Immuno 12: Case studies in Immunology Flashcards
what happens in anaphylaxis
type I hypersensitivity reaction cross-linking of IgE on mast cells leads to mast cell degranulation results in: - increased vascular permeability - smooth muscle contraction - inflammation and increased mucus production
what is the most common presentation of anaphylaxis
urticaria/ angioedema
followed by upper airway oedema
how do we treat anaphylaxis
ABC
ocygen by mask
IM adrenaline - 0.5mg for adult and may repeat
IV antihistamines (10mg chlorpheniramine)
nebulised bronchodilators
IV corticosteroids (200mg hydrocortisone) - prevents rebound anaphylaxis
IV fluids
what are the types of latex allergy
type 1 hypersensitivity
type 1 hypersensitivity to latex can gross react with foods eg avocado/banana
type 4 hypersensitivity - contact dermatitis, 24-48hrs after exposure
2 methods of investigating latex allergy
in vitro tests for IgE to latex
in vivo skin prick testing
in vivo patch testing
what disorders are associated with recurring meningococcal meningitis infections
complement deficiency - increased risk of infection by encapsulated organisms
antibody deficiency - recurrent bacterial infections - URTI/LRTI
neurological - disturbance of BBB
what history of infections suggests immune disorders
SPUR Serious Persistant Unusual Recurrent
How can we test the function of complement
CH50 - functional test of the integrity of the classical complement cascade
AP50 - functional test of the integrity of the alternative complement cascade
how do you manage a patient with a complement deficiency
meningovax penumocax HIB vaccine daily prophylactic penicillin high level of suspicion
what illness can you get after taking penicillin for an infection
serum sickness
penicillin can bind to cell surface proteins
acts as a neo-antigen which stimulates a very strong IgG response
the individual is therefore sensitised to penicillin
subsequent exposure to penicillin leads to - formation of immune complexes with circulating penicillin
production of more IgG antibodies
causes: renal dysfunction, arthralgia, purpura
what are the investigations for serum sickness
low serum C3 + C4
specific IgG to penicillin
characteristic biopsy features (skin and kidneys) - infiltration of macrophages and neutrophils, deposition of IgG, IgM and complement
how do you manage serum sickness
discontinue penicillin immediately
decrease systemic inflammation via corticosteroids
ensure appropriate fluid balance
list 3 reasons for chronic infections in a 3 year old
cystic fibrosis
local factors eg foreign body
ciliary disorders
features of X linked agammaglobulinaemia
failure of pre-B cells to mature in the bone marrow
leads to failure to produce immunoglobulin
how is X linked agammaglobulinaemia managed
immunoglobulin replacement therapy
- pooled serum Ig
- every 3 weeks
- indefinite
