Because the intensity of dyspnea associated with ambulatory activity depends on the rate of work performance (power output), patients may reduce the rate of work performance, thereby minimizing the intensity or distress of symptoms.1 Frequently, my patients tell me that they experience no breathlessness as long as they perform tasks slowly. Other patients find their activity limited by articular or neuromuscular complications—or simply by the overwhelming fatigue associated with SSc. The complaint of dyspnea is an important clue to the presence of underlying lung or cardiac disease; but the absence of dyspnea does not rule out significant pulmonary disease.
Usually, dyspnea associated with SSc is chronic. When a patient with this disease presents with acute dyspnea, the rheumatologist must consider pulmonary embolism, pneumothorax, infection, serositis, and heart failure. Acute pulmonary edema may be a manifestation of volume overload secondary to scleroderma renal crisis, other causes of renal failure, or primary scleroderma heart disease.
Cough is another symptom of lung fibrosis and usually is nonproductive and made worse by exertion. Productive cough or hemoptysis requires evaluation to rule out aspiration pneumonia or neoplasm—each of which occurs with increased frequency in SSc.
Physical examination remains key when evaluating any rheumatic disease patient. Some argue cynically that the stethoscope is obsolete in this era of high-tech diagnostic studies. To others, “the stethoscope embodies the essence of doctoring: using science and technology in concert with the human skill of listening to determine what ails a patient.”3 Laennec’s invention of the stethoscope initiated medicine’s irreversible trend toward physically separating the diagnosing physician from the patient.3 High-tech medicine has expanded the potential gap between patient and physician. For me, the hollow tube of the stethoscope is a connection to my patient and reinforces my need to listen.
Fine inspiratory (and sometimes expiratory) crackles are a finding heard in patients with ILD. Crackles may be audible at the lung bases and higher in more extensive disease; in early disease, however, crackles may not be audible. Accentuation of the pulmonic component of S2, a tricuspid regurgitation murmur, or right-sided S4 may be indicative of PAH. Right ventricular heave, jugular venous distension, and edema are later findings of PAH with right-sided heart failure. The presence of any of these physical findings requires further evaluation but, like dyspnea, their absence does not preclude ILD or PAH.
Pulmonary Function Testing
Perform pulmonary function tests (PFTs) at baseline and regular intervals in all patients. The characteristic PFT pattern of SSc-ILD is restriction, with reduced lung volumes (e.g., total lung capacity) and a proportionate reduction in diffusion capacity for carbon monoxide (DLCO). In the absence of significant obstructive airway disease, the forced vital capacity (FVC) serves as a surrogate for total lung capacity. If the FVC percent predicted is less than 75% and the ratio of the FVC percent predicted divided by the DLCO percent predicted is <1.4, the patient has a predominantly restrictive PFT pattern characteristic of ILD.
