Clinical science shite

Question 1

Complement deficiencies
C1 inhibitor (C1-INH) protein deficiency

Answer 1

1. causes hereditary angioedema
2. C1-INH is a multifunctional serine protease inhibitor
3. probable mechanism is uncontrolled release of bradykinin resulting in oedema of tissues

Question 2

Complement deficiencies

C1q, C1rs, C2, C4 deficiency (classical pathway components)

Answer 2

1. predisposes to immune complex disease

2. e.g. SLE, Henoch-Schonlein Purpura

Question 3

Complement deficiencies

C3 Deficiency

Answer 3

causes recurrent bacterial infections

Question 4

C5 deficiency

Answer 4

1. predisposes to Leiner disease

2. recurrent diarrhoea, wasting and seborrhoeic dermatitis

Question 5

C5-9 deficiency

Answer 5

1. encodes the membrane attack complex (MAC)

2. particularly prone to Neisseria meningitidis infection

Question 6

Antibiotics: mechanism of action

Inhibit cell wall formation (beta-lactams)

Answer 6

1. penicillins: binds transpeptidase blocking cross-linking of peptidoglycan cell walls
2. cephalosporins

Question 7

Antibiotics: mechanism of action

Inhibit protein synthesis: these antibiotics are bateriostatic

Answer 7

aminoglycosides (cause misreading of mRNA)
chloramphenicol
macrolides (e.g. erythromycin)
tetracyclines
fusidic acid

Question 8

Antibiotics: mechanism of action

Inhibit DNA synthesis

Answer 8

quinolones (e.g. ciprofloxacin)
metronidazole
sulphonamides
trimethoprim

Question 9

Antibiotics: mechanism of action

Inhibit RNA synthesis

Answer 9

rifampicin

Question 10

Type I - Anaphylactic

Answer 10

Antigen reacts with IgE bound to mast cells

1. Anaphylaxis
2. Atopy (e.g. asthma, eczema and hayfever)

Question 11

Type II - Cell bound

Answer 11

IgG or IgM binds to antigen on cell surface

• Autoimmune haemolytic anaemia
• ITP
• Goodpasture’s syndrome
• Pernicious anaemia
• Acute haemolytic transfusion reactions
• Rheumatic fever
• Pemphigus vulgaris / bullous pemphigoid

Question 12

Type III - Immune complex

Answer 12

Free antigen and antibody (IgG, IgA) combine

• Serum sickness
• Systemic lupus erythematosus
• Post-streptococcal glomerulonephritis
• Extrinsic allergic alveolitis (especially acute phase)

Question 13

Type IV - Delayed hypersensitivity

Answer 13

T-cell mediated

• Tuberculosis / tuberculin skin reaction
• Graft versus host disease
• Allergic contact dermatitis
• Scabies
• Extrinsic allergic alveolitis (especially chronic phase)
• Multiple sclerosis
• Guillain-Barre syndrome

Question 14

Type V

Answer 14

Antibodies that recognise and bind to the cell surface receptors.

This either stimulating them or blocking ligand binding

• Graves’ disease
• Myasthenia gravis