Inspiratory muscle dysfunction and unexplained dyspnea in systemic lupus erythematosus

Abstract

The role of inspiratory muscle dysfunction in lung volume restriction and unexplained dyspnea was studied in 16 consecutive patients with systemic lupus erythematosus. Maximal mouth inspiratory pressure PI^) and maximal transdiaphragmatic pressure (Pdi max) were measured. Pdi and its components were determined during quiet breathing. No significant associatiam was found between the activity of the disease, several serologic markers, and the inspiratory muscle dysfunction. No specific anti-skeletal muscle antibody was found in these patients. Significant correlations were found between the degree of dyspnea and PIM (r = -0.69, P < 0.01) and Pdi max (r = -0.75, P < 0.001); however, dyspnea did not correlate with specific lung compliance. Vital capacity correlated significantly with the dlegree of dyspnea (r = -0.813, P < 0.001) and with Pdi max (r = 0.544, P < 0.05). No correlation was found between vital capacity and specific lung compliance. We conclude that inspiratory muscle dysfunction can be an important mechanism in the pathogenesis of the lung volume restriction and dyspnea in patients with systemic lupus; erythematosus.In a series of patients with systemic lupus erythematosus (SLE), Hof€brand and Beck (1) found

Shrinking lung syndrome in systemic lupus erythematosus

“…Because pathologic data are unavailable, theories of its etiology are speculative. In the past, it has been attributed successively to a surfactant deficiency, [15,43] isolated diaphragmatic myopathy, [34,39,44,53,65,67] phrenic nerve dysfunction, [45,66] chest wall dysfunction, [19,71] and pleural adhesions, [31,39] but none of these hypotheses has been unequivocally confirmed.…”

Control of Breathing in a Subset of Patients With Systemic Lupus Erythematosus

“…Restriction in chest wall expansion, which has been suspected in shrinking lung syndrome of SLE,6 could modify the activity of rib cage muscle mechanoreceptors. 9 An early pulmonary interstitial involvement, which has been reported in multisystem disorders,1 may increase pulmonary vagal receptor af¬ ferent information.…”

“…are extremely scarce in SLE. 6,9 In patients with decreased respiratory muscle force, Jacobelli et al9 showed that light exercise resulted in increased venti¬ lation, mostly sustained by increase in respiratory fre¬ quency (Rf), with modest changes in tidal volume (Vt). Incomplete respiratory muscle activation during max¬ imal voluntary efforts and a shallow pattern of breath¬ ing during maximal voluntary ventilation have recently been reported in SLE with shrinking lung syndrome.6…”

Shrinking lungs syndrome, a rare manifestation of systemic lupus erythematosus

“…Most authors agree that there would exist a dysfunction of the respiratory muscles; Jacobelli et al (7) found involvement in the inspiratory muscles in 56% of the patients.…”