THREE TYPES OF PULMONARY INVOLVEMENT IN POLYMYOSITIS

Interstitial lung disease in the connective tissue diseases

The connective tissue diseases (CTDs) are inflammatory, immune-mediated disorders in which interstitial lung disease (ILD) is common and clinically important. Interstitial lung disease may be the first manifestation of a CTD in a previously healthy patient. CTD-associated ILD frequently presents with the gradual onset of cough and dyspnea, although rarely may present with fulminant respiratory failure. Infection and drug reaction should always be ruled out. A diagnosis of idiopathic ILD should never be made without a careful search for subtle evidence of underlying CTD. Treatment of CTD-ILD typically includes corticosteroids and immunosuppressive agents.

Dysphonia and dermatomyositis: an unusual manifestation

We report a case of a 39-year-old female with a recent diagnosis of dermatomyositis and dysphonia. Dermatomyositis is a connective tissue disease with multisystem involvement: cardiac, pulmonary, musculoskeletal, gastrointestinal, and dermatologic are the most common. While dermatomyositis affects thousands of individuals in the United States, laryngeal involvement has only been described in a single case report to date.

Polymyositis, dermatomyositis, and autoimmune necrotizing myopathy: clinical features

Idiopathic inflammatory myopathies are a heterogeneous group of autoimmune disorders predominantly affecting skeletal muscles, resulting in muscle inflammation and weakness. The 3 most common inflammatory myopathies are polymyositis (PM), dermatomyositis (DM), and inclusion body myositis. This review details the clinical findings noted in PM, DM, and the emerging entity of autoimmune necrotizing myopathy.

Pulmonary manifestations of the idiopathic inflammatory myopathies

Pulmonary involvement in myositis includes interstitial lung disease (ILD), respiratory muscle weakness, aspiration, infections, and drug-induced disease. ILD may precede myositis, and results in increased morbidity and mortality rates. Initial evaluation should include pulmonary function tests and high-resolution computed tomography. Nonspecific interstitial pneumonia (NSIP) is the most common histologic pattern on lung biopsy. Treatment usually consists of a combination of steroids and other immunosuppressive agents, and the response depends on the clinical presentation and underlying histology.

Interstitial lung disease in polymyositis and dermatomyositis

The aim of the study was to estimate the prevalence, characteristics, and prognostic factors of interstitial lung disease (ILD) in patients with polymyositis (PM) and dermatomyositis (DM). The medical records of 151 PM/DM patients treated at Chang Gung Memorial Hospital between January, 2000 and June, 2007 were retrospectively reviewed. Thirty of 151 (19.9%) PM/DM patients had developed ILD. Older age at PM/DM onset, anti-Jo-1 antibody, and arthritis/arthralgia were associated with the presence of ILD (p = 0.004, p = 0.008, and p = 0.026, respectively). Anti-Jo-1 was initially excluded from the multivariate analysis because only 80 patients underwent the test. An older age at onset above 45 years (odds ratio 3.28, 95% confidence interval (CI) 1.15-9.34, p = 0.026) and arthritis/arthralgia at onset (odds ratio (OR) 2.57, 95% CI 1.09-6.08, p = 0.032) were the two independent risk factors for developing ILD. If anti-Jo-1 was included in the multivariate analysis (n = 80), then an older age at onset above 45 years (OR 7.30, 95% CI 1.70-31.40, p = 0.008) and anti-Jo-1 positive (OR 7.89, 95% CI 1.18-52.87, p = 0.033) were associated with ILD, while arthritis/arthralgia was no longer significant (OR 2.64, 95% CI 0.70-10.01, p = 0.153). Of the 30 ILD patients, 16 (53.3%) died. The survival time was significantly shorter in ILD patients than in patients without ILD (p < 0.001). Poor survival in ILD patients was associated with male gender (p = 0.039), a Hamman-Rich-like presentation (p = 0.039), and a clinical diagnosis of acute interstitial pneumonia (p = 0.007).

[Interstitial lung diseases in polymyositis and dermatomyositis]

PURPOSE

Interstitial lung disease is one of the most common respiratory manifestations in polymyositis and dermatomyositis. It still remains a severe complication of the disease, leading to death related to ventilatory insufficiency in 30-66% of patients.

CURRENT KNOWLEDGE AND KEY POINTS

Time onset of interstitial lung disease is variable, although interstitial lung disease onset precedes initial manifestations of polymyositis/dermatomyositis in roughly half of the patients. Moreover, clinical presentation of interstitial lung disease can be dichotomized, according to patients' pulmonary manifestations, into: 1) both acute and aggressive lung disease similar to Hamman-Rich syndrome; 2) slowly progressive lung disease; and 3) an asymptomatic pattern. The methods of choice adopted for early diagnosis of interstitial lung disease are high-resolution computed tomography scan and pulmonary function tests, which should be performed during both initial evaluation of polymyositis/dermatomyositis and follow-up. Because anti-JO1 antibody is considered to be a marker of interstitial lung disease in polymyositis/dermatomyositis, close pulmonary follow-up of anti-JO1-positive patients with polymyositis is therefore required for early detection of subclinical impairment. Furthermore, histological lung findings provide prognostic data; patients with bronchiolitis obliterans organizing pneumonia (BOOP) indeed appear to have a more favorable outcome than those with usual interstitial pneumonia or diffuse alveolar damage. Finally, as a guide to both the severity and progress of interstitial lung disease, the significance of other investigations, notably bronchoalveolar lavage, remains controversial.

FUTURE PROSPECTS AND PROJECTS

Specific therapy of interstitial lung disease has not yet been clearly established in polymyositis/dermatomyositis patients. Corticosteroid therapy is considered the first line of therapy for polymyositis/dermatomyositis patients with interstitial lung disease. The association of cyclophosphamide and corticosteroids may be the most effective in patients with steroid-resistant interstitial lung disease. Early diagnosis and management of this disease is therefore of the utmost importance.

Pulmonary involvement in juvenile dermatomyositis: a two-year longitudinal study

OBJECTIVE

To investigate the prevalence and features of asymptomatic pulmonary involvement in juvenile dermatomyositis (JDM).

METHODS

Twelve JDM patients underwent pulmonary function tests at baseline, 12 and 24 months. Disease activity, duration, serum lactate dehydrogenase (LDH) values and antinuclear antibody (ANA) titres were also evaluated.

RESULTS

Five patients showed lung impairment at baseline and four at 12 and 24 months. Forced expiratory volume in 1s, forced vital capacity (FVC), carbon monoxide diffusing capacity (DLCO) and alveolar volume were the most frequently altered variables, indicating a restrictive pattern and impairment of diffusion. The prevalence and features of pulmonary alterations did not change during follow-up. FVC values were significantly lower in active JDM patients and were inversely related to LDH. DLCO values were significantly lower in ANA-positive patients. About half of the patients of this small case series of JDM had asymptomatic lung disease.

CONCLUSIONS

We suggest that lung function should be evaluated at disease onset and regularly during follow-up, as pulmonary function tests can detect otherwise unpredictable pulmonary involvement.

Interstitial lung disease in polymyositis and dermatomyositis

Interstitial lung disease (ILD) is common in patients with polymyositis (PM) and dermatomyositis (DM), and is a major cause of morbidity. Although its cause is unknown, it is known to be closely associated with autoimmune disorders. Its manifestation has been found to be quite heterogeneous, as demonstrated by the differences among PM/DM patients in their immunologic profiles and histopathologic findings, which suggest variations in immunopathogenetic mechanisms. We review the clinicopathologic and immunologic findings in ILD associated with PM/DM, and discuss recent advances in classification, autoantibodies, and treatment. The most critical issues are to clarify the immunopathogenesis of severe forms of ILD, such as rapidly progressive ILD associated with amyopathic DM, and to establish the most appropriate therapy.

The lung in polymyositis

Polymyositis is associated with a variety of pulmonary manifestations that may complicate an established case, occur simultaneously with the muscle manifestations, or precede the muscle disease. Included are respiratory muscle involvement, aspiration syndromes, and a variety of interstitial lung reactions.

Pulmonary disease in polymyositis/dermatomyositis: a clinicopathological analysis of 65 autopsy cases

The clinical and autopsy records of 65 patients with either polymyositis (24) or dermatomyositis (41) and pulmonary disease were reviewed. Pulmonary symptoms were recorded in 43 of the cases and included dyspnoea in 31, cough in 23, and chest pain in six. Interstitial lung disease was noted at autopsy in 27 patients; almost half of these had arthritis. Bronchopneumonia was found in 35 patients, 31 of these had received prednisone. Dysphagia was present in a similar proportion of patients with and without pneumonia. Pulmonary vasculitis was seen in five patients; pulmonary symptoms, arthritis, and raised erythrocyte sedimentation rate were present in four of these cases and all five had associated interstitial lung disease. Other pulmonary manifestations included pulmonary oedema, primary pulmonary malignancy, diffuse alveolar damage, fibrinous pleuritis, pulmonary emboli, and diaphragmatic atrophy. The mean survival after disease onset was 29 months but was much less for those with interstitial lung disease and pulmonary vasculitis.

Anaesthetic management of a child with dermatomyositis

A two years, ten months old male with dermatomyositis was anaesthetized with enflurane, nitrous oxide and oxygen by mask followed by intravenous succinylcholine to facilitate endotracheal intubation. The evoked thumb twitch in response to succinylcholine demonstrated an abnormal, short-lived contracture. The depression, duration and return to control of muscle twitch tension and a transient rise in serum potassium concentration followed a normal pattern.

Lupus lung

The morphologic findings from 18 autopsy lungs of systemic lupus erythematosus were studied. Each case revealed varying degrees of pleuropulmonary disease. A universal feature was visceral pleural thickening, while findings present in more than one half of the cases included pulmonary congestion (17/18) and edema (15/18), pleural adhesions (11/18) and pleural effusions (10/18) and intraalveolar hemorrhage (10/18). Also seen were bronchopneumonia (9/18), interstitial fibrosis (6/18), cytomegalovirus infection (3/18), interstitial pneumonitis (2/18), hyaline membranes (2/18), and acute vasculitis (1/18) and pleuritis (1/18). These results, together with those of previously reported studies of lupus lung, establish that although certain characteristic pleuropulmonary disease processes are frequently found at autopsy, none is a highly specific marker for the disease.

Pulmonary manifestations of the rheumatic diseases

The collagen vascular diseases represent a heterogeneous group of multisystem disorders with a wide range of clinicopathologic features. Although these diseases represent distinct clinical entities, a great deal of overlap exists between them. For example, the diffuse interstitial fibrosis of SLE, RA, DM-PM, PSS, and MCTD are indistinguishable clinically, radiographically, and histologically. Conversely, the pulmonary manifestations of the various vasculitides all differ significantly from each other in their clinicopathologic presentation, as well as in their response to therapy. For diagnostic purposes, histologic evidence will usually be required for the pulmonary manifestations of the rheumatic diseases. Therapy must then be individualized for each of these entities, as the protocol and response are variable.

Respiratory muscle and pulmonary function in polymyositis and other proximal myopathies

We studied 53 patients with proximal myopathy to determine at what level of muscle weakness hypercapnic respiratory failure is likely, and which tests of pulmonary function or respiratory muscle strength would best suggest this development. Respiratory muscle strength was determined from maximal static efforts and in half the patients, both inspiratory and expiratory muscle strengths were less than 50% of normal. In the 37 patients without lung disease respiratory muscle weakness was accompanied by significant decreases in vital capacity, total lung capacity, and maximum voluntary ventilation; by significant increases in residual volume and arterial carbon dioxide tension (PaCO2); and greater likelihood of dependence on ventilators, atelectasis, and pneumonia. Hypercapnia was particularly likely when respiratory muscle strength was less than 30% of normal in uncomplicated myopathy, and when vital capacity was less than 55% of the predicted value in any patient.

Pulmonary hypertension in polymyositis

Pulmonary hypertension is an uncommon but lethal complication of polymyositis. A 69-year-old woman is described who had a 20-month history of polymyositis and cardiac failure and in whom severe pulmonary hypertension was noted terminally when she was first seen at our clinic. She died within 24 hours of admission, and autopsy revealed severe plexogenic pulmonary vascular disease.

Ultrastructure of the lung in Loeffler's pneumonia

A case is presented fulfilling the diagnostic criteria of "Loeffler's eosinophilic pneumonia". No etiologic factors could be determined, and the chest roentgenogram returned to normal. Lung biopsy at the peak of the disease demonstrated an interstitial eosinophilic pneumonia without tissue necrosia or vasculitis. By electron microscopy, the alveolar capillary basement membranes were intact and exhibited no immune deposits. Normal appearing eosinophils were abundant in the alveolar capillaries, interstitium and alveolar spaces. Occasional eosinophils released their granules within the alveolar wall. Macrophages were increased in number in both the alveolar wall and alveolar spaces.