Background Renal insufficiency and/or uremia are one of the most important causes of death in rheumatoid arthritis (RA) due to AA amyloidosis (AAa), glomerulonephritis, pyelonephritis, interstitial nephritis or other reasons.
Objectives The aim of this study was to determine the prevalence, and the clinically missed diagnosis of underlying diseases and/or complications leading to renal insufficiency or uremia (U) in RA.
Methods A randomized autopsy population of 161 in-patients with RA was studied. AAa complicated RA in 34 (21.1%) of 161 cases. The cases with clinically missed diagnosis of underlying diseases leading to renal insufficiency or U were analysed retrospectively by reviewing the clinical and pathological reports, tissue samples and the histological slides.
Results Twenty-three (14.28% of 161) RA patients died of renal insufficiency or uremia. Uremia was caused by AA amyloidosis (AAa) in 17 (10.56% of 161, 73.91% of 23), by glomerulonephritis, interstitial nephritis or pyelonephritis in one patient each. Thrombovasculitis of the renal artery, renal cell carcinoma, and acute liver necrosis led to hepatorenal insufficiency in further one patient each (1.86% of 161). Renal insufficiency and/or uremia were always recognized, but not its causes, the complications of RA leading to death.
Systemic AAa was clinically diagnosed in nine patients, but in 8 (of 17) it was missed. Systemic vasculitis was recognized clinically, but the inmediate cause of acute renal insufficiency (thrombovasculitis of the renal artery) was not. Glomerulonephritis, pyelonephritis or interstitial nephritis was correctly diagnosed clinically in all three patients. Acute hepatorenal insufficiency was recognized clinically, but massive hepatic necrosis was not. Renal cell carcinoma with multiple metastases and renal insufficiency was known clinically. The underlying associated disease or background complications of RA were diagnosed clinically altogether in 13 (56.52%) of 23 patients.
Conclusions AA amyloidosis should be regarded as one of the most insidious complications of rheumatoid arthritis, which may furtively lead to death. In our autopsy population AAa was responsible for renal insufficiency or uremia in more than two thirds of the cases. According to our previous study massive renal amyloidosis was accompanied by significantly higher levels of serum creatinine (p<0.005), proteinuria (p<0.001), and erythrocyte sedimentation rate (p<0.05) in comparison with mild renal amyloidosis (1). Glomerulonephritis is a less important complication of RA in contrast to SLE. In one diabetic patient chronic pyelonephritis led to renal insufficiency, and in a further patient interstitial nephritis was the source of uremia. Acute liver necrosis was the direct cause of death in one patient, clinically presenting as hepatorenal insufficiency but not recognized as the underlying disease. Liver necrosis may have been related to the aggressive treatment of RA and was interpreted as iatrogenic. Nephrosclerosis of atherosclerotic origin or diabetic glomerulosclerosis may contribute to development of renal insufficiency but was not the cause of uremia in our autopsy population.
Bély M, Apáthy Ά: Amyloid A deposition in rheumatoid arthritis: a retrospective clinicopathologic study of 161 autopsy patients. Amyloid 2012;19:212-213
Disclosure of Interest None declared