Approach to Hypersensitivity and Autoimmune Conditions Flashcards
4 steps of Type I Hypersensitivity
- antigen exposure
- IgE cross linking on mast cell/basophil
- Mediator (histamine, PG, leukotriene, tryptase) release
- Sx within min of exposure & can return 4-8 hrs later
Sx of Type I Hypersensitivity
urticaria (hives), rhinitis, wheezing, diarrhea, vomiting, hypotension, and anaphylaxis
Examples of Type I Hypersensitivity
Pollen allergies, dust mite allergy, bee sting
3 mechanisms of Type II Cytotoxic Hypersensitivity
- Opsonization (for phagocytosis)
- Complement-mediated lysis
- Ab-dependent cellular cytotoxicity
2 Ig types involved in Type II Cytotoxic Hypersensitivity related cell destruction
IgG and IgM
Examples of Type II Cytotoxic Hypersensitivity
ABO mismatch, Graves dz, Myasthenia gravis
Characteristics of Myasthenia gravis (Type II hypersensitivity)
Ptosis, mechanism: prevents Ach from binding Ach-R.
3 steps of Type III Immunocomplex Hypersensitivity
- Antigen-antibody complex formation
- Activates complement/neutrophil invasion into tissues
- Tissue inflammation leading to sx
Sx of Type III Immunocomplex Hypersensitivity
fever, urticaria (hives), generalized lymphadenopathy, arthritis, glomerulonephritis, vasculitis, SOB
Examples of Type III Immunocomplex Hypersensitivity
SLE, RA, Farmer’s Lung
2 steps of Type IV Cell-Mediated Hypersensitivity
- Antigen exposure activates sensitized T-cells
- Tissue inflammation 48-96 hrs after antigen exposure
Examples of Type IV Cell-Mediated Hypersensitivity
poison ivy rash, ppd for TB testing
Example of? (hint a hypersensitivity)
Type IV Cell-mediated hypersensitivity
Name the condition:
- Autoimmune systematic inflammatory dz affecting synovial membranes
- Granulation tissue in joint spaces and erodes articular cartilage and bone
RA
For RA:
Presentation of RA:
- joint ____, (color) , (temperature) , and ___ ROM
- morning, >1 hr ______
- sites most affected: list 5
- lab findings:
- or - rheumatoid factor
- or - anti CCP antibody
- elevated or normal ESR and CRP
- joint swelling (soft), erythema, warmth, decreased ROM
- morning >1 hr stiffness
- PIP, MCP (boutonniere deformity), wrist, knees ankles
- lab findings:
- rheumatoid factor
- anti CCP antibody
- elevated ESR and CRP
Patients with RA are at increased risk for 3 things:
- infection from immunosuppresion
- leukemia/lymphoma
- CV disease
Name the condition:
- Collagen vascular disorder w/ persistent inflammation in 1+ joints for 6+ weeks in patients < 16 yo
Juvenile idiopathic arthritis (JIA, aka juvenile RA)
For JIA:
Which of the 3 JIA presentations is the following?
- Large joints, asymmetric
- Iridocyclitis (inflammation involving ciliary body)
- Uveitis
Pauciarticular
Which of the 3 JIA presentations is the following?
- Large and small joints, symmetric
Polyarticular
Which of the 3 JIA presentations is the following?
- Recurrent, high fevers
- Myalgias, pericarditis, lymphadenopathy, etc.
- Anemia, leukocytosis
Systemic (Still’s Disease)
Workup for JIA
- CBC
- ESR (erythrocyte sedimentation rate)
- RF/ANA (rheumatoid factor/antinuclear antibody)
- X-rays
- Synovial fluid (check for leukocytosis/elevated protein)
Name JIA presentation corresponding to complication
- Sx wax and wane over time
- half get destructive arthritis, complete resolution rare
- 70% go into remission after several yrs
- Polyarticular
- Systemic (Still’s disease)
- Pauciarticular
Name the condition:
- Inflammatory disorder common among African Americans characterized by reccurent occurence/remissions, secondary to autoantibody formation and immune complex deposition
Systemic Lupus Erythematosus (SLE)
For SLE:
To be diagnosed with SLE how many of the following sx does a patient need to have?
- Pleuritis, pericarditis, myocarditis
- Oral aphthous ulcers
- Arthritis
- Photosensitivity
- Hemolytic anemia, thrombocytopenia, leukopenia, lymphopenia
- Proteinuria or urinary cellular casts
- Positive ANA
- Positive anti-dsDNA, anti-SM, antiphospholipid
- Lupus cerebritis, seizures, psychosis
- Malar rash (photosensitive butterfly rash)
–Discoid rash
At least 4
Name the condition:
- Erosions: very rare
- Morning stiffness: minutes
- Deforming arthritis: uncommon
- ESR and CRP slightly elevated
SLE
Name the condition:
- Erosions: common
- Morning stiffness: hours
- Deforming arthritis: common
- ESR and CRP significantly elevated
RA
2 reasons patients usually die from SLE:
- end organ damage
- opportunistic infections due to immunosuppresion
Name that condition:
- Chronic, hyperproliferative inflammatory disorder characterized by thick adherent scales
- Males and females equally affected w/ genetic component
Psoriasis
Presentation of Psoriasis:
- Mild _____
- (color) plaques w/ adherent (color) scales
- Involves _____ surface
- Bilateral or unilateral?
- _____ pitting
- Can potentially worsen to _____
- Mild pruritus (itch)
- Salmon pink plaques w/ adherent silver white scales
- Involves extensor surface
- Bilateral
- Nail pitting
- Can potentially worsen to arthritis
Workup for Psoriasis
PE: Auspitz sign – pinpoint bleeding after remove scale
Biopsy (sometimes)
Name that condition:
- Demyelinating disorder of the CNS
- Peak incidence around 20-40 yo
- Females > males and maybe genetic component
MS
Presentation of multiple sclerosis (MS):
- Hint: the “MS rollercoster”
While riding the MS rollercoster I felt electricified but upon getting off, I had trouble walking. My legs were weak, tingling and numb. I was dizzy, my vision was blurred. I needed to sit on the toilet for a while to recover.
- Vision changes
- Vertigo
- Weakness
- Numbness/tingling and/or pain
- Urinary incontinence or retention
- Lhermitte’s sign – electrical sensation running down spine and LE with neck flexion
Workup for MS
- MRI
- CSF
Clinical signs that suggest a primary immunodeficiency disease
Which of the 4 primary immunodeficiencies is the following?
- Present in first 3-4 months of life
- Disseminated intracellular diseases
T cell
Example of T cell primary immunodeficiency
DiGeorge Syndrome (Thymic Aplasia, Chromosome 22 del)
Which of the 4 primary immunodeficiencies is the following?
- Present after 6 months of age (maternal antibodies disappear)
- Sinopulmonary and GI infections
B cell
Which of the 4 primary immunodeficiencies is the following?
- Combination of T-cell and B-cell features
T cell / B cell combined
Which of the 4 primary immunodeficiencies is the following?
- Sinopulmonary and soft tissue infections
Phagocytic
Example of B cell primary immunodeficiency
Common Variable Immunodeficiency (CVID)
- presents w/ spenolmegaly, lymphadenopathy
Example of T cell / B cell combined primary immunodeficiency
Severe Combined Immunodeficiency (SCID)
- Onset 3 mos
- Presents w/ diarrhea, pneumonia, failure to thrive, otitis
Example of phagocytic cell primary immunodeficiency
Chediak–Higashi syndrome
- albinism, neuropathy
Name that condition:
- Spread almost exclusively through body fluid transmission
- Male > female
HIV/AIDS
Presentation of Human Immunodeficiency Virus, Acquired Immunodeficiency Syndrome (HIV/AIDS):
- Initially _____, followed by _____-like sx
- Initially asymptomatic, followed by flu-like symptoms
Workup for HIV/AIDS
- ELISA
- Western Blot
- HIV RNA viral load
Diagnosis of AIDS requires (2 possibilities):
- CD4 count <200 OR
- Presence of AIDS defining illness (virus induced sx)
