Hyperprolactinemia — Short Notes (MS OBG)

Definition

Causes (Physiological, Pathological, Pharmacological)

• Pregnancy and lactation
• Sleep, nipple stimulation, sexual orgasm
• Stress, exercise, chest wall trauma/surgery, herpes zoster (reflex suckling arc)

• Prolactinoma (micro <10 mm / macroadenoma >10 mm) - most common pathological cause; levels >200 ng/mL strongly suggest this
• Other pituitary/hypothalamic lesions - stalk compression (non-secreting adenoma, craniopharyngioma), infiltrative disease, radiation
• Primary hypothyroidism (compensatory TRH rise)
• Chronic renal failure (decreased clearance)
• PCOS (mild elevation in some cases)
• Cirrhosis

• Antipsychotics (risperidone, haloperidol)
• Metoclopramide, domperidone
• Methyldopa, verapamil
• Estrogens, opioids
• Tricyclic antidepressants

Pathophysiology

Clinical Features (OBG relevance)

• Women: oligomenorrhea/amenorrhea (primary if before menarche, secondary if later), galactorrhea, infertility, decreased libido, vaginal dryness/dyspareunia (estrogen deficiency), long-term risk of osteoporosis
• Men: decreased libido, erectile dysfunction, infertility, gynecomastia (galactorrhea rare)
• Macroadenoma: headache, visual field defects (bitemporal hemianopia from optic chiasm compression), other pituitary hormone deficiencies

Differential Diagnosis

Investigations

1. Serum prolactin (fasting, morning sample, avoid breast exam/stress before draw)
2. TSH, free T4 (rule out hypothyroidism)
3. Renal function tests
4. Pregnancy test
5. MRI pituitary with contrast if prolactin significantly elevated or no obvious cause (drugs/hypothyroidism excluded)
6. Visual field testing if macroadenoma suspected

Management

1. Treat the cause: stop offending drug, treat hypothyroidism
2. Dopamine agonists (first-line for prolactinoma):
   • Cabergoline - preferred, longer half-life, better tolerated, more effective at normalizing prolactin and shrinking tumor
   • Bromocriptine - traditional choice, preferred if planning pregnancy (more safety data), also cheaper
3. Surgery (transsphenoidal): for dopamine agonist resistance/intolerance, or acute visual compromise from macroadenoma
4. Radiotherapy: reserved for residual/recurrent tumor not controlled by medical/surgical therapy
5. If pregnancy is desired: dopamine agonists restore ovulation and fertility in most cases; bromocriptine is usually preferred and stopped once pregnancy confirmed (monitor macroadenomas during pregnancy for growth/visual symptoms)

Exam Points to Remember

• Hyperprolactinemia is a key cause of amenorrhea-galactorrhea syndrome and must be excluded in every infertility/amenorrhea workup
• Prolactin >200 ng/mL almost always indicates prolactinoma
• Cabergoline > bromocriptine for tumor shrinkage and tolerability; bromocriptine preferred if trying to conceive
• Macroadenoma in pregnancy needs visual field monitoring due to estrogen-driven growth risk

Role of Doppler in Gynaecology — Short Notes (MS OBG)

Basic Principle

• Color Doppler: shows presence, direction, and pattern of blood flow (arterial vs venous) within a lesion or organ
• Spectral/Pulsed Doppler: gives waveform analysis and derived indices -
  • Resistance Index (RI) = (peak systolic - end diastolic velocity) / peak systolic velocity
  • Pulsatility Index (PI) = (peak systolic - end diastolic velocity) / mean velocity
  • Low resistance (low RI/PI) = high diastolic flow = often seen in malignant/highly vascular tissue (neovascularization lacks smooth muscle in vessel walls)
  • High resistance (high RI/PI) = low diastolic flow = typical of benign, normal ovarian or corpus luteal flow can be an exception (physiologically low resistance)

Clinical Applications in Gynaecology

• Malignant tumors show neovascularization: low-resistance flow, central (intratumoral) vascularity, RI <0.4-0.5
• Benign masses (simple cysts, fibromas): little to no internal flow, or peripheral flow only, higher RI
• Used as part of scoring systems (e.g., IOTA criteria) alongside morphology to triage adnexal masses before surgery

• Emergency diagnosis: color Doppler classically shows absent or diminished venous flow first (as veins are compressed before thicker-walled arteries), and in complete torsion absent arterial flow
• However, Doppler is not 100% sensitive/specific - normal flow does not exclude torsion (partial/intermittent torsion may still show some flow), so clinical suspicion should guide management even with equivocal Doppler findings

• Color Doppler helps identify the "ring of fire" sign - high-velocity, low-impedance peritrophoblastic flow around an adnexal mass, supporting the diagnosis of ectopic pregnancy when combined with an empty uterus and positive beta-hCG
• Also helps differentiate a corpus luteal cyst (which can also show peripheral vascularity) from ectopic

• Increased, chaotic, low-resistance vascularity within the myometrium or mass is characteristic, useful in diagnosis and in monitoring response/invasion (e.g., invasive mole, choriocarcinoma)

• Doppler assesses vascularity of fibroids (useful before/after uterine artery embolization, and to assess degenerative changes - red degeneration shows reduced flow)
• Helps distinguish fibroid from adenomyosis and assess perfusion pattern

• Uterine artery Doppler: assesses uterine perfusion; high resistance/impedance in uterine or subendometrial arteries is associated with poor endometrial receptivity and lower implantation rates in IVF cycles
• Ovarian stromal blood flow: studied in ovarian reserve assessment and PCOS (increased ovarian stromal vascularity is a feature of PCOS)
• Doppler of the corpus luteum used to confirm ovulation (increased vascularity around a functioning corpus luteum)

• Doppler helps evaluate endometrial polyps/submucosal fibroids (vascular pedicle sign) and assess for arteriovenous malformations (AVMs) of the uterus - a rare but important cause of severe AUB, showing a tangle of vessels with turbulent, high-velocity, low-resistance flow

• Increased peripheral vascularity/hyperemia on Doppler supports an inflammatory or infective process (e.g., in tubo-ovarian abscess, appendicitis mimics)

Exam Points to Remember

• Doppler is an adjunct to grayscale (2D) ultrasound, not a replacement - always interpreted alongside morphology
• Key indices: RI and PI; low resistance flow raises suspicion for malignancy or trophoblastic tissue
• "Ring of fire" = ectopic pregnancy / corpus luteum
• Absent flow on Doppler supports but does not confirm/exclude ovarian torsion - do not rely on Doppler alone to rule it out clinically
• Uterine artery Doppler in gynaecology (as opposed to obstetrics where it predicts preeclampsia/FGR) is mainly used for endometrial receptivity assessment in infertility