The STI Cheat sheet

Herpes

• Caused by HSV-1,2 and the presence increases the risk of HIV transmission 
• For both sexes is located anywhere in the ‘boxer short area’
  • Appears as grouped vesicles evolving toward superficial circular ulcers on an erythematous base
  • Smooth margin and base
  • Enlarged, non-fluctuant and tender inguinal lymph nodes most common in primary infection
• Diagnosis: Most often visual, can be confirmed by viral culture on 3 unroofed/wet vesicles
• Asymptomatic spread does occur, but the risk is highest during outbreaks. Patients should be advised to always use condoms.
• Treatment:
  • Ideally initiated within 72 hours (because it is the only timeframe studied), but should ideally treat anyone with lesions
  • Treatment will decrease the severity and duration of illness
  • First presentation (treatment for 7-10 days):
    • Acyclovir 400 mg po TID or 200 mg po 5 times daily OR
    • Famciclovir 250 mg po TID OR
    • Valacyclovir 1000 mg po BID
  • Episodic treatment (for 5 days):
    • Acyclovir 800 my po TID
    • Famciclovir 1000 mg po BID
    • Valacyclovir 500 mg po BID for 3 days or 1000 mg po OD for 5 days
• Complications:
  • Meningoencephilitis
  • Hepatitis, pneumonitis, disseminated infection, Transverse Myelitis

Syphilis

• Caused by Treponema pallidum 
• Classically in the 20-29 age group, but increasing in those >65 years old

• Primary Syphilis
  • Painless chancre: clean based ulceration 1-2 cm in size
  • Develops at any site of inoculation
  • Associated lymphadenopathy
• Secondary Syphilis
  • Occurs in 25% of patients
  • Occurs over weeks –> months
  • Rash, lymphadenopathy, mucous membrane lesions, systemic symptoms
  • Epitrochlear lymph nodes is a classic presentation
  • Latent phase:
    • <12 months = Early Latent AND is infectious
    • >12 months = Late, non-infectious (except for transmission via pregnancy)
• Tertiary Syphilis 
  • Untreated risk of progression: 25-40%
  • CV disease, gummatous disease, aortitis, aortic anerysms and neuro syphilis
  • Neurosyphilis:
    • Altered mental status, meningitis, CNS abscess, stroke, cranial nerve, auditory and ophthalmic abnormalities.
• Diagnosis
  • Syphilis serology (VDRL) is not as accurate in primary syphilis (70-80%), so recommend Darkfield microscopy of ulcer or Treponemal-specific enzyme immunoassay (EIA).
    • A positive non-treponemal test should always be confirmed with a specific treponemal test because of a high false-positive rate
  • All other stages of syphilis can be accurately diagnosed with VDRL (sensitivity approaches 100%)
• Treatment
  • Primary/Secondary/Early Latent
    • Pen G 2.4 million units IM x one
  • Late latent/Tertiary
    • Pen G 2.4 million units IM x 3 weekly doses
  • Neurosyphilis
    • Pen G 3-4 million units IV q4h x 10-14 days

Chancroid

• Ulcerating STI caused by Haemophilus ducreyi
• Most common in the developing world
• Presents with tender erythematous papule at the inoculation site
  • Irregular borders, inflammed
  • May have associated tender lymphadenopathy that may develop into a ‘bubo’ (a large, painful, fluctuant node which may drain purulent material)
• Chancroid is a clinical diagnosis, as it is hard to culture
• Treatment: 
  • Azithromycin 1000 mg po in a single dose OR
  • Ceftriaxone 250 mg IM/IV

Trichomonas

• Caused by Trichomonas vaginalis
• Globally, this is the most common non-viral STI
• Occurs in the urogenital tract, and compared to STI predominantly in older females
• Presentation ranges from asymptomatic to PID:
  • May develop pruritis, dysparenuria, discharge, and postcoital bleeding
  • Green-yellow, frothy discharge
• Diagnosis is made via NAAT
• Treatment:
  • Flagyl 500 mg po BID x 7 days

Gonorrhea

• Gram negative Diplococcus – Neisseria gonorrhaeae
• In males may be asymptomatic, or with urethral discharge, dysuria
• Females are often asymptomatic until they develop signs of ascending infection
• Various presentations:
  • Gonococcal proctitis: Rectal pain, tenesmus, D.C bleeding
  • Gonococcal pharyngitis: Have a high pre-test based on Hx
  • Gonococcal conjunctivitis: maternal spread (rare, because of drops given at birth), usually develops from rubbing the eye with inoculated hand. Significant purulent secretions with significant associated morbidity
  • Disseminated Gonococcal Infection (DGI)
    • Rash (petechial, pustular, distal extremities)
    • Polyarthralgia
    • tenosynovitis
    • Septic arthritis
    • Rare: myocarditis/hepatitis/meningitis
• Diagnosis:
  • NAAT – via swabs or first catch urine
    • 1st catch urine sensitivity in females is 94% (swab is 98.3%)
    • 1st catch urine sensitivity in males is 96% (swab is 97.8%)
    • Swabs are not FDA approved for pharynx/rectal diagnosis, but labs have demonstrated appropriate sensitivities
    • Swabs may be done cervical/vaginal/urethral – which is why self-swabbing is acceptable
• Treatment:
  • Ceftriaxone 250 mg IV/IM
  • Azithromycin 1000 mg po –> For synergy and possible co-infection with chlamydia
  • When seen without diagnostic testing results available, if you have a high pre-test probability, consider emperic treatment

Chlamydia

• Most prevalent STI in the United States
• If symptomatic, presents with urethral discharge, dysuria
• Without treatment will likely progress to upper tract infection: PID, orchitis/epididymitis
• Diagnosis: via NAAT, similar sensitivity/specificity profile to gonorrhea above
• Swabs may be done cervical/vaginal/urethral – which is why self-swabbing is acceptable
• Treatment: 
  • Azithromycin 1000 mg po
  • Ceftriaxone 250 mg IM/IV –>co-infection is common, so most would advocate to treat for both
  • When seen without diagnostic testing results available, if you have a high pre-test probability, consider emperic treatment

PID

• Ascending infection from the endocervix –> upper reproductive tract
• Most commonly due to chlamydia/gonorrhea, but can include any potential GU pathogens
• PID IS A CLINICAL DIAGNOSIS 
  • Minimum criteria:
    • Cervical motion tenderness OR
    • Adnexal tenderness OR
    • Uterine tenderness
  • Additional criteria:
    • Mucopurulent cervical discharge
    • Cervical friability
    • Fever
    • Elevated ESR, CRP
    • WBC on microscopy of vaginal secretions
    • Positive NAAT for chlaymdia/gonorrohea
• Treatment:
  • Outpatient management:
    • Empirically treat for Chlamydia/Gonorrhea, plus:
      • Doxycycline 100 mg po BID x 14 days OR
      • Azithro 500 mg po once, and then 250 mg po OD to complete a 7 day course
  • Inpatient management:
    • Cefoxitin 2 g IV q6h PLUS Doxycycline 100 mg po/IV q12h OR
    • Clindamycin 900 mg IV q8h PLUS gentamycin (3-5 mg/kg IV)

Orchitis/Epididymitis

• Ascending infection in the upper reproductive tract
• Most cases present with testicular pain, swelling, and tenderness
• Usually infectious, but may be traumatic or autoimmune in nature
• In younger males (<35) or those with risk factors, is typically Chlamydia/Gonorrhea
• In older males (>35) or for those without risk factors, is typically E. Coli, coliforms or pseudomonas
  • Important to note the distinction should be primarily made based on history
• The Diagnosis is clinical. Testing is to identify the pathogen, and to rule out other emergent causes of testicular pain (i.e.: testicular torsion)
  • Send urine culture and NAAT
• Treatment:
  • <35 or with STI risk factors:
    • Ceftriaxone 250 mg IV/IM AND Doxycycline 100 mg po BID X 10 days
  • >35 or no STI risk factors:
    • Levofloxacin 750 mg po OD x 10 days
  • If no improvement within 72 hours, consider a return to ED/completing U/S to rule out underlying abscess

Bacterial Vaginosis

• Alteration in vaginal flora by replacing lactobacillus with polymicrobial organisms
• Malodorous/fishy smell/white discharge
  • Key to note: does not cause vaginitis symptoms (i.e.: dysuria, pruritis, burning or vaginal inflammation) – would suggest an alternative diagnosis
• Diagnosis:
  • Based on the Amsel critiera:
    • Homogenous, thin, greyish-white discharge that smoothly coats the vaginal walls
    • Vaginal pH > 4.5
    • Presence of clue cells (if microscopy available)
    • Fishy odour/positive whiff test
  • Culture: gold standard
    • Is often ‘indeterminate’ – requires clinical correlation to symptoms during QA/follow up process
• Treatment:
  • Flagyl 500 mg po BID x 7 days

Vulvovaginal Candidiasis

• Candida albicans. 75% of females in their life time will develop this
• Discharge, pruritis, dysparenuria, dysuira (external)
• Vulvar erythema, satellite lesions, thick curdy white discharge
• Diagnosis: Made clinically
• Treatment:
  • Topical azoles versus oral fluconazole
  • Cure rates are similar
  • Topical agents have quicker symptom relief (1-2 days) but less convenience to single oral treatment agent
  • Oral is cheaper, but with slightly higher side effect profile