In our report, 52 patients with a diagnosis of idiopathic nephrotic syndrome and kidney biopsy criteria between the ages of 1 month and 18 years were evaluated, this would be the first pediatric report of kidney histopathological findings in Honduras. Kidney biopsy is described as an invasive but safe procedure required to classify the different clinical spectrum of kidney disease in children, these findings are of vital importance to determine an accurate diagnosis and a long-term prognosis, and thus establish a therapy more effectively [12].
The median age of the study patients was 9 (IQR, 3.0–12.0) years, similar to that reported in pediatric populations in Latin America: Venezuela (11 years) [13], Colombia (11 years) [14] and Panama (8.3 years) [15], and slightly higher than that reported in Mexico (5.9 years) [16], also in East Asian and European countries similar ages are reported in Egyptians (9.2 years) (12), in Sudan (8.71 years) [17], Saudi Arabia (10.6 years) [18], India (7.9 years) [19], Pakistan (11.2 years) [20], Croatia (10 years) [7], other studies have revealed an earlier age at diagnosis [21].
The indication for kidney biopsy prevailed in the male gender (55.8%), similar to that reported in other studies [7, 12, 20, 22]. Of the total of cases studied, the most frequent indication for biopsy was cortico-resistant nephrotic syndrome, representing 36.5% of cases, followed by 34.6% cortico-dependent nephrotic syndrome, 21.2% sensitive to steroids, and 7.7% % as nephrotic syndrome of the infant. Arif MK et al. (2016), showed similar data in Tanzania with 48% cortico-resistant, 33.3% of cortico-sensitive children, and only 13.3% cortico-dependent [20], likewise, Bakr A, et al. (2014), reported 28.4% of cortico-resistant children [12]. These results are consistent with those reported in other countries following a similar pattern of presentation and differ slightly from other studies. For example, Ali A. (2008), reports different figures with a greater predominance of cortico-sensitive children representing 87% and 13% cortico-resistant [23], in Serbia the most frequent indication was cortico-dependent (32%), [24] differing from what was observed in this report.
In the last three decades, minimal change disease has been established as the most common cause of INS, with a prevalence that varies between 77–99% in different studies [25]. However, changes in histopathological patterns have been observed in recent years. The results show that minimal change disease is the most frequent histological variant in 36.5% of cases, however, it does not present the high percentages reported by other authors [25].
Focal and segmental glomerulosclerosis was identified as the second most frequent cause with 28.8% of cases, followed by diffuse mesangial hypercellularity (19.2%). In other series, FSGS is increasingly common in children with INS, ranking as the main cause [17, 19, 20, 26], which would warrant a kidney biopsy to establish a diagnosis and precise management even in places with scarce resources such as ours. The prevalence of FSGS could be explained by its behavior of complicating other glomerular injuries and its resistance to steroids with a poor subsequent prognosis [27]. The reason for the disparity between MCD and FSGS is uncertain, but it is attributed to demographic, environmental and genetic factors [28].
In this series, no patient with IgA nephropathy was reported, countries such as Morocco, Egypt and India also have no or low rates of IgA nephropathy [12, 29–30]. In countries of East Asia and Europe, IgA nephropathy is the most frequent histopathological diagnosis in kidney biopsies [7, 31–32]. International reports differ in the histopathological diagnosis between the predominance of one glomerulopathy over another, attributable to geographical variation and racial predisposition and the different indications for kidney biopsy that were taken into account in each study; different histological methods for diagnosis must also be taken into consideration, and the use of different pathological classifications [7]. This study shows histological patterns that differ from what is reported in the international literature as the most frequent.
17.3% of the patients presented tubular atrophy and interstitial fibrosis, respectively, most of these presenting in the FSGS, which would demonstrate a chronicity of the disease and little response to steroid therapy. Therefore, these patients present an increased risk of progressing to chronic disease and developing more side effects [33].
Our study represents a sample of patients with INS with kidney biopsy criteria, defining the INS as the presence of proteinuria > 40mg/m2/h, hypoalbuminemia < 2.5g/dL and hypercholesterolemia > 200mg/dL; INS continues to be the main indication for kidney biopsy, agreeing with the majority of studies [34–35]. European countries such as Italy and England place proteinuria as the main indication [36], in Hong Kong systemic diseases rank first [37]. By comparing different studies, in different regions, we could demonstrate that the indications for kidney biopsy have changed in recent years.
The most important limitation of the study is its retrospective nature, limiting access to information and the lack of electron microscopy since this method is not available in Honduras and it is currently considered an essential component to describe glomerular pathology. There was no exclusion of cases, all biopsies performed from 2016–2020 were studied. This pediatric study is the first report of kidney histopathological findings in Honduras that will lay the foundations for future research in the country. These findings are important for the diagnosis, prognosis, and therapeutic approach in the clinical evaluation of Honduran children. The results belong to two second-level care hospitals, being the centers of greatest reference on the north coast of the country, but they are not representative of the total population, due to the selection bias, limiting the true emergence of kidney disease in Honduran children. Since the performance of a kidney biopsy in all children who present biopsy criteria depended on the consent of the parents and their economic condition to pay for it, it is not a procedure available within the public services of the country.