Infectious disease 2

Question 1

What deficiency contribute to prolonged measles?

Answer 1

Vitamin A deficiency

Question 2

Measles pathognomic clinical features?

Answer 2

Koplik spots

Macular blanching rash starting at face and descends

Question 3

Treatment of ADEM? Acute disseminated encephalomyelitis?

Answer 3

IV Methylprednisolone

Question 4

What antibodies found in ADEM?

Answer 4

anti-MOG

Question 5

NMDA encephalitis strongly associated with?

Answer 5

Ovarian teratoma

Question 6

How does HSV1 gain entry into brain?

Answer 6

Trigeminal nerve

Question 7

Commonest organism to cause IE?

Answer 7

Staph aureus

Question 8

Transpeptidation meaning?

Answer 8

Peptidoglycan layer formation by PBP protein

Question 9

Enterococcus faecalis IE - treatment?

Answer 9

Ampicillin and Ceftriaxone as effective as

Ampicillin and Gentamicin

Question 10

When can Staph aureus bacteremia treated for only 2 weeks?

Answer 10

No implanted prosthesis
No endocarditis
No more MRSA in f/up blood cultures
No any further sites of infection
No more fever post treatment - > 72 hours

Question 11

Dexamethasone given for which meningitis and why?

Answer 11

Pneumococcal meningitis
Reduce brain edema and Neuronal hearing loss
Reduce effect of antibiotic-mediated bacteriolysis

Question 12

Benzylpenicillin given for which meningitis?

Answer 12

Listeria meningitis

Question 13

When considered ceftriaxone resistant meningitis?

Answer 13

MIC > 0.5 - So add vancomycin in this case

Question 14

Neisseria meningitis prophylaxis?

• normal population?
• pregnancy?

Answer 14

Normal population-Rifampicin

Pregnancy - IM ceftriaxone

Question 15

Spleen remove what?

Answer 15

Encapsulated bacteria
Opsonized bacteria (properdin)

Question 16

Commonest organism to cause of OPSI?

Answer 16

H. Influenzae and Streptococcus pneumonia

Question 17

Which meningococcal is difficult to vaccinate against?

Answer 17

MEN Type B - polysaccharide similar to fetal nerve cells - very non-immunogenic

Question 18

Why conjugate better than polysaccharide vaccine?

Answer 18

T-cell mediated - produce alot of MEMORY B CELLS

Question 19

why give conjugate vaccine prior to polysaccharide vaccine?

Answer 19

Polysaccharide causes HYPER-responsiveness of immune system

Question 20

Risk factors for OPSI

Answer 20

Children < 5 yrs old
Splenectomy for hematological disease
Post splenectomy - first 2- 3 yrs

Question 21

Infectivity of Covid19 formula?

To stop pandemic aim R to ?

Answer 21

R0 ( reproduction number) = c x p x d
New cases generated directly from single case where EVERYONE is susceptible

c = Contacts per unit time
p = probability of transmission
d = duration of infectiousness of cases

Rt =effective reproduction number
New cases generated directly from a single case where not everyone is susceptible

R < 1

Question 22

What is herd immunity threshold?

Answer 22

Proportion of immune individuals in a population that must be exceeded to prevent disease transmission

HIT = 1 - 1/R0

Question 23

What is secondary attack rate - SAR?

Answer 23

Proportion of susceptible individuals who have contact with positive cases = become infected, developing disease and infect others

*Spouse has highest SAR

Question 24

Multi-lobular pneumonia suspicious for?

Answer 24

Atypical pneumonia

Question 25

Nitrites in urine?

Answer 25

Only Gram NEGATIVE bacteria

nitrate convert to nitrite

Question 26

Impetigo a/w mainly?

Answer 26

Nasal carriage pathogen - Staph aureus,

Staph pyogenes is 2nd commonest

Question 27

Cellulitis commonest bacteria?

If cellulitis with DM - what antibiotics?

Answer 27

Strep pyogenes

Pip-Taz = cover pseudomonas + anaerobic

Question 28

Erypsipelas - commonest cause?

Answer 28

Strep pyogenes

Question 29

Commonest STI in women?

Answer 29

Chlamydia trachomatis

Question 30

Fitz-Hugh Curtis clinical features?

Answer 30

Gonoccal perihepatitis

RUQ mimicking Cholecystitis
violin-string = perihepatitis ( adhesion between liver capsule/peritoneum)

Question 31

Gonococcal infection main symptoms

Triad symptoms?

Answer 31

anorectal pain and discharge

Poly digs my tendons

• Polyarthritis
• Dermatitis
• Tenosynovitis