STIs (7.1) Flashcards
Outline the demographics of STIs
- 42,000 diagnosed in 2017
- Highest rate amongst 16-24 yo
- Increase in cases in the last 10 years
Bacterial STIs: Gonorrhoea
Causative agent, symptoms, diagnosis and treatment
Causative agent: Neisseria gonorrhoeae
- Virulent factors: Pilus, LPS endotoxin, resists phagocytosis
Symptoms: Develop 2-7 days after infection
- 50 % females = asymptomatic
- Purulent vaginal/urethral discharge
- Dysuria
- Neonatal gonococcal eye infection
- PID
- Untreated ▻infertility
Diagnosis
MC & S
Swab - warm charcoal enriched transport medium sent immediatley
NAAT
Treatment:
- Single dose oral azithromycin
Bacterial STIs: Chlamydia
Causative agent, symptoms, diagnosis and treatment
Causative agent: Chlamydia trachomatis serotypes D - K
Life cycle: Elementary bodies (EB) → reticular bodies (RB) → EB → Release by cell lysis
Symptoms:
- Asymptomatic in 50 % of males and 70 % of females
- Females: vaginal discharge, dyspareunia, intramenstrual bleeding, abdominal pain, discomfort
- Males: Urethral discharge, dyuria
- Neonates: May cause blindness and increased risk of C trachomatis pneumonia
Diagnosis:
MC & S
NAAT and ELISA
Treatment:
Deoxycycline for 7 days (contraindicated in pregnancy)
Bacterial STIs: Syphilus
Causative agent, symptoms, diagnosis and treatment
Causative organism: Treponema pallidum (spirochete)
Symptoms:
Primary: 10 -90 days post infection. Small red oral/gential lesions. Chancre (PAINLESS lesions)
Secondary: 2 - 10 week after primary stage. Brown rash on palms and soles, fever, joint and muscle pain, lymphadenopathy, mucosal rash
Latent: Asymptomatic
Tertiary: Disfiguration, neuropathy, CVS abnormality, gumma
Diagnosis:
MC & S (Cannot be cultured in vitro)
Treatment:
Single dose of Penicillin G for primary, secondary and early latent
3 week course of penicillin G for later cases
Bacterial STIs: Chancroid
Causative agent, symptoms, diagnosis and treatment
Causative agent: Haemophilus ducreyi
Symptoms:
- Painful genital ulcers (may look like herpes)
- Lymphadenopathy
Diagnosis
MC & S
Treatment
Azithromycin/erythromycin
Bacterial STIs: Enteric bacterial urethritis
Causative agent, symptoms, diagnosis and treatment
Causative agent: Gut flora - enterobacteriaceae
♦ May be caused by poor personal hygiene or anal sex
Symptoms:
- Dysuria
- Urethral discharge
Diagnosis:
Treatment:
Mostly amoxicillin (treat according to sensitivity pattern)
Viral STIs: Herpes
Causative agent, symptoms, diagnosis and treatment
Causative agent: HSV I (oral) HSV 2 (genital)
Symptoms:
- Genital itching
- Genital lesions/fluid filled blisters
- Fever
- Muscle pain
- Malaise
Diagnosis
Treatment:
Symptomatic relief
⋆ Suppressive acyclovir if pregnant
Viral STIs: Genital wart
Causative organism, symptoms, diagnosis and treatment
Causative agent: HPV types 6 and 11
- HPV 16 and 18 are high risk → cervical cancer
Symptoms:
- Itching or burning sensation
- Raised ‘lumps’ with classic cauliflower appearance
Diagnosis:
Treatment:
Surgical/liquid nitrogen removal
Topical application of trichloroacetic acid
Viral STIs: HIV
Causative organism, symptoms, diagnosis and treatment
Causative agent: HIV
pg120 binds CD4 on T helper cells. Leads to immune symstem compromise
Symptoms:
- Immune system compromise
- May lead to AIDS
Viral STIs: Hepatitis
Causative agent, symptoms, diagnosis and treatment
Causative agent: Primarily Hepatitis B
May also be acquired through drug use, occupational hazards etc.
Symptoms:
- Fatigue
- Aching
- High temperature
- Jaundice
- Pale coloured stools
- Abdominal pain
Diagnosis:
Serology and Ig presence testing
Treatment:
Symptomatic relief
Anti-viral
Fungal STIs: Thrush
Causative agent, symptoms, diagnosis and treatment
Causative agent: Candida albicans
Symptoms:
- Itching
- Vaginal discharge
Diagnosis:
MC & S
Treatment:
Topical antifungal e.g. Clotrimazole
Protozoa STIs: Trichomonaisis
Causative organism, symptoms, diagnosis and treatment
Causative organism: Trichomonas vaginalis
Symptoms:
- Vaginal/urethral discharge
- Dysuria
- Vaginitis
Diagnosis:
MC, NAAT
Treatment:
Metronidazole or tinidazole
Define Protozoa
A single celled eukaryote.
Protozoal STIs: Pubic Lice
Causative organism, symptoms, diagnosis and treatment
Causative organism: Crab louse Phthirus pubis
Symptoms:
- Incubation period: 5 days - 1 week
- Louse bites lead to a a hypersensitivity reaction and rash development
Diagnosis:
Microscopy
Treatment:
As per head lice
Malathion applied to dry hair
Protozoal STIs: Scabies
Causative organism, symptoms, diagnosis and treatment
Causative organism: Itch mite, Sarcoptes scabiei
Symptoms:
- Symptoms seen after 3 - 6 weeks
- Nocturnal pruritus
Diagnosis
- Microscopy
- NAAT
Treatment
As per head lice
Permethrin or malathion cream
List the most common bacterial, viral, fungal and protozoan STIs
Bacterial: Gonorrhoea, chlamydia, syphilis, chancroid, enteric bacterial urethritis
Viral: Herpes, genital warts, HIV, HBV
Fungus: Candidia Albicans
Protozoan: Trichomonasis, Pubic lice, Scabies
Outline the demographics of STIs - Global and national
GLOBAL
- > 1 million STIs acquired everyday
- Trichomoniasis is most common
UK
- 42,000 diagnosed 2017
- 16-24 most prominent group
- Chlamydia is the most common STI
- Increased syphilis and gonorrhoea infections in the last 10 years
List the impacts of STIs on population health
- Mortality
- HPV → Cervical, penile and throat cancer
- HBV and HCV → Hepatic cancer
- Placental transfer: Congenital deformity, blindness
- Untreated STI → Infertility
Relate national policies to STI service provision
WHO: Prevent, testing, care provision, treatment and chronic care
Public Health England provisions:
- Local care provisions
- Identify risk groups
- Health promotion
- Prevention and control
Expectation from STI services: Prompt and open, confidential, free treatment, counselling and support
Outline the guidelines for partner notification
- Under legal age - encourage to inform parents
- Patient or provider may inform partners
Describe the factors influencing the outcomes of STI management and prevention
STI management:
- Emergence of anti-microbial strains
- Compliance: Physical, psychological, socio-cultural (e.g. propaganda)
STI prevention:
- Risk factors: Age and sex (females > risk due to > genital SA)
- Behavioural: > 1 sexual partner, unprotected sex
- Socio-cultural: Poverty, limited health care access, stigma
- Screening
- Vaccination: HPV and HBV
- Education/awareness
