Systemic lupus erythematosus

Systemic lupus erythematosus (SLE), like Sjögren’s syndrome, is a type of autoimmune connective tissue disorder that may have both genetic and environmental causes.

Systemic lupus erythematosus (SLE), like Sjögren’s syndrome, is a type of autoimmune connective tissue disorder that may have both genetic and environmental causes. Connective tissue disorders are chronic inflammatory autoimmune disorders affecting the connective tissues. All connective tissues, i.e. joints, muscles, skin and blood vessels can be affected and therefore the disorders have multiple effects on many different organs throughout the body.

They may develop slowly over many years, or they may present abruptly and show rapid progression. There are more than 200 different disorders affecting connective tissues, including SLE, Sjögren’s syndrome, scleroderma and mixed connective tissue disease.

The presence of autoantibodies in the serum of patients is a very typical phenomenon for connective tissue disorders. Most of the autoantibodies are not specific and can be detected in patients with different diseases. However, in some cases, autoantibodies occur specifically in a certain disease and can aid in the diagnosis.

Systemic lupus erythematosus (SLE or lupus), is a systemic autoimmune disease (or autoimmune- connective tissue disease) that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage. The disease is nine times more common in women than in men. The disease can affect all ages but most commonly begins from 20-45 years of age. There seems to be an ethnic factor as lupus is somewhat more frequent in African Americans and people of Chinese and Japanese descent.

Symptoms

People with SLE can develop a large number of symptoms and often in combinations. Common complaints and symptoms include fatigue, low-grade fever, loss of appetite, muscle aches, arthritis, ulcers of the mouth and nose, facial rash (the classical "butterfly rash"), sensitivity to sunlight, pleuritis pericarditis, and Raynaud's phenomenon (poor circulation to the fingers and toes with cold exposure). Complications of organ involvement can lead to further symptoms depending on the organ affected and/or severity of the disease. Over half of the people with SLE develop a characteristic red, flat facial rash over the bridge of their nose. Because of its shape, it is frequently referred to as the "butterfly rash" of SLE. Most people with SLE will develop arthritis during the course of their illness. Arthritis in SLE commonly involves swelling, pain, stiffness, and even deformity of the small joints of the hands, wrists, and feet. Sometimes, the arthritis of SLE can mimic that of rheumatoid arthritis. More serious organ involvement with inflammation occurs in the brain, liver, and kidneys. White blood cells and blood-clotting factors also can be characteristically decreased in SLE, known as leukopenia and thrombocytopenia, respectively. Leukopenia can increase the risk of infection, and thrombocytopenia can increase the risk of bleeding. Other sites of inflammation related to SLE are muscles (myositis), blood vessels (vasculitis), and the kidneys. Kidney inflammation may lead to end-stage disease with complete renal failure requiring dialysis. Involvement of the brain can cause personality changes, thought disorders (psychosis), seizures, and even coma. Brain involvement is commonly referred to as lupus cerebritis.

Since individuals with SLE can have a wide variety of symptoms and different combinations of organ involvement, accurate differential diagnosis is difficult. As it is, no single test establishes the diagnosis of systemic lupus. The American College of Rheumatology has issued 11 criteria to facilitate the diagnosis of SLE.

Pathogenesis

Being a systemic disease, SLE often involves a number of organs such as the heart, joints, skin, lungs, blood vessels, liver, kidneys, and nervous system. When only the skin is involved, the condition is called lupus dermatitis or cutaneous lupus erythematosus. A form of lupus dermatitis that can be isolated to the skin, without internal disease, is called discoid lupus. The skin rash in discoid lupus is most commonly found on the face and scalp. Over time, 5%-10% of those with discoid lupus may develop SLE. When internal organs are involved, the condition is referred to as systemic lupus erythematosus.The course of the disease is unpredictable, with periods of illness (called flares) alternating with remissions.

Relevant Literature

  1. Abu-Shakra M, Urowitz MB, Gladman DD, Gough J. Mortality studies in systemic lupus erythematosus. Results from a single center. II. Predictor variables for mortality. J Rheumatol. 1995;22:1265-70.
  2. Danchenko N, Satia JA, Anthony MS. Epidemiology of systemic lupus erythematosus: a comparison of worldwide disease burden. Lupus 2006;15:308-18.
  3. D'Cruz DP, Khamashta MA, Hughes GR. Systemic lupus erythematosus. Lancet 2007;369:587-96.
  4. Munoz LE et al. SLE - a disease of clearance deficiency? Rheumatology (Oxford). 2005;44:1101-7.
  5. Rahman A, Isenberg DA. Systemic lupus erythematosus. N Engl J Med. 2008;358:929-39.
  6. Uramoto KM et al. Trends in the incidence and mortality of systemic lupus erythematosus, 1950-1992. Arthritis Rheum. 1999;42:46-50.