Lecture 39: Genital ulcers and lesions

Question 1

Insert slide one picture of the tongue. Describe the appearance of this tongue and the likely cause:

Answer 1

Bacterial overgrowth + ulceration following general illness, not eating, not drinking.

Not candida b/c these are not plaques.

It is likely herpes simplex virus (Primary infection can be quite bad)

Question 2

How does herpes simplex infection change with recurrent infections?

Answer 2

Primary infections can be quite bad

Question 3

What is used to treat syphilis?

Answer 3

benzathine penicillin

Question 4

What are the probable diagnosis for genital ulcer presentations?

Answer 4

1st - Syphilis (Chancre, big)
2nd - Herpes (multiple small lesions)

Question 5

Describe the herpes virus:

Answer 5

• Enveloped, double stranded DNA virus, large viruses.
• Latency and potential for reactivation

Question 6

Describe the hang out place for latent herpes viruses:

Answer 6

HSV1 (cold sores), HSV2 (Genital ulcers), Chicken pox = Establish latency in sensory ganglia

EBV - Latency in B cells
CMV - Latency in myeloid cells

Question 7

Does HSV1 exclusively cause cold sores?

Answer 7

Majority causes cold sores, some can cause genital herpes. Same for HSV2. (spectrum)

Question 8

How many people are symptomatic with herpes?

Answer 8

20-50% of those infected have no primary illness.
- Can shed virus asymptomatically
- Lesions can be very minor and spread virus

Question 9

What is used to treat HSV?

Answer 9

Acyclovir

Question 10

How does acyclovir work?

Answer 10

• Taken up by infected and non-infected cells
• ONLY IN INFECTED CELLS, VIRAL thymidine kinase phosphorylates acyclovir activating it. (di or tri, = acyclo-guanosine-triphosphate)
• AGT enters host nucleus and is incorporated into viral DNA chain, which jams viral DNA polymerase and stops replication
• DNA polymerase is not affected as viral thymidine kinase is 3000x more active in phosphorylating acyclovir.

Question 11

Compare and contrast acyclovir and valacyclovir?

Answer 11

Acyclovir, F = 15%, water soluble
Valacyclovir, F = 60%, not water soluble

Valacyclovir is much better to be absorbed through the brush border, metabolised into acyclovir by 1st pass metabolism

Question 12

What are the potential complications of HSV1?

Answer 12

HSV1 encephalitis - Fever, seizures, coma (high mortality), , ICU + IV Acyclovir

(In immunocompromised people tissue necrosis can occur)

Question 13

What are the potential complications of HSV2?

Answer 13

HSV2 meningitis - self limiting

Question 14

How is HSV diagnosed?

Answer 14

Clinical: Cold sores, typical genital lesions

Swab - vesicle fluid or ulcer base -> PCR

Question 15

What is tropnema pallidum and hows it spread? can it be grown?

Answer 15

Syphilis

Sexually

Cant be grown in a lab

Question 16

Describe the timeline of a syphilis infection:

Answer 16

Sex -> 21 days incubation (bactereamia to organs) -> Primary syphilis (chancre, heals 3-6 weeks)

This can become either:

Latent syphilis: No current illness, abnormal serology, no hx treatment. (<4 years reinfection common, >4yrs reinfection rare)

Secondary syphilis: Disseminated (symptoms can occur in any organ), Rash (90%), fever, lymphadenopathy, can be meningitis…. up to 75% asymptomatic

Finally: Tertiary syphilis (can occur many years after)

Question 17

What are the types of tertiary syphillus:

Answer 17

Neurosyphillus: range of presentations. (dementia, pain etc, asympt chronic meningitis)

Cardiovascular syphilis: Destruction of the vaso vasorum of the aorta, hypertension and aneurysms

Gummatous syphilis: Granulomatous lumps in any organ (very rare)

Question 18

How is syphilis diagnosed?

Answer 18

Primary: Swab chancre, fluorescent microscopy

Other stages: Serology i.e
1. Enzyme immunoassay (sensitive, non-specific)
2. Specific antibody test (troponum pallidum particle agglutination)
3. Quantify IgM/IgG antibody (reactive plasma reagin)

Question 19

Why would you test for syphilis?

Answer 19

1. Suspect disease
2. Screening people at increased risk

i.e a person with chlamydia; a gay man with recent casual partners, pregnant women?

Question 20

Whats the main problem with HPV?

Answer 20

Oncogenesis; genital, head and neck

Some HPV cause cancer, some cause warts hence broad spectrum vaccine

Question 21

Describe the HPV vaccine:

Answer 21

The HPV vaccine is a virus like particle, essentially an empty shell of virus surface proteins

Protects against: HPV6,11,16,18,31,33,45,52,58….

Of which cause 90% of some cancers..