Immuno 12: Case studies in Immunology Flashcards

1
Q

what happens in anaphylaxis

A
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
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2
Q

what is the most common presentation of anaphylaxis

A

urticaria/ angioedema

followed by upper airway oedema

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3
Q

how do we treat anaphylaxis

A

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

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4
Q

what are the types of latex allergy

A

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

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5
Q

2 methods of investigating latex allergy

A

in vitro tests for IgE to latex
in vivo skin prick testing
in vivo patch testing

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6
Q

what disorders are associated with recurring meningococcal meningitis infections

A

complement deficiency - increased risk of infection by encapsulated organisms
antibody deficiency - recurrent bacterial infections - URTI/LRTI
neurological - disturbance of BBB

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7
Q

what history of infections suggests immune disorders

A
SPUR 
Serious 
Persistant 
Unusual 
Recurrent
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8
Q

How can we test the function of complement

A

CH50 - functional test of the integrity of the classical complement cascade
AP50 - functional test of the integrity of the alternative complement cascade

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9
Q

how do you manage a patient with a complement deficiency

A
meningovax 
penumocax 
HIB vaccine 
daily prophylactic penicillin 
high level of suspicion
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10
Q

what illness can you get after taking penicillin for an infection

A

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

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11
Q

what are the investigations for serum sickness

A

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

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12
Q

how do you manage serum sickness

A

discontinue penicillin immediately
decrease systemic inflammation via corticosteroids
ensure appropriate fluid balance

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13
Q

list 3 reasons for chronic infections in a 3 year old

A

cystic fibrosis
local factors eg foreign body
ciliary disorders

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14
Q

features of X linked agammaglobulinaemia

A

failure of pre-B cells to mature in the bone marrow

leads to failure to produce immunoglobulin

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15
Q

how is X linked agammaglobulinaemia managed

A

immunoglobulin replacement therapy

  • pooled serum Ig
  • every 3 weeks
  • indefinite
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16
Q

features of MM

A
unusual or vertebral fractures 
high ESR 
high calcium 
measure Ig/ electrophoretic strip 
urinary BJP 
skeletal survey 
refer to haematoligist for specialist management
17
Q

features of rheumatoid arthritis

A

peripheral, symmetrical polyarthritis + stiffness
persists for >6w
may be associated with RF +/ anti-CCP antibodies
post-partum presentation common

18
Q

what is rheumatoid factor

A

antibody against Fc region of human IgG
assays look for IgM RF usually
also look at anti-CCP antibodies (highly specific)

19
Q

list genetic predispositions to rheumatoid arthritis

A

HLA DR - DR4, DR1
PADI type 2 and 4
PTPN 22

20
Q

how is rheumatoid arthritis managed

A

1st line - methotrexate (DMARD)
sulphasalazine/ hydroxychloroquine/leflunomide

further - anti TNF alpha
rituximab - anti CD20
abatacept - binds CD80 and CD86
tcilizumab - against IL6 receptor