Hyperprolactinemia

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Hyperprolactinemia: Definition & Physiology - Milky Messengers

  • Definition: Persistently elevated serum prolactin (PRL) levels.
    • Normal PRL: <25 ng/mL (non-pregnant women), <20 ng/mL (men).
  • Source: Lactotroph cells in the anterior pituitary gland.
  • Primary Functions:
    • Induces & maintains lactation (milk production).
    • Breast development (mammogenesis).
  • Regulation:
    • Predominantly inhibitory control by dopamine from hypothalamus.
    • Stimulatory factors: TRH, estrogen, suckling, serotonin. Hypothalamic-pituitary-prolactin axis

⭐ Dopamine is the primary physiological inhibitor of prolactin secretion from the anterior pituitary.

Etiology of Hyperprolactinemia - Prolactin's Partners in Crime

CategoryCauses
PhysiologicalPregnancy, lactation, stress, sleep, nipple stimulation, exercise
PathologicalProlactinoma (PRL >200 ng/mL highly suggestive), other pituitary tumors (stalk compression), primary hypothyroidism (↑TRH), CKD, cirrhosis, PCOS, chest wall trauma
Pharmacological📌 DAMA: Dopamine antagonists (e.g., phenothiazines, haloperidol, metoclopramide, domperidone), Antihypertensives (e.g., methyldopa, verapamil, reserpine), Many psychotropics (TCAs, SSRIs, MAOIs), Acid blockers (cimetidine), Estrogens, Opiates

Clinical Features of Hyperprolactinemia - Telltale Signs & Symptoms

FemalesMales
* Oligomenorrhea / Amenorrhea* Decreased libido
* Galactorrhea (non-puerperal milk)* Erectile dysfunction
* Infertility (anovulation)* Infertility (oligospermia, asthenospermia)
* Decreased libido* Gynecomastia
* Dyspareunia (vaginal dryness)* Galactorrhea (rare)
* Bone loss (long-term estrogen deficiency)* Visual field defects (e.g., bitemporal hemianopia if pituitary macroadenoma)
* Headaches (if tumor)

Diagnosis & Investigations in Hyperprolactinemia - Unmasking the Culprit

  • Initial Tests:
    • Serum prolactin (repeat if mild ↑). Levels:
      • 25-100 ng/mL: Various causes.
      • >100 ng/mL: Suspect prolactinoma.
      • >200-250 ng/mL: Highly indicative.
    • TSH, RFTs, β-hCG.
  • Hook Effect: Suspect with very large tumors & moderately ↑ prolactin; dilute sample.

⭐ Pituitary MRI (sellar MRI) is the imaging modality of choice when prolactin levels are significantly elevated (e.g., >100 ng/mL) or a tumor is suspected, to look for microadenoma (<1cm) or macroadenoma (≥1cm).

Pituitary MRI showing prolactinoma

Management of Hyperprolactinemia - Taming the Tide

Goals: Normalize prolactin, restore gonadal function, ↓ tumor size, alleviate symptoms.

  • Treat cause: Stop offending drugs, manage hypothyroidism.
  • Prolactinomas:
    • Dopamine Agonists (DA): 1st line.
      • Cabergoline (preferred): Start 0.25-0.5 mg weekly.
      • Bromocriptine: Start 1.25-2.5 mg daily.
    • Surgery (Transsphenoidal): For DA resistance/intolerance, or visual defects not improving with DA.
    • Radiotherapy: Rare.
  • Asymptomatic microprolactinoma: Observation.

⭐ Dopamine agonists (e.g., Cabergoline, Bromocriptine) are the first-line medical treatment for symptomatic prolactinomas, effective in normalizing prolactin and shrinking tumor size.

High-Yield Points - ⚡ Biggest Takeaways

  • Prolactinomas are the most common cause; drug-induced (antipsychotics, metoclopramide) is also frequent.
  • Presents as galactorrhea, amenorrhea (females), ↓ libido, infertility, and gynecomastia (males).
  • Prolactin levels > 200 ng/mL strongly suggest prolactinoma; levels 25-100 ng/mL can be due to various causes.
  • Dopamine agonists (cabergoline preferred over bromocriptine) are first-line treatment for prolactinomas.
  • Always exclude pregnancy, hypothyroidism (TRH stimulates prolactin), and renal failure.
  • Macroadenomas (>1 cm) can cause visual field defects (bitemporal hemianopia) by compressing the optic chiasm.
  • Consider the hook effect with very high prolactin levels leading to falsely low immunoassay results; dilute sample if suspected.

Practice Questions: Hyperprolactinemia

Test your understanding with these related questions

Ramkali bai, a 35-year-old female presented with a one-year history of menstrual irregularity and galactorrhoea. She also had off and on headache, her examination revealed bitemporal superior quadrantanopia. Her fundus examination showed primary optic atrophy. Which of the following is a most likely diagnosis in this case -

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Flashcards: Hyperprolactinemia

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_____ cells with a pyknotic nucleus seen predominantly in the first half of the menstrual cycle and are estrogen dependent

TAP TO REVEAL ANSWER

_____ cells with a pyknotic nucleus seen predominantly in the first half of the menstrual cycle and are estrogen dependent

Acidophilic

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