Autoimmune Disorders Flashcards
What is systemic lupus erythematosus?
What is its mechanism?
Autoimmune disorder (type III hypersensitivity)
caused by immune complexes fromed antinuclear antibodies (ANAs) which deposit in tissue causing damage and activate complement
What are the clinical features of SLE?
comes in flares and has periods of remission
- fever, fatigue, malaise, weight loss
- malar “butterfly” rash, or discoid rash that are worse with sun exposure
- arthritis
What is the epidemiology of SLE?
- significanlty more common in females
- young to middle aged adults (20-40)
- more common in minority populations
- more common in poor SES
What findings are used to diagnose SLE?
(11)
RASH OR PAIN
Rash (malar or discoid) Arthritis Serositis Hematologic
Oral Renal
Photosensitivity ANA Immunologic disorder (anti-dsDNA/Sm) Neurologic
4 of the following 11
Skin:
- malar rash
- discod rash
- photosensitivity
- oral/nasopharyngeal ulcers
Organs
- symmetric, nonerosive arthritis
- serositis (pleurisy, caridac rub, pericarditis on EKG, etc.)
- nephritits
- neuro symptoms (seizures or psychosis)
Labs
- some or all components of pancytopenia
- positive serum ANA (most commonly dsDNA; anti-Sm and antiphospholid also found)
- ANAs on immunofluorescence
What is the association (statistical) between positive ANA and SLE?
What particular Abs are associated with SLE?
ANAs are sensitive (~95%) but not specific (negative ANA = no lupus; positive ANA = possible lupus or something else)
- anti-dsDNA is specific (70%); also coorelates with flares
- anti-Sm (highly specific, poorly sensitive ~30%)
- antiphospholipid Ab can be found
Other than ANA, what are additional expected lab findings with SLE?
Blood:
- elevated ESR
- hemolytic anemia/thrombocytopenia/leukopenia/lymphopenia
- decreased C3/C4
- decreased CH50
Urine:
- proteinuria
- casts
What are possible complications of SLE?
Early:
-infection
Late:
- atherosclerosis -> CVD (most common CoD)
- nephritits -> ESRD (worst prognosis)
- Libman-Sacks endocarditis
What is Libman-Sachs endocarditis?
non-infectious endocarditis
- caused by formation of sterile vegetations on heart valves
- highly associated with SLE
- embolization is common
What is the treatment/management for SLE?
Treatment:
- hydroxychloroquine
- glucocorticoids (immune supression)
- NSAIDs
- other immunosupressants
Management:
- avoid sun exposure; wear sunscreen
- influenza and pneumococcal vaccines
- cancer screenings (increased risk)
What is antiphospholipid antibody syndrome?
What is its mechanism?
Autoimmune disorder
caused by antiphospholipid Abs which typically target molecules that regulate coagulation
What are the clinical features of antiphospholipid antibody syndrome?
recurrent thrombosis (both arterial and venous)
- DVT
- PE
- stroke
- MI
- miscarriage (placental arteries)
How does antiphospholipid antibody syndrome relate to SLE?
Primary APS:
-more common than secondary
Secondary APS
-occurs in 1/3 of SLE cases
What specific antibodies are associated with antiphospholipid antibody syndrome?
What features are noted with each antibody?
- lupus anticoagulant -> prolonged aPTT
- anticardiolipin -> false positive for syphilis (positive VDRL/RPR)
- anti-β2-glycoprotein
What is the treatment for antiphospholipid antibody syndrome?
-life long anticoagulation
What is drug-induced lupus and how does it compare to SLE?
- positive ANA but with antihistone antibodies (no dsDNA antibodies)
- typically caused by certain drugs; remvoing drugs resolves symptoms
More mild over all:
- systemic symptoms less common
- renal and neuro symptoms absent
What medications cause drug-induced lupus?
SHIPPE
- Sulfa
- Hydralazine
- Isoniazid
- Procainamide
- Phenytoin
- Etanercept (TNF inhibitors)
What is neonatal lupus and how does it compare to SLE?
-affects newborns whose mothers have anti-Ro/anti-La (ANAs)
Can result in permanent heart block
Other symptoms are transient
- rash
- arthritis
- hemolytic anemia/thrombocytopenia
What is discoid lupus and how does it compare to SLE?
ANA is frequently negative but symptoms are caused by similar deposits of immune complexes in affected skin
- mostly limited to skin involvement; systemic/organ system symptoms absent
- well-defined erythematous plaques -> discoid rash (central atrophy w/ peripheral erythema) which resolve into disfiguring scars
- most common appears on the head
What is Sjögren syndrome?
What is its mechanism?
Autoimmune T-cell mediated (type IV HSR) destruction of lacrimal and salivary glands
What are the clinical features of Sjögren syndrome?
Sicca syndrome (and other glandular):
-
dry eyes (keratoconjunctivitis)
- foriegn body sensation
-
dry mouth (xerostomia)
- dental carries
- difficulting eating dry foods (dysphagia)
- parotitis
- vaginal dryness -> dyspareunia
Extraglandular
- arthritis
What is the epidemiology of Sjögren syndrome?
- significanlty more common in females
- older adults (40-60)
What is the association (statistical) between positive ANA and Sjögren syndrome?
What particular Abs are associated with Sjögren syndrome?
ANAs are sensitive (~97%) but not specific (negative ANA = no Sjögren; positive ANA = could be something else)
-anti-Ro/SSA Ab and anti-La/SSB Ab (70%); not specific
Other than ANA, what are additional expected lab findings with Sjögren syndrome?
- elevated ESR
- rheumatoid factor (w/ or w/o rheumatoid arthritis)
- anemia of chronic disease
What is used to diagnose Sjögren syndrome?
-lip biopsy (looking at minor salivary glands) looking for lymphocytic sialadenitis
