Immunology Flashcards
Type 1 Hypersensitivity rxn:
Anaphylactic
Type 2 Hypersensitivity rxn:
Cytotoxic
Type 3 Hypersensitivity rxn:
Immune complex-mediated
Type 3 Hypersensitivity rxn:
Cell-mediated/delayed
Causes of Type 1 HS rxn
Anaphylaxis [food, bees, medications, rubber], atopy, hay fever, urticaria, allergic rhinitis,
Cause of angioedema?
C1 esterase inhibitor, C4 complement is low
Causes of Type 4 HS rxn
TB skin test, contact dermatitis [poison ivy, nickel earrings, cosmetics, medications], chronic transplant rejection, granulomas (sarcoidosis)
If a patient wants HIV testing because of recent risk-taking behavior and the initial test is negative, what should be done next?
Retest patient in 6 months since it takes up-to 12 weeks for antibodies to develop in patients recently exposed to HIV
HIV and pneumonia, dx?
PCP, look for patient with severe hypoxia, normal XR or diffuse bilateral interstitial infiltrates
Features of IgA deficiency
Most common primary immunodeficiency.
Recurrent respiratory and GI infections.
IgA low, IgG subclass 2 low.
Anaphylaxis to blood transfusion
Features of Bruton agammaglobulinemia
X-linked agammaglobulinemia:
- X-linked recessive (affects males)
- low or absent B cells
- Infection begin after 6 months of age when maternal antibodies disappear
- recurrent lung or sinus infections with Strep and Haemophilus species.
Cause of DiGeorge syndrome
Hypoplasia of the 3rd and 4th pharyngeal pouches
Presentation of DiGeorge syndrome
Cleft palate Abnormal facies Thymic aplasia -> t cell deficiency Cardiac defects (Tetrology of Fallot or Transposition og GV) Hypocalcemia (p/w tetany) 22q11
Most common cause of SCID
Adenosine deaminase deficienecy, AR, defects in B and T cells resulting in severe infections in the first few months of life.
- W/o B-cells: risk of pyogenic infections to organisms with polysaccharide capsules (Strep pneumo, H influenzae, N meningitidis)
- W/o T-cells: risk of opportunistic pathogens (PCP, Herpesviridae)
- Absent or dysplastic THYMIC SHADOW and no lymph nodes
Classic Triad of Wiskott-Aldrich syndrome
Wiskott Aldrich Thrombocytopenia purpura Eczema Recurrent infections (usually respiratory)
Features of Chediak-Higashi syndrome
AR, problem with microtubule polymerization interrupting lysosomal trafficking b/c there is no phagosome-lysosome fusion resulting in GIANT granules in NEUTROPHILS, pyogenic infections, oculocutaneous ALBINISM, peripheral neuropathy
Features of Chronic granulomatous disease
X-linked recessive, affecting males
Defect in NADPH oxidase
Recurrent infections with CATALASE-POSITIVE ORGs
Abnormal NBT dye reduction test NEGATIVE
CATALASE-POSITIVE organisms
Nocardia Pseudomonas Listeria Asergillus Candida E. coli S. aureus Serratia
When do you start PCP ppx for HIV? With?
CD4 count
PCP pneumonia can p/w?
Elevated LDH, interstitial infiltrates, hypoxia, nodular/papular lesions of external auditory meatus
If patient is allergic to Bactrim (TMP-SMX), what alternative medications can they use?
Dapsone, aerosolized pentamidine, atovaquone
When do you start Mycobacterium avium complex ppx?With?
CD4 count
Recommended vaccines for HIV pts:
- MMR vaccine (if CD4>200)
- Varicella vaccine (if CD4>200)
- Influenza yrly
- Tdap + Td q10yrs
- PCV13 + PPSV23
- Hep A and Hep B
Infants from HIV + mothers should receive what at birth?
Zidovudine for at least 6 weeks after delivery
What stain is used on sputum to detect PCP?
Silver stain (Wright Geimsa or Geimsa)
What pathogen causes chronic watery diarrhea in HIV patients?
Cryptosporidium
Complement deficiencies of C5 and C9 through C9 recurrent infections with genus of bacteria?
Neisseria species
Job-Buckley syndrome
Hyper IgE syndrome (T cell disorder)
- coarse facies (fair skin)
- cold staph abscess
- retained primary teeth
- ecezema (red hair)
