Immunology 8 - case studies Flashcards
What is the most common clinical presentation of anaphylaxis?
Urticaria/angioedema
Management of anaphylaxis in an adult
ABC (may need intubation/tracheostomy) Mask O2, inhaled salbutamol IM 1 in 1000 0.5mg adrenaline IV 200mg hydrocortisone IV 10mg chlorphenamine IV fluids
What is IV hydrocortisone important for in anaphylaxis?
Prevents rebound anaphylaxis
What are the 2 types of latex allergy?
Type I hypersensitivity (latex food syndrome), spectrum of sx
Type IV contact dermatitis
Risk factors for latex allergy
PREM
Indwelling latex devices e.g. VP shunt for hydrocephalus
Multiple urological procedures
Why are people with latex allergy prone to tropical fruit allergy? (latex-fruit syndrome)
Cross reactivity
What drug class does contact dermatitis not respond to? (type IV)
Anti-histamines
Ideal investigation for IgE specific to latex in patient who presented with anaphylaxis?
In vitro test i.e. blood test as skin prick has risk of anaphylaxis
What investigation done to test for type IV latex allergy?
Skin patch testing (taped to skin for 24-48 hrs)
For which allergens is desensitisation effective?
Insect venom and aero-allergens e.g. grass pollens
Disorders associated with recurrent meningococcal meningitis?
Complement deficiency (especially C5-C9) Anitbody deficiency ANy disturbance to BBB e.g. hydrocephalus, skull fracture
What kind of infections make you suspicious of an immunodeficiency?
SPUR Serious Persistent Unusual Recurrent
Suggested complement deficiency, what investigations do you order?
C3, C4
CH50
AP50
Normal C3
Normal C4
Absent CH50
Absent AP50
Indicates deficiency in final common pathway (C5-C9)
Tests to investigate lupus nephritis?
Urinalysis –> proteinuria, microscopic haematuria
Urine microscopy –> red cells and red cell casts
REnal biopsy –> diffuse proliferative nephritis, immune complex and complement deposition
What type of hypersensitivity is SLE?
Type iII (immune-complex mediated)
Penicillin for CAP –> 3 days later:
Fever, arthralgia, vasculitic skin rash, proteinuria, haematuria, raised transaminases, disorientation
Serum sickness
How does penicillin cause serum sickness?
Penicillin binds to cell surface proteins and is recognised as a neo-antigen: SENSITISATION. stimulates a strong IgG response
On next exposure –> IMMUNE COMPLEX FORMATION w circulating penicillin + mass IgG production –> complex deposits in glomeruli + skin + joints
Ix to confirm Dx of serum sickness
C3+ C4 levels (LOW)
Specific IgG to penicillin
Biopsy of skin and kidneys
What would biopsy of skin and kdineys show in serum sickness?
Infiltration of macrophages and neutrophils
Deposition of IgG and IgM and complement
Serum sickness type of hypersensitivity disorder
Type III
FTT +recurrent infections (tonsillitis, pneumonia, ROM, cellulitis):
Ddx?
CF Foreign body Atopy Bruton's SCID HyperIgM
Evaluation of lymphocyte immunodeficiency - which Ix?
CD4+ CD8+ T cells
Quantif B cells
IgM, IgG, igA
Specific antibodies to known antigens to which one has been exposed e.g. vaccination
Treatment of Bruton’s agammaglobulinaemia
IVIG every 3 weeks indefinitely (HSCT is permanent cure)
