CHEST Guidelines-A-60-Year-Old-Man-With-Dyspnea,-Proximal-Muscle-We

A-60-Year-Old-Man-With-Dyspnea,-Proximal-Muscle-We

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The article discusses the case of a 60-year-old man presenting with dyspnea, proximal muscle weakness, and pulmonary arterial hypertension (PAH). The patient had a significant history of smoking but no exposure to statins or other medications. Clinical assessments revealed low oxygen saturation, muscle weakness, and pulmonary complications, including interstitial lung disease (ILD) and PAH.<br /><br />Laboratory tests indicated a markedly elevated creatine kinase (CK) level, while imaging showed mild nonspecific interstitial changes. Echocardiography and right heart catheterization confirmed severe pulmonary arterial hypertension. Treatment with PAH-specific drugs (tadalafil, macitentan, selexipag) improved his breathing.<br /><br />Electromyography revealed diffuse myositis, and muscle biopsy showed necrotic fibers with macrophage infiltration, leading to a diagnosis of seronegative immune-mediated necrotizing myopathy (IMNM). Prednisone and mycophenolate mofetil were administered, normalizing CK levels and alleviating respiratory and muscular symptoms over months.<br /><br />IMNM is an inflammatory myopathy marked by proximal muscle weakness and often associated with specific antibodies unless it is seronegative, necessitating extensive testing and biopsy. ILD is the most common extramuscular manifestation. PAH drugs should be considered for patients with inflammatory myopathy and PH if lung involvement is minimal. Seronegative IMNM necessitates screening for malignancy due to a high association risk.<br /><br />Given these findings, clinicians should assess respiratory muscle strength and consider ILD in differential diagnoses where in-depth evaluation and prompt treatment can prevent progression. Immune suppressants combined with PAH-specific drugs showed therapy success in improving patient outcomes, highlighting the importance of a comprehensive treatment approach in similar cases.

Keywords

dyspnea

proximal muscle weakness

pulmonary arterial hypertension

interstitial lung disease

seronegative immune-mediated necrotizing myopathy

creatine kinase

macrophage infiltration

immune suppressants

respiratory muscle strength

treatment approach