The prevalence of crescentic glomerulonephritis is around 2% to 10% of all glomerulonephritis cases in most studies: found at a rate of 7.4% in Morocco and 8.2% in South Africa (
4- 6). In Germany ( 7), as in the current study, the prevalence was 5.33%. The annual incidence in France was 0.7/100,000 ( 8). In an Iranian study about histopathologic patterns of adult renal disease, Mardanpour found a prevalence of 4.5% of crescentic glomerulonephritis ( 9). The patients of the current study were young (mean age 33.9 years) with a female predominance (the male: female gender ratio was 0.53). These results are similar to those reported in the literature ( 6, 10- 13). In the current study, the mean time from first symptoms to admission in a care unit was 40 ± 29.66 days. This time limit exceeded 15 days for 70% of patients. This could be explained by the fact that patients were treated in health centers or by traditional medicine before coming to the nephrology unit. Hypertension was found in 65% of cases, associated with oligoanuria in 62.5%. In Ozturk’s series, 21 patients (51.2%) had oliguria-anuria ( 14).
Upon admission, renal failure was found in 75% of patients, close to the value of 64% in the series published by Husseini (
10), versus 90% in the Arrayhani series ( 4), and 92.4% in the series described by Zheng ( 6) ( Table 3). However, Ozturk found that 22 patients (53.7%) were on dialysis because of acute clinical and laboratory indications ( 14). Histologically, crescents were cellular in 60.5% of cases. This was similar to Arrayhani’s results, showing cellular crescents in 61.7% of patients ( 4). However, Husseini found that 27% of patients had cellular crescents in his series ( 10). Crescents were fibrous in 32.5% of cases in the current study versus 11.7% in the Husseini’s series ( 10). The presence of fibrinoid necrotic lesions, cellularity and rupture of Bowman’s capsule leads to active inflammatory lesions ( 2). The percentages of completely sclerotic glomeruli (5.15%), interstitial fibrosis (20%), and tubular atrophy (50%) attest to the chronicity of these lesions. Lesions of different duration show a rapid evolution towards chronicity in the absence of early treatment. The importance of these tubular/interstitial lesions found in the current series could be explained by the excessive use of phytotherapy in 47% of patients; this aggravated the renal disease. The severity of these histological lesions found in the current series may explain why only 6 patients (19.27%) had a favorable outcome with total recovery of renal function.
Table 3. Clinical Etiological and Evolution Parameters in Different Studies
Current study (n = 40) Arrayhani and Amraoui ( 4) (n = 68) El-Husseini et al. ( 10) (n = 128) Andrassy et al. ( 7) (n = 33) Tang et al. ( 6) (n = 172) Ozturk et al. ( 14) (n = 41) Clinical presentation Hypertension 65 76.5 68.4 - 60.4 46.3 Oligoanuria 62.5 44.6 48 - 50.6 51.2 Renal insufficiency 75 64 90 - 92.4 53.7 Etiology Lupus 32.5 42.6 28 9 20.5 9.8 ANCA vasculitis 27.5 27.9 4.6 75.7 - 63 Acute Post infectious glomerulonephritis 17.5 17.6 17.9 0 28.7 4.9 Evolution to ESRD 48.8
aValues are expressed as %.
Regarding the etiologies, lupus was the first cause of ECGN found in the current series, with a percentage of 32.52%. This finding is similar to that of previous studies by Arrayhani and Amraoui (
4), Husseini et al. (28%) ( 10), and Tang et al. ( 6) (20.5%), whereas it was found only in 9% of cases in Andrassy’s German series ( 7) and 9.8% of cases in Ozturk’s Iranian series ( 14). The high incidence of lupus in these African series could be explained by ethnic and racial factors. Indeed, the prevalence of lupus is more important in African-American populations than in Caucasian-American populations ( 8). According to an English study conducted in Nottingham, prevalence of lupus is 24.7/100 000 in the population as a whole against 207/100 000 for the black population of the same region ( 8). Vasculitis was responsible for ECGN in 75.7% of cases in the German series ( 7) and 63.4% in the Iranian series ( 14), whereas it was the cause of lesions in 27.5% of the patients of the current study, 27.9% in a Moroccan series ( 4) and 4.6% in an Egyptian series ( 14). Infections related to ECGN were found in 17.5% of cases for the current series, 17.6% for Arrayhani ( 4), 17.9% for Husseini ( 10) and 28.7% for Zent ( 15). This etiology was found in 4.9% of cases in Ozturk series ( 14) and not found in Andrassy’s work. The decrease in the incidence of post-infectious ECGN in Europe could be explained by improved standards of living and better medical care in Western countries compared to the developing world ( Table 3).
On an evolutionary level, after an average follow-up of 7 months, 3 patients died. Of the remaining 30 patients, 18% had normal renal function while 53% had kidney failure. Forty-three percent (43%) of cases in the current study developed end-stage renal disease (ESRD), as in most other series except for Andrassy’s (
7) where the progression was considerably better, with 55% recovering normal renal function. In Ozturk’s series, twenty patients developed end-stage renal disease ( 14). This could be due either to ethnic factors (Caucasian versus African and Asian), etiological factors (vasculitis being the dominant etiology in this European series) or socio-economic factors. The economic level allows better access to care, availability of treatment, and comprehensive care. The ECGN secondary to lupus seemed to have a better prognosis in the current series and in the Arrayhani series ( 4), unlike that of Zent et al. ( 15) where 87% of patients had either ESRD or were deceased. Of these risk factors, 3 were common in the 4 series: oligoanuria, high creatinine level on admission and a high percentage of fibrous crescents. The current research was consistent with the series by Arrayhani and Amraoui ( 4), showing a high percentage of sclerotic glomeruli. 4.1. Conclusions
In conclusion, ECGN is a cause of rapid and irreversible renal function impairment. It was relatively common in the current study. Etiologies were dominated by lupus and infections. The relatively long period of treatment delayed diagnosis and management. This was at the root of poor recovery of renal function in the current series. The risk factors identified in the current series could improve the prognosis of ECGN in the studied population.