A cluster of haematuria cases in a pesticide-manufacturing plant

In a pesticide manufacturing and formulating facility, 10 employees out of 48 were shown to have haematuria on dipstick testing. They included seven of the 27 production workers, all of whom had worked in both of two particular areas prior to the commencement of the routine urine testing. Five of the seven production workers with haematuria underwent further investigations, and in all five the haematuria was glomerular in origin. Two underwent renal biopsy, which showed irregular attenuation of the glomerular basement membrane (GBM) but no abnormality by light microscopy. Immunofluorescence studies were negative. This case series of glomerular haematuria is not readily explained by chance, false positive dipstick testing, or a recognizable non-occupational cause. Thin GBM disease, which is a benign condition, appears the likely explanation. Thin GBM disease is usually an autosomal dominant condition, but clustering of these genotypes in this small population is improbable.