hemodialysis were initiated with patient's condition precluding kidney biopsy. Serology workup for rapidly progressive glomerulonephritis was negative. On day 7, the patient required mechanical ventilation; bronchoscopy showed alveolar hemorrhage and plasmapheresis was initiated. Renal biopsy revealed IgA-PIGN with endocapillary and focal extracapillary proliferative and exudative features. IgA-PIGN occurs in diabetic elderly (mean age of 60 years), 0-16 weeks after an infection mainly by Staphylococcus. However, this nondiabetic patient had normal complement IgA-PIGN with fatal pulmonary-renal syndrome. Understanding the pathogenesis and identifying the nephrotoxic bacteria species and the aberrant IgA molecule will open new insights toward prevention and treatment.

Keywords: acute kidney injury; alveolar hemorrhage; starry-sky; subepithelial deposits.

Figure 1

Microscopic finding of kidney biopsy with hematoxylin and eosin stain Periodic acid Schiff (PAS) stain, and Jones methionine silver (JMS) stain. Notes: (A) Nodular sclerosis (big arrow) and thickened basement membrane (small arrow) – JMS. (B) Mesangial proliferation – PAS. (C) Neutrophil infiltration – PAS. (D) Cellular crescent. (E) RBC cast (arrow). (F) Focal acute tubular injury – JMS (arrow). (G) IF: C3 glomerulus. (H) IF: IgA glomerulus. G and H show the “starry sky” appearance. Abbreviations: RBC, red blood cell; IF, Immunofluorescence; PIGN, post infectious glomerulonephritis.