Objective: To investigate the clinical characteristics of primary small vessel vasculitis with involvement of lungs.
Methods: 13 cases of primary small vessel vasculitis with involvement of lungs from 1993 to 1998 were analyzed retrospectively.
Results: Among 13 cases 7 were microscopic polyangiitis (MPA) and 6 were Wegener granulomatosis (WG). The ages of onset were from 17 to 68 years old with average age 48.8 years old. 69%(9/13) were ANCA positive, among them 100%(7/7) MPA were ANCA positive (6/7 were P-ANCA positive, 1/7 was C-ANCA positive), while 33%(2/6) WG were ANCA positive (one case of P-ANCA and another case of C-ANCA was positive respectively). The major symptoms of respiratory system included hemoptasis 69% (9/13), dyspnea 23%(3/13), dry cough 15%(2/13) and chest pain 15%(2/13). The chest x-rays showed multiple patchy shadows in both lungs were mainly found in MPA (3/7) and single or multiple masses or nodular shadows were mainly found in WG (5/6) with or without cavity formation. The appearance of lungs in MPA 71% (5/7) had been explained as "pulmonary infection" and that of WG had been explained as "primary lung cancer or metastatic carcinoma". Symptoms of respiratory system might occur before (3/5) or after (2/5) occurrence of acute renal failure. The treatments with corticosteroid and CTX were effective in these cases, in particularly, pulmonary lesions improved obviously.
Conclusions: It is very difficult to make diagnosis of primary small vessel vasculitis with involvement of lungs and this should be paid more attention. ANCA detection is very useful in diagnosis of MPA. Corticosteroid and CTX are most effective in treating these diseases.