The Shrinking Lungs Syndrome in Systemic Lupus Erythematosus

Abstract

A comprehensive review of the literature on shrinking lungs syndrome (SLS) in systemic lupus erythematosus involved a MEDLINE search (1965–1997) of case reports and clinical series of patients with the diagnosis of SLS. A total of 49 well-documented cases of SLS were reviewed. Shrinking lungs syndrome is characterized by unexplained dyspnea, a restrictive pattern on pulmonary function test results, and an elevated hemidiaphragm. The cause of SLS remains controversial, with several authors attributing the disorder to diaphragmatic weakness and others suggesting that chest wall restriction accounts for the clinical syndrome. No definitive therapy exists. Corticosteroids have been reported to lessen symptoms and improve pulmonary function in some patients with SLS, but other methods of treatment have occasionally been found to be helpful. Clinical presentation, method of diagnosis, pathogenesis, and treatment modalities are summarized in this review. An uncommon complication of systemic lupus erythematosus, SLS causes significant morbidity and, occasionally, mortality. A comprehensive review of the literature on shrinking lungs syndrome (SLS) in systemic lupus erythematosus involved a MEDLINE search (1965–1997) of case reports and clinical series of patients with the diagnosis of SLS. A total of 49 well-documented cases of SLS were reviewed. Shrinking lungs syndrome is characterized by unexplained dyspnea, a restrictive pattern on pulmonary function test results, and an elevated hemidiaphragm. The cause of SLS remains controversial, with several authors attributing the disorder to diaphragmatic weakness and others suggesting that chest wall restriction accounts for the clinical syndrome. No definitive therapy exists. Corticosteroids have been reported to lessen symptoms and improve pulmonary function in some patients with SLS, but other methods of treatment have occasionally been found to be helpful. Clinical presentation, method of diagnosis, pathogenesis, and treatment modalities are summarized in this review. An uncommon complication of systemic lupus erythematosus, SLS causes significant morbidity and, occasionally, mortality. The reported incidence of pulmonary disease in systemic lupus erythematosus (SLE) has been variable, with some authors suggesting that pleural or pulmonary involvement may occur in as many as 60% of patients with SLE.1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar Subclinical involvement occurs even more frequently, with autopsy series reporting a prevalence of up to 93%.2Ropes MW Systemic Lupus Erythemalosus. Harvard University Press, Cambridge, Mass1976Google Scholar The most common pleuropulmonary manifestation of SLE is pleuritis, with or without pleural effusion. Other pulmonary manifestations include acute lupus pneumonitis, chronic interstitial lung disease with fibrosis, alveolar hemorrhage, bronchiolitis obliterans, pulmonary vascular disease with pulmonary hypertension, and pulmonary embolism.1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar A less common entity is the shrinking lungs syndrome (SLS), characterized by unexplained dyspnea, small lung volume with restrictive physiology, and an elevated diaphragm.3Hoffbrand BI Beck ER “Unexplained” dyspnoea and shrinking lungs in systemic lupus erythematosus.BMJ. 1965; 1: 1273-1277Crossref PubMed Scopus (107) Google Scholar The exact prevalence of this condition remains to be determined. An early report of 30 consecutive patients with SLE, not selected by respiratory symptoms, suggested that 23% of the patients had SLS.4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar However, the small amount of published data on this condition and the fact that it is seldom seen in clinical practice seem disproportionate to this reported prevalence. A comprehensive review of the literature on SLS in SLE involved a MEDLINE search (1965–1997) of case reports and clinical series of patients with the diagnosis of SLS. A total of 49 well-documented cases of SLS were reviewed. The time to onset of SLS ranges from 4 months to 24 years after the diagnosis of SLE.5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar Only 2 cases were reported in which SLS was the initial presenting feature of SLE.6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar Patients with SLS presented with dyspnea on exertion, which progressed over several weeks to months, resulting in markedly decreased exercise tolerance and eventually dyspnea at rest. Pleuritic chest pain was a commonly recognized symptom. On clinical examination, patients were tachypneic, with rapid, shallow breathing and marked limitation of chest wall expansion.1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar, 4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar, 6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 7Thompson PJ Dhillon DP Ledingham J Turner-Warwick M Shrinking lungs, diaphragmatic dysfunction, and systemic lupus erythematosus.Am Rev Respir Dis. 1985; 132: 926-928Google Scholar, 8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar, 9Pines A Kaplinsky N Olchovsky D Rozenman J Frankl O Pleuro-pulmonary manifestations of systemic lupus erythematosus: clinical features of its subgroups: prognostic and therapeutic implications.Chest. 1985; 88: 129-135Crossref PubMed Scopus (84) Google Scholar, 10Walz-Leblanc BA Urowitz MB Gladman DD Hanly PJ The “shrinking lungs syndrome” in systemic lupus erythematosus—improvement with corticosteroid therapy.J Rheumatol. 1992; 19: 1970-1972Google Scholar, 11Soubrier M Dubost JJ Pielte JC et al.Shrinking lung syndrome in systemic lupus erythemalosus: a report of three cases.Rev Rhum Engt Ed. 1995; 62: 395-398Google Scholar, 12Van Veen S Peeters AJ Sterk PJ Breedveld FC The “shrinking lung syndrome” in SLE, treatment with theophylline.Clin Rheumatol. 1993; 12: 462-465Crossref PubMed Scopus (47) Google Scholar, 13Munoz-Rodriguez FJ Font J Badia JR et al.Shrinking lungs syndrome in systemic lupus erythematosus: improvement with inhaled beta-agonist therapy.Lupus. 1997; 6: 412-414Crossref PubMed Scopus (38) Google Scholar, 14Rubin LA Urowitz MB Shrinking lung syndrome in SLE—a clinical pathologic study.J Rheumatol. 1983; 10: 973-976Google Scholar Use of accessory muscles of respiration was noted often, and paradoxical abdominal movement with the patient supine has been reported.7Thompson PJ Dhillon DP Ledingham J Turner-Warwick M Shrinking lungs, diaphragmatic dysfunction, and systemic lupus erythematosus.Am Rev Respir Dis. 1985; 132: 926-928Google Scholar Auscultation of the lungs was generally unrevealing, but a few patients had bibasilar crackles, attributed to basal atelectasis.6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 10Walz-Leblanc BA Urowitz MB Gladman DD Hanly PJ The “shrinking lungs syndrome” in systemic lupus erythematosus—improvement with corticosteroid therapy.J Rheumatol. 1992; 19: 1970-1972Google Scholar Five patients had clinical or biochemical evidence of a myopathy at presentation, and 3 patients had a history of myositis. Two patients developed a generalized myopathy more than a year after their presentation with SLS, giving a total of 10 patients with myopathy.1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar, 4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar, 5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 10Walz-Leblanc BA Urowitz MB Gladman DD Hanly PJ The “shrinking lungs syndrome” in systemic lupus erythematosus—improvement with corticosteroid therapy.J Rheumatol. 1992; 19: 1970-1972Google Scholar, 12Van Veen S Peeters AJ Sterk PJ Breedveld FC The “shrinking lung syndrome” in SLE, treatment with theophylline.Clin Rheumatol. 1993; 12: 462-465Crossref PubMed Scopus (47) Google Scholar, 14Rubin LA Urowitz MB Shrinking lung syndrome in SLE—a clinical pathologic study.J Rheumatol. 1983; 10: 973-976Google Scholar, 15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar These 10 patients represent 27% of patients with SLS reported in the literature if 1 case series in which patients with myositis were specifically excluded is not counted8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar (Table 1).Table 1Clinical Characteristics of Patients With Shrinking Lungs Syndrome*EUipses indicate data are not available.ReferenceNo. of casesMean age (y)No. of femalesNo. of malesNo. (%)with pleurisyNo. (%) with evidence of myositisHoffbrand & Beck,3Hoffbrand BI Beck ER “Unexplained” dyspnoea and shrinking lungs in systemic lupus erythematosus.BMJ. 1965; 1: 1273-1277Crossref PubMed Scopus (107) Google Scholar 1965844714(50)1(13)Gibson et al, 1977729707 (100)2(29)Martens et al,5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar 198374761…2(29)Jacobellielal,5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar1985238201(50)1(50)Wilcoxetal,16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar19882…….Laroche et al,8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar 19891233939(75)…Stevens et at,6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar 199020102…1(50)Soubrieretal, 1995332301 (33)NoneSingle case reports,†Sex of patient not specified in L case report. 1985-19976355…None3(50) Total494039722 (45)10 (20)* EUipses indicate data are not available.† Sex of patient not specified in L case report. Open table in a new tab Twenty-two patients (45%) had a history of pleurisy, often recurrent, and 4 patients (8%) had a history of pericarditis.1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar, 10Walz-Leblanc BA Urowitz MB Gladman DD Hanly PJ The “shrinking lungs syndrome” in systemic lupus erythematosus—improvement with corticosteroid therapy.J Rheumatol. 1992; 19: 1970-1972Google Scholar, 11Soubrier M Dubost JJ Pielte JC et al.Shrinking lung syndrome in systemic lupus erythemalosus: a report of three cases.Rev Rhum Engt Ed. 1995; 62: 395-398Google Scholar, 15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar Positive findings in SLS include chest radiographic abnormalities, characteristically showing elevated hemidiaphragms (Figure 1).14Rubin LA Urowitz MB Shrinking lung syndrome in SLE—a clinical pathologic study.J Rheumatol. 1983; 10: 973-976Google Scholar, 15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar Other chest radiographic findings include pleural thickening in 7 patients (14%)5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar, 16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar and small pleural effusions in 4 patients (8%).5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar, 16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar Screening of the diaphragm, when performed, revealed “sluggish” movement of 1 or both hemidiaphragms.1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar, 7Thompson PJ Dhillon DP Ledingham J Turner-Warwick M Shrinking lungs, diaphragmatic dysfunction, and systemic lupus erythematosus.Am Rev Respir Dis. 1985; 132: 926-928Google Scholar, 11Soubrier M Dubost JJ Pielte JC et al.Shrinking lung syndrome in systemic lupus erythemalosus: a report of three cases.Rev Rhum Engt Ed. 1995; 62: 395-398Google Scholar and 1 patient with severe respiratory compromise was noted to have no movement of the diaphragm at all.14Rubin LA Urowitz MB Shrinking lung syndrome in SLE—a clinical pathologic study.J Rheumatol. 1983; 10: 973-976Google Scholar Laboratory examination revealed normal blood cell count and electrolyte, creatinine, and liver enzyme levels, whereas the erythrocyte sedimentation rate and serum levels of antinuclear antibodies were invariably increased. Creatine kinase levels were within normal limits in patients without a generalized myopathy.6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 9Pines A Kaplinsky N Olchovsky D Rozenman J Frankl O Pleuro-pulmonary manifestations of systemic lupus erythematosus: clinical features of its subgroups: prognostic and therapeutic implications.Chest. 1985; 88: 129-135Crossref PubMed Scopus (84) Google Scholar, 11Soubrier M Dubost JJ Pielte JC et al.Shrinking lung syndrome in systemic lupus erythemalosus: a report of three cases.Rev Rhum Engt Ed. 1995; 62: 395-398Google Scholar Five patients (10%) with myopathy at presentation with SLS had increased muscle enzyme values. In 1 study, no correlation was found between severity of respiratory dysfunction and clinical activity of SLE, mean prednisone dosages, disease duration, antinuclear antibodies, antinuclear DNA antibodies, or C3 levels.4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar Results of pulmonary function testing were abnormal in all patients described in the literature, characteristically showing a restrictive defect with decreased lung volumes (Table 2).Table 2Pulmonary Function Findings in Patients With Shrinking Lungs Syndrome*Dlco = diffusion coefficient; MIP = maximal inspiratory pressure; Pdi = transdiaphragmatic pressure; TLC = total lung capacity; VC = vital capacity. Ellipses indicate data are not available.ReferenceNo. of casesPredicted (%)mean VCPredicted (%) mean TLCPredicted (%)mean DlcoCases (%) with low MIPCases (%)with low PdiHoffbrand & Beck,1Orens JB Martinez FJ Lynch III, JP Pleuropulmonary manifestations of systemic lupus erythemalosus.Rheum Dis Clin North Am. 1994; 20: 159-193Google Scholar 1965861…………Gibson et a],4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar 1977755638883100Martens et al,5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar 19837476689…100Jacobellietal,15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar1985237……100100Wilcox et al,16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar 198826962…100100Laroche et al,8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar1989125559104825Stevens et al,6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar19902507490100…Soubrier et al, 199535063………Single case reports 1985-199762943100100100* Dlco = diffusion coefficient; MIP = maximal inspiratory pressure; Pdi = transdiaphragmatic pressure; TLC = total lung capacity; VC = vital capacity. Ellipses indicate data are not available. Open table in a new tab Vital capacity ranged from 18% to 90% of predicted, with an overall mean value of 52%. Patients with evidence of myositis had lower lung volumes, with a mean vital capacity of 40%. The diffusing capacity for carbon monoxide was decreased, but the diffusion constant (Kco) that corrects for lung volume was normal or only slightly decreased (range, 77%-104%; mean, 95%). Maximal inspiratory and expiratory pressures at the mouth, performed to assess global respiratory muscle function, were decreased in several studies.4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar, 6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 10Walz-Leblanc BA Urowitz MB Gladman DD Hanly PJ The “shrinking lungs syndrome” in systemic lupus erythematosus—improvement with corticosteroid therapy.J Rheumatol. 1992; 19: 1970-1972Google Scholar, 13Munoz-Rodriguez FJ Font J Badia JR et al.Shrinking lungs syndrome in systemic lupus erythematosus: improvement with inhaled beta-agonist therapy.Lupus. 1997; 6: 412-414Crossref PubMed Scopus (38) Google Scholar, 14Rubin LA Urowitz MB Shrinking lung syndrome in SLE—a clinical pathologic study.J Rheumatol. 1983; 10: 973-976Google Scholar, 15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar, 16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar These measurements, however, may underestimate respiratory muscle strength in some patients because of incomplete acti vation of the muscles during the maneuver.17De Troyer A Estenne M Limitations of measurement of transdiaphragmatic pressure in detecting diaphragmatic weakness.Thorax. 1981; 36: 169-174Crossref Scopus (60) Google Scholar For this reason, Laroche et al8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar also assessed maximal respiratory pressures during a sniff maneuver, which has been shown to produce more reliable activation of the inspiratory muscles. Only 1 of their 12 patients had a decreased maximal inspiratory pressure by this technique, whereas other studies reported abnormalities in 94% of patients with SLS. Arterial blood gas measurements with the patient at rest were either normal or showed mild arterial hypoxemia that worsened with exertion.7Thompson PJ Dhillon DP Ledingham J Turner-Warwick M Shrinking lungs, diaphragmatic dysfunction, and systemic lupus erythematosus.Am Rev Respir Dis. 1985; 132: 926-928Google Scholar, 12Van Veen S Peeters AJ Sterk PJ Breedveld FC The “shrinking lung syndrome” in SLE, treatment with theophylline.Clin Rheumatol. 1993; 12: 462-465Crossref PubMed Scopus (47) Google Scholar Further investigations, described subsequently, were performed to exclude other pathologic conditions that could account for the lung restriction and dyspnea. Findings on ventilation-perfusion scans were invariably normal. Bronchoscopy and bronchoalveolar lavage were unrevealing.6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 11Soubrier M Dubost JJ Pielte JC et al.Shrinking lung syndrome in systemic lupus erythemalosus: a report of three cases.Rev Rhum Engt Ed. 1995; 62: 395-398Google Scholar, 13Munoz-Rodriguez FJ Font J Badia JR et al.Shrinking lungs syndrome in systemic lupus erythematosus: improvement with inhaled beta-agonist therapy.Lupus. 1997; 6: 412-414Crossref PubMed Scopus (38) Google Scholar Computed tomography of the chest was remarkable for small pleural effusions in 2 cases.6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar, 11Soubrier M Dubost JJ Pielte JC et al.Shrinking lung syndrome in systemic lupus erythemalosus: a report of three cases.Rev Rhum Engt Ed. 1995; 62: 395-398Google Scholar pleural thickening in 2,8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar and minor lower lobe opacities thought to represent areas of atelectasis in 3.8Laroche CM Mulvey DA Hawkins PN et al.Diaphragm strength in the shrinking lung syndrome of systemic lupus erythematosus.Q JMed. 1989; 71: 429-439Google Scholar However, there was no evidence to suggest interstitial pulmonary disease or severe pleural disease in any of the patients studied. Lung biopsy, open or transbronchial, demonstrated normal lung tissue, and an open pleural biopsy, performed to investigate an area of pleural thickening on chest radiography, showed fatty tissue.6Stevens WM Burdon JG Clemens LE Webb J The “shrinking lungs syndrome”—an infrequently recognised feature of systemic lupus erythematosus.Aust NZ J Med. 1990; 20: 67-70Crossref Scopus (25) Google Scholar In 1 study,15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar no correlation was found between severity of respiratory dysfunction and clinical activity of SLE, mean prednisone dosages, disease duration, antinuclear antibody, antinuclear DNA antibodies, or C3 levels. The etiology of SLS remains unclear. In 1954, 3 different groups of investigators recognized a subgroup of SLE patients with small lung fields and elevated diaphragms, not accounted for by associated pulmonary or pleural involvement.18Harvey AM Shulman LE Tumulty PA Conley CL Schoenrich EH Systemic lupus erythematosus: review of the literature and clinical analysis of 138 cases.Medicine (Baltimore). 1954; 33: 291-437Crossref PubMed Scopus (524) Google Scholar, 19Tumulty PA The clinical course of systemic lupus erythematosus.JAMA. 1954; 156: 947-953Crossref PubMed Scopus (28) Google Scholar, 20Ellman P Cudkowicz L Pulmonary manifestations in the diffuse collagen diseases.Thorax. 1954; 9: 46-57Crossref PubMed Scopus (14) Google Scholar In 1965, Hoffbrand and Beck3Hoffbrand BI Beck ER “Unexplained” dyspnoea and shrinking lungs in systemic lupus erythematosus.BMJ. 1965; 1: 1273-1277Crossref PubMed Scopus (107) Google Scholar noted that these patients with raised “sluggish” diaphragms had a restrictive pattern on pulmonary function testing and a progressive loss of lung volume. They thus coined the term shrinking lungs and postulated that excessive surface tension secondary to surfactant failure resulted in diffuse alveolar atelectasis, which was not radiologically detectable. In a 1977 study of 7 patients who had SLE with SLS, Gibson et al4Gibson CJ Edmonds JP Hughes GR Diaphragm function and lung involvement in systemic lupus erythematosus.Am J Med. 1977; 63: 926-932Abstract Full Text PDF PubMed Scopus (134) Google Scholar found abnormalities in transdiaphragmatic pressures (using esophageal and gastric balloons) consistent with diaphragm dysfunction. They suggested that this was due to either severe diaphragm weakness or immobility of the diaphragm after extensive pleural adhesions and fibrosis. Martens et al5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar demonstrated decreased maximal transdiaphragmatic pressures, which further supported a hypothesis of diaphragm dysfunction. They reported that patients with SLS also had decreased maximal expiratory esophageal and gastric pressures, concluding that inspiratory and expiratory muscles were affected. The muscle weakness was attributed to the underlying SLE and not to malnutrition or to the use of corticosteroids.5Martens J Demedts M Vanmeenen MT Dequeker J Respiratory muscle dysfunction in systemic lupus erythematosus.Chest. 1983; 84: 170-175Abstract Full Text Full Text PDF PubMed Scopus (77) Google Scholar Other smaller studies and case reports have described abnormal transdiaphragmatic pressures, suggesting diaphragmatic weakness in patients with SLS.7Thompson PJ Dhillon DP Ledingham J Turner-Warwick M Shrinking lungs, diaphragmatic dysfunction, and systemic lupus erythematosus.Am Rev Respir Dis. 1985; 132: 926-928Google Scholar, 13Munoz-Rodriguez FJ Font J Badia JR et al.Shrinking lungs syndrome in systemic lupus erythematosus: improvement with inhaled beta-agonist therapy.Lupus. 1997; 6: 412-414Crossref PubMed Scopus (38) Google Scholar, 15Jacobelli S Moreno R Massardo L Rivero S Lisboa C Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus.Arthritis Rheum. 1985; 28: 781-788Crossref Scopus (35) Google Scholar, 16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar Specifically, gastric pressures were persistently negative in 1 report.7Thompson PJ Dhillon DP Ledingham J Turner-Warwick M Shrinking lungs, diaphragmatic dysfunction, and systemic lupus erythematosus.Am Rev Respir Dis. 1985; 132: 926-928Google Scholar Phrenic nerve electromyographic studies excluded the presence of a demyelinating neuropathy and provided strong evidence against axonal degeneration as the cause of diaphragm weakness in these patients.16Wilcox PG Stein HB Clarke SD Pare PD Pardy RL Phrenic nerve function in patients with diaphragmatic weakness and systemic lupus erythematosus.Chest. 1988; 93: 352-358Crossref PubMed Scopus (72) Google Scholar Consistent with this hypothesis, the only clinicopathologic study of a patient with SLS in the literature reported that at autopsy both hemidiaphragms wer