Immunology Flashcards
What is a type 1 hypersensitivity reaction
IgE antibodies
Mast cells and basophils - histamines and cytokines
Immediate reaction- FIRST reaction
Itchy, face swelling, urticaria, anaphylaxis
What is a type 2 hypersensitivity reaction
IgG and IgM antibodies
Activate complement system
Haemolytic disease of new born/ transfusion
BLOOD
What is type 3 hypersensitivity reaction ?
Auto immune
Immune complexes gather in tissue
SLE, RA, HSP
Some of these have 3 letters
What is a type 4 hypersensitivity reaction
T Lymphocytes
Damage in local tissue
Organ transplant rejection
Contact dermatitis
Inflam where the source is
What is the management of anaphylaxis
ABCDE
Airway
Oxygen if needed
Circulation - IV bolus
Lie patient flat
Look for flushing, urticaria and angio-oedema
IM adrenaline 0.5ml of 1 in 1000 and repeat after 5 mins
Steroids- IV hydrocortisone
Antihistamines- chlorphenamine/ cetirizine
Admit child and monitor for biphasic reaction
How do you confirm anaphylaxis
Serum mast cell try-taste within 6 hrs
Training on epipen use
What are the features of allergic rhinitis
IgE type 1
Seasonal- hay fever
Year round- dust mite
Occupational
Runny, blocked itchy nose, sneezing, itchy red eyes
Associated with atopy
Can be triggered by pollen grass, pets and dust mites
Management
Oral antihistamines prior to exposure
Non-sedating- cetirizine, loratidine
Sedating- chlorphenamine, promethazine
Nasal antihistamines- good for rapid onset symptoms
What are the features of Cow’s milk protein allergy
IgE mediated if reaction within 2 hrs
Non-IgE mediated if slower
Bloating, wind, abdo pain, diarrhoea, vomiting
Urticarial rash, angiooedema, sneezing, coughing, watery eyes
breast feeding mums avoid dairy
Replace formula with hydrolysed formulas
Most children outgrow by 3
Every 6 months can be tried on the milk ladder and progress until they develop symptoms
What are the features and management of SCID
Immunodeficiency
Failure to thrive, persistent diarrhoea, opportunistic infection (CMV, pneumocystis jiroveci, chicken pox)
Very unwell after vaccines
Causes
-Usually X-linked recessive inheritance mutation on T and b cells
-JAC3 mutation
-Adenosine deaminase deficiency
Management
Immunoglobulin therapy and sterile environment
Avoid live vaccines
Haematopoietic stem cell transplant
What is Omenn syndrome
Rare cause of SCID
Mutations in RAG1 and RAG2
Autosomal recessvie
Red scaly dry rash
Hairloss
Diarrhoea
Failure to thrive
Lymphadenopathy
Hepatosplenomegaly
What are the features of selective immunoglobulin A deficiency
Most common
Low IgA but normal IgG and IgM
IgA protects against infections on mucuous membranes
Mild immunodeficiency
Patients asymptomatic or have LRTI or autoimmune conditions (eg. Coeliac)
What are the features of common variable immunodeficiency
Genetic mutation in B cells
IgG and IgA deficiency
No deficiency in IgM
Recurrent RTI with chronic lung disease over time
No immunity to infections/ vaccines
Prone to immune disorders- RA and cancers - non-Hodgkins lymphoma
Manage with regular immunoglobulin infusions and infection treatment
What are the features of X linked agammaglobulinaemia
X-linked recessive
All immunoglobulins deficient
What are the features of DiGeorge syndrome
Under developed thymus gland= no T cells
Chromosome 22
Defect in the 3rd pharyngeal pouch and 3rd brachial cleft
CATCH-22
Congenital heart disease
Abnormal facies
Thymus not developed
Cleft palate
Hypoparathyroisism and hypocalcaemia
22nd chromosome affected
What are the features of purine nucleoside phosphorylase deficiency
Autosomal recessive
Build up of dGTP which is toxic to T cells
Normal level of B cells and immunoglobulins
Immunity gradually gets worse over time
