Sexually Transmitted Di⅘?.; 0pseases and Infections
AIDS and HIV Overview
Acquired Immunodeficiency Syndrome (AIDS) progression and prognosis
Without treatment, people with AIDS typically survive about 2 ext{ years}.
With highly active antiretroviral therapy (HAART), most patients survive >10 ext{ years}.
HIV infection without ART usually progresses to AIDS within about 10 ext{ years}.
Definition of AIDS
AIDS is defined by an absolute CD4 cell count of fewer than 200 ext{ cells/mm}^3 along with specific opportunistic infections and malignancies.
Normal CD4 levels
Healthy individuals have CD4 counts ranging from 500 to 1400 cells/mm^3.
AIDS-defining signs and opportunistic infections
Oral candidiasis, tuberculosis (TB), Pneumocystis jirovecii pneumonia (PCP), CNS toxoplasmosis, histoplasmosis, cryptosporidiosis, Kaposi’s sarcoma, and others.
P. jirovecii is a leading opportunistic infection in patients with HIV.
Acute HIV Infection (Acute Retroviral Syndrome)
Symptomatology and infectiousness
An estimated 10 o60 ext{%} of individuals with early HIV infection may be asymptomatic.
Symptoms usually develop over 2 ext{ to }4 ext{ weeks} after exposure.
The initial immune response may resemble mononucleosis: fever, headache, sore throat, lymphadenopathy, rash, joint ache, myalgia, sometimes diarrhea and weight loss.
Very infectious at this stage due to extremely high viral load, often >10^5 ext{ copies/mL} in blood and genital secretions.
Painful ulcerative oral lesions may occur due to HIV or coinfection with herpes simplex, syphilis, or chancroid.
Serology and testing in acute infection
Most people (≈ 97 ext{%}) develop HIV antibodies within about 3 ext{ months} after exposure.
If acute HIV infection is strongly suspected, order the HIV RNA PCR test, which can detect infection about 7 ext{ to }28 ext{ days} after exposure.
Prophylaxis and transmission tips
Pneumocystis pneumonia (PCP) prophylaxis is advised when CD4 count is ext{≤}200 ext{ cells/mm}^3.
Acute retroviral syndrome is highly infectious; best if HIV is treated as early as possible.
Disseminated Gonococcal Infection (DGI)
Incidence and presentations
A very small percentage (0.5 o3 ext{%}) of individuals with gonococcal infection may progress to DGI.
Classic forms:
Triad of tenosynovitis (unique to DGI), dermatitis, and polyarthralgia with fever, chills, malaise.
Purulent arthritis without the classic triad.
Demographics and associated findings
Consider in sexually active individuals under 40, those with multiple partners, and in men who have sex with men (MSM).
Look for characteristic skin lesions: typically painless pustular or vesiculopustular lesions.
May be accompanied by signs of other STDs (e.g., cervicitis, urethritis).
Localized infections and complications
Localized infections of urethra, cervix, rectum, or pharynx often precede DGI.
May be complicated by perihepatitis (Fitz-Hugh–Curtis syndrome), and rarely endocarditis or meningitis.
Management and referral
Refer to an infectious disease specialist when DGI is suspected.
Practical tip
If STD symptoms with new onset swollen knee on one side (or another joint), DGI may be the cause.
Normal Findings and STD Screening (CDC Guidelines)
STD incidence and screening statistics
There are approximately 19 ext{ million STI incidents} each year in the United States; almost half occur in people aged 15 ext{ to }24.
Routine screening recommendations
Routine annual screening of all sexually active females ≤ 25 years for Chlamydia trachomatis and gonorrhea. If positive, retest for chlamydia and gonorrhea 3 months after treatment (reinfection check, not test-of-cure).
Annual testing for syphilis, chlamydia, and gonorrhea in persons with HIV infection.
Minors: In many jurisdictions, parental consent is not required for STD testing or treatment; no state requires parental consent for STD care.
STD screening includes taking a sexual history and assessing risk factors (the five Ps: Partners, Practices, Protection, Past STDs, Prevention of pregnancy).
Physical exam for STDs includes inspection of skin, pharynx, lymph nodes, anus, pelvic/genital area, and neurologic system.
Complications of untreated STD/STIs include infertility, ectopic pregnancy, congenital infections, cervical cancer, chronic pelvic pain, chronic hepatitis, chronic syphilis, and HIV/AIDS.
Men who have sex with men (MSM)
Annual screening for chlamydia and gonorrhea at sites of contact (urethra, rectum), regardless of condom use; screen every 3–6 months if at increased risk.
Annual testing for HIV and syphilis; retest more frequently if at risk.
Hepatitis B screening for all; consider hepatitis C screening in all adults >18 unless positivity rate <0.1%.
If history of anal-receptive intercourse, offer digital anorectal examination as part of STD care.
Pregnant patients
Some STDs (e.g., chlamydia, gonorrhea, genital herpes) can be transmitted to infant during vaginal delivery; others (HIV, herpes, syphilis, hepatitis) can cause congenital infections.
Screen all pregnant patients for HIV, syphilis, and HBsAg at first prenatal visit.
Screen all pregnant patients ≤ 25 years or those at increased risk for chlamydia and gonorrhea; retest for reinfection at 3 months and, in pregnancy, 4 weeks after treatment for test-of-cure in select cases.
Consider hepatitis C screening except in settings where positivity rate is <0.1%.
Chlamydia Trachomatis (C. trachomatis)
Microbiology and epidemiology
A small gram-negative bacterium; obligate intracellular parasite.
Most common bacterial STD in the United States; highest prevalence among 14 ext{ to }24 years.
Screening recommendations
Annual screening of all sexually active women < 25 years and at-risk older women.
Screen young men in high-prevalence settings (e.g., correctional facilities, sexual health clinics).
Annual screening for MSM at sites of contact (urethra, rectum), regardless of condom use; repeat every 3–6 months if at increased risk.
Screen persons with HIV at first HIV evaluation and then annually.
Clinical syndrome and complications
Females: cervicitis; dysuria–pyuria syndromes due to urethritis; pelvic inflammatory disease (PID); perihepatitis (Fitz-Hugh–Curtis).
Males: urethritis, epididymitis, prostatitis.
All: conjunctivitis, pharyngitis, proctitis/rectal infection, lymphogranuloma venereum (LGV), reactive arthritis.
Complications: PID, pregnancy complications (premature rupture of membranes, preterm delivery, low birth weight, ectopic pregnancy, infertility), upper genital tract infections, chronic pelvic pain, cervical cancer risk with chronic infection, and possible chronic hepatitis/HIV co-infection.
Diagnostic approach
NAATs (nucleic acid amplification tests) are the preferred diagnostic tests for genital and extragenital infection.
Sample types: vaginal/cervical swabs, urethral swabs, rectal swabs, pharyngeal swabs, or urine (male patients).
Self-collected vaginal swabs are as sensitive/specific as clinician-collected swabs for NAATs.
Treatment (Chlamydia)
Doxycycline 100 mg orally twice daily for 7 days: preferred for nonpregnant individuals.
Azithromycin 1 g PO in a single dose: alternative; preferred for pregnant individuals or when adherence is uncertain.
Fluoroquinolones (e.g., levofloxacin 500 mg daily for 7 days) only if fluoroquinolone-susceptible pathogens and nonpregnant.
All treated individuals should undergo retesting at 3 months to detect reinfection.
Test-of-cure is not routinely recommended but may be indicated at 4 weeks for select patients (e.g., pregnancy, persistent symptoms, concerns about nonadherence).
Special considerations
If cervicitis, perform a bimanual exam to assess if infection has ascended to the upper genital tract (rule out PID).
Test and treat for other STIs, including HIV and N. gonorrhoeae.
If chlamydia is diagnosed, do not give empiric gonorrhea prophylaxis unless indicated.
Partner management
Partners should ideally be examined, tested, and treated; expedited partner therapy (EPT) is permissible in many states.
EPT allows treating a patient’s sexual partner(s) without a clinical evaluation; status varies by state.
Pregnancy considerations
Azithromycin 1 g PO in a single dose is acceptable in pregnancy; doxycycline is avoided in pregnancy.
Test-of-cure 4 weeks after treatment and retest in the third trimester if indicated.
Laboratories and Diagnostics: Gonorrhea and Chlamydia
NAAT testing is highly sensitive for both gonorrhea and chlamydia.
Specimens: vaginal, cervical, urethral, rectal, pharyngeal swabs; urine can be used in men.
Vaginal swab is the specimen of choice in women (self-collected or clinician-collected).
First-ccatch urine (15–20 mL) is preferred for men.
Rapid NAAT-based tests
XPert CT/NG assay can provide results within ≈ 90 ext{ minutes}; usable on endocervical/vaginal swabs and urine.
Tests not routinely recommended
Culture, serology, antigen detection, genetic probe methods (in general).
Gram stain (for gonorrhea in men)
Visualization of PMNs with intracellular gram-negative diplococci can be diagnostic.
Treatment overview (Chlamydia and gonorrhea)
Chlamydia treatment detailed above (Doxycycline or Azithromycin).
Gonorrhea first-line therapy: Ceftriaxone 500 mg IM in a single dose (or 1 g IM if weight ≥ 150 ext{ kg}).
If chlamydia infection is not excluded, cotreat with doxycycline 100 mg PO BID for 7 days.
Pregnancy: azithromycin 1 g PO single dose is preferred if chlamydia is suspected.
Test-of-cure for uncomplicated urogenital/rectal gonorrhea is not routinely required after treatment; for pharyngeal gonorrhea, testing is indicated 7–14 days after therapy.
Sexual partner management
Expedited partner therapy (EPT) recommended for partners who cannot present for clinical evaluation (single-dose cefixime 800 mg with presumptive CT treatment if indicated).
DGI and PID considerations
DGI management involves IV antibiotics and specialist involvement.
Herpes Simplex Virus (HSV) and Genital Herpes
HSV types and transmission
HSV-1 usually oral; HSV-2 usually genital but with oral-genital transmission possible.
Asymptomatic shedding occurs intermittently; infected individuals remain contagious.
Transmission primarily via contact with mucosal secretions or skin during oral–oral, oral–genital, and genital–genital contact.
Primary clinical features and timing
Primary infection presents with acute onset of vesicles that rupture to form painful ulcers; can be more severe than recurrences and lasts 2 ext{ to }4 ext{ weeks}.
Oral ulcers worsened by acidic foods; primary infection has greatest viral shedding.
Diagnostic tests
HSV culture or PCR assay for HSV-1/HSV-2 RNA (PCR more sensitive).
Tzanck smear: rapid, simple, but has poor sensitivity and specificity; shows multinucleated giant cells when positive.
Treatment plans
First episode (primary genital herpes): Valacyclovir 1000 mg PO BID × 7–10 days; Acyclovir 400 mg PO TID × 7–10 days; Famciclovir 250 mg PO TID × 7–10 days.
Episodic treatment (flare-ups): Acyclovir 800 mg TID × 2 days or 800 mg BID × 5 days; Famciclovir 1,000 mg BID × single duration or 125 mg BID × 5 days or 500 mg once, then 250 mg BID × 2 days; Valacyclovir 500 mg BID × 3 days or 1,000 mg once daily × 5 days.
Chronic suppressive therapy: for severe or frequent recurrences; options include Acyclovir 400 mg PO BID, Famciclovir 250 mg PO BID, or Valacyclovir 500 mg once daily or 1,000 mg once daily.
Adjunctive therapy: analgesics for severe painful episodes; sitz baths can help; treat primary episodes within 24 hours of lesion onset when possible.
Pregnancy considerations
Podophyllotoxin and imiquimod are contraindicated in pregnancy; mechanical methods (e.g., currettage, laser, excision) may be used.
Practical tips
First-episode regimens are longer; flare-ups require shorter courses.
Important to distinguish recurrence patterns and counsel on transmission risk.
HIV Infection: Transmission, Testing, ART, and Prevention
Transmission and prevalence
HIV attacks CD4 T-lymphocytes and is spread via unprotected sexual contact (anal or vaginal), maternal transmission during pregnancy/birth/breastfeeding, sharing needles, and exposure to infected blood products.
HIV-1 is the most common; HIV-2 accounts for < 0.2% of infections.
In the U.S., ≈ 1.2 ext{ million} people have HIV; about 13 ext{%} are unaware of their infection.
Routine HIV screening recommendations
CDC recommends routine screening at least once in a lifetime for individuals aged 13 ext{ to }64 years, with more frequent testing for higher-risk groups.
Opt-out screening means patients are informed that HIV testing is included unless they decline.
Diagnostic testing and staging
Fourth-generation HIV tests detect HIV-1/HIV-2 antibodies and p24 antigen; reflex testing performs confirmatory antibody differentiation if positive.
HIV RNA PCR detects HIV-1 RNA and can identify infection as early as 7 ext{ to }28 ext{ days} after exposure and is used in indeterminate cases or to assess infants of HIV-positive mothers.
CD4 T-cell counts (norm 500$–$1500 cells/mm^3) are used to stage infection and monitor ART response.
HIV viral load (HIV RNA copies per mL) measures actively replicating virus; the best sign of ART success is an undetectable viral load, defined as <50 ext{ copies/mL}.
Monitoring and drug treatment principles
After starting ART, HIV RNA is checked every 2 o8 ext{ weeks}, then every 1 o2 ext{ months} until undetectable; CBC, lipids, and CD4 counts every 3 o4 ext{ months} for the first 2 ext{ years}.
Annual Pap cytology is recommended until three consecutive negatives, then every 3 years.
PrEP and PEP
Pre-exposure prophylaxis (PrEP) reduces HIV transmission by >90 ext{%} with daily oral medications; indicated for sexually active individuals at substantial risk (e.g., ongoing sex with HIV-positive partners with detectable viral load, multiple partners, injection drug users).
Postexposure prophylaxis (PEP) should be started as soon as possible after exposure; if source status is unknown, begin PEP while awaiting rapid HIV testing; duration is typically 4 weeks.
Baseline labs: HIV rapid test, HIV antibody/antigen immunoassay, HCV RNA, HBsAg, HBV surface antibody; HIV RNA PCR if acute HIV suspected.
Pregnancy and perinatal HIV management
Fully suppressive ART during pregnancy markedly decreases mother-to-child transmission; ART can be begun once pregnancy is diagnosed; avoid breastfeeding.
Preferred ART regimens for treatment-naïve pregnant patients include dual nucleoside reverse transcriptase inhibitors with either dolutegravir or ritonavir-boosted darunavir as the third drug.
Newborn prophylaxis: start zidovudine (Retrovir) within 8 hours of birth; ZDV reduces perinatal transmission by ext{70%};
monitor CBC for bone marrow suppression.
Human Papillomavirus (HPV) and vaccines
Almost all cervical cancers are caused by HPV, especially types 16 and 18.
HPV vaccine (Gardasil 9) prevents infections with oncogenic HPV types.
CDC recommends vaccination starting at age 11–12; catch-up vaccination up to age 26.
For vaccination of some adults aged 27 o45, shared decision-making is recommended; two doses are sufficient if first dose given before age 15; three doses if starting at age 15 or older.
Human Papillomavirus (HPV) and Condyloma Acuminata (Anogenital Warts)
Condyloma acuminata overview
External anogenital warts caused by HPV infection; appearance: soft white, flesh-colored, erythematous, or brown pedunculated, flat, or papular growths.
Common HPV types: 6 and/or 11.
Warts may appear on vagina, cervix, external genitals, urethra, anus; can also involve penis, nasal mucosa, oropharynx, conjunctiva.
Biopsy is not required before therapy unless lesion has suspicious features (fixation, irregular bleeding, ulceration, abnormal pigmentation, induration) or in immunocompromised patients.
Distinguishing HPV-related lesions
Do not confuse condyloma acuminata with condyloma lata (secondary syphilis).
HPV types 16 and 18 are oncogenic/carcinogenic.
Treatment options
Patient-applied topicals:
Podophyllotoxin (Condylox) 0.5% gel/cream: apply BID x 3 days, cycle up to 4 times; contraindicated in pregnancy.
Imiquimod (Aldara) 5% or Zyclara 3.75%: apply thin layer 3x weekly at bedtime for up to 16 weeks; leave on 6–10 hours; may cause irritation and hypopigmentation; contraindicated in pregnancy.
Sinecatechins 10% ointment (Veregen): apply ~0.5 cm strand per wart up to 3x daily for up to 16 weeks; may weaken condoms further; avoid in vagina/rectum.
Provider-applied therapies
Cryotherapy, trichloroacetic acid (TCA), surgical excision, electrosurgery, CO2 laser.
Cryotherapy/TCA best for small warts; surgical excision for large (>1 cm).
Pregnancy considerations
Mechanical destruction methods favored; podophyllotoxin and imiquimod contraindicated in pregnancy.
Tips and notes
Imiquimod is an immune-modulator; patient can self-administer.
Neisseria Gonorrhoeae (Gonorrhea)
Clinical features and screening
Gonorrhea is a gram-negative diplococcus; can infect urinary/genital tracts, anorectum, pharynx, and conjunctiva.
Gonorrhea can be systemic or disseminated if untreated; presumptive CT treatment is not recommended unless CT testing has not been excluded.
Women are more likely to be asymptomatic or present with PID; men more likely to have urethritis.
Screening recommendations
Screen all sexually active women < 25 years annually.
Screen MSM at least annually at sites of contact (urethra, rectum, pharynx), regardless of condom use.
During pregnancy, screen all pregnant women at first visit and rescreen if high risk.
Screen individuals with HIV at first evaluation and then annually.
Diagnostic testing
NAAT is the preferred test for gonorrhea; culture may be used to assess antibiotic susceptibility when resistance is suspected.
NAATs for gonorrhea and chlamydia can be performed on vaginal/cervical or urethral, rectal, pharyngeal specimens, and on first-catch urine.
Clinical syndromes by site
Cervix/uterus: cervicitis with purulent discharge; possible PID if ascended infection.
Urethra: urethritis with discharge and dysuria.
Pharynx: pharyngitis.
Rectum: proctitis with discharge, tenesmus, rectal pain.
Treatment (Gonorrhea)
Uncomplicated gonorrhea: Ceftriaxone 500 mg IM in a single dose (1 g IM if weight ≥ 150 ext{ kg}) plus cotreatment for chlamydia (doxycycline 100 mg PO BID × 7 days) if chlamydia not excluded; in pregnancy, azithromycin 1 g PO in a single dose; avoid doxycycline in pregnancy.
Test-of-cure: not routinely required for uncomplicated urogenital/rectal infection; for pharyngeal gonorrhea, test-of-cure is indicated 7 days after therapy by culture or 14 days by NAAT.
Discharge management and partner therapy
Expedited partner therapy (EPT) recommended for partners who cannot present for clinical care; cefixime 800 mg with presumptive chlamydia treatment if indicated.
Partners of MSM should be encouraged to seek evaluation due to higher risk of coexisting infections.
Disseminated gonococcal infection (DGI)
Ceftriaxone 1 g IV every 24 hours (duration 7–14 days) with hospitalization and/or infectious disease consultation as needed.
Acute proctitis and other complications
Acute proctitis: Ceftriaxone 500 mg IM once (1 g if weight ≥ 150 ext{ kg}$) + doxycycline 100 mg BID × 7 days; add HSV treatment if perianal ulcers present (valacyclovir 1 g PO BID × 7–10 days).
Pelvic Inflammatory Disease (PID) and Related Complications
PID overview and risk factors
Acute ascending polymicrobial infection of the upper genital tract.
Risk factors include sexual activity, history of PID, multiple partners, age 15–25, inconsistent condom use, iatrogenic disruption of vaginal flora, bacterial vaginosis.
Classic presentation
Lower abdominal or pelvic pain with new vaginal discharge and/or intermenstrual bleeding.
Cervical motion tenderness, uterine or adnexal tenderness; dyspareunia; fever. May have perihepatitis (Fitz-Hugh–Curtis syndrome).
Diagnostic approach
Rule out pregnancy first.
NAAT for C. trachomatis, N. gonorrhoeae, and M. genitalium via vaginal swab (preferred in females) or first-catch urine (preferred in males).
HIV screening; serologic testing for syphilis; CBC/ESR/CRP; gynecologic exam findings support PID diagnosis.
Management (outpatient and inpatient)
Outpatient: Ceftriaxone 500 mg IM (or 1 g if ≥150 kg) × 1 dose + doxycycline 100 mg PO BID × 14 days + metronidazole 500 mg PO BID × 14 days.
Hospitalization indications include severe illness, pregnancy, suspected tubo-ovarian abscess, or nonresponse to outpatient therapy.
Follow-up within 72 hours to assess clinical improvement.
Complications and related conditions
Fitz-Hugh-Curtis syndrome (perihepatitis) in about 10% of PID cases; RUQ pain with violin-string inflammatory adhesions on liver capsule.
Key pearls
PID is a clinical diagnosis; treat presumptively if signs and symptoms are present even if tests are negative for gonorrhea/chlamydia.
Adnexal tenderness is the most sensitive physical exam finding for PID.
Syphilis: Serology, Stages, and Treatment
Serologic testing and diagnostic algorithm
Two types of tests: non-treponemal (screening) and treponemal (confirmatory).
Non-treponemal screening tests: Rapid Plasma Reagin (RPR) or Venereal Disease Research Laboratory (VDRL).
If reactive, confirm with treponemal tests: Fluorescent treponemal antibody absorption (FTA-ABS), T. pallidum particle agglutination (TP-PA), T. pallidum enzyme immunoassay (TP-EIA), or chemiluminescence immunoassay.
In patients without prior syphilis, diagnosis requires reactive non-treponemal and treponemal tests.
For patients with prior treated syphilis, a positive non-treponemal test may indicate new infection, treatment response, or treatment failure.
If the initial test used is RPR, use sequential RPR to monitor treatment response; if VDRL used, monitor with sequential VDRL.
Disease staging and monitoring
Early syphilis: primary, secondary, or early latent (<1 year).
Late latent (>1 year) or tertiary syphilis without neurosyphilis.
Neurosyphilis: neurologic/ophthalmic/otic involvement; requires IV penicillin G.
Follow-up: recheck RPR/VDRL at 6 and 12 months post-treatment; look for at least a fourfold titer decrease from baseline.
Serofast phenomenon: some patients may retain low-positive non-treponemal tests for years even after successful therapy; recheck titers as appropriate.
Treatment regimens
Early syphilis (primary, secondary, early latent): Benzathine penicillin G 2.4 million units IM
as a single dose.Late latent or tertiary without neurosyphilis: Benzathine penicillin G 2.4 million units IM weekly for 3 consecutive weeks.
Neurosyphilis or ocular/otic syphilis: IV penicillin G 3–4 million units IV every 4 hours or 18–24 million units/day by continuous infusion for 10–14 days.
Penicillin allergy: doxycycline 100 mg PO BID for 28 days or ceftriaxone 2 g IV/IM daily for 10–14 days (desensitization for pregnant patients if penicillin allergy).
Pregnancy considerations
Penicillin G benzathine therapy is used in pregnancy; penicillin desensitization if allergic.
All pregnant women should be screened for syphilis at the first prenatal visit with repeat testing during pregnancy if high risk.
Follow-up and partner management
Recheck RPR/VDRL titers at 6 and 12 months; treat sexual partners from the preceding 90 days even if serology is negative.
Refer to infectious disease specialist for suspected neurosyphilis or poor treatment response.
Jarisch-Herxheimer reaction
Acute, self-limited febrile reaction within 24 hours after therapy for syphilis; fever, chills, headache, myalgia, diaphoresis; managed with supportive care.
HIV Infection: Education, Prevention, and Public Health Aspects
HIV education and prevention strategies
Do not handle cat litter or eat undercooked meat to reduce toxoplasmosis risk; avoid bird droppings to reduce histoplasmosis risk; gloves when cleaning animal cages; promote healthy lifestyle and adherence to ART.
Preventing transmission: use condoms consistently; do not share needles; avoid sharing personal items that may have blood; HIV-infected mothers should not breastfeed; limit sexual partners.
Occupational exposure and frontline risk
Among healthcare occupations, nurses have the highest rate of occupationally acquired HIV/AIDS.
Risk of needlestick injury increases with deep injury, visibly contaminated devices, needle placement in a vein/artery, and source patient with terminal illness; infectious fluids include blood, semen/preseminal, vaginal fluids, breast milk; transmission requires mucous membranes or damaged tissue or direct injection into bloodstream.
Vaccines and vaccination guidance for HIV patients
Inactivated vaccines recommended: hepatitis A/B, inactivated influenza, pneumococcal, Td/Tdap every 10 years, HPV vaccine (through age 26), and others as needed.
Vaccinations work best if CD4 counts exceed 200 ext{ copies/mm}^3 (note: typically written as 200 cells/mm^3; this document uses a similar threshold).
Cervical cancer screening: annual Pap until three negatives, then every 3 years.
Diagnostic testing and monitoring in HIV care
Fourth-generation HIV testing (antibody/antigen) with reflex confirmatory testing.
ELISA and Western blot are older tests; rapid HIV tests are point-of-care with rapid results.
HIV RNA PCR is used for acute infection and infant testing; monitors viral replication.
PrEP and PEP (pre/postexposure prophylaxis)
PrEP reduces HIV transmission by >90 ext{%} with daily oral therapy; recommended for at-risk populations (e.g., ongoing risk with an HIV-positive partner with detectable viral load, high-risk sexual behavior, IDU).
PEP should be started promptly after exposure; do not delay for confirmatory testing; duration 4 weeks; baseline labs and monitoring as above.
Perinatal HIV management and infants
Maximally suppressive ART during pregnancy to reduce mother-to-child transmission.
Preferred regimens in treatment-naïve pregnant patients include dual NRTIs plus a boosted protease inhibitor or integrase inhibitor as the third agent.
Newborn prophylaxis: zidovudine (Retrovir) started within 8 hours of birth; monitor CBC due to potential bone marrow suppression.
Vaccinations and cancer screening in HIV patients
Maintain routine vaccines as appropriate; screen for cervical cancer with Pap testing per guidelines; vaccines are more effective when CD4 counts are adequate.
Human papillomavirus (HPV) and cervical cancer linkage
HPV is the primary driver of cervical cancer; vaccination helps prevent infection with oncogenic HPV types; vaccination schedule and eligibility as above.
Human Immunodeficiency Virus Prophylaxis and Exposure (PEP and PrEP) — Practical Guidelines
Preexposure prophylaxis (PrEP)
Indicated for at-risk individuals, including those with ongoing sexual relationships with infected partners, MSM, women with high-risk exposure, and people who inject drugs.
Daily oral regimens; requires baseline HIV testing and periodic monitoring every 3 months thereafter.
Postexposure prophylaxis (PEP)
Start as soon as possible after potential exposure; do not wait for lab results to begin PEP if exposure risk is high.
Baseline labs: HIV rapid test and HIV antibody/antigen immunoassay, HCV RNA, HBsAg, and HBV surface antibody; HIV RNA PCR if acute HIV suspected.
Minimum duration: 4 weeks of ART; 72 hours post-exposure is the outer limit for initiating PEP.
Immunizations, Screening, and Cancer Prevention in HIV/AIDS
Vaccines and follow-up
Inactivated vaccines are safe and recommended for HIV patients; vaccines work best when CD4 counts are higher than 200 ext{ cells/mm}^3; regular cervical cytology (Pap) screening.
Pap tests and cervical cancer screening
Annual Pap tests until traditionally three consecutive negatives, then every 3 years.
Vaccines, Screening, and Care in Pregnancy and Special Populations
Pregnancy considerations for HIV, HPV, and other STIs
HIV-infected pregnant patients should start antiretroviral therapy as soon as possible; zidovudine prophylaxis for the infant if indicated; avoid breastfeeding.
Screening for HIV, syphilis, and other infections during pregnancy; additional Chlamydia/Gonorrhea testing if risk factors present.
HPV vaccination and anogenital warts management during pregnancy focus on non-pregnancy contraindicated therapies; some topical therapies are avoided.
Practical Clinical Pearls and Quick References
Testing windows and test types
Fourth-generation HIV tests can detect infection 18 to 45 days after exposure (screening); HIV RNA tests can typically detect infection about 10$–$33 days after exposure.
For infants of HIV-positive mothers or indeterminate serology, HIV RNA PCR is used.
Treatment principles and safety notes
Always check for pregnancy status before prescribing certain STI therapies (e.g., doxycycline is avoided in pregnancy).
When treating chlamydia and gonorrhea concomitantly, cotreatment for both infections is common unless microbiology excludes one.
EPT can reduce transmission but requires consideration of local laws.
Preventive care and follow-up
Reinfection is common for chlamydia and gonorrhea; routine retesting at 3 months is recommended.
Routine STI screening is a key part of preventive health in sexually active populations.
Connections to Foundational Principles and Real-World Relevance
Public health and epidemiology: standardized screening intervals (CDC guidelines) reduce community transmission and enable early case finding.
Immunology and pathophysiology: CD4 T-cell depletion drives opportunistic infections; ART suppresses viral replication and restores immune function, as reflected by rising CD4 counts and falling viral loads.
Pharmacology and antibiotic stewardship: combinations (e.g., Ceftriaxone + doxycycline) are designed to cover coinfections and prevent resistance; EPT improves partner treatment rates.
Ethical, social, and policy considerations: opt-out HIV screening, minors’ consent for STI care, and PrEP/PEP access reflect balancing public health with individual rights.
Clinical reasoning: differentiation of primary vs recurrent infections (HSV, syphilis, HPV) relies on characteristic presentations, serology, and lesion morphology; testing algorithms optimize sensitivity and specificity.
Vaccine science and cancer prevention: HPV vaccination reduces oncogenic HPV infections and related cancers; routine vaccination schedules improve long-term outcomes.
Summary of Key Formulas and Thresholds to Memorize
AIDS definition: CD4 < 200 \text{cells/mm}^3 with opportunistic infections/malignancies.
Healthy CD4 range: 500 \le CD4 \le 1400 \text{ cells/mm}^3.
Acute infection infectious load: >10^5 \text{ copies/mL}.
Undetectable viral load: <50 \text{ copies/mL}.
PCP prophylaxis threshold: CD4 \le 200 \text{ cells/mm}^3.
DGI risk factor: age < 40, multiple partners, MSM; skin lesions are typically painless pustules.
Chlamydia treatment (nonpregnant): Doxycycline\ 100\text{ mg BID} \times 7\text{ days}; alternative: Azithromycin\ 1\ g\ PO\ in\ a\ single\ dose.
Gonorrhea treatment (uncomplicated): Ceftriaxone 500\ mg\ IM (or 1\ g\ IM if weight ≥ 150\ kg) + doxycycline 100 mg BID x 7 days (if chlamydia not excluded).
Syphilis treatment (early): Benzathine penicillin G 2.4 MU IM x 1 dose; (late/tertiary without neurosyphilis): 2.4 MU IM weekly x 3 weeks; Neurosyphilis: IV penicillin G 3–4 MU IV q4h for 10–14 days.
HIV prevention: PrEP reduces transmission by >90\%; PEP duration 4 weeks; start within 72 ext{ hours}$$ after exposure.
Vaccination touchpoints: HPV vaccine schedule 2 doses if started before age 15; 3 doses if started at age 15+; Gardasil 9 covers oncogenic HPV types 16/18 and others.
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