Exhaustive Guide to Vaginal and Sexually Transmitted Infections

Vaginal and Genitourinary Infections Overview

• Vaginal candidiasis (Vulvovaginal Candidiasis - VVC):
      * Definition: A mucosal inflammation caused by the fungus Candida albicans.
      * Pathophysiology: The fungus invades the vaginal epithelial tissue, leading to inflammation.
      * Microbiology: Typically caused by Candida albicans.
      * Epidemiology: Extremely common; approximately $8\%$ of women worldwide experience candidiasis annually. Most individuals will experience it at least once in their lives.
      * Signs and Symptoms: Classic presentation includes a thick, white, curd-like vaginal discharge (often compared to cottage cheese). Common locations for yeast overgrowth include the vagina, diaper areas in infants, and under abdominal pannices in immunocompromised patients.
      * Risk Factors: Conditions that suppress the immune system or create an opportunistic environment, including:
          * Diabetes mellitus.
          * Antibiotic use (disrupts normal flora).
          * Immunosuppression.
      * Diagnosis: Assessment of vaginal pH and microscopy; budding yeast can be identified on a slide. It can also be cultured.
      * Treatment: Antifungal medications.

• Bacterial Vaginosis (BV):
      * Definition: A state of dysbiosis or alteration in the vaginal microbiome where normal protective bacteria are replaced by anaerobic pathogens.
      * Pathophysiology: The prevalence of Lactobacilli (which normally maintain a healthy environment) decreases, allowing anaerobic pathogens to overgrow by $10$ to $100$ times.
      * Pathogens Involved: Peptostreptococcus, Gardnerella vaginalis, and various other anaerobes.
      * Epidemiology: The most prevalent vaginal infection, fluctuating between $20\%$ and $60\%$ prevalence. It exists on a spectrum from mild fluctuation to severe infection.
      * Signs and Symptoms:
          * Thin, yellow-gray vaginal discharge.
          * A strong, distinctive "fishy" odor.
          * Positive "Whiff test."
      * Microscopic Diagnosis: Presence of "clue cells" under the microscope.
      * Risk Factors:
          * Activities that disrupt the microbiome, such as the use of sex toys.
          * Multiple sex partners (introducing different bacteria into the vaginal flora).
          * Note: It is not strictly a sexually transmitted infection (STI), as it can occur without sexual activity due to other factors disrupting flora.
      * Diagnosis: Nucleic acid testing or microscopy.
      * Treatment: Metronidazole (an older medication that treats parasites, bacteria, and trichomonads).
      * Complications: Usually none, though it has been rarely associated with upper tract infections.

General Principles of Sexually Transmitted Infections (STIs)

• Epidemiology:
      * Approximately $26$ million newly acquired STIs occur per year.
      * $50\%$ of these occur in the youth population due to higher risk behaviors during sexual expression.
• Risk Factors:
      * Receptive partners in oral, vaginal, or anal sex.
      * Uncircumcised men (the area under the foreskin can create a hospitable environment for pathogen growth).
• Common Symptoms (General): While many STIs are asymptomatic, patients may present with:
      * Pain.
      * Discharge.
      * Burning sensations.
      * Visible lesions.
• Clinical Evaluation and the Five P's of Sexual History:
      1. Partners: Number of partners.
      2. Practices: Specific types of sexual acts/practices.
      3. Protection: Methods used for STI prevention.
      4. Past History: Previous history of STIs.
      5. Pregnancy Intentions: Current approach to reproduction.
• Case Study Anecdote (History Taking): A provider encountered a patient whose partner (a trans female) had syphilis. The medical note was inadequate because it failed to specify contact practices (penile-vaginal, oral, dental dams, use of toys). Thoroughness is essential for legal protection and appropriate patient education regarding transmission.
• Diagnostic Tools:
      * Nucleic acid amplification test (NAAT).
      * Gram stains and cultures.
      * Syphilis-specific tests: VDRL antigens and Rapid Plasma Reagin (RPR). Note: Non-syphilitic diseases can cause false positives.
• Public Health Goals: Treatment is vital to prevent impaired fertility, Pelvic Inflammatory Disease (PID), and sepsis.

Bacterial Sexually Transmitted Infections

• Gonorrhea:
      * Microbiology: Neisseria gonorrhoeae, an aerobic, non-spore-forming, Gram-negative diplococcus.
      * Pathogenesis: Humans are the only natural host. The bacteria have hair-like structures (pili) that help them attach to cells. It infects columnar, transitional, and stratified squamous epithelial cells.
      * Clinical Presentation: Often asymptomatic but can cause urethritis, cervicitis, proctitis, pharyngitis, and conjunctivitis.
      * Neonatal Impact: Prophylactic antibiotic ointment is applied to the eyes of newborns to prevent gonorrheal conjunctivitis.
      * Complications: Pelvic pain, disseminated infection (in immunocompromised individuals).

• Chlamydia:
      * Microbiology: Chlamydia trachomatis, a Gram-negative bacterium that behaves similarly to a parasite because it is unable to reproduce without a host cell.
      * Pathogenesis: Operates via endocytosis to enter the cell and use it for reproduction, eventually rupturing the cell and causing inflammation. It primarily affects superficial squamous columnar and columnar epithelial cells.
      * Clinical Presentation: Frequently asymptomatic; can lead to urethritis, epididymitis, and cervicitis.
      * Lymphogranuloma Venereum (LGV): A rare strain of chlamydia involving three stages:
          * Stage 1: Primary lesions.
          * Stage 2: Inflammation and swelling of lymph nodes.
          * Stage 3: Persistent inflammation due to lymphatic system obstruction.
      * Neonatal Impact: Can infect the respiratory tract or the eyes (conjunctivitis).

• Syphilis:
      * Microbiology: Treponema pallidum, an anaerobic, cork-shaped (spirochete) bacterium.
      * Transmission: Infects any body tissue; present in exudate from moist mucosal cutaneous tissues. Can cross the placental membrane as early as week $9$.
      * Primary Syphilis: Localized reaction; appears $12$ days to $12$ weeks after exposure (average $3$ weeks). Characteristic lesion is the hard chancre: a painless, firm, eroded ulcer. Associated with enlarged lymph nodes.
      * Secondary Syphilis: Systemic manifestation involving low-grade fever, malaise, sore throat, and rashes (notably on the palms of the hands and soles of the feet).
      * Latent Syphilis: Can last from one year to a lifetime; patient is asymptomatic; divided into early and late stages.
      * Tertiary Syphilis: The most severe stage. Features include:
          * Gummas: Destructive lesions of the bone and soft tissues.
          * Neurosyphilis: Can present as dementia or other neurological issues.
      * Congenital Syphilis: Part of the TORCH infections; causes severe physical destruction in infants if untreated. Historically, before penicillin, this led to facial bone destruction requiring prosthetic noses/glasses.

• Chancroid:
      * Pathogen: Haemophilus ducreyi (Gram-negative).
      * Presentation: Acute infection characterized by tender (painful) ulcers, which differentiates it from the painless chancre of syphilis.

• Granuloma Inguinale:
      * Pathogen: Klebsiella granulomatis.
      * Note: Very rare, mostly seen in international settings or mission trips.

Viral Sexually Transmitted Infections

• Herpes Simplex Virus (HSV):
      * HSV-1: Typically oral (lips/mouth).
      * HSV-2: Typically genital. (Note: These types are interchangeable regarding site of infection).
      * Prevalence: Estimated at $47.8\%$.
      * Pathophysiology: Transmitted through contact with a person shedding the virus. Initial replication occurs in the dermis and epidermis, causing cell destruction and vesicles. The virus then travels intra-axonally to the dorsal root ganglion, where it remains latent.
      * Reactivation: Triggered by stress, sunlight, febrile illness, or immunosuppression.
      * Signs/Symptoms: Small painful vesicles on an erythematous base. Prodomal symptoms include burning or itching.
      * Viral Shedding: Transmission can occur even in the absence of visible ulcers or pustules.
      * Neonatal Impact: Very serious for immunocompromised newborns; can lead to skin, eye, or disseminated infection.

• Human Papillomavirus (HPV):
      * Microbiology: Double-stranded DNA virus; over $200$ types exist.
      * Epidemiology: Nearly $1$ in $4$ adults have at least one strain; almost all sexually active people will acquire HPV.
      * Pathogenesis: Trauma to the epithelium allows the virus to contact basal cells. It enters nuclear DNA and alters cell protein expression.
      * Clinical Manifestations:
          * Genital Warts (Condylomata acuminata): Soft, skin-colored, pink, or brown growths. Types $6$ and $11$ cause $90\%$ of warts.
          * Cancer: Types $16$ and $18$ are the primary cause of cervical, penile, vulvar, oral, and anal cancers. Other high-risk types include $31$, $33$, $45$, $51$, and $58$.
          * Laryngeal Papilloma: In infants/children, causes stridor, hoarseness, and respiratory distress.

• Molluscum Contagiosum:
      * Definition: Not exclusively an STI; transmitted by skin-to-skin contact, auto-inoculation, or fomites (towels, sponges). Common among children in daycare or wrestlers.
      * Presentation: Clusters of pink, dome-shaped, smooth, waxy, or pearly umbilicated papules.

• Other Sexually Transmitted Viruses:
      * Epstein-Barr Virus (EBV): "Kissing disease" (mononucleosis); associated with Burkitt and Hodgkin lymphoma.
      * Cytomegalovirus (CMV): Herpes virus type $5$; transmitted via blood/fluids; part of TORCH; causes severe systemic disease in neonates.
      * Zika Infection: Mosquito-borne but also sexually transmitted; causes fever, rash, and muscle pain; can be transmitted intrauterine.
      * MPOX: Structurally similar to smallpox; transmitted via fluids, droplets, or wound exudate. Presents with fever, malaise, and maculopapules/vesicles that eventually scab.
      * HIV: Destroys T-helper cells (CD4), impacting the adaptive, innate, and inflammatory immune systems. Causes opportunistic infections.
      * Hepatitis B: DNA virus spread via blood or mucosal contact.
      * Hepatitis C: Sexual transmission is relatively rare.

Protozoal and Ectoparasitic Infections

• Trichomoniasis:
      * Pathogen: Trichomonas vaginalis, a flagellated protozoan.
      * Clinical Presentation:
          * Females: Often asymptomatic or presents with a yellow-green discharge and a "strawberry cervix" (petechiae on the cervix).
          * Males: Often asymptomatic; may have slight discharge.
      * Diagnosis: Microscopy showing the flagellated protozoa swimming across the slide.
      * Anecdote: A patient once adamantly denied sexual activity and suggested she contracted it from her cat; however, it is primarily spread through penile-vaginal sex.

• Scabies:
      * Pathogen: The adult female itch mite (Sarcoptes scabiei).
      * Transmission: Prolonged, close skin-to-skin contact. Common in healthcare settings, families, and nursing homes.
      * Symptoms: Intense pruritus (itching).

• Pubic Lice ("Crabs"):
      * Transmission: Sexual contact or shared bed linens.
      * Life Cycle: $25$ to $30$ days. Involves an egg and three nymph stages before becoming an adult.
      * Treatment: Requires topical cream rinses/shampoos and rigorous laundering of bedding; often requires a second treatment in one week to kill newly hatched lice.

Pelvic Inflammatory Disease (PID)

• Definition: Acute inflammation of the upper genital tract (fallopian tubes, ovaries, and uterus).
• Epidemiology: $4\%$ of females aged $18$ to $44$ report an episode of PID.
• Clinical Indicators:
      * Chandelier Sign: Severe cervical motion tenderness during a pelvic exam; the patient may reach up toward the ceiling/chandelier in pain.
      * Physical findings: Uterine tenderness and adnexal tenderness.
• Pathophysiology: Caused by STIs (usually gonorrhea or chlamydia) migrating from the lower genital tract. Inflammation involves macrophages and fibroblastic activity, leading to permanent damage of the ciliated epithelium of the uterine tubes.
• Risk Factors: History of PID, high-risk behaviors/STIs, lower socioeconomic status, and douching (which alters protective flora and may push pathogens upward).
• Diagnosis: Gonorrhea/Chlamydia testing, pregnancy test, ultrasound, or CT scan.
• Complications: Permanent scarring and adhesions leading to infertility and ectopic pregnancies.