8.3 Gynecology: Menstruation, Menopause, PCOS, and Vaginal Infections

Gynecology: Menstruation, Menopause, PCOS, and Vaginal Infections

Why This Matters for PANCE

Gynecologic pathology represents a high-yield outpatient focus on the PANCE. You must master the PALM-COEIN classification of abnormal uterine bleeding, the clinical evaluation of postmenopausal bleeding, the diagnostic criteria and systemic complications of PCOS, and the microscopic and clinical differences between the three major vaginal infections.

Abnormal Uterine Bleeding (AUB)

Abnormal Uterine Bleeding (AUB) refers to any menstrual bleeding that deviates from normal frequency, duration, or volume.

• PALM-COEIN Classification:
  • Structural (PALM): Polyp (hyperplastic epithelial overgrowths), Adenomyosis (endometrial tissue within the myometrium, presenting with a globally enlarged, symmetric, boggy, and tender uterus), Leiomyoma (uterine fibroids, presenting with an asymmetric, firm, non-tender uterus), and Malignancy/hyperplasia.
  • Non-Structural (COEIN): Coagulopathy (e.g., von Willebrand disease, especially in adolescents with heavy menses since menarche), Ovulatory dysfunction (e.g., PCOS, hypothyroidism, or perimenopause, causing irregular bleeding), Endometrial (primary dysfunction of endometrial local hemostasis), Iatrogenic (due to anticoagulants, IUDs, or hormonal contraceptives), and Not yet classified.
• Diagnostic Workup:
  • Initial Test: Transvaginal ultrasound (TVUS) to assess endometrial thickness and rule out structural pathologies.
  • Endometrial Biopsy (EMB): Indicated in all women aged >= 45 years with AUB. In women < 45 years, EMB is indicated if there is a history of unopposed estrogen exposure (e.g., chronic anovulation in PCOS), obesity, or failed medical management.
  • Postmenopausal Bleeding: Any vaginal bleeding occurring >= 12 months after the cessation of menses is considered endometrial cancer until proven otherwise. A TVUS is performed first. If the endometrial stripe is > 4 mm (or if bleeding is persistent), an endometrial biopsy is mandatory.

Menopause

Menopause is the permanent cessation of menses due to the loss of ovarian follicular activity.

• Definition & Diagnosis: Defined retrospectively as 12 consecutive months of amenorrhea without another physiological cause. The average age is 51. Diagnosis is clinical. Laboratory evaluation is generally unnecessary but will show a marked elevation in Follicle-Stimulating Hormone (FSH) > 30 mIU/mL due to the loss of negative feedback from estradiol.
• Clinical Presentation: Vasomotor symptoms (hot flashes, night sweats), sleep disturbances, mood changes, and the Genitourinary Syndrome of Menopause (vaginal dryness, burning, dyspareunia, and recurrent UTIs due to vaginal pH rising above 4.5 and loss of tissue elasticity).
• Hormone Replacement Therapy (HRT) Safety Rules:
  • Intact Uterus: Women with an intact uterus MUST receive combined estrogen-progesterone therapy. Unopposed estrogen therapy leads to endometrial hyperplasia and a high risk of endometrial cancer.
  • Prior Hysterectomy: Women who have undergone a hysterectomy can safely receive estrogen-only therapy.
  • Contraindications to Systemic HRT: History of breast cancer, estrogen-dependent cancers, active thromboembolic disease (DVT/PE), history of stroke or myocardial infarction, active liver disease, or undiagnosed abnormal vaginal bleeding.
  • Vaginal Estrogen: For isolated vulvovaginal symptoms (vaginal dryness/atrophy), low-dose topical vaginal estrogen is preferred and carries minimal systemic absorption.

Polycystic Ovary Syndrome (PCOS)

PCOS is a common endocrine disorder characterized by insulin resistance and hyperandrogenism.

• Pathophysiology: Insulin resistance leads to compensatory hyperinsulinemia. Insulin acts synergistically with luteinizing hormone (LH) to stimulate androgen production by ovarian theca cells. Insulin also suppresses hepatic production of Sex Hormone-Binding Globulin (SHBG), which increases free testosterone. Furthermore, an abnormal GnRH pulsatility results in an elevated LH-to-FSH ratio (often > 2:1 or 3:1), which prevents follicle maturation, causing chronic anovulation.
• Rotterdam Criteria: Diagnosis requires at least two of the following three:
  1. Oligomenorrhea or anovulation (irregular or absent menstrual cycles).
  2. Clinical or biochemical hyperandrogenism (hirsutism, acne, male-pattern baldness, or elevated free/total testosterone).
  3. Polycystic ovaries on ultrasound (multiple peripheral subcentimeter follicles resembling a "string of pearls" or ovarian volume > 10 mL).
• Clinical Presentation and Risks: Patients present with obesity, hirsutism, acne, and acanthosis nigricans (velvety, hyperpigmented plaques on intertriginous areas indicating insulin resistance). Long-term risks include type 2 diabetes, metabolic syndrome, obstructive sleep apnea, cardiovascular disease, and a significantly increased risk of endometrial adenocarcinoma due to chronic unopposed estrogen (lack of progesterone protection due to anovulation).
• Management:
  • First-Line (General): Lifestyle modifications (weight loss and exercise) to improve insulin sensitivity and restore ovulation.
  • Cycle Regulation & Hirsutism: Combined Oral Contraceptives (COCs) are the first-line pharmacotherapy. The progesterone component protects the endometrium, and the estrogen increases SHBG to lower free testosterone.
  • Insulin Resistance: Metformin.
  • Refractory Hirsutism: Spironolactone (an anti-androgen). Warning: Due to risk of teratogenicity (feminization of a male fetus), it must be paired with effective contraception.
  • Infertility/Ovulation Induction: Letrozole (aromatase inhibitor, first-line) or clomiphene.

Vaginitis (Vaginal Infections)

Differentiating the three major causes of vaginal discharge is a highly tested clinical skill.

• Bacterial Vaginosis (BV): A non-STI dysbiosis caused by a loss of lactobacilli and overgrowth of anaerobes like Gardnerella vaginalis. Diagnosed via the Amsel criteria: thin gray-white discharge, pH > 4.5, positive whiff test (with 10% KOH), and clue cells on saline wet mount (epithelial cells covered in bacteria obscuring the cell border). Treatment is oral Metronidazole 500 mg BID for 7 days. Pearl: Patients must avoid alcohol during and for 48 hours after treatment to prevent a disulfiram-like reaction.
• Vulvovaginal Candidiasis: Fungal overgrowth, often after antibiotic use. Presents with intense pruritus, erythema, and a thick, white, clumpy, "cottage cheese-like" discharge. Vaginal pH is normal (4.0-4.5). Microscopic examination on KOH prep shows pseudohyphae and budding yeast. Treatment is a single dose of oral Fluconazole (150 mg).
• Trichomoniasis: An STI caused by the flagellated protozoan Trichomonas vaginalis. Presents with a copious, frothy, yellow-green, malodorous discharge, and a strawberry cervix (cervical petechiae). Vaginal pH is > 4.5. Saline wet mount shows motile flagellated trichomonads. Treatment is oral Metronidazole (500 mg BID for 7 days). Must treat sexual partners and counsel to avoid alcohol.

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Endometriosis

Endometriosis is the presence of functional endometrial glands and stroma outside the uterine cavity, most commonly on the ovaries, fallopian tubes, pelvic peritoneum, and cul-de-sac. It is an important reproductive blueprint topic.

• Pathophysiology: Retrograde menstruation is the leading theory — endometrial tissue flows backward through the fallopian tubes and implants on pelvic structures. These ectopic implants respond to cyclic hormonal stimulation, causing inflammation, adhesions, and endometriomas ("chocolate cysts" on the ovaries).
• Clinical Presentation: The classic triad is chronic pelvic pain, dysmenorrhea, and dyspareunia (painful intercourse). Pain often begins before menses. Infertility may be the presenting complaint. Severity of symptoms does NOT correlate well with the extent of disease.
• Physical Exam: Fixed, retroverted uterus; tender adnexa; nodularity of the uterosacral ligaments on bimanual/vaginal exam; tender posterior fornix.
• Imaging: Pelvic ultrasound may show endometriomas (homogeneous, low-level echo "chocolate" cysts). MRI is more sensitive for deep infiltrating disease. Definitive diagnosis requires diagnostic laparoscopy with biopsy showing endometrial glands and stroma outside the uterus.
• Management:
  1. NSAIDs — first-line for mild pain.
  2. Hormonal suppression — combined oral contraceptives (cyclic or continuous), progestins (e.g., medroxyprogesterone, norethindrone), or the levonorgestrel IUD. Goal: suppress menstrual cycling and ectopic endometrial growth.
  3. GnRH agonists (e.g., leuprolide) — for severe refractory disease. Induces a temporary menopausal state. Add-back therapy (norethindrone or low-dose estrogen) is given to prevent bone loss and vasomotor symptoms.
  4. Surgery — laparoscopic ablation/excision for refractory pain, large endometriomas, or infertility. Hysterectomy with bilateral salpingo-oophorectomy is definitive for severe disease in patients who have completed childbearing.
• PANCE Trap — Endometriosis vs. Adenomyosis: Endometriosis is endometrial tissue outside the uterus and presents with dyspareunia and nodular uterosacral ligaments. Adenomyosis is endometrial tissue within the myometrium and presents with a symmetrically enlarged, boggy, tender uterus and menorrhagia. Both cause dysmenorrhea.

Classic PANCE Traps & Clinical Pearls

• Metronidazole Alcohol Warning: Always counsel patients to avoid alcohol with metronidazole. This applies to both BV and Trichomoniasis treatments.
• pH is the Key: Candidiasis is the only one of the three with a normal vaginal pH (4.0-4.5). An elevated pH (>4.5) points to BV or Trichomoniasis.
• Adenomyosis vs. Fibroids: Adenomyosis presents with a globally enlarged, symmetrically boggy, and tender uterus. Fibroids present with an asymmetrically enlarged, firm, and non-tender uterus. Both cause heavy menstrual bleeding.