Lecture 7: Approach to Hypersensitivity/Autoimmune Topics Flashcards
What antibody mediates a type I hypersensitivity reaction?
IgE cross-linking on mast cell/basophil surfaces
What is the main mediator of a type I hypersensitivity reaction?
Histamine
What are some symptoms of a type I hypersensitivity reaction?
- Urticaria (hives)
- Rhinitis
- Wheezing
- Diarrhea
- Vomiting
- Hypertension
- Anaphylaxis
What are examples of type I hypersensitivities?
- Pollen allergies
- Dust mite allergies
- Bee sting
What antibody mediates a type II hypersensitivity reaction?
IgM or IgG destroy cells
- opsonization
- complement mediated lysis
- cytotoxicity
What are examples of type II hypersensitivities?
- ABO mismatch
- Grave’s disease
- Myasthenia Gravis
What is the cause of Myasthenia Gravis?
Antibodies to acetylcholine receptor, preventing acetylcholine to bind
What are symptoms of Myasthenia Gravis?
- Ptosis
- Fatigue
- Blurry vision
What mediates a type III hypersensitivity reaction?
Antigen-antibody complex that activates complement and neutrophil infiltration of tissue
What are some symptoms of a type III hypersensitivity reaction?
- Fever
- Urticaria
- Generalized lymphadenopathy
- Arthritis
- Glomerulonephritis
- Vasculitis
What are examples of type III hypersensitivities?
- Systemic Lupus Erythematosus
- Rheumatoid Arthritis
- Farmer’s lung
What mediates a type IV hypersensitivity reaction?
Antigens activating T cells
-symptoms appear 48-96 hours after exposure
What are examples of type IV hypersensitivities?
- Poison Ivy
- PPD testing for tuberculosis
Rheumatoid arthritis is a systemic infalmmatory disease that affects what?
Synovial membranes
-granulation tissue develops in joint spaces and erodes into articular cartilage and bone
What are signs of rheumatoid arthritis?
- Morning stiffness
- joint swelling
- warmth and erythema
- decreased ROM
What parts are most affected by rheumatoid arthritis?
- PIP
- MCP
- wrist
- knees
- ankles
In rheumatoid arthritis, what time for deformities are found in bilateral ring finger?
MCP joint - boutonniere
Does rheumatoid arthritis get better throughout the day or worse?
Gets better (osteoarthritis gets worse)
What is juvenile idiopathic arthritis?
Collagen vascular disorder in one or joints for more than 6 weeks in patients under age 16
What are symptoms of juvenile idiopathic arthritis?
- Large joints
- Iridocycylitis (inflammation involving ciliary body)
- Uveitis (inflammation of middle layer of eye)
- Can have fevers
Who is at highest risk of systemic lupus erythematosus?
Females (especially African American women)
What is systemic lupus erythematosus?
Type III hypersensitivity
- immune system attacking self body
- can affect joints, skin, kidneys, blood cells, brain, heart, and lungs
What are some of the symptoms of systemic lupus erythematosus?
- Pleuritis, pericarditis, myocarditis
- Oral aphthous ulcers
- Arthritis
- Photosensitivity
- Anemia
- Butterfly rash
- Discoid rash
What will test positive in patients with systemic lupus erythematosus?
Positive ANA
Positive anti-dsDNA, anti-SM, antiphospholipid
What can differentiate systemic lupus erythematosus and rheumatoid arthritis?
- Erosions common in RA
- Morning stiffness lasts only minutes in SLE
- Arthritis not too common in RA
- Untreated RA: high levels of ESR and CRP
What is psoriasis?
Chronic, hyperproliferative inflammatory disorder characterized by thick adherent scales
How does psoriasis present?
- Mild pruritus
- Pink plaques
- Bilateral
- Nail pitting
What is multiple sclerosis?
Demyelinating disease in which the immune system attacks protective covering of nerves
How does multiple sclerosis present?
- Vision changes
- Vertigo
- Weakness
- Numbness/tingling/pain
- Urinary incontinence
- Lhermitte’s sign: electrical sensation running down spine and lower extremities with neck flexion
When do T cell immunodeficiencies present?
First 3-4 months of life
What is an example of a T cell immunodeficiency?
DiGeorge
- absent thymus
- hypoparathyroidism
- hypocalcemia
When do B cell immunodeficiencies present?
First 6 months
-mostly sinopulmonary and GI infections
What is an example of a B cell immunodeficiency?
Common Variable Immunodeficiency
What is SCID?
Absence of both T and B cells
- onset around 3 months
- diarrhea, pneumonia, otitis, sepsis
What is Chediak-Higashi syndrome?
Rare autosomal recessive lysosomal disorder
- problem with phagocytosis
- increased sinopulmonary and soft tissue infections
What are symptoms of HIV/AIDs
Flu-like:
- Myalgia
- Fever
- Anorexia
- Headache
- Fatigue
- Pharyngitis
