Allergy/Immunology Flashcards
Skin testing for which type of allergy is fairly unreliable?
Food allergies
For how long can food allergy symptoms continue to progress after ingestion?
2 hours
What are some common allergies in infants and toddlers?
Eggs
Milk
Soy
Wheat
Usually outgrown by 5 years
What medications blunt the effect of epinephrine?
Beta blockers
Give glucagon to reverse the effect and then give epi
What are the features of a true milk protein allergy?
- True IgE mediated allergy
- GI symptoms + extraintestinal symptoms
- Vomiting, diarrhea, GI bleeding
- Eczema, wheezing
What are the features of food protein induced enteropathy?
- aka, Formula induced enteropathy
- Sxs: diarrhea +/- emesis, bloody stool while on formula but not on clears or non-whole-protein-containing formulas
- Dx: flexible sigmoidoscopy with bx
- Tx: stop milk, change to hydrolysate formula or amino acid derived formula
What are the 4 types of hypersensitivity reactions?
- Type 1: IgE mediated, Anaphylactic (PCN allergy, if rxn occurs >24 hrs after administration, it is not a PCN allergy)
- Type 2: antiBody mediated = B cell = Humoral
- Type 3: immune Complex
- Type 4: Delayed = T cell mediated = Cellular immunity
What are the drugs that cause and symptoms of Anticonvulsant Hypersensitivity Syndrome?
- Drugs: Carbamazepine, Phenobarbital, Phenytoin
- Sxs: Fever + LAD + Rash +/- Visceral involvement
What are the symptoms of and treatment for serum sickness?
- Sxs: arthritis, arthralgias, nephritis, rash within 1 to 2 weeks of exposure
- Tx: remove offending agent, anti-histamines for pruritis and rashes, NSAIDs for fever, steroids for severe symptoms
How do you test for humoral defects?
AntiBody tests
- Isohemagglutinins
- Serum IgG (subclasses from previous vaccination to tetanus, varicella, rubella)
What tests do you do to check for cellular defects?
Type IV Delayed Type Hypersensitivity Anergy
- Skin testing: PPD, candida, mumps, tetanus
- Candida delayed type hypersensitivity intradermal test.
- If >10mm after 48 hrs, cellular immunity is intact, no primary T cell defects
- If test is negative ->
- Lymphocyte count, T-cell subtype with flow, lymphocyte stim test
T-cell mediated immunity includes activation of antigen specific cytotoxic T lymphocytes, macrophages, NK cells, and CD4 cells
How do you test for phagocytic defects?
DHR test
Nitroblue Tetrazolium dye
How do you test for complement defects?
Total complement assay (CH50)
What are the clinical features of T-cell mediated immunity?
- Activation of antigen specific cytotoxic T lymphocytes, macrophages, and NK cells
- Recurrent viral, fungal, and bacterial infections
What are the clinical features of severe combined immunodeficiency (SCID)?
- T and B cell deficiency
- Lymphopenia
- No LAD
- thymus
- BMT is an option
- All kinds of infections (viral, bacterial, fungal, opportunistic)
What are the five cardiac associations with DiGeorge syndrome?
“A curious George INTERRUPTS you to look through all FOUR TRUNKS full of treasure. His greatest find is a PALM tree studded with Very Sparkly Diamonds which he accidentally drops into the CANAL.”
INTERRUPTS = interrupted aortic arch FOUR = tetralogy of fallot TRUNKS = truncus arteriosus PALM = pulmonary stenosis with Very Sparkly Diamonds = VSD CANAL = AV Canal
What are the clinical features of DiGeorge syndrome?
- 22Q11.2
- Diagnosed with FISH
- No thymus (BMT does not cure) -> no T cells -> no antigen presentation -> no B cells
- Cardiac problems
- Hypoparathyroidism
- Velocardiofacial Syndrome: palatal abnormalities + cardiac abnormalities + craniofacial abnormalities (unusual palpebral fissures, broad nasal root, narrow upper lip)
What are the clinical features of ataxia telangiectasia?
ATAXIA A: ataxia (cerebellar) T: telangiectasias A: AFP elevated X: visual motor disturbances I: immune deficiency (pneumonia, decreased T cell fxn, increased risk of malignancy) A: abnormal cognition and neuro
What are the clinical features of common variable immune deficiency?
- B cells fail to transform into plasma cells
- Deficiency of all Ig subtypes
- Tx: IVIG
What kind of infections are those with B cell deficiencies predisposed to?
Encapsulated organisms "Some Nasty Killers Have Some Capsular Protection." Streptococcus pneumoniae Neisseria meningitidis Klebsiella pneumoniae Haemophilus influenzae Salmonella typhi Cryptococcus neoformans Pseudomonas aerginosa
What are the clinical features of Hyper IgM Syndrome?
- IgM to IgG switch does not occur due to missing signal
- Lymphocytosis and neutropenia
- T-cell abnormality
- Tx: IVIG
What are the clinical features of Bruton’s Agammaglobulinemia?
- X-linked = only in boys
- High T-cell counts
- Total absence of B cells
- No nodes
- Recurrent infections with encapsulated organisms
- No PCP pneumonia
- Tx: IVIG, BMT
What are the clinical features of transient hypogammaglobulinemia of infancy?
- B cells are not deficient
- Low levels of IgG +/- IgA
- Infections similar to Bruton’s around 3 to 6 months
- No treatment in asymptomatic patients
- Usually outgrow by 3 to 6 years of age
What are the clinical features of Hyper IgE syndrome?
- Autosomal dominant
- Impaired neutrophil chemotaxis
- Eosinophilia + Eczema + Elevated IgE
- Eczema starting the first week of life
- Recurrent sinus and pulmonary infections
- Pneumatoceles seen on chest x-ray after a pneumonia
- “Cold” staph infections (no surrounding erythema due to impaired neutrophil chemotaxis)
- Delayed shedding of primary dentition
What do patients with C5-9 complement deficiency get frequently?
Neisseria infections
What conditions have low complement levels?
"Even though CPS is COMPLEMENTARY, they need MANy more MEMBerS of their staff to Hack it." Cryoglibulinemia Poststreptococcal glomerulonephritis Systemic lupus erythematosis MANY: multiple myeloma MEMBranoproliferative glomerulonephritis Sjögren's syndrome Hepatitis C
What are the clinical features of leukocyte adhesion deficiency?
- Adhesion defect -> neutrophils can’t leave the vasculature to get to infected areas
- No pus/inflammation
- Delayed umbilical cord separation
- Delayed wound healing
- Leukocytosis, Neutrophilia
- Dx: CD11/CD18 flow cytometry
What are the clinical features of Chediak-Higashi syndrome?
CHINA
Chediak
Higashi
Infections: skin, lung
Neutropenia (poor neutrophil chemotaxis, platelet dysfunction) - Neutrophils contain giant lysosomal granules
Neurologic dysfunction (peripheral neuropathy)
Albinism (oculocutaneous)