Renal Involvement in Idiopathic Inflammatory Myopathies

Area of Science:

• Nephrology
• Rheumatology
• Immunology

Background:

• Renal involvement in idiopathic inflammatory myopathies (IIM) is more common than previously believed, affecting approximately 20% of patients.
• Kidney manifestations in IIM include acute kidney injury (AKI) secondary to rhabdomyolysis and chronic glomerulonephritis.
• AKI in rhabdomyolysis is caused by myoglobinuria's toxic effects on renal tubules, while immune-mediated glomerulonephritis has an autoimmune basis.

Purpose of the Study:

• To review the current evidence on renal involvement in IIM.
• To provide practical guidance for the diagnosis and management of kidney complications in IIM patients.
• To highlight strategies for preventing or delaying the progression of kidney damage.

Main Methods:

• Comprehensive review of existing literature and case series on renal involvement in IIM.
• Analysis of clinical presentations, diagnostic approaches, and therapeutic interventions.
• Synthesis of evidence regarding management of rhabdomyolysis-induced AKI and immune-mediated glomerulonephritis.

Main Results:

• AKI due to rhabdomyolysis can often be managed conservatively with aggressive hydration and alkalinization, avoiding dialysis.
• Immune-mediated glomerulonephritis requires accurate diagnosis, often aided by renal biopsy, and immunosuppressive therapy.
• Renin-angiotensin-aldosterone system inhibitors and lifestyle modifications (smoking cessation, weight loss, salt restriction) are beneficial in reducing proteinuria and slowing disease progression.

Conclusions:

• Timely diagnosis and appropriate management are crucial for improving outcomes in IIM patients with renal involvement.
• Conservative measures are effective for rhabdomyolysis-induced AKI, while immunosuppression and supportive care are vital for glomerulonephritis.
• Integrated management strategies, including pharmacotherapy and lifestyle changes, can preserve renal function in IIM.