Letter to the Editor NEPHRON Nephron 1996;72:365-366 Occurrence Rate of Polyarteritis nodosa in Chronic Renal Diseases Osman Erk Tulay Turfanda Veli Uysal Departments of Nephrology and Pathology, Istanbul University, Istanbul Medical School, Capa, Istanbul. Turkey Dear Sir. Polyarteritis nodosa is a systemic necro tizing vasculitis characterized histologically by inflammation and fibrinoid necrosis of medium-sized or small arteries. It has 2 his tological forms; classical or macroscopic and microscopic. However, overlapping between these groups occurs. The classical type refers to systemic vas culitis, predominantly affecting muscular ar teries at branch points with varying ages and various sizes of focal aneurysms. Hyperten sion and ischemia of glomerular lesions are commonly found in this form of polyarteri tis. Microscopic polyarteritis is character ized by a necrotizing inflammation of the smaller arteries, and venules. In this type, vascular lesions occur usually at similar ages and aneurysm formation is uncommon. Hy pertension is rarely seen and glomeruli are typically involved by segmental necrotizing and crescentic glomerulonephritis [ 1 ]. The overlapping form refers to cases in which combined features of both macro scopic and microscopic forms of polyarteri tis are present. In this form both small and larger blood vessels might be involved; these may be caused by vasculitis oflarger arteries associated with glomerulonephritis. Polyarteritis has varied clinical manifes tations, depending on the location of the involved arteries. The kidneys, heart and gastrointestinal tract are commonly in volved in macroscopic forms: lungs and skin arc often spared. Whereas in the microscopic forms, lungs and dermis are the most fre quent sites of involvement. In the overlap ping form, both large and small arteriolar lesions arc seen [2], In polyarteritis, patients might present with only renal findings which might be con fused with other primary glomerular dis eases. Therefore patients with primary renal disease should always be examined for other systemic diseases. Owing to the problems in classification and overlapping with other disease entities, the incidence of renal involvement in polyar teritis has been reported to vary greatly. It has been given as 80% by Droz et al. [3], 70% by Fujimoto and Yamamoto [4], and 26% by Guillevin et al. [5], However, studies on the occurence rate of polyarteritis among chronic renal diseases are very few. It is reported to be 2.4% by Cohen et al. [6]. We therefore planned a study to find the inci dence of polyarteritis among patients pre senting with glomerular diseases. 834 renal biopsies obtained from pa tients with chronic renal disease have been reviewed. 27 patients were found to have histopathological lesions of polyarteritis no dosa giving an incidence of 3.2%. Of these 27 patients, 11 (40.7%) were females and 16 (59.2%) were males with a mean age of 34 ± 2 years (range 13-58). The duration of the disease was about 11 ± 2 months (range 1 month to 7 years). The clinical and laborato ry findings are presented in tables 1 and 2. Hypertension was present in 66.6% of cases. Renal function was found to be less than 25% of normal in 33.3% (9 cases). Of 27 cases of polyarteritis, 18 (66.6%) showed nephritic syndrome and 33.3% (9 Table 1. Clinical findings in polyarteritis nodosa Cases % Nephritic syndrome 18 66.6 Nephrotic syndrome 9 33.3 Lung lesion 3 11.1 Hepatomegaly 7 25.9 Splenomegaly 1 3.7 Fever 15 55.5 Arthralgia 4 14.8 Vasculitis 26 96.3 Purpura 18 66.6 Raynoud phenomon 3 15.0 Polyneuropathy 6 22.2 Joint and muscle pain 11 40.7 Lumbar pain 15 55.5 Abdominal pain 9 33.3 Stomach lesions (ulcus) 2 7.4 Myocardial infarction 2 7.4 Pericarditis 7 25.9 Arrhythmia 5 18.5 Hypertension 18 66.6 Hemiplegia 2 7.4 Visual disturbances 12 44.4 cases) nephrotic syndrome. Histological study of the kidney revealed mesangioproli- ferativc glomerulonephritis in 13 cases (48%), focal segmental proliferative glomer ulonephritis in 6 cases (22.2%), membrano- prolifcrative nephritis in 5 cases (18.5%), membranos nephropathy in 3 cases (11%). KARGER E-Mail kargcr(akargcr.ch Fax + 41 61 306 12 34 © 1996 S. Karger AG. Basel 0028-2766/96/0722-0365S8.00/0 Osman Erk Istanbul Oniversitesi Istanbul Tip Fakiiltcsi Acil Dahiliyc Klinigi TR-Çapa. istanbul (Turkey)