Micro

Question 1

What are the centor criteria?

Answer 1

• tonsillar exudate
• tender anterior cervical adenopathy
• fever over 38^C
• absence of cough

Question 2

What is the centor criteria?

Answer 2

An indication of the likelihood of a sore throat being caused by a bacterial infection

Question 3

Streptococcus pyogenes

Answer 3

Gram positive (purple)
Lancefield group A
Beta-haemolytic
Causes pharyngitis

Question 4

Causes of pharyngitis

Answer 4

Viral (70-80%)
Rhinovirus, adenovirus, Epstein Barr virus, acute HIV

Bacterial
Streptococcus pyogenes, mycoplasma pneumoniae (occurs in epidemics), neisseria gonorrhoea, corynebacterium diphtheria

Question 5

Corynebacterium diphtheria

Answer 5

(Travel e.g. Russia)
Children with grey membrane on tonsils

Treatment: antitoxin and erythromycin

Question 6

Epiglottitis

Answer 6

Formerly illness of children aged 2-4
Primarily caused by haemophilus influenzae, reduction in cases due to vaccine
Enlargement of the epiglottis causes narrowing of the airway
“Thumb sign” on x-ray

Question 7

Haemophilus influenzae

Answer 7

Gram negative cocobaccili

Treated with amoxicillin, doxycycline/co-amoxiclav (20% are beta lactamase producers)

Question 8

Bordatella pertussis

Answer 8

Gram negative bacillus
Cause of whooping cough, babies vaccinated at 2 months with 6-in-1
Clinical features:
- incubation
- catarrhal phase; rhinorrhoea, conjunctivitis, low-grade fever
- paroxysmal phase; coughing spasms, inspiratory “whoop”

Treatment: clarithromycin

Question 9

Atypical pathogens

Answer 9

Legionella pneumophilia (air conditioning/spain)
Mycoplasma pneumoniae
Chlamydophila pneumoniae

Need “special” antibiotics
Not susceptible to b-lactams/penicillins
Treat with: macrolides, fluoroquinolones, tetracyclines

Question 10

Staphylococcus aureus

Answer 10

Gram positive cocci - clusters
Main cause of ventilator-acquired pneumonia/hospital-acquired
Treatment: flucloxacillin
If MRSA, vancomycin

Question 11

Mycoplasma pneumoniae

Answer 11

Epidemics every 4 years
May have extra-pulmonary features: cold agglutinins cause haemolytic anaemia and raynauds (peripheral vasoconstriction)
Treatment: macrolides (erythromycin), fluoroquinolones, tetracyclines

Question 12

Legionella pneumophilia

Answer 12

Associated with water - air-conditioning units, water towers etc. and spain
Tends to affect elderly, immunocompromised
Extra-pulmonary features: diarrhoea, abnormal LFTs, hyponatraemia
Treatment: macrolides, fluoroquinolones, tetracyclines

Question 13

Mild severity pneumonia in community - CURB65 0-1

Treatment?

Answer 13

Amoxicillin or clarithromycin/doxycycline if penicillin allergic

Question 14

Moderate severity pneumonia in community - CURB65 2

Answer 14

Amoxicillin + clarythromycin

Question 15

Severe pneumonia in community - CURB65 3-5

Answer 15

IV co-amoxiclav + clarythromycin

alternatives: cerufoxime + clarythromycin

Question 16

Streptococcus Pneumoniae

Answer 16

Gram positive diplococci - chains
Main cause of community acquired pneumonia
Treatment: Amoxicillin or clarythromycin

Question 17

Klebsiella pneumoniae

Answer 17

Gram negative bacilli
Normal flora of mouth and intestines
Homeless, alcoholic, hospital-associated
Treatment: co-amoxiclav, cephalosporins (e.g. cefuroxime)

Question 18

Mycobacterium tuberculosis

Answer 18

Aerobic, non-motile, non-sporing rods
Acid fast (ziehl neelson)
Causes TB
Resists phagolysosomal killing by macrophages
Bacilli settle in apex of lung (aerobic bacteria, more aerated)