Renal involvement in systemic sclerosis

Systemic sclerosis is a rare autoimmune vasculopathy associated with dysregulated innate and adaptive immunity that leads to generalized systemic fibrosis. Renal involvement occurs in a significant proportion of systemic sclerosis patients, and is associated with worse outcome. Scleroderma renal crisis (SRC) is the most studied and feared renal complication described in systemic sclerosis. However, with the emergence of ACE inhibitors and better management, the mortality rate of SRC has significantly decreased. Renal disease in systemic sclerosis offers a wide array of differential diagnoses that may be challenging for the clinician. The spectrum of renal manifestations in systemic sclerosis ranges from an isolated decrease in glomerular filtration rate, increased intrarenal arterial stiffness, and isolated proteinuria due to SRC to more rare manifestations such as association with antiphospholipid antibody nephropathy and ANCA-associated vasculitis. The changes observed in the kidneys in systemic sclerosis are thought to be due to a complex interplay of various factors, including renal vasculopathy, as well as the involvement of the complement system, vasoactive mediators such as endothelin-1, autoimmunity, prothrombotic and profibrotic cytokines, among others. This literature review aims to provide an overview of the main renal manifestations in systemic sclerosis by discussing the most recent epidemiological and pathophysiological data available and the challenges for clinicians in making a diagnosis of renal disease in patients with systemic sclerosis.