EENT

Question 1

list the types of hypersensitivity 4 groups

Answer 1

type 1: immediate, mediator-IgE monomers, example - anaphylaxis

type 2: cytotoxic, mediator IgG/IgM monomers, example - drug-induced haemolysis

type 3: immune complex, mediator - IgG/IgM complexes, example - serum sickness

type 4: delayed, mediator - T-cells, example - contact dermatitis

Question 2

describe type 1/immediate hypersensitivity

Answer 2

• called immediate
  -IgE mediated
• affects mast cell degranulation
  -releases mediators e.g. histamines and leukotrienes

1 - sensitization - antigen contact + IgE production
2 - Elicitation - IgE triggers mast cell activation and degranulation to release immediate and inflammatory mediators. Cross-links IgE receptor on mast cells.

Examples:
-Allergic Rhinitus
- Asthma
-Food allergies
-Anaphylaxis

Question 3

what is hypersensitivity

Answer 3

exaggerated response of the immune system
mediated by adaptive immune system
occurs on sensitisation step - not seen on 1st contact.

Question 4

how does type 2 hypersensitivity occur

Answer 4

caused by IgG or IgM
mechanisms -
complement-mediated cytolysis: antibodies bind to target cells and activate C1 causing destruction of the membrane

antibody-dependant cell mediated cytotoxicity:
IgM pr IgG bind to target cells and cause phagocytosis by effector cells

Question 5

How does type 3 hypersensitivity occur?

Answer 5

IgM or IgG
-forms a immune complex with antigen and antibody excess.
- insoluble complexes cause deposits in different organ systems leading to tissue injury.
-example: Glomerulonephritis - causes leakage of serum proteins

Question 6

How does type 4 hypersensitivity occur?

Answer 6

• caused by T cells
• prev sensitised T cells exposed to antigens and stimulated (delayed/cell mediated)
• release cytokines and other inflammatory mediators
  -macrophages and other T cells destroy surrounding tissue

Question 7

what pathogens are associated with otitis media

Answer 7

Bacteria - haemophilus influenza, strep pneumoniae
virus - RSV, rhinovirus, influenza virus

Question 8

what is the epidemiology and clinical aspects of otitis media

Answer 8

inflammation in the middle ear, associated with effusion, and rapid onset of symptoms and ear infection. Infected fluid in middle ear.

most common in children, more prone to infection and shorter eustachian tubes, occurs in the winter more commonly.

symptoms: rapid onset, earache, redness of tympanic membrane, difficulty sleeping, fever and irritability

Question 9

what is the management of acute otitis media?

Answer 9

lasts about 3 days - week.

offer paracetamol or ibuprofen for pain.
consider ear drops if no antibiotics given

if patient is child and systemically unwell offer immediate antibiotic prescription and refer to hospital if severe systemic infection or other complications

Question 10

what are the treatments for congestion, rhinitis + sinusitis?

Answer 10

congestion - steam inhalation, saline sprays e.g. sterimar, corticosteroid nasal sprays e.g. Beconase, oral decongestants e.g. pseudoephedrine

rhinitis - saline solution, avoid triggers, antihistamines, decongestants, internasal corticosteroids

sinusitis - no antibiotic treatment if symptoms less than 10 days, self management. Chronic requires antibiotics

Question 11

how do we treat congestion

Answer 11

activate sympathetic system (agonists at alpha adrenergic receptors) or inhibit parasympathetic system (antagonists at cholinergic receptors) to promote vasoconstriction and stop leaking vasodilated vasculature.

Question 12

how do we treat inflammation

Answer 12

antihistamines - inverse agonists at H1 receptors)

Question 13

what increases selectivity for the alpha 1 adrenergic receptor?

Answer 13

presence of 2-phenolic hydroxyl on catechol