English papers were searched from PubMed, Blackwell, Elsevier, Springer and OVID in 1986-2009 using various combinations of “IFN”, “HCV”, “IP” and “pulmonary toxicity”. References in the papers were reviewed as additional sources.
Twenty-four cases (with detailed data available from 20) reported in 17 articles were included in this review. Their main characteristics are shown in Table . Of these cases, 11 (46%) were males and 13 (54%) were females. Their mean age was 54.2 years (range 39-72 years). IP occurred in a comparable proportion of females and males, and was more frequent in older patients. The mean IFN treatment time before the diagnosis of IP was 11.8 wk (range 2-48 wk) and less than 12 wk in 73% of them. Of the 24 cases, 3 were given Sho-saiko-to (a Chinese herbal drug that increases the risk of IP), 12 were treated with ribavirin and IFN, and 9 were given IFN without any other medications. The most common symptoms were dyspnoea (80%, 16/20), dry cough (75%, 15/20) and fever (55%, 11/20), followed by fatigue (25%, 5/20), arthralgia or myalgia (20%, 4/20), and anorexia (15%, 3/20). Physical examination revealed unilateral or bilateral lung field fine crackles in 10 out of 11 patients.
Case reports of interstitial pneumonitis associated with interferon therapy for hepatitis C virus
Detailed PFT information was available from 14 cases with a restrictive pulmonary functional impairment pattern. Of the 14 cases, 8 were accompanied with an obstructive pathological change. Arterial blood gas (ABG) analysis showed different extents of hypoxemia in 88% (15/17) of the patients. Chest radiography showed no evidence of lung disease and HRCT showed diffuse infiltration in 4 cases after pulmonary symptoms occurred[10-12,16
]. Chest CT scanning showed symmetrical, bilateral interstitial abnormality with areas of ground glass opacity predominantly involving middle lung fields and lung bases (Figure ), and visible resolution of inflammatory infiltration following symptom improvement with less dyspnoea and cough (Figure ), in 14 out of 21 cases.
Figure 1 Chest computed tomography scanning showing symmetrical, bilateral interstitial abnormality with areas of ground glass opacity predominantly involving middle lung fields and lung bases (A), and visible resolution of inflammatory infiltration following (more ...)
Bronchoscopy with bronchoalveolar lavage (BAL) was performed for 19 cases. BAL fluid (BALF) analysis demonstrated that the number of lymphocytes, macrophages and other inflammatory cells was increased with an elevated proportion of CD8+/CD4+ cells[27
]. Culture and staining of bronchial lavage were negative for bacteria, fungi, acid fast bacilli (AFB) and viruses in these cases. Of the 24 cases included in the review, 17 were diagnosed as IP, which was confirmed by lung biopsies including transbronchial, thoracoscopic lung and open lung biopsies. A biopsy was considered positive for IP when histology demonstrated interstitial infiltration, principally of lymphocytes with macrophages, interstitial fibrosis with thickening of alveolar walls and without evidence of granulomatous lesions in parenchyma[28
], although bronchial biopsy showed normal epithelium in 3 cases[12,13,16