STD Flashcards
Neisseria gonorrhoeae characters:
- flow of seed
- gram negative diplococcus
- resembles coffee bean
- fastidious: requires special media + CO2
Gonorrhea Virulence:
- Pilli: attachment/antigenic variation (evade immunity from previous infection)
- Por protein: intracellular survival by evading destruction
- Opa Protein: mediates binding to epithelial cells
- Lipooligosaccharides + Beta lactamase enzyme: resistance to penicillin
Gonorrhea Pathogenesis:
- attaches to mucosal cells via pili and penetrates the cells
- infection of the subepithelial space
- Lipooligosaccharides stimulate inflammatory response (TNF/cytokines/WBC) = discharge
Gonorrhea Epidemiology:
- humans only host
- direct mucosal contact
- no toilet sets transmission
- adolescents more susceptible
- 90% males symptomatic, 50% females
Gonorrhea Diagnosis:
- gram stain of urethral discharge in men
- culture on thayer martin media (culture all sites)
- Non-culture based have become the gold standard (do not require CO2):
PCR, NAAT, assays with single swab, urine based
Gonorrhea signs/treatment:
- urethritis (men)
- cervicitis (women)
- treat with single dose injection of ceftriaxone + oral azithromycin
- always treated for chlamydial co-infection
Chlamydia trachomatis characters:
- obligate intracellular bacterium
- small gram negative bacillus
- sterotypes
- requires living tissue for culture
- no lasting immunity
- SILENT: can live up to 2 years in female genital tract (PID), 75% female 50% male infections asymptomatic = tubal infertility
Chlamydia sterotypes:
- Endemic trachoma (eye disease): A, B, C
- Genitourinary syndromes: D-K
- Lymphogranuloma venereum (LGV): L1-L3
Two forms of Chlamydia
Elementary body: infectious form
Reticulate body: noninfectious intracellular form that promotes replication
Chlamydia pathogenesis:
receptors for EB found only on mucous membranes of
- urethra
- endocervix, endometrium, fallopian tubes
- anorectum
- respiratory tract
- conjuctiva
EB enters cells, replicates, infects other cells
Inflammatory response: granulocytes, lymphocytes, plasma cells
inflammatory response with re-infection is strong and can lead to end organ damage (blindness, sterility)
also causes uretheritis (men) and cervicitis (women)
Chlamydia Epidemiology:
- humans only host
- direct mucosal contact
- more widespread than gonorrhea
- most common infectious disease in US
- adolescents
Clamydia Diagnosis/treatment:
- same as gonorrhea
- single swab for both
- azithromycin, single dose
- doxycycline
Urethritis
men
- Dysuria, discharge, burning
- Diagnose with gram stain, if intracellular gram negative diplococcic seen it is gonorrhea
Epididymitis
men
- Swelling, erythema or scrotal sac, unilateral, tender
- May not have discharge
Mucopurulent cervicitis
Women
- Asymptomatic
- dyspareunia, bleeding, dysuria, lower abdominal pain
- Positive swab test, NOT gram test (low sensitivity)
PID
-Presents as tubo-ovarian abscess, endometritis, or peritonitis
-1 in 4 develop chronic sequelae • Antimicrobial therapy has no effect on subsequent rates • Ectopic pregnancy 7 fold increase risk • Infertility 10-15% risk increase • Chronic pelvic pain
Disseminated gonococcal infection (GC)
- Dermatitis arthritis (skin lesions)
- Septic monoarticular arthritis
- Treatment: IV certriaxone initially then switch to oral
Gonococcal infections at other sites:
- pharyngeal
- conjuctivitis
- perirectal
- skin lesions
Chlamydia infection at other sites:
- perirectal
- conjuctivitis (less symptomatic than GC
- Dysuria-Pyuria Syndrome: young women with pyuria (WBC in urine)
Lymphogranuloma Venereum:
- caused by L1-L3 or chlamydia
- endemic in africa, asia, india, south america, caribbean
- presents as inguinal lymphadenopathy (lymph node disease)
- look for groove sign (swollen inguinal canal)
- proctitis
- presents with fever, tenesmus, bleeding, rectal pain
- extends into colon
Lymphogranuloma Venereum proctitis:
- inflammation of rectum seen in MSM and het women
- pelvic nodes and lumbar nodes involved
Reactive arthritis:
- post infectious sequelae more common after CT than GC
- Classic triad: arthritic, conjuctivitis, urethritis
- also see skin lesions
Treponema pallidum
- syphilis
- corkscrew shaped, helical
- cannot be cultured
- cant see under light microscope
Endemic Treponemal diseases:
- yaws: africa
- pinta: central/south america
- bejel: middle east
Syphilis pathogenesis:
- enters via skin/mucus membrane
- travels to lymphatics and then blood
- invades CNS in 30-40% of patients with primary or secondary disease
- stages of primary, secondary, latent, and tertiary
primary syphilis:
- chancre at site of inoculation (mouth, genitals)
- women usually dont even see it and are asymptomatic
- painless ulcer with smooth base, border raised rolled or indurated
- heals spontaneously usually without scar in 1-6 weeks
- serologic tests for syphilis may not be positive at this time
secondary syphilis
- can go to many organ systems
- 2-8 weeks after ulcer
- sprochetes disseminated, meninges seeded
“great imitator”
- skin manifestations: rash, alopecia, condylomata lata (plagues on genitals)
- PALMAR/PLANTAR LESIONS
- fever, malaise, anoerxia, wt loss, pharyngitis, myalgia
- mucus patches
- adenopathy (enlarged lymph)
- CNS: headaches, meningitis
- arthritis, hepatitis, osteitis all possible
Latent syphilis:
- no manifestations
- positive serology
- after four years patient is noninfectious and resistant to reinfection
Tertiary syphilis:
- gummatous syphilis (10-15 years): lesions in skeletal, spinal, and mucosal areas, eye and viscera (lung, stomach, liver, genitals, breast, brain heart)
- Cardiovascular syphilis (20-30 years): aortic aneurysm
- neurosyphilis: stroke in young people, psych wards, eye disease, tabes dorsal (gait)
Diagnosis of syphilis:
- cannot culture
- darkfield microscopy
- nontreponemal (screening)
- specific treponemal (confirmatory)
Syphilis treatment:
- penicillin
- allergic individuals can use doxycycline
