Linear anti-glomerular basement membrane IgG but no glomerular disease: Goodpasture's syndrome restricted to the lung.

C.V. is a 22-year-old woman, who presented to the emergency room (ER) with shortness of breath, coughing and frank haemoptysis. She had been seen in the ER twice over the previous 3 weeks for similar symptoms, but with only mild blood-tinged sputum. Chest X-ray showed bilateral infiltrates. She was treated with Zithromax and subsequently Biaxin for a presumed pneumonia. There was no history of fevers, chills or weight loss. However, the haemoptysis persisted with increasing shortness of breath, forcing her back to the ER. Her history was significant in that she is a smoker and works as a bartender in a smoky restaurant. Laboratory investigations at admission: haemoglobin 10 gm/dl, platelet count 309 10/ml, sodium 138mEq/l, potassium 3.8mEq/l, serum creatinine 0.7mg/dl, blood urea nitrogen 11mg/dl, total bilirubin 1.5mg/dl, PCO2 34, PO2 48. Urinalysis was unremarkable. Chest X-rays showed worse diffuse alveolar infiltrates compared with the previous X-rays. The clinical diagnosis was that of acute interstitial lung disease with haemoptysis and included a differential diagnosis Wegner’s granulomatosis, lupus, sarcoidosis, pneumonitis, Goodpasture’s disease, etc. Titres for anti-GBM antibodies returned high positive (>32U/ml, normal <3U/ml). Remaining serological tests were negative. A renal biopsy was done to confirm Goodpasture’s disease and to document whether renal disease was present or not.