Snapshot A 24-year-old female graduate student presents to the student health clinic with a complaint of dysuria and pain in her right knee. On physical exam, her knee is erythematous and tender with pain elicited on passive range of motion. Pelvic examination is significant for purulent endocervical discharge. The patient is sexually active and recalls having unprotected sexual intercourse with her most recent partner. Gram stain of a cervical swab shows gram-negative, kidney-shaped cocci in pairs. Introduction Classification Neisseria Gram-negative diplococci often intracellular within neutrophils Epidemiology incidence the second most common bacterial sexually-transmitted infection after Chlamydia location genital tract risk factors unprotected sexual intercourse Pathogenesis mechanism molecular biology pili facilitate attachment to mucosal surfaces antigenic variation IgA protease allows invasion of mucosal surfaces contains lipooligosaccharides (LOS) with strong endotoxin activity invasion of mucosal surfaces results in inflammation transmission sexual perinatal Associated conditions septic arthritis neonatal conjunctivitis (2-5 days after birth) prophylaxis with erythromycin eye drops pelvic inflammatory disease (PID) Fitz-Hugh-Curtis syndrome Presentation Symptoms dysuria purulent discharge fever prostatitis (men) endocervicitis (women) urethritis Studies Labs cervical and urethral culture Thayer-Martin agar selects for growth of Neisseria contains vancomycin, trimethoprim, colistin, and nystatin to inhibit growth of gram-positive organisms, gram-negative organisms except for Neisseria, and fungi nucleic acid amplification testing (NAAT) Histology Gram stain of a cervical swab gram-negative, kidney-shaped diplococci Differential Chlamydia distinguishing factor visualization of intracytoplasmic inclusions (reticulate bodies) on histology Urinary tract infection distinguishing factor lack of growth on Thayer-Martin agar Genital herpes simplex distinguishing factor painful vesicles and ulcers Treatment Medical IM ceftriaxone add azithromycin or doxycycline for possible concomitant chlamydial infection treat sexual partner to prevent reinfection Complications Fitz-Hugh-Curtis syndrome perihepatitis infection and inflammation of liver capsule adhesions of peritoneum to liver Pelvic inflammatory disease (PID) may include salpingitis, endometritis, hydrosalpinx, tubo-ovarian abscess risk factor for ectopic pregnancy, infertility, chronic pelvic pain, and adhesions Disseminated gonococcal infection (DGI) presents with a triad of: polyarthralgias asymmetric and migratory tenosynovitis vesiculopustular lesions most commonly on extremities, including palms and soles diagnosis arthrocentesis elevated leukocyte count (up to 50,000/mm^3) Gram stain positive <25% of cases culture can also culture blood, skin lesions, or mucosal sites molecular testing