An Overview of the Pathophysiology of Systemic Lupus Erythematosus
written by: Norene A
• edited by: Diana Cooper
• updated: 5/23/2011
For an overview of the pathophysiology of systemic lupus erythematosus (SLE), a chronic autoimmune disorder, read the following to learn how autoantibodies, T lymphocytes and circulating immune complexes affect each body system.
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How is Systemic Lupus Erythematosus Diagnosed?
The Mayo Clinic reports a diagnosis of systemic lupus erythematosus (SLE) requires the presence of four of the 11 criteria established by the American College of Rheumatology as follows:
Butterfly-shaped rash across the nose bridge and cheeks
Rash after exposure to sunlight
Joint pain and swelling in at least two joints
Swelling of the tissue around the heart or lungs
Seizures, psychosis, or other neurological disorder
Low blood count
Positive antinuclear antibody tests
Other positive autoimmune disease blood tests.
The pathophysiology of systemic lupus erythematosus is complex and affects body systems with specific inflammatory responses. Diagnostic testing for SLE symptoms includes a complete blood count, urinalysis, and blood chemistry panel.
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Heart and Blood Vessels
Pericarditis, which is inflammation of the tissue surrounding the heart, is the most common form of heart complications from SLE, according to WebMD. Pericarditis causes pain that resembles a heart attack. Other heart and blood vessel damage includes hardening of the arteries, heart valve malformations, and intermittent interruptions of arterial blood flow to the hands, which can cause Raynaud syndrome.
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The most visible affect of SLE is on the skin, the largest organ of the body. Four of the 11 diagnostic criteria for SLE are skin related, according to the SLE Lupus Foundation. The patches of red and raised skin lesions that develop on areas exposed to the sun can spread to the scalp and cause permanent hair loss. Hives or welts that remain following treatment with antihistamines, corticosteroids and anti-serotonin medications may indicate inflammation of the blood vessels.
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The digestive system includes the mouth, esophagus, stomach, intestines, colon and rectum. Surrounding organs involved in the digestive process include the liver, gallbladder, pancreas and bile ducts. The effects of SLE on the digestive system, according to the University of Illinois Medical Center at Chicago, can be seen in many ways, such as:
Diarrhea, nausea and vomiting
Loss of appetite
Perforated intestines from inflamed blood vessels
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Chronic inflammation of the kidneys caused by SLE is called lupus nephritis. The Mayo Clinic reports that about half of adults with lupus develop some form of lupus nephritis, which can lead to kidney failure. The pathophysiology of lupus nephritis involves a buildup of autoantibodies in the small blood vessels of the kidneys.
Symptoms of SLE in the kidneys include high blood pressure, swelling of the lower extremities, and urine that contains white blood cells, blood and protein. A kidney biopsy may be required to determine the extent of damage from SLE.
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The most common effect of SLE on the lungs is pleuritis, which is an inflammation of the membrane surrounding the lung, according to the Lupus Foundation of America, Inc. Other lung conditions related to SLE include:
Lupus pneumonitis -- inflammation within the lung tissue caused by an infection
Chronic diffuse interstitial lung disease -- scarring of the lung tissue
Pulmonary hypertension -- high blood pressure in the lung blood vessels
Pulmonary emboli -- blood clots in the pulmonary arteries
Pulmonary hemorrhage -- bleeding into the lung.
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Musculoskeletal aches and pains are common symptoms associated with SLE. The Lupus Foundation of America, Inc. reports that more than 90 percent of people with lupus will have some type of muscle or joint pain, and more than 50 percent report joint pain as the first symptom. The causes related to SLE and musculoskeletal pain include:
Lupus arthritis, which is stiffness, tenderness, swelling and warmth in the joints
Lupus myositis, which is inflammation of skeletal muscles such as the neck, shoulders, upper arms, thighs and pelvis
Tendonitis and bursitis, which occur when the synovial membrane is inflamed
Avascular necrosis of the bone, which may occur in lupus patients due to corticosteroid use.
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There are three nervous systems in the body, and SLE affects each differently, according to the Lupus Foundation of America, Inc. When the central nervous system, which is the brain and spinal cord, is affected by SLE, symptoms that may occur include headaches, vision problems, depression, confusion, seizures and difficulty concentrating.
The peripheral nervous system includes motor responses and sensation. Symptoms of SLE affecting the peripheral nervous system include facial pain, carpel tunnel syndrome, ringing in the ears, dizziness and eyelid drooping.
The autonomic nervous system is the body function regulator controlling bladder and bowel functions, muscle movement, heart rate, breathing, blood pressure and release of adrenalin. When SLE affects the autonomic nervous system, symptoms that may present include mental confusion, headaches, numbness, tingling, burning, vomiting, nausea and diarrhea.