A 19 year old woman attended antenatal clinic at 16 weeks’ gestation (gravida 2, para 0+1). Routine urine dipstick testing identified blood (+++) and protein (++). Similar findings had been recorded three weeks earlier. She described tiredness and occasional painless minor haemoptysis. She had a history of chlamydial infection and a spontaneous miscarriage two years earlier. She occasionally smoked marijuana but did not drink alcohol. Her body mass index was 32.2. She had no family history of note. Examination was unremarkable except for bilateral renal angle tenderness. Sequential urine specimens were culture negative. ### 1 What is the differential diagnosis? #### Short answer Once infection has been excluded, haematoproteinuria identified by dipstick analysis is indicative of glomerulonephritis; coexistent haemoptysis makes multisystem autoimmune disease a strong possibility that needs urgent investigation. #### Long answer Asymptomatic bacteriuria is present in 2-10% of women. At least 1% of women of childbearing age have chronic kidney disease, depending on the definition used.1 Some asymptomatic disease will be identified through pregnancy related screening. Glomerular disease is a possibility when haematoproteinuria is present and urine cultures are sterile, but substantial proteinuria should raise suspicions of underlying glomerular disease even in the presence of urine infection. In this patient, the presence of haemoptysis raises particular clinical suspicion and concern. The differential diagnosis for coexisting haemoptysis and haematoproteinuria is primarily anti-neutrophil cytoplasmic antibody (ANCA) associated vasculitis and anti-glomerular basement membrane disease (anti-glomerular basement membrane disease; also known as Goodpasture’s syndrome when lung and kidney are both involved). Although rare diseases, with a combined incidence of around 20 per million population per year, both can cause rapidly …