What are the implications of myositis with impaired renal function and pulmonary hypertension?

From the Guidelines

Myositis with renal involvement and pulmonary hypertension requires immediate initiation of high-dose corticosteroids, such as prednisone 1 mg/kg/day, as the first line of treatment, as recommended by the most recent guidelines 1. The treatment approach should be multidisciplinary, involving specialists from rheumatology, cardiology, and nephrology.

• For myositis, the treatment typically involves high-dose corticosteroids as initial therapy, followed by a gradual taper over months based on clinical response.
• Immunosuppressants like methotrexate (15-25 mg weekly), mycophenolate mofetil (1-3 g daily), or rituximab (375 mg/m² weekly for 4 weeks) are often added as steroid-sparing agents.
• For pulmonary hypertension, specific medications such as phosphodiesterase-5 inhibitors (sildenafil 20 mg three times daily), endothelin receptor antagonists (bosentan 62.5-125 mg twice daily), or prostacyclin analogs may be necessary, as outlined in the guidelines for pulmonary hypertension management 1.
• Renal involvement requires careful monitoring of kidney function, blood pressure control, and possibly ACE inhibitors or ARBs if appropriate. Regular monitoring should include:
• Muscle enzyme levels (CK, aldolase)
• Pulmonary function tests
• Echocardiography to assess pulmonary pressures
• Renal function tests Physical therapy is essential to maintain muscle strength and function. This complex condition results from autoimmune inflammation affecting multiple organ systems, with shared pathophysiological mechanisms involving vascular damage, immune complex deposition, and inflammatory cytokine production that simultaneously impact muscles, kidneys, and pulmonary vasculature, as discussed in the management of immune-related adverse events in patients treated with immune checkpoint inhibitor therapy 1.

From the Research

Myositis with Renal Pulmonary Hypertension

• Myositis refers to a group of diseases characterized by inflammation of the muscles, including dermatomyositis, polymyositis, and inclusion body myositis 2.
• Pulmonary hypertension (PH) is a condition characterized by high blood pressure in the arteries of the lungs, which can be caused by various underlying conditions, including left-sided heart disease, chronic lung disease, and connective tissue diseases 3.
• The prevalence of PH in patients with polymyositis (PM) has been reported to be around 16.39%, with interstitial lung disease (ILD) and pericardial effusion (PE) being independently associated with PH in these patients 4.

Treatment and Management

• The treatment of myositis typically involves the use of glucocorticoids, with some patients requiring add-on immunosuppressive therapy due to insufficient response or relapses 5.
• Established therapies beyond glucocorticoids, such as methotrexate and azathioprine, continue to have a major role in managing patients with myositis, with novel agents being tried for refractory manifestations of myositis 5.
• The treatment of PH depends on the underlying cause, with targeted therapies available for patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH) 3.

Prognosis and Survival

• The 5- and 10-year survival estimates for patients with polymyositis and dermatomyositis have been reported to be around 77% and 62%, respectively, with increased age at diagnosis, non-Caucasian race, and male sex being associated with lower survival 6.
• The use of intravenous corticosteroids has been associated with a higher risk of death among Caucasians, while early survival between patients treated with methotrexate versus azathioprine has been similar, with survival at 10 years being higher for the methotrexate-treated group 6.