Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Interstitial lung disease associated with Polymyositis
- Radiologic Findings
- Fig 1. Chest PA shows subsegmental consolidation in right middle lung zone.
Fig 2-1 to 2-4. High-resolution CT images shows irregular linear increased attenuations, small consolidations, interlobular septal thickening and intralobular intertitial increased attenuations seen in subpleural regions of both basal lungs. These findings are suggesting NSIP or UIP. Subsegmental consolidation in right middle lobe is thought to be seuqle of previous aspiration or pneumonia.
- Brief Review
- Polymyositis is an autoimmune inflammatory myopathy characterized by symmetric weakness of the limb girdle and anterior neck muscles. Dermatomyositis is similar to polymyositis except for the presence of a characteristic skin rash. Polymyositis and dermatomyositis have an incidence of approximately 5-10 cases per million per year and occur twice as often in women as in men, with a bimodal peak age of occurrence during childhood and middle adulthood [1,2,3]. The thorax is commonly affected, generally in one or more of three forms: (a) hypoventilation and respiratory failure as a result of involvement of the respiratory muscles; (b) interstitial pneumonitis, usually with a histologic pattern of usual interstitial pneumonia or nonspecific interstitial pneumonia ; and (c) aspiration pneumonia secondary to pharyngeal muscle weakness (probably the most common pulmonary complication) [1, 4].
Interstitial lung disease associated with polymyositis or dermatomyositis has a wide spectrum of histopathologic features. Three major groups can be identified on the basis of histologic patterns: BOOP, usual or nonspecific interstitial pneumonia, and diffuse alveolar damage. Histologic appearance is useful for determining the prognosis.
Patients with diffuse alveolar damage r usual interstitial pneumonia have a poor prognosis, with only a 33% survival rate at 5 years; however, patients with nonspecific interstitial pneumonia have a good prognosis. Patients with BOOP have an excellent prognosis.
The frequency of radiographic parenchymal abnormalities is low (about 5%). The most common is a symmetric, predominantly basal reticular pattern that may become diffuse over time and progress to honeycombing [1,3]. Bilateral areas of consolidation develop in some patients over a 2- to 3-week period. This abnormality usually corresponds histologically to diffuse alveolar damage or BOOP. Initial high-resolution CT findings of pulmonary involvement in patients with polymyositis or dermatomyositis are prominent interlobular septa, ground-glass attenuation, patchy consolidation, parenchymal bands, irregular eribronchovascular thickening, and subpleural lines. Honeycombing may be seen in up to 16% of patients who have abnormal chest radiographic findings or pulmonary function.[1,5]
- References
- 1. Eun A Kim, Kyung Soo Lee, Takeshi Johkoh, Tae Sung Kim, Gee Young Suh, O Jung Kwon, Jounho Han. Interstitial lung diseases associated with collagen vascular diseases: Radiologic and histoloic findings. Radiographics 2002; 22:151-165.
2. Jennifer P. Mayberry, Steven L. Primack, Nestor L.Muller. Radiographics 2000; 20:1623-1635.
3. Schwarz MI. The lung in polymyositis. Clin Chest Med 1998;19:701?02.
4. Tazelaar HD, Viggiano RW, Pickersgill J, et al. Interstitial lung disease in polymyositis and dermatomyositis: clinical features and prognosis as correlated with histologic findings. Am Rev Respir Dis 1990;141:727?33.
5. Ikezoe J, Johkoh T, Kohno N, Takeuchi N, Ichikado K, Nakamura H. High-resolution CT findings of lung disease in patients with polymyositis and dermatomyositis. J Thorac Imaging 1996; 11:250?59.
- Keywords
- Lung, Lung, Interstitial lung disease, Polymyositis, Connective tissue diseases, ILD,