LAUSR

Introduction: Rapidly progressive Glomerulonephritis (RPGN) is a syndrome which was first described in 1942 by Ellis.It is caused by glomerulonephritis which results in rapid decline in renal function over a short period of time. Its histological hallmark is extensive crescent formation. It is a heterogeneous disease with various aetiologies leading to glomerular injury.Recent studies of the characteristics of RPGN in adults in South Africa have been sparse, although there was a recent retrospective study from Paediatric nephrology in Cape Town. A study from Senegal found RPGN in 5.33% of renal biopsies conducted over 5 years. The aetiologies were mainly lupus in 32.5% of cases, followed by ANCA-related vasculitis in 27.5% of cases, and infectious causes in 17.5% of cases.This differs from aetiologies of RPGN from other parts of the world where the most common cause in ANCArelated vasculitis. Methods: The number of renal biopsies performed at three tertiary hospitals during the study period were determined. The biopsies with crescentic glomerulonephritis were further scrutinized. The demographical data which includes, age, gender, race, and the baseline estimated glomerular filtration rate (eGFR) as determined by the Modified Diet in Renal Disease (MDRD) formula will be collected. The serological test results of ANA, p-ANCA, c-ANCA, ASOT, antiGBM antibody, C3 and C4 level were also be recorded. The underlying disease process of each of the RPGN cases were recorded into anti-GBM disease, Immune complex mediated, pauci-immune vasculitis, idiopathic or double antibody disease. Results: There were a total of 1513 biopsies performed at the three tertiary hospitals between 1 January 2015 to 31 December 2019. Of these, 980 were native kidney biopsies and 400 allograft biopsies. There were 43 crescentic glomerulonephritidies (4.38%). The average age was 30.7 years, there were 13 male and 30 female patients. The patients comprised of 38 black, 2 Indian, 2 white and 1 mixed race patient. The majority of them (90.7%) were immune complex mediated and the remainder were ANCA mediated. The underlying cause of the 39 immune complex mediated crescentic glomerulonephritides was lupus nephritis in 32 (82%), post infection glomerulonephritis in 2 (5%), IgA nephropathy in 1 case (2.6%) and 4 (10.2%) with an undetermined underlying cause. Conclusions: The aetiologies of RPGN vary according to the demographics being studied. In predominantly Caucasian societies the most common cause is ANCA vasculitis. In studies from South Africa conducted in the 1980s, the most common cause of RPGN was post infectious GN. This contrasts with more recent studies from subSaharan Africa. This study yielded similar results with the predominant cause of RPGN being Lupus nephritis in 82 % of the patients followed by post infectious glomerulonephritis in 5 %. This is not surprising as SLE is common in black patients and the change in the pattern of aetiologies over the last few decades may be due to improved screening for SLE. The reduction in the cases of RPGN attributable to PIGN is likely to widespread antibiotic use. The prevalence of RPGN ranges between 2 and 10% and in the recent study from Senegal was 5.3 % . This is similar to this study with a prevalence of 4.38%. This study emphasizes the variation in aetiologies of RPGN in sub-Saharan Africa over the last four decades. No conflict of interest