Epidemiology of STIs & HIV

Question 1

Major STIs in Britain

Answer 1

Chlamydia - caused by Chlamydia trachomatis
Gonorrhea - due to bacteria Neisseria gonorrhoeae
Herpes - caused by HSV (type 2)
Syphilis - caused by bacteria Treponema pallidum

Question 2

General STI epidemiology

Answer 2

Steady, slow increase
Men have higher rate (160,000/year compared to 110,000 in 2002) but this difference in reduced now (210,000 to 200,000 in 2011)
MSM and young people at greatest risk, also inner city and black.

Question 3

Chlamydia - symptoms

Answer 3

Can cause dysuria, discharge or intermenstrual bleeding but is often asymptomatic (50% in men and 70-80% in women) –> can lead to PID or infertility if untreated.

Question 4

Chlamydia - treatment

Answer 4

Either single dose of azithromycin or a week of doxcycline BD
95% of infections are effectively cleared

Question 5

Chlamydia - epidemiology

Answer 5

Most common STI, over 186,000 new cases in 2011, about half diagnosed in community centres. m=f but previously it was more men. Numbers largely steady over ten years but with recent upswing

Question 6

Gonorrhea - symptoms

Answer 6

Develop within 10 days, In men –> thick coloured discharge, dysuria, foreskin inflammation & poss testicular pain, 10% asymptomatic
In women –> thick coloured discharge, dysuria, low abdo tenderness and bleeding. half asymptomatic. Risk of complicated infection or PID

Question 7

Gonorrhea - treatment

Answer 7

Usually treated by 500mg ceftriaxone IM and azithromycin 1g oral stat
Drug resistance is a major problem

Question 8

Gonorrhea - epidemiology

Answer 8

2nd most common STI, General downward trend over decade with recent upswing. 16,000/year in men and 8,000 in women.
Shows significant geographic and orientation clustering.

Question 9

Herpes - symptoms

Answer 9

Usually presents as multiple painful ulcers during primary infection. can have a febrile, flu-like prodrome of 5-7 days. tingling, neuropathic pain in genital area, dysuria, discharge and local swelling. tender inguinal nodes. recurrence are either asymptomatic or mild, self limiting episodes

Question 10

Herpes - treatment

Answer 10

Supportive (saline wash) or oral aciclovir (200mg QDS for 5 days in early stages or in patients with HIV. similar treatments for recurrence or suppressive treatment if >6 attacks/year.

Question 11

Herpes - epidemiology

Answer 11

Steady increase in cases, 10,000/year in men and 20,000 in women. prevalence of HSV-2 are higher in sex workers, HIV pos and LEDCs.
rates are highest in 20-24yros but rate in 45-64yos has doubled

Question 12

Syphilis - timecourse (acquired)

Answer 12

9-90 days incubation for local infection, 1-6months for generalised infection (2nd syphilis)—> can then be latent for 2yrs or more (early or late latent syphilis) then emerge as tertiary syphilis (cardiovascular/neurosyphilis/gummatous syphilis)

Question 13

Syphilis - timecourse (congential)

Answer 13

Early congenital syphilis occurs within the first 2 years or life, and late congenital syphilis in children older than two

Question 14

Syphilis - epidemiology

Answer 14

Still a rare infection but greatly increasing in numbers (1580 in 2003, 3762 in 2007). Increase is almost all MSM who account for 70% of cases, and there is a strong relationship with HIV co-infection
Also an increase in congenital syphilis

Question 15

Syphilis - symptoms (primary)

Answer 15

small, painless papule at site of infection with forms an painless, round ulcer (chancre) leaking clear serum. may also be enlarged regional lymph nodes.
Heals in 2-6 weeks

Question 16

Syphilis - symptoms (secondary)

Answer 16

appears between 6 weeks and 6 months after primary lesion. includes systemic symptoms (headache, rash, malaise, fever or aches) with painless lymphadenopathy and rash on palms, soles of feet and face. may have papules (enlarging to condylomata lata) and mucocutaneous lesions

Question 17

Syphilis - symptoms (tertiary)

Answer 17

Occurs in 40% of infections. Cardiovascular –> aortitis, leading to regurgitation, aneurysm,angina. Neurological –> can be asymptomatic or lead to dementia, mengiovascular involvement or dorsal column loss (tabes doralis). Gummatous –>locally destructive inflammatory fibrous nodules/plaques effecting bones or skin

Question 18

Syphilis - treatment

Answer 18

Contact tracing and STI test. For 1”, 2” or early latent–> benzylpenicillin 2.4 megaunit IM or oral azithromycin single dose
Late latent–> Benzylpenicillin weekly for 3 weeks
Neurosyphilis–> procaine penicillin 2.4units IM daily for 17 days with oral probenecid 500mg TDS or doycycline 200mg BD for 28 days

Question 19

Jarisch-Herxheimer reaction

Answer 19

an acute reaction to treatment causing febrile illness with headache, myalgia, chills and rigors. resolves within 24 hours. common in early syphilis but usually not important unless there is neurological or ophthalmic involvement. treat with pred and anti-pyretics.

Question 20

Interuterine syphilis

Answer 20

In pregnant infected women 70-100% of infants will be infected and stillbirth occurs in 1/3. in rest will lead to significant and multiple morbidity

Question 21

Lymphogranuloma venereum - LGV

Answer 21

A preveiously rare infection of the lymphatics due to chlamydia infection. Previously considered a tropical STI it is now becoming much more common in MSM who are co-infected with HIV. causes local abscesses and proctitis

Question 22

HIV and STIs

Answer 22

Rarer infections are more common in people who are immunosuppressed by HIV
Also STIs makes sexual transmission of HIV more likely due to local inflammation

Question 23

HIV Epidemiology

Answer 23

100,000 people with HIV in the UK - 6,300 new cases in 2012, half of which are MSM
24% unaware of infection
50% of diagnoses are made ‘late’ (very late)

Question 24

Trends in HIV in UK

Answer 24

First major spike in 1984 when an effective test was invented, then AIDs deaths increased until HAART being introduced in 1995. between 1999-2006 there was a steep rise in cases due to immigration from africa.

Question 25

Routes of HIV infection in Britain

Answer 25

MSM in britain is still largest and steadily increasing, as is heterosexual infection in britain, but at lower numbers
Heterosexuals infected abroad are greatly decreased due to reduced immigration, and vertical transmission and IVDU is very low

Question 26

HIV in MSM

Answer 26

Still largest group, with infection rate at 5% for whole group, and 9% in london.
Generally recently infected when diagnosed

Question 27

Screening for HIV

Answer 27

Universal offering at high risk clinical settings –> TB, lymphoma clinics etc,
Should be routinely offered to high-risk patients (MSM, IVDU etc)
Calls for opt-out testing of all patients where prevalence is over 0.2 (all London)

Question 28

Is HIV a notifiable disease?

Answer 28

No