Q: Make an exam oriented notes on given source A: Here are comprehensive, exam-oriented notes on Sexually Transmitted Infections STIs from your textbook source: --- SEXUALLY TRANSMITTED INFECTIONS STIs - EXAM NOTES --- QUICK REFERENCE TABLE: CAUSATIVE AGENTS Disease Agent ------ Gonorrhea Neisseria gonorrhoeae Non-gonococcal urethritis Chlamydia trachomatis D-K serotypes Syphilis Treponema pallidum Lymphogranuloma venereum Chlamydia trachomatis L serotypes Chancroid Haemophilus ducreyi Granuloma inguinale Donovania granulomatis Bacterial vaginosis Gardnerella vaginalis Trichomonas vaginitis Trichomonas vaginalis Monilial vaginitis Candida albicans AIDS HIV 1 or HIV 2 Genital herpes HSV 2 Condyloma acuminata HPV usually types 6, 11 CIN HPV 16, 18, 31 Molluscum contagiosum Pox virus Scabies Sarcoptes scabiei Pediculosis pubis Crab louse Phthirus pubis --- 1. GONORRHEA Key Facts - Organism: Neisseria gonorrhoeae - gram-negative diplococcus - Incubation period: 3-7 days - Primary sites: endocervix, urethra, Skene's gland, Bartholin's gland - 50% of patients are asymptomatic - N. gonorrhoeae is often co-present with other STIs; women with gonorrhea are at risk for incubating syphilis - one-third of such cases are associated with chlamydial infection Clinical Features Local symptoms: - Dysuria 25% - Excessive irritant vaginal discharge 50% - Acute unilateral pain/swelling over labia Bartholin's gland - Bartholin's gland: palpably enlarged, tender, fluctuant abscess formation - Signs: mucopurulent vaginal discharge, congested ectocervix Distant/Metastatic Perihepatitis + Septicemia: - Septicemia: low grade fever, polyarthralgia, tenosynovitis, septic arthritis, perihepatitis, meningitis, endocarditis, skin rash PID: 15% of untreated cervicitis can ascend to cause acute PID Complications - Chronic PID, infertility, ectopic pregnancy tubal damage, dyspareunia, chronic pelvic pain, tubo-ovarian mass, Bartholin's gland abscess Diagnosis - HIGH YIELD NAAT Nucleic Acid Amplification Testing of urine or endocervical discharge is the test of choice - First void morning urine preferred or sample at least 1 hour after last void - Sensitivity: NAAT is very sensitive and specific 95% - Gram stain: gram-negative intracellular diplococci - Culture: Thayer-Martin medium - Drug sensitivity test should be done Treatment CDC Recommended Drug Dose ------ Ceftriaxone 250 mg IM + Azithromycin 1 g PO once OR Doxycycline 100 mg BID x 7 days Conjunctivitis of newborn: Ceftriaxone 20-30 mg/kg IM + gentamicin eye ointment 1% Follow up: Cultures at 7 days, repeat at monthly intervals for 3 months. Persistently negative = declared cured --- 2. SYPHILIS Key Facts - Organism: Treponema pallidum - anaerobic spirochete - Incubation: 9-90 days - Tubes are NOT affected; infertility does NOT occur unless associated with gonococcal infection - exam favorite! Stages Stage Features ------ Primary Chancre Single/multiple painless ulcer, smooth shiny floor, raised margins, enlarged discrete painless inguinal nodes; heals in 1-8 weeks leaving a scar Secondary Within 6 weeks - 6 months; condyloma lata flat, moist necrotic lesions; maculopapular rash on palms and soles; generalized lymphadenopathy; mucosal ulcers; alopecia Latent Quiescence phase after secondary resolves; duration 2-20 years Tertiary 1/3 of untreated cases; CNS, CVS, musculoskeletal damage; gumma characteristic - deep punched ulcer with rolled out margins, painless with moist leather base; cranial nerve palsies III, VI, VII, VIII Tertiary syphilis is characterized by GUMMA - exam key point Diagnosis of Syphilis - HIGH YIELD 1. History of exposure 2. Identification of organism - smear from primary chancre, examined under dark ground illumination; treponema appear as motile bluish white cork-screw shaped organisms 3. Serological Tests: - VDRL - common flocculation test; positive after 6 weeks of initial infection - Specific tests: TPHA, EIA, FTA-Abs, TPI - FTA-Abs - expensive but confirmatory; FTA-IgM only in active infection; declines after adequate treatment - VDRL and TPHA used for screening; FTA-Abs for confirmation - Serological tests always positive in secondary syphilis - After successful treatment: nonspecific tests become negative; specific tests remain positive Treatment CDC 2010b - Early syphilis primary, secondary, early latent 1 year: Benzathine penicillin G 2.4 million units IM single dose - Penicillin allergy: Tetracycline 500 mg 4x/day x 14 days OR Doxycycline 100 mg BID x 14 days - Late syphilis: Benzathine penicillin G 2.4 million units IM weekly x 3 weeks 7.2 million units total - Alternative: Doxycycline 100 mg twice daily OR Tetracycline 500 mg 4x/day x 4 weeks - Follow up: Serological test at 1, 3, 6, 12 months post-treatment of early syphilis --- 3. CHLAMYDIAL INFECTIONS Key Facts - Organism: Chlamydia trachomatis D-K serotypes - obligatory intracellular gram-negative bacteria - More prevalent than N. gonorrhoeae in developed countries - Incubation: 6-14 days longer than gonorrhea 3-7 days - Superficial invasion only no deeper penetration - Infection mostly localized to urethra, Bartholin's gland, cervix - Associated with gonococcal infection 20-40% Clinical Features - Mostly nonspecific and asymptomatic 75% - Dysuria, dyspareunia, postcoital bleeding, intermenstrual bleeding - Mucopurulent cervical discharge, cervical edema, cervical ectopy, cervical friability Complications - Urethritis, bartholinitis - Chlamydial cervicitis spreads upward → endometritis, salpingitis - Chlamydial salpingitis is asymptomatic in majority - Causes tubal scarring → infertility + ectopic pregnancy - Fitz-Hugh-Curtis syndrome perihepatitis - more common cause than gonococcus Diagnosis - Chlamydial NAAT by PCR - very sensitive and specific 95%; first void urine specimen most effective - Chlamydia antigen by ELISA lipopolysaccharide from endocervix - less sensitive than NAAT - Tissue culture McCoy cell monolayers - 100% specific; expensive, takes 3-7 days Treatment CDC 2010b Drug Dose ------ Azithromycin 1 g orally single dose OR Doxycycline 100 mg orally BID x 7 days OR Ofloxacin 200 mg orally BID x 7 days OR Erythromycin base 500 mg orally QID x 7 days --- 4. CHANCROID SOFT SORE Key Facts - Organism: Haemophilus ducreyi - gram-negative streptobacillus - Incubation: very short 3-5 days or less - Always painful contrast with syphilitic chancre which is painless - Starts as multiple vesicopustules → shallow ulcers with foul purulent/hemorrhagic discharge - Unilateral inguinal lymphadenitis buboes may form abscesses Diagnosis - Syphilis must be ruled out first - Demonstration of Ducreyi bacillus in specialized culture is confirmatory - Discharge from ulcers/pus from lymph glands - Gram stain shows organisms classically as "Shoal of fish" pattern - Difficult to grow in culture Treatment CDC 2010b - Ceftriaxone 250 mg IM single dose most effective - Azithromycin 1 g PO single dose - Treat sexual partner simultaneously --- 5. HIV INFECTION AND AIDS The Virus - Causative agents: HIV 1 and HIV 2 retroviruses - double stranded RNA - Enzyme: reverse transcriptase allows viral RNA → DNA - Basic structure: icosahedral RNA-retrovirus with core protein P-24, glycoprotein GP 120 GP41, GP 40 - P-24 is most widely used for investigation study - GP 120 has some protective role - Destroyed by heating at 56°C for 30 minutes or by disinfectants with glutaraldehyde Risk Factors for AIDS Table 12.4 - Multiple sex partners - Prostitution - Homosexual males - Intravenous drug abusers IVDA - Multiple transfusions of blood/blood products - Sexually transmitted disease - Mother to infant Modes of Transmission - Sexual intercourse predominant worldwide - heterosexual and homosexual - Intravenous drug abusers - Transfusion of infected blood/products - Contaminated needles - Breastfeeding 10-20%; more with cracked nipples - Perinatal transmission - vertical transmission 25-35%; in utero 30%, delivery 70-75% via contaminated secretions/blood of birth canal Immunopathogenesis - Target: CD4 receptor molecule on CD4+ T lymphocytes, monocytes, macrophages, antigen-presenting cells - Progressive depletion of CD4+ T cells Timeline of Infection - Primary infection: 3-6 weeks - Acute syndrome: 1 week to 3 months - Immune response to HIV: 1-2 weeks - Clinical latency: 7-10 years Immunological Markers - CD4 T lymphocyte count: 200-500 cells/mm³ = HIV related symptoms; 200 cells/mm³ = AIDS defining criteria - HIV RNA levels by RT-PCR and bDNA assays - monitored every 3-4 months - Raised P-24 core antigen titer = reflects viral load - Raised serum β₂ microglobulin = reflects immune response Clinical Presentation - Antibodies develop within 8-12 weeks of exposure - Acute infection syndrome: fever, skin rash, arthralgia, lymphadenopathy, diarrhea = seroconversion illness; lasts 2-3 weeks, resolves spontaneously - Median time to develop AIDS: 7-10 years - AIDS-related complex ARC: clinical features without full blown AIDS weight loss, fever, diarrhea, skin rash, lymphadenopathy, herpes simplex, PID, tubo-ovarian abscess, thrombocytopenia KEY DEFINITION: Any HIV infected individual with CD4+ T cell count 200/µL has AIDS by definition regardless of the presence of symptoms or opportunistic diseases Gynecological Symptomatology - Vaginitis - recurrent candidiasis, oral/esophageal candidiasis - Pelvic inflammatory diseases with other STIs more likely - Increased incidence of CIN and carcinoma of cervix → colposcopy and cervical cytology routinely - Increased vulvar intraepithelial neoplasia VIN Diagnosis of HIV - Detection of IgG antibody to Gp 120 - most commonly used; window period up to 3 months antibodies not protective - Viral P-24 antigen - detected very soon after infection; disappears by 8-10 weeks - ELISA - 99.5% sensitive but less specific; easy, cheap, 2-5 hours; used as screening - Western blot or Immunoblot - highly specific, 1-2 days, expensive; confirmatory - HIV RNA by PCR - gold standard for diagnosis; amplifies cDNA from viral RNA; reliable up to 40 copies/mL Absolute CD4 count below 200/mm³ is the cut-off point for risk of opportunistic infections Antiretroviral Therapy HAART - A. NRTIs Nucleoside Reverse Transcriptase Inhibitors: Zidovudine, Zalcitabine, Lamivudine, Abacavir - B. NNRTIs Non-Nucleoside Reverse Transcriptase Inhibitors: Delavirdine, Nevirapine, Efavirenz - C. Protease Inhibitors PI: Indinavir, Saquinavir, Ritonavir - D. Entry Inhibitor: Enfuvirtide - E. Integrase Inhibitor: Raltegravir HAART = Highly Active Antiretroviral Therapy combination therapy Drug combination: 2 NRTIs from Group B or 2 from Group A + 1 from Group C PI When to Start Therapy - Acute HIV infection syndrome - Symptomatic HIV infection - Asymptomatic but CD4 350 cells/mm³ or HIV RNA 50,000 copies/mL - Postexposure prophylaxis - CD4 200/mm³ → also add trimethoprim + sulfamethoxazole PCP prophylaxis - Pregnant women or women with HIV-associated nephropathy → should have HAART therapy Efavirenz is first line therapy in ALL patients UNLESS she is planning to conceive and has primary NRTI or NNRTI resistance When to Change Therapy - Failure to reduce viral load - Persistently declining CD4+ T cell count - Clinical deterioration - Presence of severe side effects due to drugs Drug Side Effects Lactic acidosis, anemia, granulocytopenia, pancreatitis, peripheral neuropathy, hepatic dysfunction, carbohydrate intolerance Postexposure Prophylaxis - Combination of two NRTIs: zidovudine 300 mg BID + lamivudine 150 mg BID for 4 weeks immediately following exposure CDC 2001 --- 6. GENITAL WARTS CONDYLOMA ACUMINATA Key Facts - Caused by HPV types 6 and 11 usually - Malignant transformation associated with HPV types 16, 18, 45, 56 - Anatomical distribution of anogenital HPV: Cervix 70%, Vulva 25%, Vagina 10%, Anus 20% - Papillary lesions, multiple, grow in clusters along a narrow stalk giving cauliflower appearance - Conditions predisposing: immunosuppression, diabetes, pregnancy, local trauma Treatment - HPV vaccine Types 6 and 11 - can prevent 90% of condyloma - Most low risk and 2/3 of high risk HPV infections are spontaneously eradicated over 24 months - Other modalities: Cryotherapy liquid nitrogen, laser therapy, surgical excision, topical trichloroactic acid, trichloroactic acid, imiquimod cream, intralesional interferon, photodynamic therapy --- 7. MOLLUSCUM CONTAGIOSUM - Pox virus - transmitted by body contact or towels/clothing - Common in immunodeficient subjects or with HIV - Size up to 1 cm, dome-shaped, pearly-white, all umbilicated, multiple - Microscopy: numerous inclusion bodies molluscum bodies in cytoplasm - Giemsa stain Treatment - Evacuation of caseous material under local anesthesia - Chemical treatment with ferric subsulfate or trichloroacetic acid 85% - Cryotherapy with liquid nitrogen until a halo of ice forms --- 8. PEDICULOSIS PUBIS - Infective agent: Crab louse Phthirus pubis - affects coarse hair of pubis - Transmitted by sexual contact or infected clothes, inadequate hygiene - Causes intense pruritis → scratching → secondary infection → suppuration Treatment - Permethrin cream 1% over affected area, wash off after 10 minutes - Lindane 1% used as shampoo - Gamma-benzene hexachloride or malathion 0.5% cream; do not wash for 12 hours; repeat after 4 days if needed - Treat contacts; sterilize clothings by boiling --- 9. SCABIES - Caused by Sarcoptes scabiei - Intense itching and often excoriation of skin - Associated with poor local hygiene Treatment - Permethrin cream 5% or malathion 0.5% aqueous solution - applied to all areas of body below neck; wash off after 8-14 hours - OR 25% benzyl benzoate emulsion for the entire body below the neck - single application often enough - Boil clothings; treat family members simultaneously --- HIGH-YIELD EXAM MNEMONICS & COMPARISONS Feature Gonorrhea Syphilis Chancroid Chlamydia --------------- Organism N. gonorrhoeae T. pallidum H. ducreyi C. trachomatis Incubation 3-7 days 9-90 days 3-5 days 6-14 days Primary lesion Discharge Painless chancre Painful ulcer Usually none Lymph nodes Suppurative Discrete, painless Suppurative buboes Variable Lab NAAT 95% VDRL/FTA-Abs Gram stain shoal of fish NAAT/PCR 95% Treatment Ceftriaxone 250 mg IM Benzathine penicillin G Ceftriaxone 250 mg IM Azithromycin 1g --- FREQUENTLY TESTED POINTS EXAM TRAPS 1. Gonorrhea does NOT affect tubes primarily - infertility only if with gonococcal infection 2. Syphilis - Tubes NOT affected; infertility does NOT occur unless associated with gonorrhea 3. NAAT sensitivity is 95% - both gonorrhea and chlamydia 4. Chancroid is ALWAYS painful - syphilis chancre is painless 5. CD4 200/µL = AIDS by definition regardless of symptoms 6. P-24 most widely used for HIV investigation study 7. ELISA is screening; Western blot is confirmatory for HIV 8. HIV RNA PCR is the gold standard for diagnosis 9. Efavirenz is first line HAART unless planning conception or NRTI/NNRTI resistance 10. HPV 6, 11 = condyloma acuminata; HPV 16, 18 = CIN/malignancy 11. VDRL positive after 6 weeks of initial syphilis infection 12. FTA-Abs remains positive even after successful treatment; VDRL becomes negative 13. Fitz-Hugh-Curtis syndrome is more commonly due to Chlamydia than gonorrhea 14. Benzathine penicillin G 2.4 MU IM single dose = early syphilis treatment 15. Perinatal HIV transmission: 70-75% during delivery; 30% in utero; 10-20% breastfeeding ---
