💊 Key Point: Dopamine agonists (cabergoline) are first-line and effective in most patients ✅. Surgery is reserved for intolerance, resistance, or visual compromise ⚠️ — not routinely required.

📖 About

🧠 Most common functioning pituitary adenoma (~30–40%)
♀ : ♂ ≈ 10:1 (microadenomas more common in women; men often present later with macroadenomas)
🔍 Frequently incidental (microadenomas may be asymptomatic)
💊 Excellent prognosis with medical therapy

🩺 Clinical Features

🔇 May be asymptomatic (especially microprolactinomas)
👩‍🍼 Galactorrhoea (common in women, uncommon in men)
⚠️ Hypogonadism: amenorrhoea, oligomenorrhoea, infertility, ↓ libido
♂ Erectile dysfunction, ↓ testosterone
🦴 Chronic hypogonadism → ↓ bone mineral density (osteopenia/osteoporosis)
🧠 Mass effect (macroadenoma): headache, bitemporal hemianopia

🔍 Investigations

🧪 Serum prolactin (fasting, repeat if mildly elevated):
- Very high PRL (>5000 mU/L) → strongly suggests prolactinoma
- Moderate elevation → consider stalk effect or drugs
⚠️ Exclude secondary causes: pregnancy test, TFTs (hypothyroidism), renal function
🧬 Check for macroprolactin (biologically inactive → avoids overdiagnosis)
🧠 Pituitary MRI with contrast → microadenoma (<10 mm) vs macroadenoma
👁️ Visual field assessment if tumour near optic chiasm
🧪 Full pituitary profile (LH/FSH, cortisol, TSH, sex hormones)
❤️ Baseline echocardiogram recommended before long-term cabergoline (UK practice)

🧠 Mechanism: Prolactin secretion is tonically inhibited by hypothalamic dopamine. Dopamine agonists (e.g. cabergoline) stimulate D2 receptors → suppress prolactin + induce tumour shrinkage. 💡 Loss of dopamine inhibition (e.g. stalk compression) explains “stalk effect” hyperprolactinaemia.

🧾 Differential Diagnosis

🤰 Physiological: pregnancy, lactation
💊 Drug-induced: antipsychotics, SSRIs, metoclopramide, opioids
🧠 Stalk effect from non-functioning pituitary adenoma
🦋 Primary hypothyroidism (↑ TRH → ↑ prolactin)
🧬 Chronic kidney disease (reduced prolactin clearance)

💊 Management

✨ First-line: Dopamine agonist (cabergoline preferred)
🚀 Cabergoline dosing: typically 0.25–0.5 mg twice weekly → titrate to PRL normalisation
📉 Normalises PRL in ~80–90% and shrinks tumour in most cases
🔄 Consider trial withdrawal after ≥2 years if PRL normal + no visible tumour
❤️ Valvulopathy risk: very low at endocrine doses (<2 mg/week); monitor if long-term/high dose
🔪 Surgery (transsphenoidal):
- Indications: drug intolerance, resistance, or acute visual compromise
☢️ Radiotherapy: rarely used (refractory disease)
⚠️ Malignant prolactinoma: extremely rare

📚 References

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Prolactinoma ✅