Sexually Transmitted Infections (STIs)

• What is an STI?

  An infection spread by sexual contact

  Those withsexual contact as the sole/predominant modeof transmission would cover chlamydia & gonorrhoea.

  Those withother modeswould include Hep A, B, C, and HIV

  Not called STD because STIs are not always symptomatic.
• What are some risk factors for STIs?

  Young age (especially <20yrs)

  
  

  Single

  
  

  >2 partners in preceding 6/12

  
  

  Use of non-barrier contraception

  
  

  Residence in inner city

  
  

  Symptoms in partner

  
  

  Current STI & history of previous STIs

  
  

  Sexual orientation

  
  

  Chemsex
• Summarise the main STIs and the pathogenic cause of each.

  Bacterial:-Chlamydia-Gonorrhoea-Syphilis

  Viral:-Genital herpes-Genital warts-HIV

  Fungal:-Candidiasis

  Parasitic:-Pediculosis Pubis-Genital Scabies

  
• What host defences does our body have and how do the microbes overcome them?

  
• What is the causative organism in chlamydia and describe it?

  Chlamydia trachomatis

  It's anobligate intracellular bacterium

  Hasextracellular(elementary body) andintracellular(reticulate body) forms

  There are multiple serotypes of it, including A-K and L1, L2, & L3 (D-K are genital & L types are LGV)

  
• How does the chlamydia bacterium enter the body?

  It binds to specific receptors and enters via parasite-specified endocytosis
• Is chlamydia transmission common?

  Yes, it's the most common STI in the UK

  Alsocongenitaltransmission is well-recognised, and that can also cause neonatal conjunctivitis in 30-50% of cases (and very rarely, you can get pneumonitis)
• What are the signs and symptoms of chlamydia in females?

  Symptoms:80% asymptomaticPV bleeding/purulent discharge/lower abdominal pain/dyspareunia/proctitis

  Signs:NormalCervicitis (discharge/contact bleeding)/adnexal tenderness
• What are the signs and symptoms of chlamydia in males?

  Symptoms:50% asymptomaticUrethral discharge/dysuria/testicular pain/proctitis

  Signs:NormalUrethral discharge
• What are some potential complications of chlamydia?

  Female:

  Ascending infection can lead to pelvic inflammatory disease (PID)PID = endometritis/salpingitis/tubule damage/chronic pelvic painIncreased risk of ectopic pregnancy (pregnancy outside the uterus) and infertility

  Male:

  EpididymitisIn either auto-inoculation may cause chlamydial conjunctivitis
• How do you diagnose and treat chlamydia?

  Diagnosis:

  Nucleic acid amplification testing (NAAT)

  -High sensitivity and specificity for genital sites

  -Also used for extra-genital sites (rectal/pharyngeal/ophthalmic)

  Treatment:

  Azithromycin1g STAT

  Doxycycline100mg BD 7/7
• What is the causative organism of gonorrhoea and describe it?

  Neisseria gonorrhoea

  Gram negative diplococciwhich are facultatively intracellular

  
• By what method does the bacterium in gonorrhoea enter the body?

  Site of entry = mucosal surfaces (vaginal / urethral / rectal)

  
  

  Adhesive mechanism ensures it evades mechanical removal by secretions

  
  

  Produces IgA protease to disable host secretory antibodies

  
  

  Replicates in intracellular vacuoles which fuse with basement membrane releasing bacterium into connective tissue

  
  

  Elicits host inflammatory response with resultant tissue damage
• Can gonorrhoea be transmitted congenitally?

  Yes and can result in neonatal conjunctivitis
• What are the signs and symptoms of gonorrhoea in females?

  Symptoms:70% asymptomaticVaginal dischargeLow abdominal or pelvic pain

  Signs:Urethral dischargeCervicitisCervical dischargeCervical excitation
• What are the signs and symptoms of gonorrhoea in males?

  Symptoms:85% with urethral infection develop symptoms in 10/7Commonly discharge or dysuriaRarely asymptomatic

  Signs:MeatitisUrethral discharge
• What are some extra-genital sites that can be affected by gonorrhoea?

  Conjunctivitis

  Pharyngitis

  Pharyngeal exudate

  Proctitis

  Rectal discharge
• What are some potential complications of gonorrhoea?

  Female:Bartholinitis (inflammation of bartholin glands)Endometritis (Inflammation of endometrium)SalpingitisPeritonitis (inflammation of the peritoneum)Tubo-ovarian abscess

  Male:EpididymitisLocal abscess formation

  Very rarely, it can disseminate further and cause septicaemia, arthritis, or skin lesions
• How do you diagnose and treat gonorrhoea?

  Diagnosis:NAAT as per ChlamydiaDue to resistance always perform culture and sensitivity

  Treatment:Depends on local guidelines and resistance patternCeftriaxone500mg IM STAT +Azithromycin1g PO STAT
• What is the causative organism of syphilis and describe it?

  Treponema pallidum

  
  

  Motile spirochaete

  
• How is syphilis transmitted?

  Sexual contact

  Can also be transmittedtransplacentally(microbes from a pregnant woman's bloodstream cross the placenta and enter the bloodstream of the fetus)
• What are the stages of syphilis?

  Primary, secondary, tertiary
• Describe the features of primary syphilis.

  10-90 days post-exposure

  
  

  Develop papule at site of inoculation

  
  

  Ulcerates and becomes painless, firm chancre

  
  

  May go unnoticed (cervical/rectal ulcer)

  
  

  Spontaneous resolution within 2-3 weeks
• Describe the features of secondary syphilis.

  4-10 weeks

  Constitutional symptoms(fever/sore throat/malaise/arthralgia)

  Generalised lymphadenopathy

  Generalised skin rashes(classically palms and soles)

  Condylomata lata(warty, plaque-like lesions typically peri-anal region)

  Superficial confluent ulceration of mucosal surfaces(‘snail track ulcers’)

  Acute neurological signs(aseptic meningitis)

  Without treatment, resolves after 3-12 weeks (gives false sense of security)

  
• Describe the features of tertiary syphilis.

  Years after inoculation

  Gumma(granulomatous, ulcerating lesions) affecting skin typically at sites of trauma

  Can affect bone and visceral organs

  Cardiovascular manifestations(aorititis/aortic regurgitation)

  Neurosyphilisalso occurs (affecting nervous system)

  
• How do you diagnose syphilis?

  -Dark field microscopy (definitive diagnostic method)

  Presumptive diagnosis of syphilis requires 2 tests:

  -Treponemal specific

  -Non-treponemal specific

  
• How do you treat syphilis?

  Penicillin G, administered parenterally, is the preferred drug for treating persons in all stages of syphilis

  
  

  Dosage, and length of treatment depend on the stage and clinical manifestations of the disease
• What is the causative organism in genital herpes?

  Herpes simplex virus (HSV) types 1 & 2 (both can infect mouth or genitals)
• How is genital herpes transmitted?

  Close physical contact (sexual or oro-genital)

  
  

  Viral shedding by infected partner

  
  

  Sporadic (irregular), not necessarily associated with symptoms
• What are the symptoms and signs of genital herpes?

  It's variable

  
  

  You can get a severe primary episode within 2-12/7 of acquisition

  
  

  70-80% asymptomatic
• What can the first severe clinical episode (does NOT necessarily imply recent infection) of genital herpes include?

  Febrile illness (prodrome) 5-7 days

  
  

  Dysuria, urinary frequency

  
  

  Painful inguinal lymphadenopathy

  
  

  Tingling/neuropathic pain (genitals/buttocks/legs)

  
  

  Genital blisters, ulcers, fissures

  
  

  Untreated episode may last 3 weeks
• What are potential complications of genital herpes?

  Very rarely, you can get acute urinary retention/constipation /aseptic meningitis
• What are the symptoms & signs of reactivated genital herpes?

  Recurrent episodes usually mild

  Neuropathic prodrome (tingling/burning)

  Erythema/blisters/fissures/ulcers

  Resolution within 3-4 days
• What are some risk factors for genital herpes?

  Age (<20yrs)

  Severe 1st episode

  Occurs within 3 mths of 1° episode

  HSV type 2

  HIV or other immunodeficiency
• How do you diagnose genital herpes?

  Swab for HSV PCR (false negatives)

  
  

  Do not delay treatment for results

  
  

  Serology rarely performed
• How do you treat primary genital herpes?

  Usually settles within 5-7 days or beyond but new lesionsAciclovir200mg x5/day for 5-7 days

  Analgesics/bathing indilute saline solution/laxativesif required
• How do you treat reactivated genital herpes or frequent/prolonged herpes?

  Reactivation:Analgesics/saline washes/petroleum jelly to lesions

  Frequent/prolonged:>6 episodes/yr or episodes last> 4 days at a timeConsider prophylactic therapy
• What is the causative organism of genital warts and describe it?

  Human papillomavirus (HPV)

  
  

  Over 80 types of which 30 associated with genital infection

  Most common 6, 11, 16, 18, 31 and 33
• How are genital warts transmitted?

  Close physical contact (skin to skin)

  Almost always genital for genital warts

  Auto-inoculation from other sites is rare
• What is the incubation period for genital warts?

  3-18mths (can be longer)Frequently transmitted without presence of visible wart