What is systemic lupus erythematosus (SLE)?
Systemic lupus erythematosus (SLE) is a chronic inflammatory disease of unknown cause that can affect virtually every organ. Immunologic abnormalities, particularly the production of a number of antinuclear antibodies, are another prominent feature of the disease. Women are affected more frequently than men.
SLE has protean clinical manifestations that can affect virtually every organ, and can vary dramatically from patient to patient. The most common pattern is a mixture of constitutional complaints with skin, musculoskeletal, mild hematologic, and serologic involvement. However, some patients have predominately hematologic, renal, or central nervous system manifestations. The pattern that dominates during the first few years of illness tends to prevail throughout the disease course. The clinical course of SLE is highly variable among patients and may be characterized by periods of remissions and of chronic or acute relapses. treatment.
CLINICAL MANIFESTATIONS — Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with a wide range of clinical and serological manifestations that can affect any organ. The disease course is marked by remissions and relapses and may vary from mild to severe.
Constitutional symptoms — Constitutional symptoms such as fatigue, fever, and weight loss are present in most lupus patients at some point during the course of the disease.
— Weight change
Arthritis and arthralgias — Arthritis and arthralgias occur in over 90 percent of patients with SLE and are often one of the earliest manifestations.
Skin and mucous membrane involvement — Most patients develop skin and mucous membrane lesions at some point during the course of their disease. There is tremendous variability in the type of skin involvement in SLE. The most common lesion is a facial eruption that characterizes acute cutaneous lupus erythema (ACLE) (also known as “the butterfly rash”) that presents as erythema in a malar distribution over the cheeks and nose (but sparing the nasolabial folds), which appears after sun exposure.
Many patients develop oral and/or nasal ulcers, which are usually painless, in contrast to herpetic chancre blisters. Nonscarring alopecia is also observed in many SLE patients at some point during the course of their disease. Scarring alopecia can occur in patients with discoid lupus erythematosus (DLE).
Vascular disease — A variety of vascular abnormalities can occur in patients with SLE.
— Raynaud phenomenon — Raynaud phenomenon in SLE is a vasospastic process induced by cold or emotion that occurs in up to 50 percent of patients with SLE.
— Vasculitis — Small vessel involvement is the most common, often manifesting as cutaneous lesions; however, medium and large vessel involvement have also been observed. Other specific types of vasculitic involvement in SLE include mesenteric vasculitis, hepatic vasculitis, pancreatic vasculitis, coronary vasculitis, pulmonary vasculitis, retinal vasculitis as well as vasculitis of the peripheral or central nervous system. The most frequent type of vasculitis in patients with SLE is cutaneous small vessel vasculitis which can manifest as palpable purpura, petechiae, papulonodular lesions, livedo reticularis, panniculitis, splinter hemorrhages, and superficial ulcerations.
— Thromboembolic disease — Thromboembolic disease can complicate SLE, particularly in the context of antiphospholipid antibodies. Thromboembolic disease can affect both the venous and arterial circulations leading to an arterial thrombotic event and/or a venous thrombotic event (VTE).
Renal involvement — Renal involvement is clinically apparent in approximately 50 percent of SLE patients, and is a significant cause of morbidity and mortality.
Gastrointestinal involvement — Gastrointestinal symptoms are common in SLE patients, occurring in up to 40 percent of patients. The majority of gastrointestinal symptoms are caused by adverse medication reactions and viral or bacterial infections. SLE-related gastrointestinal abnormalities can involve almost any organ along the gastrointestinal tract and include esophagitis, intestinal pseudo-obstruction, protein-losing enteropathy, lupus hepatitis, acute pancreatitis, mesenteric vasculitis or ischemia, and peritonitis.
Pulmonary involvement — During the course of their disease, many patients develop symptoms secondary to pulmonary involvement of SLE. Pulmonary manifestations of SLE include pleuritis (with or without effusion), pneumonitis, interstitial lung disease, pulmonary hypertension, shrinking lung syndrome, and alveolar hemorrhage. Respiratory symptoms must also be distinguished from infection, particularly in patients on immunosuppressive therapy.
Cardiac disease — Cardiac disease among patients with SLE is common and can involve the pericardium, myocardium, valves, conduction system, and coronary arteries. Pericarditis, with or without an effusion, is the most common cardiac manifestation of SLE.
Ophthalmologic involvement — Any structure of the eye can be involved in SLE, with keratoconjunctivitis sicca being the most common manifestation as a result of secondary Sjögren’s syndrome. The next most common pathologic condition involving the eye in lupus patients is retinal vasculopathy in the form of cotton wool spots. Other less common ophthalmologic manifestations of SLE include optic neuropathy, choroidopathy, episcleritis, scleritis, and anterior uveitis (iritis, iridocyclitis).
Hematologic abnormalities — Hematologic abnormalities are common in SLE, and all three blood cell lines can be affected:
— Anemia of chronic disease is the most common type of anemia among patients with SLE. Autoimmune hemolytic anemia is relatively rare, but can be severe requiring immediate therapy.
— Leukopenia is common in SLE patients, occurring in approximately 50 percent of patients.
— Mild thrombocytopenia is also a common hematologic abnormality. Rarely, severe thrombocytopenia can occur and requires treatment.