[The problem of rheumatoid nephropathy].

Area of Science:

• Nephrology
• Rheumatology
• Pathology

Background:

• Rheumatoid arthritis (RA) is a systemic autoimmune disease.
• Renal involvement is a significant but often underdiagnosed complication of RA.

Purpose of the Study:

• To investigate the clinical and morphological spectrum of kidney diseases in patients with RA.
• To determine the frequency and characteristics of renal pathology in RA.

Main Methods:

• Prospective study of 268 RA patients over 25 years.
• Utilized routine lab tests, imaging (urography, scintigraphy, ultrasound), and renal tissue analysis (histology, immunohistochemistry, electron microscopy).
• Morphological verification of renal lesions in 98 patients, including 60 lifetime biopsies.

Main Results:

• Renal lesions were morphologically verified in 37% of RA patients.
• Common diagnoses included chronic pyelonephritis (117 cases), nephrolithiasis (42), and arterial hypertension (96).
• Glomerulonephritis (GN) variants occurred in 35 patients, with 28 combined with amyloidosis. Amyloidosis was also found in 16 patients diagnosed with pyelonephritis.

Conclusions:

• Morphological findings confirm a high incidence of renal pathology in RA patients.
• Renal disease severity can exceed clinical presentation; uncontrolled RA nephritis may progress to amyloidosis.
• Proposed "nephropathy" for unclassifiable RA-related renal disease and emphasized reflecting renal involvement in RA classification.