STI

Question 1

Name the risk factors for STI

Answer 1

Unprotected sex (no condom), those with multiple sexual partners, those with sexual contact with those with multiple sexual partners, men who have sex with men (MSM), prostitution (CSW), illicit drug use (IV drug abusers who share needles)

Question 2

Name the individual prevention methods for STI

Answer 2

Abstinence, reduction of number of sexual partners, male latex condoms when used correctly and consistently, avoid drug abuse and sharing needles, pre-exposure vaccination (Hep B and HPV), pre-and-post exposure prophylaxis (HIV)

Question 3

Name the characteristics of gonorrhoea (caused by Neisseria gonorrhoea)

Answer 3

incubation period: 1 week after sexual contact

transmission: sexual contact, mother-to-child during childbirth

symptoms: purulent discharge from the urethra or vagina, pain upon urination
(dysuria), increased urinary frequency

complications (if untreated), males: epididymitis, prostatitis, urethral stricture, disseminated disease
complications (if untreated), females: infertility, pelvic inflammatory disease, ectopic pregnancy, disseminated disease

disseminated disease: skin lesions, tenosynovitis, monoarthicular arthritis; other sites it may infect: urethritis, cervicitis, proctitis, pharyngitis, conjuctivitis

Question 4

Name the diagnosis method for gonorrhoea

Answer 4

gram stain of genital discharge sample, culture from genital discharge sample, NAAT (PCR) from urine/genital discharge

Question 5

Name the antibiotic treatment regime for gonorrhoea

Answer 5

Ceftriaxone IM 500mg x 1 dose (for persons weighing < 150kg)
Ceftriaxone IM 1g x 1 dose (for patients weighing >= 150kg)

OR Gentamicin IM 240mg x 1 dose + Azithromycin PO 2g x 1 dose

+/- doxycycline PO 100mg BD x 7 days, if chlamydia has not been excluded

Question 6

Name the monitoring for gonorrhoea (incl. management of sex partners)

Answer 6

Test of cure is recommended

Partners within the last 60 days should be evaluated in treated. If last sexual encounter > 60 days, the most recent partner to be treated.

Patient is to abstain from sexual intercourse for 7 days after treatment to minimize transmission. Patient is to abstain from sexual intercourse until all sex partners have been treated to prevent re-infection.

Question 7

Name the characteristics of chlamydia (caused by Chlamydia trachomatis)

Answer 7

incubation: 1 to 3 weeks

transmission: sexual contact, mother to child during child birth

symptoms: purulent discharge from urethra / vagina, dysuria, increased urinary frequency - less severe than gonorrhoea

complications (if untreated), male: epididymitis, prostatitis , urethral stricture, disseminated disease
complications (if untreated), female: pelvic inflammatory disease, infertility, ectopic preganncy, disseminated disease

disseminated disease: skin lesions, tenosynovitis, monoarthricular arthritis, others sites of possible infection: urethritis, proctitis, cervicitis, pharyngitis, otitis media, conjuctivitis

Question 8

Name the diagnosis method for chlamydia

Answer 8

NAAT (PCR)

Question 9

Name the antibiotic treatment regime for chlamydia

Answer 9

Doxycycline PO 100mg BD x 7 days

OR Azithromycin PO 1g x 1 dose
OR Levofloxacin PO 500mg OD x 7 days

Question 10

Name the monitoring for chlamydia (incl. management of sexual partners)

Answer 10

Test of cure is not required, unless specific concerns (e.g. pregnancy, non-adherance) or symptoms persist

Patient is to abstain from sexual activity for 7 days after treatment (if single dose azithromycin is given) or until completion of the entire duration of therapy (7 days, for doxycycline, or levofloxacin) and resolution of symptoms if present, to minimize transmission. Patient is to abstain from sexual intercourse until all their sex partners have been treated, to minimize re-infection

Question 11

Name the characteristics of syphilis (caused by Treponema Pallidum)

Answer 11

incubation period: 1 week to 3 months

transmission: sexual contact, mother to child transplacental during pregnancy

symptoms:
primary syphilis: painful sore/ulcers at the ano-genital area, mouth or throat, that heals spontaneously in 1-8 weeks
secondary syphilis: skin rash, mucotaneous lesions, patchy alopecia, lymphadenopathy, disappears in 4-10 weeks if untreated
tertiary syphilis: joint lesions, cardiac involvement leading to aortic insufficiency
neurosyphilis: cognitive dysfunction, motor and sensory deficit, opthalmic or auditory symptoms, signs and symptoms of meningitis, stroke etc.

Question 12

Name the methods of diagnosis for spyhillis

Answer 12

Require 2 serological testings: treponema and non-treponema test

treponema test: TPHA (T. pallidum haemagglutination ) test or TPPA (T. pallidum passive particulate agglutination) assay
-> used to confirm diagnosis, not for monitoring and response to treatment

non-treponema test: VDRL (Venereal Disease Research Laboratory) slide test or RPR (rapid plasma reagin) card test
-> antibody titre (e.g. 1:16) used as a correlate to disease activity; treatment success requires at least a four-fold decrease in antibody titre (e.g. from 1:64 -> 1:16)

+ Darkfield microscopy of exudates from lesions

Question 13

Name the antimicrobial treatment for syphilis

Answer 13

primary, secondary or early latent (<1 yr): Benzathine Pen G IM 2.4 MU x 1 dose
OR Doxycycline PO 100mg BD x 14 days

late latent (>1 year) or tertiary: Benzathine Pen G IM 2.4 MU once a week x 3 doses
OR Doxycyline PO 100mg BD x 28 days

neurosyphilis: Crystalline Pen G IV 3-4 MU q4h or 18-24 MU/day as a continuous infusion x 10-14 days
OR Procaine Pen G IM 2.4 MU daily + Probenecid 500mg QDS x 10-14 days
OR Ceftriaxone IV/IM 2g OD x 10-14 days (if concern for cross-sensitivity, skin test to confirm penicillin allergy, de-sensitize if necessary)

Question 14

Name the monitoring for syphilis (incl. management of sexual partners)

Answer 14

Adverse effects: Jarisch-Herxheimer reaction which is an acute febrile reaction accompanying headache, myalgia and other symptoms that usually occur 24h after therapy for syphilis is started

For primary/secondary/latent syphilis: VDRL/RPR test at 3,6,12,18,24 months (min: 6, 12 and 24 months) to test for antibody titer; treatment success is the decrease in titre by at least four-fold at 6 months

For neurosyphilis: CSF examination every 6 months until CSF is normal

All at risk sexual partners of the patient should be evaluated and treated if positive. Patients to abstain from sexual intercourse until syphilis lesions are completely healed, they need careful assessment of whether they have responded and if their symptoms have resolved, to check in with doctor.

Question 15

Name the characteristics of gernital herpes (caused by HSV-1 / HSV-2)

Answer 15

chronic and life long viral infection with intermittent viral shedding from epithelial cells (transmissible even when patient is asymptomatic)

cycle of HSV infection: primary mucocutaneous infection, infection of the nerve ganglia, establishment of latency, reactivation, recurrent outbreak/flairs

transmission: transfer of body fluids and intimate skin to skin contact

signs and symptoms of first infection/outbreaks: multiple painful vesicles (also known as blisters), local itching, pain, lymphadenopathy, flu like symptoms (fever, headache, malaise) during the first few days after appearance of lesions, prodromal symptoms prior to recurrent lesions (mild itching, burning, tingling) - symptoms less severe in recurrent disease (less lesions, heal faster, milder symptoms)

Question 16

name the method of diagnosis for genital herpes

Answer 16

virlogic test: viral cell culture and NAAT for HSV DNA from the lesions

type specific (HSV-1/HSV-2) serology test (test for antibodies produced in patients’ bodies): takes 6-8 weeks to turn positive after first episode

Question 17

name the supportive care / non-pharmacological advice for genital herpes (HSV-2):

Answer 17

warm saline bath to relieve discomfort of lesions, analgesia and anti-itch for lesions, good genital hygiene to prevent superinfection, counselling regarding natural history

Question 18

name the antiviral treatment regime for genital herpes (HSV-2), for first episode:

Answer 18

Acyclovir PO 400mg TDS x 7-10 days
OR Acyclovir IV 5-10mg/kg q8h x 2-7 days and to complete with PO for a total of 10 days
OR Valacyclovir PO 1g BD x 7-10 days

treatment may be extended if healing is incomplete after 10 days of therapy
counselling: take w or w/o food, after food if GI upset
S/E: malaise, headache (main S/E for valacyclovir), N/V/D, maintain adequate hydration to prevent crystalluria

Question 19

name the antiviral treatment regime for genital herpes (HSV-2), for episodic recurrence:

Answer 19

Acyclovir PO 800mg BD x 5 days
(Acyclovir PO 400mg TDS x 5 days is also effective but not recommended due to frequency of dosing)
OR Acyclovir PO 800mg TDS x 2 days
OR Valacyclovir PO 1g OD x 5 days
OR Valacyclovir PO 500mg BD x 3 days

Question 20

name the antiviral treatment for chronic suppresive therapy for genital herpes (HSV-2):

Answer 20

Acyclovir PO 400mg BD
OR Valacyclovir PO 1g OD
OR Valacyclovir PO 500mg OD (less effective for frequent recurrences)

Question 21

name the counselling for patients with HSV infection (incl. management of sexual partners)

Answer 21

educate patient on natural history of disease, encourage them to inform sexual partners, sexual transmission of HSV can still occur during asymptomatic periods, and only chronic suppressive therapy + consistent and correct use of latex condom can prevent transmission during sexual intercourse, patients should abstain from sexual intercourse when lesions or pro-dromal symptoms present, risk for mother to child transmission during child birth, increased risk for HIV acquisition

symptomatic partners to be evaluated and treated.
asymptomatic partners of patients should be questioned concerning histories of genital lesions, encouraged to examine themselves for lesions and seek medical attention early if lesions occur. may be offered type specific serologic testing for HSV-2

Question 22

Name the modes of transmission of HIV

Answer 22

specific body fluids: semen, genital fluids, blood, breast milk

Question 23

Name the diagnosis method for HIV infection

Answer 23

serum antibody detection: HIV EIA, western blot
HIV RNA detection/quantification (viral load): nucleic acid amplification (PCR)

Question 24

Name the different stages of clinical presentations of HIV

Answer 24

1. Acute/primary viral infection: fever, chills, malaise, swollen lymph nodes (“flu-like” illness) lasting 2-3 weeks
2. Asymptomatic/latent stage: no signs or symptoms, this stage persists for many years
3. Persistent generalised lymphadenopathy: swollen lymph nodes at the neck, underarms and groin area
4. AIDS (acquired immunodeficiency syndrome) and AIDS-defining diseases: CD4 cell count <200 cells/mm^3, opportunistic infections (such as bacterial pneumonia, pneumocystis pneumonia, tuberculosis, cytomegalovirus infection, candidiasis), rare cancers (lymphoma, Kaposi’s sarcoma), diseases (AIDS associated dementia complex), systemic symptoms (fevers, unexplained weight loss/wasting syndrome, diarrhoea)

Question 25

Name the surrogate markers in HIV

Answer 25

CD4 cell count (indicator of immune function), HIV RNA / viral load (indicator of response to ART; effective regimen generally achieves viral suppression by 8 to 24 weeks)

Question 26

Name the recommended combinations of ART for patients who are naiive to ART

Answer 26

2 NRTIs + 1 INSTI
- Tenofovir + Emtricitabine + Bictegravir
- Tenofovir + Emtricitabine + Dolutegravir
- Abacavir + Lamivudine + Dolutegravir (3 in 1, Triumeq)

OR 1NRTI + 1INSTI
- Emtricitabine + Dolutegravir
not for patients who have co-infection with HBV, with HIV RNA >500,000 copies/mL, in whom ART is to be started without genotypic resistance testing or HBV testing

Question 27

Name the PK/PD characteristics, S/E, DDIs (if any) for NRTIs (nucleoside reverse transcriptase inhibitors; tenofovir, emtricitabine, abacavir, lamivudine, zidovudine)

Answer 27

DDI: nil (renally cleared)

elimination: renal, dose adjustment required for renal impaired except for abacavir

S/E (class): mitochondrial toxicity (lactic acidosis, hepatic steatosis, lipoatrophy)(more for zidovudine)

S/E (specific):
- tenofovir: N/V/D, can cause renal impairment (nephrotoxicity), loss of BMD (increased risk for osteopenia/osteoporosis) [tenofovir alafenamide < tenofovirdisoproxil fumarate]

• abacavir: hypersensitivity in patients with HLA-B*57:01 allele (rash, fever, malaise, loss of appetite, sore throat, cough, shortness of breath), N/V/D, association with myocardial infarction
• emtricitabine: minimal toxicities, N/D, hyperpigmentation
• lamivudine: minimal toxicities, N/V/D
• zidovudine: N/V/D, myopathy, bone marrow suppression (increased anemia or neutropenia)

Question 28

Name the PK/PD characteristics, S/E, DDIs for INSTI (integrase strand transfer inhibitors: bictegravir, dolutegravir, raltegravir, elvitegravir)

Answer 28

DDI: polyvalent cations (lowers bioavailability of oral formulations), bictegravir and dolutegravir are CYP3A4 substrates

Elimination: hepatic, CYP3A4 substrates

S/E (general): weight gain, N/D, headache, depression and suicidality (rare, but primarily reported in patients with pre-existing psychiatric conditions)

S/E (specific):
- bictegravir: increase in SCr

• dolutegravir: increase in SCr
• raltegravir: fever, CK elevation (rhabdomyolysis)

Question 29

Name the PK/PD characteristics, S/Es, DDIs for NNRTI (non-nucleoside reverse transcriptase inhibitors; efavirenz, rilpivirine)

Answer 29

DDIs: potential for CYP450 drug interactions, use with PPI is contraindicated for rilpivirine (increase in gastric pH lowers oral absorption)

Elimination: hepatic, some are CYP450 inhibitors, some are inducers

S/E (general): rash, SJS (more for efavirenz than rilpivirine), QTc prolongation

S/E (specific):
- efavirenz: hyperlipidemia (increase in LDL-C and TG), neuropsychiatric effects (dizziness, depression, insomnia, abnormal dreams, hallucination), hepatotoxicity

• Rilpivirine: depression, headache, generally less toxicities than efavirenz hence NNRTI drug of choice

Question 30

Name the PK/PD characteristics, S/Es, DDIs for PI (protease inhibitors; ritonavir, lopinavir, atazanavir, darunavir, fosamprenavir - coformulated with ritonavir or cobicistat)

Answer 30

DDIs: CYP450 3A4 inhibitors and substrates, use of PPI is contraindicated in atazanavir (increase in gastric pH lowers oral absorption)

Elimination: hepatic

S/E (general): metabolic complications including dyslipidemia and insulin resistance N/V/D, hepatotoxicity (esp. with chronic hep B and C), lipohypertrophy (fat maldistribution), increased risk for osteopenia/osteoporosis

S/E (specific):
- ritonavir: paresthesia (numbness of extremities), taste perversion

• darunavir: good GI tolerability, less lipid effects, skin rash and SJS (sulphonamide)
• azatanavir: good GI tolerability, less lipid effects, skin rash, hyperbilirubinemia, QTc prolongation

Question 31

Name the PK/PD characteristics, DDI and S/E of fusion inhibitor (enfuvirtide; injected SC 2x/day)

Answer 31

DDI: nil

Elimination: -

S/E: injection site reaction (including erythema/induration, nodules/cyst, bruising, pruritis), rare hypersensitivity (fever, rash, chills, hypotension), increased bacteria pneumonia

Question 32

Name the PK/PD characteristics, DDI and S/E of CCR5 antagonist (maraviroc - Selzentry; to perform co-receptor tropism assay before initiation)

Answer 32

DDI: CYP3A4 substrate

Elimination: hepatic

S/E: abdominal pain, cough, dizziness, musculoskeletal symptoms, fever, rash, URTI, hepatotoxicity, orthostatic hypotension