Gonorrhea
Second most reported STI in the US — gram-negative diplococcus (Neisseria gonorrhoeae); rising antimicrobial resistance has shaped current ceftriaxone-based therapy.
Also known as: gonorrhea, Neisseria gonorrhoeae, GC, the clap
Overview
Sexually transmitted infection caused by Neisseria gonorrhoeae, a fastidious gram-negative diplococcus. Infects mucosal columnar epithelium (cervix, urethra, rectum, pharynx, conjunctiva). Disseminated infection (DGI) involves skin, joints, and rarely endocardium/meninges.
Epidemiology
Over 700,000 US cases in 2022 (CDC); second most reported notifiable disease. Disproportionately affects young adults, MSM, and Black populations. Antimicrobial resistance is a major and growing concern — particularly emerging cephalosporin resistance.
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Risk factors
- Age <25, multiple partners, new partner within 60 days
- Inconsistent condom use
- Sex work, MSM (pharyngeal/rectal infection)
- Concurrent STIs (especially chlamydia)
- Mother with untreated gonorrhea (neonatal ophthalmia)
Pathophysiology
Pili and outer membrane proteins (Opa) mediate attachment to columnar epithelium. Bacteria invade epithelial cells, induce inflammation, and produce purulent exudate. Antigenic variation of pili allows immune evasion and reinfection. Disseminated infection occurs in 0.5-3%, often associated with complement deficiency (C5-C9).
Clinical presentation
Symptoms
- Men (urethritis): purulent yellow-green urethral discharge, dysuria 2-5 days post-exposure; ~10% asymptomatic
- Women (often asymptomatic ~50%): mucopurulent cervical discharge, intermenstrual bleeding, dysuria, dyspareunia
- Rectal: often asymptomatic; proctitis with pain, tenesmus, discharge
- Pharyngeal: usually asymptomatic; mild pharyngitis
- Disseminated gonococcal infection (DGI): polyarthralgia → migratory asymmetric arthritis or septic monoarthritis, tenosynovitis, pustular skin lesions on extremities; fever
- Neonatal ophthalmia (within 2-5 days of life): bilateral purulent conjunctivitis, can perforate cornea
Signs / physical exam
- Purulent urethral or cervical discharge
- Cervical motion tenderness, adnexal tenderness if PID
- DGI triad: dermatitis (pustular/papular lesions), tenosynovitis (especially wrists/fingers/Achilles), polyarthralgia/asymmetric oligoarthritis
- Neonate: copious purulent conjunctival discharge with eyelid edema
Classic findings
Young sexually active patient with copious purulent urethral discharge — gonorrhea until proven otherwise. DGI: polyarthralgia, tenosynovitis, and pustular skin lesions in a young woman around menses or pregnancy.
Differential diagnosis
- Chlamydia — Less purulent discharge, frequent coinfection; treat both if clinical PID
- Trichomoniasis — Frothy, malodorous vaginal discharge, strawberry cervix
- Bacterial vaginosis — Thin gray discharge, fishy odor, clue cells
- Mycoplasma genitalium — Persistent urethritis after treatment; NAAT
- UTI — Dysuria with pyuria, no urethral discharge; positive urine culture
- Septic arthritis from other pathogens — S. aureus most common monoarthritis; arthrocentesis with Gram stain/culture
- Reactive arthritis — Asymmetric oligoarthritis with conjunctivitis/urethritis after GU/GI infection; HLA-B27
Diagnostic workup
Diagnostic criteria
Positive NAAT, culture, or Gram stain (men with symptomatic urethritis) for N. gonorrhoeae.
Labs
- Nucleic acid amplification test (NAAT) — preferred for genital, rectal, and pharyngeal sites (sensitivity >95%)
- Specimens: first-catch urine or urethral swab (men), endocervical or vaginal swab (women), pharyngeal and rectal swabs as exposure dictates
- Culture (with antimicrobial susceptibility testing) — important when treatment failure suspected; required at extragenital sites in some labs
- Gram stain of urethral discharge (men): gram-negative intracellular diplococci have high PPV in symptomatic men
- Test for concurrent chlamydia, syphilis, HIV; consider hepatitis B/C
- Blood and joint cultures for DGI; arthrocentesis with Gram stain/culture/NAAT
Imaging
- Pelvic ultrasound if PID/tubo-ovarian abscess suspected
- Joint imaging for septic arthritis
Diagnostic algorithm
| Site/Syndrome | Therapy | Co-coverage |
|---|---|---|
| Urogenital/rectal/pharyngeal | Ceftriaxone 500 mg IM x 1 | Doxycycline 100 mg BID x 7 d if chlamydia not excluded |
| Pharyngeal — test of cure | 7-14 days post-treatment | NAAT or culture |
| DGI / septic arthritis | Ceftriaxone 1 g IV daily x 7+ d | Joint drainage if purulent |
| Endocarditis | Ceftriaxone 1-2 g IV q12-24h x 4 wk | Surgical evaluation |
| Neonatal ophthalmia | Ceftriaxone 25-50 mg/kg IV/IM x 1 | Saline irrigation; admit |
| Severe beta-lactam allergy | Gentamicin 240 mg IM + azithromycin 2 g PO | Less effective; reserve |
Treatment
First-line
- Uncomplicated urogenital, rectal, or pharyngeal gonorrhea (CDC 2021):
- • Ceftriaxone 500 mg IM × 1 (1 g IM if patient weighs ≥150 kg)
- • Empiric chlamydia coverage with doxycycline 100 mg PO BID × 7 days IF chlamydia not excluded (azithromycin 1 g PO × 1 if pregnant)
- • Mantra: 'Ceftriaxone for gonorrhea + doxycycline for chlamydia'
- Disseminated gonococcal infection: ceftriaxone 1 g IV/IM daily × 7+ days; switch to oral therapy after improvement (cefixime if susceptibility confirmed)
- Gonococcal arthritis/endocarditis/meningitis: ceftriaxone 1-2 g IV q12-24h × longer course (7-14 days arthritis, 4 weeks endocarditis, 10-14 days meningitis)
- Neonatal ophthalmia: ceftriaxone 25-50 mg/kg (max 250 mg) IV/IM × 1; saline lavage of conjunctiva; hospitalize
- Neonatal prophylaxis: erythromycin 0.5% ophthalmic ointment to all newborns
Second-line / adjunct
- Cephalosporin allergy: gentamicin 240 mg IM + azithromycin 2 g PO × 1 (less effective; reserve for true severe beta-lactam allergy)
- Cefixime 800 mg PO × 1 — alternative for urogenital infection if ceftriaxone unavailable; less effective for pharyngeal infection
- Expedited partner therapy where legal
- Rescreen at 3 months; test of cure at 7-14 days for pharyngeal infection or treatment failure
Complications
- PID, tubal scarring → infertility, ectopic pregnancy, chronic pelvic pain
- Epididymitis, prostatitis, urethral stricture
- Disseminated gonococcal infection: arthritis (purulent or arthralgia-tenosynovitis-dermatitis syndrome), rarely endocarditis or meningitis
- Neonatal: ophthalmia neonatorum with risk of corneal perforation and blindness, scalp abscess, sepsis
- Increased HIV transmission risk
- Antimicrobial resistance threatening current regimens
PANCE pearls
- Ceftriaxone dose was DOUBLED to 500 mg IM in CDC 2021 guidelines to combat emerging resistance.
- Pharyngeal gonorrhea is hard to eradicate — perform test of cure 7-14 days after treatment.
- Always co-treat for chlamydia if not excluded by NAAT — coinfection is common.
- DGI: think of complement deficiency (C5-C9) in recurrent disseminated gonococcal infection — order CH50.
- Newborn with bilateral purulent conjunctivitis at 2-5 days of life — assume gonococcal until proven otherwise; emergency treatment to prevent corneal perforation.
References
- CDC 2021 — Sexually Transmitted Infections Treatment Guidelines, 2021 (MMWR Recommendations and Reports)
- CDC Surveillance — Sexually Transmitted Disease Surveillance — Gonorrhea chapter and GISP resistance data
- USPSTF 2021 — Screening for Chlamydia and Gonorrhea: US Preventive Services Task Force Recommendation Statement
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