14.2 Cervical Screening (Pap Smear) & Pelvic Inflammatory Disease

14.2 Cervical Screening (Pap Smear) & Pelvic Inflammatory Disease

Cervical cancer screening and the diagnosis of Pelvic Inflammatory Disease (PID) represent fundamental pillars of clinical gynaecology in India. Cervical carcinoma is the second most common cancer among Indian women, yet it is almost entirely preventable through organized screening and HPV vaccination. Concurrently, PID remains a major cause of preventable tubal factor infertility, chronic pelvic pain, and ectopic pregnancy.

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Cervical Cancer Pathogenesis & HPV Virology

Persistent infection with high-risk oncogenic Human Papillomavirus (hrHPV) strains—specifically HPV 16 and 18 (accounting for >70% of invasive cervical cancers globally)—is the essential etiological factor for cervical intraepithelial neoplasia (CIN) and invasive carcinoma. Other high-risk types include 31, 33, 35, 39, 45, 51, 52, 56, 58, and 59.

Molecular Mechanism of Oncogenesis

• E6 Viral Oncogene: Binds to and promotes ubiquitin-mediated degradation of the p53 tumor suppressor protein, preventing p53-dependent apoptosis and DNA repair.
• E7 Viral Oncogene: Binds to and inactivates the Retinoblastoma (pRb) tumor suppressor protein, releasing the E2F transcription factor and driving unrestricted G1-to-S phase cell cycle progression.
• Transformation Zone (Squamocolumnar Junction - SCJ): The physiological site on the cervix where ectocervical non-keratinized stratified squamous epithelium meets endocervical simple columnar epithelium. Metaplastic squamous cells within this dynamic zone are uniquely vulnerable to hrHPV integration.

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Cervical Cancer Screening Modalities & Guidelines

1. Cervical Cytology (Pap Smear)

• Conventional Cytology: Uses an Ayre spatula (for ectocervix) and Endocervical Cytobrush rotated 360° to harvest cells from the transformation zone. Cells are immediately fixed on a glass slide with 95% ethanol.
• Liquid-Based Cytology (LBC): The sampling device is rinsed directly into a preservative vial (ThinPrep / SurePath). Reduces unsatisfactory slides, removes mucus/blood background, and permits ancillary high-risk HPV DNA testing from the same vial.

The Bethesda System (2014 Revision) for Reporting Cytology

2. Visual Inspection Techniques (VIA & VILI) for Low-Resource Settings

In primary health centres under India's National Health Mission (NHM), visual inspection provides instant point-of-care results:

• Visual Inspection with 3–5% Acetic Acid (VIA): Application of dilute acetic acid dehydrates cellular cytoplasm. High-density dysplastic cells with elevated nuclear-to-cytoplasmic ratios coagulate proteins, producing opaque, distinct acetowhite epithelial lesions near the squamocolumnar junction within 1 minute.
• Visual Inspection with Lugol's Iodine (VILI): Glycogen in normal mature squamous cells reacts with iodine to stain dark mahogany brown. Dysplastic cells are glycogen-deficient and fail to take up iodine, appearing mustard-yellow or saffron-yellow (VILI Positive).

3. Screening Algorithms & Target Populations

• Age to Begin: 21 years (or 30 years in low-resource public health settings in India).
• Screening Intervals (US Preventive Services Task Force / FOGSI):
  • Ages 21–29: Cytology alone every 3 years.
  • Ages 30–65: Primary hrHPV testing every 5 years (preferred), OR Co-testing (Cytology + hrHPV) every 5 years, OR Cytology alone every 3 years.
  • Screening Cessation: Age 65, provided 3 consecutive negative cytology results or 2 consecutive negative hrHPV co-tests within the past 10 years, with the most recent test within 5 years.

Reid's Colposcopic Index (RCI):
Scores 0 to 8 based on 4 criteria (0-2 points each):
1. Lesion Margin & Surface Configuration
2. Color / Acetowhitening Density
3. Vascular Pattern (Fine vs Coarse Punctation & Mosaicism)
4. Iodine Staining (Mahogany brown vs Mustard-yellow)
Score 0-2: Likely Low-Grade CIN 1
Score 3-5: Intermediate (CIN 1-2)
Score 6-8: High-Grade CIN 2-3

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Pelvic Inflammatory Disease (PID)

Pelvic Inflammatory Disease is an acute ascending infectious syndrome encompassing any combination of endometritis, salpingitis, tubo-ovarian abscess (TOA), and pelvic peritonitis. It is predominantly acquired via sexual transmission.

Microbiology & Etiology

• Primary Pathogens (85%): Neisseria gonorrhoeae (Gram-negative intracellular diplococcus causing severe purulent inflammation) and Chlamydia trachomatis (obligate intracellular bacterium causing insidious, silent tubal destruction).
• Secondary Co-pathogens: Anaerobes (Bacteroides fragilis, Peptostreptococcus), Gardnerella vaginalis, Mycoplasma genitalium, and Gram-negative enteric bacilli.
• IUD-Associated PID: Actinomyces israelii (Gram-positive branching filamentous bacteria with characteristic sulfur granules) is specifically associated with long-standing copper IUD use.

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Diagnostic Criteria (CDC 2021 Guidelines)

Because of the catastrophic long-term sequelae of unrecognized PID, empirical antimicrobial treatment must be initiated in sexually active young women presenting with pelvic/lower abdominal pain if one or more minimal criteria are present on pelvic examination and no other cause can be identified:

1. Minimum Clinical Criteria (Empirical Treatment Threshold)

• Cervical Motion Tenderness ("Chandelier sign" – severe pelvic pain elicited by lateral movement of the cervix during bimanual exam).
• Uterine Tenderness.
• Adnexal Tenderness (unilateral or bilateral).

2. Additional Supportive Criteria (Increases Diagnostic Specificity)

• Oral body temperature >38.3°C (101°F).
• Abnormal cervical or vaginal mucopurulent discharge.
• Abundant white blood cells (WBCs) on saline wet mount microscopy of vaginal fluid.
• Elevated Erythrocyte Sedimentation Rate (ESR) or C-Reactive Protein (CRP).
• Laboratory confirmation of cervical infection with N. gonorrhoeae or C. trachomatis (via Nucleic Acid Amplification Test - NAAT).

3. Definitive Criteria

• Transvaginal sonography or MRI showing thickened, fluid-filled fallopian tubes (hydrosalpinx / pyosalpinx) or tubo-ovarian complex.
• Endometrial biopsy demonstrating histopathological endometritis.
• Diagnostic Laparoscopy revealing tubal erythema, edema, purulent exudate, or pelvic adhesions (gold standard investigation, though reserved for ambiguous or severe cases).

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Acute & Long-Term Complications of PID

1. Fitz-Hugh-Curtis Syndrome (Perihepatitis): Occurs in 5–15% of PID cases. Ascending infection along the right paracolic gutter leads to inflammation of the liver capsule and adjacent anterior abdominal wall peritoneum without involvement of the hepatic parenchyma. Symptoms include acute right upper quadrant (RUQ) pain radiating to the right shoulder, mimicking acute cholecystitis. Laparoscopy demonstrates pathognomonic "violin-string" fibrous adhesions between the anterior liver capsule and abdominal wall.
2. Tubo-Ovarian Abscess (TOA): End-stage inflammatory mass involving tube, ovary, and adjacent pelvic structures. Rupture of a TOA causes surgical abdomen, peritonitis, and septic shock, carrying a mortality rate of up to 10%.
3. Tubal Factor Infertility (TFI): Tubal mucosal scarring and occlusion. Infertility risk rises exponentially with repeat PID episodes: ~12% after 1st episode, ~25% after 2nd episode, and ~50% after 3rd episode.
4. Ectopic Pregnancy: 6- to 10-fold increased risk due to impaired tubal ciliary function and endosalpingeal synechiae.
5. Chronic Pelvic Pain: Occurs in ~20% of affected women secondary to dense pelvic adhesions and chronic visceral hypersensitivity.

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Evidence-Based Treatment Regimens (CDC Guidelines)

Outpatient Empirical Regimen (Mild to Moderate PID)

Must cover N. gonorrhoeae, C. trachomatis, and anaerobes:

• Ceftriaxone: 500 mg IM in a single dose (1 g if weight ≥150 kg)
• PLUS Doxycycline: 100 mg orally BID for 14 days
• PLUS Metronidazole: 500 mg orally BID for 14 days (added to ensure anaerobic coverage and treat co-existing bacterial vaginosis/trichomoniasis)

Inpatient Parenteral Regimen

Indications for hospitalization include: surgical emergencies (e.g., appendicitis) cannot be excluded, pregnancy, tubo-ovarian abscess, severe illness/nausea/high fever, or failure of outpatient oral therapy after 72 hours.

• Regimen A: Cefotetan 2 g IV q12h OR Cefoxitin 2 g IV q6h PLUS Doxycycline 100 mg PO/IV q12h.
• Regimen B: Clindamycin 900 mg IV q8h PLUS Gentamicin loading dose 2 mg/kg IV followed by 1.5 mg/kg q8h.
• Transition: Continue IV therapy for 24–48 hours post-clinical improvement, then step down to oral Doxycycline (100 mg BID) to complete a total 14-day course.