Lupus Terminology – Top 10 Series

1. What is systemic lupus erythematosus (lupus)?
2. What are commonly used abbreviations related to lupus?
3. What are the common cardiac (heart-related) terms that lupus patients should know?
4. What are the common pulmonary (lung-related) terms that lupus patients should know?
5. What are the common dermatological (skin-related) terms that lupus patients should know?
6. What are the common musculoskeletal (muscle- and joint-related) terms that lupus patients should know?
7. What are the common renal (kidney-related) terms to know for lupus patients?
8. What are the common neurological (nervous system-related) terms that lupus patients should know?
9. What are the common hematologic (blood- and blood cells-related) terms that lupus patients should know?
10. What tests are commonly ordered in lupus patients?

1. What is systemic lupus erythematosus (lupus)?

Systemic lupus erythematosus (SLE or lupus) is a chronic, inflammatory autoimmune disease. In a person with lupus, persistent lupus-specific autoantibodies (antibodies that attack healthy proteins your body forms naturally) that are present in the blood cause organ inflammation and damage. Commonly affected organs in lupus patients are skin, joints, kidneys, and blood cells. Common symptoms include fatigue, joint pain and swelling, fever, skin rash (especially “butterfly rash” on the face), and sensitivity to light.

The purpose of this Top 10 Series review is an overview of terms that patients may encounter during an evaluation of a lupus diagnosis and treatment. Additional information on lupus disease presentation and management can be found in other articles on this website, including Managing and Treating Lupus.

2. What are commonly used abbreviations related to lupus?

3. What are the common cardiac (heart-related) terms that lupus patients should know?

The heart tissue is made of three layers, the endocardium, myocardium, and pericardium.

• Endocardium: lines the inner heart chambers, composed of smooth muscles and elastic fibers.
• Myocardium: the muscular layer of the heart and is responsible for heart contractions.
• Pericardium: a two-layered sac inside which the heart sits. It protects and lubricates the outside of the heart.

When different parts of the heart are affected by lupus, some of the commonly used terms include:

• Libman-Sacks endocarditis: the inflammation of the valves, causing dysfunction and poor closure of the valves.
• Myocarditis: the inflammation of the myocardium, leading to contractile dysfunction of the heart.
• Pericarditis: inflammation of the pericardium, which can cause chest pain. Pericardial effusion occurs when the two layers of the pericardium fill with excess fluid, which can compress the heart, and reduce its ability to pump.

Lastly, cardiac atherosclerosis is a deposition of plaques on the blood vessels that feed the heart, leading to narrowing of blood vessels. When atherosclerosis develops, the heart cannot pump blood as efficiently through these vessels, potentially leading to vascular complications like ischemia (reduced blood perfusion to tissue and organs) or myocardial infarction (MI), lack of blood perfusion to tissue or organs due to obstruction of a vessel.

4. What are the common pulmonary (lung-related) terms that lupus patients should know?

Lungs are a complex system of two balloon-like structures that are made of thousands of small air-sacs called alveoli. These sacs are intertwined with blood vessels, allowing for oxygen to pass from the air into the bloodstream. The two lungs sit inside of a two-layered sac called the pleura that is lubricated between its layers and allows for easy expansion and contraction of the lungs. The outer layer of the pleura is connected to the diaphragm and the muscles of the chest, which pull on the pleura and lungs, causing inhalation to occur.

• Pleural disease: The pleura can become inflamed, causing pleuritis, causing a constrictive sensation for patients, and leading to difficulty breathing. Lupus can also trigger pleural effusions, where fluid flows between the two layers of the pleural sac, putting pressure on the lung.
• Pneumonitis: damage to the alveoli, disrupting the flow of oxygen into the bloodstream. This can cause rapid-onset fevers, cough, and difficulty breathing.
• Interstitial lung disease: scarring of the lung tissue, causing restrictive breathing.
• Pulmonary hypertension: high blood pressure within the blood vessels in lungs, causing difficulty breathing, cough, heart palpitations, and fatigue.
• Pulmonary embolism: This is when a clot travels to the arteries that supply blood to your lungs. Pulmonary embolisms prevent a portion of the lung from participating in gas exchange, causing decreased oxygenation.

5. What are the common dermatological (skin-related) terms that lupus patients should know?

Patients with lupus commonly have skin findings. Cutaneous lupus erythematosus can be divided into acute, subacute, and chronic.

• Acute cutaneous lupus typically presents with a malar rash, a butterfly-like rash across the bridge of the nose and not affecting the eyes.
• Subacute cutaneous lupus presents with a rash on any part of the body exposed to sun. The rash can present as red papules, plaques, or circular lesions with central clearing. This type of rash typically heals without scarring.
• Chronic cutaneous lupus can have three different skin presentations.
  • Discoid rash: circular rashes that are red and scaly, which eventually scars.
  • Tumid lupus: a rash whose spots are red and flatter to the skin, and do not frequently scar.
  • Lupus panniculitis: a rash that presents with swelling under the skin, frequently painful.

6. What are the common musculoskeletal (muscle- and joint-related) terms that lupus patients should know?

Joints are the connection between two bones, and they can be classified by their different types of tissue: fibrous, cartilaginous, and synovial. For instance, bones of the pelvis are fused together with cartilaginous joints. There are joints that are enclosed in a capsule (the bones are held within the capsule), and the capsule is lubricated by a fluid called synovium, which allow for movement and flexibility of the joint. The synovium is the connective tissue that lines, lubricates, and protects the joint capsule.

• Synovitis is inflammation in the synovium.
• Arthralgia is pain in the joint without swelling.
• Arthritis is swelling and tenderness in the joint (patients can also experience redness warmth due to joint inflammation).
• Polyarthralgia and polyarthritis are arthralgias and arthritis affecting five or more joints.
• Jaccoud’s arthropathy is a deforming arthritis that lupus patients can experience due to loosening joint capsules.
• Arthrocentesis is a procedure where a needle is inserted into the joint, and the joint fluid is pulled out for examination.

7. What are the common renal (kidney-related) terms to know for lupus patients?

The kidney helps filter blood and concentrates elements in blood that are excreted in urine. Each kidney is comprised of about one million filtration units, which are called nephrons. A nephron includes the glomerulus, which is the main filtration system, tubules, and a collecting duct, which leads to excretion of urine. The glomerulus utilizes pressure to filter the blood. The glomerulus also has supporting cells, called mesangial cells.

Patients with lupus may experience a renal disease called lupus nephritis (LN) when your body attacks the renal tissue, resulting in the breakdown of the glomerulus barrier. This can cause a host of adverse effects, including high blood pressure, anemia (low red blood cells), and swelling.

• Proteinuria, or protein in the urine, occurs when the filtration barrier is disturbed, leading to excess protein released into the urine.
• Lupus nephritis classification determines the severity and character of damage to the kidneys:
  • Type 1 - minimal mesangial glomerulonephritis is the mildest type and occurs when a minimal amount of mesangial cells (supportive cells) are attacked. Type 1 LN has minimal symptoms.
  • Type 2 - mesangial proliferative glomerulonephritis occurs due to damage of a larger area of mesangium. This results in proliferation of the supportive cells. Minor amounts of protein and blood in the urine may occur.
  • Type 3 - focal glomerulonephritis involves damage to less than half of the glomeruli in the kidneys. There is blood and excess protein in the urine, sometimes associated with high blood pressure.
  • Type 4 - diffuse proliferative nephritis involves more than half of the glomeruli in the kidneys. Possible high blood pressure and possible need for dialysis if not treated aggressively.
  • Type 5 - membranous glomerulonephritis involves immune damage to mesangial cells and a layer of the filtration portion of the glomerulus. This stage involves a high level of protein lost in the urine.
  • Class 6 - advanced sclerotic occurs with 90% damage to the kidneys. This stage may necessitate dialysis, or potentially a kidney transplant.

8. What are the common neurological (nervous system-related) terms that lupus patients should know?

There are 19 different clinical neuropsychiatric (NP) problems that can be associated with Lupus (12 categorized as neurological and 5 categorized as psychiatric). Clinical problems covered under NP lupus include numerous neurological syndromes and psychiatric disorders.

Neurological syndromes

• Seizure disorder: two unprovoked episodes of seizures, periods where there is loss of consciousness or control over movements.
• Aseptic meningitis: inflammation of the meninges (protective layer around the brain) without an infectious cause.
• Demyelinating syndromes: damage to the sheath that surrounds nerves, leading to delays in neurological conduction. Patients can experience vision loss, numbness, or weakness.
• Myelopathy: injury to the spinal cord due to compression. Based on the level of compression, patients can experience pain, numbness, clumsiness or incoordination of the affected limbs
• Headache
• Cerebrovascular disease: is disease of the blood vessels that supply the brain, potentially leading neurological complications due to impaired oxygenation of the brain.
• Movement disorders: conditions that either cause increased, unwanted movements or delayed or slow movements.
• Autonomic disorders: disorders that affect the autonomic nervous system, such as uncontrolled changes in blood pressure, sexual dysfunction, urinary dysfunction.
• Myasthenia gravis: a neuromuscular junction autoimmune disease where antibodies attack the junction where nerves communicate to muscles. This leads to skeletal muscle weakness.
• Polyneuropathy: multiple peripheral nerves malfunction. Symptoms include loss of coordination, numbness, and balance issues.
• Sensorimotor polyneuropathy: damage to the sensory or motor nerves, causing weakness or numbness in limbs, or difficulty with movement. More often the symptoms begin more distally in the limbs (that is, toes) before affecting the proximal (upper part of legs).
• Cranial neuropathy: damage to the nerves damage to the nerves of the brain that are responsible for seeing, hearing, balancing, tasting, smelling, and sensation in the face.
• Inflammatory demyelinating polyradiculoneuropathy, also known as Guillain-Barre syndrome: an ascending motor-neuron disease. Condition where a patient’s immune system attacks the body’s peripheral nerves, causing gradual and symmetric muscle weakness In rare cases, this can lead to paralysis of the respiratory muscles.
• Mononeuropathy: damage to a singular nerve. This can cause numbness, pain, or weakness in a particular area of the body.
• Plexopathy: damage to a network or region of nerves. Areas of the body are innervated by a network of nerves, such as the arms, pelvic region, and thighs. Damage to a plexus can cause numbness, pain, or weakness in a coordinated area.

Psychiatric disorders

• Anxiety disorders
• Psychosis: a sudden confused state due to inflammation in the brain
• Glucocorticoid-induced psychosis: an adverse side-effect due to medication
• Acute confusional state
• Cognitive dysfunction: impaired cognitive functioning, impaired attention, memory deficits
• Mood disorders: major depressive disorder is often experienced by lupus patients

9. What are the common hematologic (blood- and blood cells-related) terms that lupus patients should know?

• Leukopenia: a white blood cell count of less than 4,000. White blood cells are a component of the body’s immune system.
• Lymphopenia: a lymphocyte count of less than 1500 lymphocytes per microliter of blood.
• Thrombocytopenia: A platelet count of less than 150,000/mL. A low platelet count increases a patient’s susceptibility to bleeding.
• Autoimmune hemolytic anemia (AIHA): a rare blood disorder where antibodies in the body attack red blood cells, leading to anemia, fatigue, dark urine, back-aches, and potential gallstones.
• Thrombotic thrombocytopenic purpura (TTP): a rare blood disorder that occurs when blood cannot properly break up clots. This results in small clots traveling throughout the body. TTP causes low platelet count, damage to the kidney, anemia, and neurological issues.

10. What tests are commonly ordered in lupus patients?

• ANA: Antinuclear antibodies help detect inflammation in the body. A positive test does not confirm a lupus diagnosis, but a negative test is specific for ruling out lupus.
• Anti-dsDNA: Anti-double stranded DNA Antibody. A positive Anti-dsDNA test has a high sensitivity for a Lupus diagnosis for the patient.
• Anti-Smith antibodies: A positive Anti-Smith test has a high sensitivity for a lupus diagnosis.
• Anti-Ro/La: An antibody that has sensitivity for lupus, particularly with skin manifestations.
• Anti-RNP: Anti-U1 ribonucleoprotein is a non-specific antibody that is positive in lupus and other rheumatic diseases.
• Complete blood count (CBC): Patients with lupus have a low blood count of platelets, red blood cells, and white blood cells. A low CBC helps confirm a diagnosis of lupus
• Complement levels: The complement system works in tandem with the immune system to initiate and provide a supplementary immune response. Lupus autoantibodies also trigger the complement system. Low complement serum levels of C3 and C4, two of the proteins, indicate that the proteins have been activated and deposited on organs in the body.
• C-reactive protein: indicator of inflammation, but more important in detecting disease activity.
• Erythrocyte sedimentation rate (ESR): indicates inflammation. A patient’s cells are spun together, and the rate that the cells stick together and settle at the bottom indicates the level of inflammation. High ESR with no other indication of inflammation can indicate lupus activity.
• Renal biopsy: helps determine the severity of Lupus, and whether the kidneys have been damaged. This directs the level of treatment a Lupus patient may need.
• Urinalysis (UA test): Urinalysis can show an increased level of proteins, indicating a severity of kidney damage due to lupus.
• Antiphospholipid antibodies (aPL): Antiphospholipid syndrome, a rare blood clotting disorder, is more common in lupus patients. Lupus patients will be tested for autoantibodies to blood components to determine whether they have anti-phospholipid syndrome.

Posted: 1/25/2024

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