Infectious disease & GUM

Question 1

Ix for HIV?

Answer 1

Combined HIV abs (4th gen) & p24 antigen tests

if +ve –> second sample required for confirmation

if -ve following HIV exposure –> repeat 12wks later to confirm

Question 2

HIV - Acute worsening of inf after starting ART?

Answer 2

IRIS

Question 3

HIV - Reduced visual acuity + “perivascular infiltrates”

Answer 3

CMV retinitis

Question 4

HIV - odynophagia + “white mucosal plaques” at endoscopy

Answer 4

oesophageal candidiasis

Question 5

Desaturation on exertion in HIV?

Answer 5

Pneumocystis jirovecii pneumonia

Question 6

HIV - Brain MRI with “ring-enhancing lesions”?

Answer 6

toxoplasmosis encephalitis

Question 7

HIV - Violaceous plaques + HHV8

Answer 7

Kaposi sarcoma

Question 8

STI causes of genital ulcer - DDx?

Answer 8

Question 9

Syphilis Tx? Name of immune reconstitution reaction? Ix?

Answer 9

Tx:

• Neurosyphilis –> IV aqueous benzylpenicillin 10-14 days
• Latent syphilis –> IM Benzathine benzylpenicillin STAT
• Otherwise –> IM Benzathine benzylpenicillin x3/2wks

Jarisch-Herxheimer reaction - acute febrile illness in 1st 24hrs post-Tx

• Acute headache, fever, myalgia

Ix:

• Lesion present - dark field microscopy (coiled spirochaete bacterium with corkscrew appearance with motility)
• Otherwise - Treponema serological testing (+ve active & past)

Question 10

Painless ulcer, painful unilateral inguinal LNs and proctocolitis?

Answer 10

Lymphogranuloma venereum (LGV)

Question 11

Painful ulcer + LNs

Answer 11

Chancroid

Question 12

TB drug SEs?

Answer 12

Question 13

TB Ix?

Answer 13

Question 14

CSF with low glucose, high proteins, lymphocytes

Answer 14

TB meningitis

Question 15

TB Tx durations?

Answer 15

Question 16

Clostridium difficile is associated with which abx? RFs? Mx?

Answer 16

RFs:

• >65yrs
• Abx (cephalosporins, penicillins, quinolone), PPIs
• prolonged hospitalisation, co-morbid
• Prev Hx/exposure to infected individuals

Question 17

Chronic abdo pain, altered bowel habit, no identifiable cause

Answer 17

Post-inf IBS

Question 18

Malaria Def? Ix? Tx?

Answer 18

Def:

• ≥10% RBCs infected
• ≥1 sign of severe disease

Ix: thick & thin blood film

Mx:

• Non-severe: oral artemisinin based combo therapy (ACT)
• Severe: artemisinin derivative IV followed by oral ACT

Question 19

General malaise, relative bradycardia & rose spots?

Answer 19

salmonella typhi

Question 20

Fever, headache, retro-orbital pain, myalgia & rash

Answer 20

Dengue

Question 21

“Bull’s eye rash” - erythema chronicum migrans

Answer 21

Lyme disease

Question 22

Proctitis + Lymphadenopathy + unprotected anal sex with male partner - Dx?

Answer 22

Lymphogranuloma venereum

Question 23

STI types? Ix? Mx?

Answer 23

• Chlamydia (Chlamydia trachomatis) – obligate intracellular G-ve (can’t be cultured on agar)
  
  • Classification: Serovars A-C = trachoma; D-K = genital, ophthalmia neonatorum, L1-3 = Lympho-granuloma venereum (LGV)
  • Ix: genital swab/urine sample –> NAAT
  • Mx: Azith 1g STAT/Doxy 100mg BD 7 days
  • Complications: PID (infertility/ectopic/chr pain)
• Gonorrhoea (Neisseria gonorrhoeae) – obligate intracellular G-ve diplococcus
  
  • Ix: swabs/urine sample –> culture
  • Mx: ceftriaxone 250mg IM STAT
• Syphilis (Treponema pallidum) – obligate G-ve spirochaete
  
  • Ix: dark-ground microscopy (from primary lesions)
    
    • Ab non-treponemal tests (non-specific antigens): VDRL, RPR (false positives common, declines with treatment)
    • Ab treponemal tests (specific antigens): EIA/FTA/TPHA/TP-PA (confirmatory, +ve for years despite treatment)
  • Mx: IM Ben Pen STAT
• Genital ulcers:
  
  • Painful = herpes > chancroid
  • Painless = syphilis > lymphogranuloma venereum (LGV) + granuloma inguinale

Question 24

What eye condition are you at risk of if you have herpes zoster opthalmicus? What is Hutchinson’s sign? Tx?

Answer 24

Anterior uveitis

Hutchinson’s sign: vesicles extending to the tip of the nose. This is strongly associated with ocular involvement in shingles

Oral antivirals ± steroids

• If eye involvement –> urgent ophthalmological review
• Eye lubricant if blink reflex affected to prevent damage to corneal epithelium

Question 25

Candidiasis Mx?

Answer 25

Miconazole

Fluconazole if invasive oesophagitis (difficulty swallowing)

Question 26

HIV eye conditions in low CD4?

• With visual blurring & flashing lights - Dx? Tx?
• Pain, rapid loss of vision in 1wk - Dx?
• Also oral lesions - Dx?

Answer 26

CMV retinitis (very common pre-ARTs)

• Painless blurring, floaters
• Fundoscopy: yellow-white exudates + haemorrhages on back of retina
• Tx: valganciclovir

HSV

• Pain, rapid loss of vision in 1wk (acute retinal necrosis)
• Fundoscopy: peripheral lesions

Candida - oral lesions

Question 27

HIV +ve, fevers, frontal headaches (around eyes), seizure, low CD4

CT has ring-enhancing lesions

DDx?

Answer 27

DDx:

• Toxoplasmosis - cat faeces, commonest CNS inf in HIV, flu-like illness, eye & basal ganglia involvement
• Primary CNS lymphoma

NOTE: PML - non-enhancing lesions in white matter (JC virus)

Question 28

Infectious disease + rash DDx?

Answer 28

Viral

• Measles
  
  • Maculopapular rash over hairline/forehead/behind ears, spreading downwards.
  • Koplik spots - white papules on buccal mucosa
• Rubella
  
  • Erythematous maculopapular rash on face –> spreads to extremities
  • Tender lymphadenopathy
• Infectious mononucleosis (EBV)
  
  • Morbilliform rash, pharyngitis, fatigue, myalgia
  • Hepatosplenomegaly, lymphadenopathy

Bacterial

• Meningococcal disease
  
  • Meningism + non-blanching rash
• Scarlet fever
  
  • Erythema of axilla/neck/chest –> progress to pink papules on erythematous background –> 7-10 days later = hand/foots desquamation
  • Pastia’s lines (linear petechial streaks in body folds), red strawberry tongue