[Clinical characteristics of 57 patients with polyarteritis nodosa and renal involvement]

Objective: To investigate the clinical characteristics of polyarteritis nodosa (PAN) patients with renal involvement. Methods: PAN patients admitted to the department of rheumatology, department of pediatrics, department of nephrology, general internal medicine department and department of vascular surgery at Peking Union Medical College Hospital from June 2012 to August 2018 were enrolled in this study and were divided into two groups according to renal involvement or not. The clinical characteristics were analyzed. Results: A total of 94 PAN patients were finally enrolled and 57 (60.64%) presented kidney manifestation. The mean age of onset was (37.76±17.40) years old and the interval from onset to diagnosis was 10 (0 to 240) months. Forty patients were misdiagnosed once or more times. In patients with renal involvement, 9 cases suffered from renal ischemia or infarction, 31 with microscopic haematuria, 26 with proteinuria, renal artery or its branch involved in 17 cases, renal vein thrombosis in 1 case, 4 cases with pyeloureterectasis, one case with renal fascia thickening, 33 cases with impaired renal function (serum creatinine>84 μmol/L) including creatinine>140 μmol/L in 10 patients. Renal artery branch stenosis was the most common presentation [9 cases (52.94%)] of renal vascular involvement, other abnormalities including nodular dilatation [4 cases (23.53%)], occlusion [3 cases (17.65%)]. There were significant differences (P<0.05) in the PAN patients with and without renal involvement in the following: age of onset [(33.72±16.13) years vs. (43.97±17.66) years, t(2)=2.901, P=0.005], weight loss(≥4kg since PAN onset) [25(43.86%) vs. 7(18.92%), χ(2)=6.216, P=0.013], elevation of diastolic blood pressure [22(38.60%) vs. 7(18.92%), χ(2)=4.072, P=0.044], acromegaly gangrene [18(31.58%) vs. 21(56.76%), χ(2)=5.859, P=0.015], and gastrointestinal artery involvement [20(35.09%) vs. 6(1.22%), χ(2)=3.993, P=0.046]. Laboratory parameters and the application of glucocorticoid and cyclophosphamide therapies were similar in two groups (all P>0.05). Conclusion: Young PAN patients are more likely to be associated with renal involvement, especially gastrointestinal arteries.