Table 2 1990 criteria for the classification of polyarteritis nodosa (American College of Rheumatology) [26]

1

Weight loss ≥ 4 kg

Loss of 4 kg or more of body weight since illness began, not due to dieting or other factors

2

Livedo reticularis

Mottler reticular pattern over the skin of portions of the extremities or torso

3

Testicular pain or tenderness

Pain or tenderness of the testicles, not due to infection, trauma, or other causes

4

Myalgias, weakness or leg tenderness

Diffuse myalgias (excluding shoulder and hip girdle) or weakness of muscles or tenderness of leg muscles

5

Mononeuropathy or polyneuropathy

Development of mononeuropathy, multiple mononeuropathies, or polyneuropathy

6

Diastolic BP > 90 mmHg

Development of hypertension with the diastolic BP higher than 90 mmHg

7

Elevated BUN or creatinine

Elevation of BUN > 40 mg/dL or creatinine > 1.5 mg/dL, not due to dehydration or obstruction

8

Hepatitis B Virus

Presence of hepatitis B surface antigen or antibody in serum

9

Arteriographic abnormality

Arteriogram showing aneurysms or occlusions of the visceral arteries, not due to arteriosclerosis, fibromuscular dysplasia, or other non-inflammatory causes

10

Biopsy of small or medium-sized artery containing PMN

Histologic changes showing the presence of granulocytes or granulocytes and mononuclear leukocytes in the artery wall