Introduction: AA amyloidosis is a systemic disorder of protein misfolding characterized by the deposition of serum amyloid A (SAA) protein in various tissues, most commonly the kidneys. Although its global incidence has declined with better infection control, India continues to report a considerable burden, largely linked to tuberculosis. Objective: The objective of this study was to describe the clinical, laboratory, and histopathological features of biopsy-proven renal AA amyloidosis in patients from a tertiary care hospital in North India. Materials and Methods: This retrospective study included 18 patients with histologically confirmed renal AA amyloidosis diagnosed between March 2022 and May 2024. Demographic, clinical, biochemical, and histopathological data were collected and analyzed. The association between serum albumin levels and urinary protein excretion was assessed using the Mann–Whitney U -test. Results: The cohort comprised 15 men (83.3%) and 3 women (16.7%), with a mean age of 37.2 years. Chronic infections, predominantly tuberculosis, accounted for 77.8% of cases, whereas autoimmune diseases were responsible for 16.7%. Proteinuria was universal, reaching nephrotic levels in 38.9% of patients. Severe hypoalbuminemia (<2.5 g/dL) was seen in 66.6%, and acute kidney injury occurred in 33.3%. Severe hypoalbuminemia correlated significantly with higher proteinuria ( P = 0.0123). Renal biopsies demonstrated Congo red–positive amyloid with strong SAA immunoreactivity; chronic interstitial nephritis was noted in 44.4% of cases. Conclusion: Renal AA amyloidosis in India remains predominantly infection related, with tuberculosis as the leading etiology. Early diagnosis through renal biopsy and prompt management of the underlying condition are crucial to prevent irreversible renal damage, particularly in resource-limited settings.
Alam et al. (Thu,) studied this question.