🧠 Pituitary Adenomas in PLAB 2: Master Hormonal Disorders, Mass Effects, and Emergencies
- Ann Augustin
- Jun 27
- 4 min read
Updated: Jun 28
🧠 What Is a Pituitary Adenoma?
A pituitary adenoma is a benign tumour of the anterior pituitary gland. Though benign, it can cause significant systemic effects due to:
Pituitary adenomas can cause either hormonal excess or hormonal deficiency, depending on the type, size, and location of the tumor
Pressure effects on adjacent structures (non-functioning adenomas)
🧪 Hormones Secreted by the Anterior Pituitary
Hormone | Full Name | Target Organ(s) | Main Function(s) |
ACTH | Adrenocorticotropic hormone | Adrenal cortex | Stimulates cortisol production (mainly from the zona fasciculata) |
TSH | Thyroid-stimulating hormone | Thyroid gland | Stimulates T3 and T4 synthesis and secretion |
LH | Luteinising hormone | Gonads (ovaries/testes) | Triggers ovulation and corpus luteum formation in females Stimulates testosterone production in males |
FSH | Follicle-stimulating hormone | Gonads (ovaries/testes) | Stimulates follicle development in ovaries Stimulates spermatogenesis in testes |
GH | Growth hormone (somatotropin) | Liver, bones, muscles | Stimulates growth, cell reproduction, and IGF-1 secretion from the liver |
Prolactin | — | Mammary glands | Stimulates milk production |
🧪 Hormones Released by the Posterior Pituitary
Hormone | Produced By | Main Functions |
ADH (Vasopressin) | Hypothalamus (supraoptic nucleus) | - Increases water reabsorption in the kidneys (collecting ducts) - Helps maintain blood pressure by conserving water |
Oxytocin | Hypothalamus (paraventricular nucleus) | - Stimulates uterine contractions during labour - Promotes milk ejection ("let-down reflex") in lactating women |
🚨 Clinical Presentations (GP Setting)
Symptom Group | Presentation |
Hormonal excess Hormonal overproduction (functioning adenomas) | - Galactorrhoea, amenorrhoea, infertility (↑ Prolactin) - Acromegaly signs (↑ GH) - Cushingoid features (↑ ACTH) |
Mass effects | - Headache - Visual field defect (classically bitemporal hemianopia) |
Hypopituitarism | - Fatigue, cold intolerance, weight gain (↓ TSH) - Amenorrhoea, loss of libido (↓ LH/FSH) - Secondary adrenal insufficiency |
🔍 OSCE Tip: Look for progressive symptoms, visual changes, or multiple hormone disturbances to suspect pituitary involvement.
Prolactin-secreting adenoma (Prolactinoma)
Galactorrhoea (nipple discharge)
Amenorrhoea or oligomenorrhoea in females
Infertility
Loss of libido (both genders)
Erectile dysfunction in males
Growth Hormone-secreting adenoma (Acromegaly)
Increase in shoe or ring size
Coarse facial features
Jaw protrusion (prognathism)
Excessive sweating (hyperhidrosis)
Joint pain (arthralgia)
Headaches
Carpal tunnel syndrome symptoms (tingling, numbness in hands)
ACTH-secreting adenoma (Cushing’s Disease)
Weight gain (especially central obesity)
Facial rounding (“moon face”)
Thin skin, easy bruising
Purple striae (especially abdomen)
Proximal muscle weakness
New onset hypertension or diabetes
Mood changes (depression, irritability)
TSH-secreting adenoma (very rare)
Symptoms of hyperthyroidism:
Palpitations
Heat intolerance
Tremors
Weight loss despite normal/increased appetite
Non-functioning adenoma (mass effect symptoms)
Headache
Visual changes (especially bitemporal hemianopia)
Hypopituitarism symptoms:
Fatigue, weakness
Cold intolerance
Loss of body hair
Amenorrhoea, infertility
Hypotension (if adrenal insufficiency)
General Red Flags for Pituitary Apoplexy
Sudden severe headache
Visual loss or diplopia
Ophthalmoplegia (e.g. ptosis, inability to move eye)
Altered consciousness
Systematic Questioning Framework
When ruling out functional symptoms in PLAB 2:
✅ Ask about menstrual history, libido, and galactorrhoea
✅ Ask about changes in appearance, hands, feet, and facial features
✅ Ask about weight changes and features of cortisol excess
✅ Ask about thyroid symptoms
✅ Always screen for headaches and visual symptoms
🏥 Examination Findings
Systemic Clues | What to Look for |
Eyes (visual fields) | Bitemporal hemianopia on confrontation test (compression of optic chiasm) |
Face & Hands | Coarse facial features, prognathism, large hands (Acromegaly) |
Skin | Thin skin, striae, hirsutism (Cushing’s) |
Breast | Galactorrhoea |
🧪 Investigations (Initial Workup in GP)
Test | Purpose |
Serum Prolactin | For prolactin-secreting tumours |
IGF-1 | For growth hormone excess (acromegaly) |
Overnight dexamethasone suppression test | Screening for Cushing’s disease |
TSH, Free T4 | Check for secondary hypothyroidism |
LH, FSH, Oestradiol/Testosterone | Assess gonadal function |
9 AM Cortisol | Assess for adrenal insufficiency |
📌 PLAB 2 Station Alert: If the patient is acutely unwell with fatigue and hypotension, consider secondary adrenal insufficiency and give hydrocortisone before awaiting cortisol results.
🔎 Red Flags Needing Urgent Referral
Visual field defect or sudden vision loss
Features of raised intracranial pressure
Pituitary apoplexy (sudden headache, visual loss, ophthalmoplegia, hypotension)
Suspicion of functioning macroadenoma
🧑⚕️ Specialist Investigations (Endocrinology & Neurosurgery)
Investigation | Why It's Done |
MRI Pituitary | Confirm diagnosis, measure tumour size |
Formal Visual Field Testing | Quantify and document extent of chiasmal involvement |
Dynamic hormonal testing (e.g. OGTT for GH, CRH test) | Confirm diagnosis of hormone excess |
ACTH levels | Differentiate between Cushing’s disease and other causes |
💊 Management Summary
In General Practice:
Task | Details |
Identify & suspect | Based on symptoms and basic labs |
Safety netting | Headaches + visual symptoms = red flag |
Refer to endocrinology/neuro | As per local 2-week wait or urgent referral |
Initiate treatment (if trained) | E.g., dopamine agonists in known prolactinoma (with specialist input) |
In Specialist Setting:
Adenoma Type | Management |
Prolactinoma | Dopamine agonists (e.g. Cabergoline) first-line |
GH-secreting | Surgery + somatostatin analogues (e.g. Octreotide) |
ACTH-secreting | Transsphenoidal surgery + medical therapy if needed |
Non-functioning | Surgery if mass effect; otherwise monitor |
Large macroadenomas | Surgical debulking; monitor hormonal recovery |
🧠 Complications to Know
Hypopituitarism post-treatment
Permanent visual loss if not addressed early
Recurrence of tumour after surgery
Pituitary apoplexy (emergency) is a sudden and life-threatening condition caused by hemorrhage or infarction (loss of blood supply) within the pituitary gland, usually in a pituitary adenoma (often undiagnosed).
🪜 Differential Diagnoses
Condition | How to Differentiate |
Hypothyroidism | Normal prolactin, diffuse symptoms, no mass effect |
PCOS | Raised LH:FSH, no visual symptoms |
Depression | Non-specific symptoms, normal pituitary hormones |
Cushing’s syndrome (non-pituitary) | Dexamethasone suppression test not suppressed, no pituitary mass |
Craniopharyngioma | More common in children, calcifications on imaging |
👨⚕️ PLAB 2 Communication Tip
Be empathetic and avoid jargon (e.g., say “a growth near a gland in your brain” instead of “pituitary adenoma”)
Always address fertility concerns, vision symptoms, and hormonal imbalances
Offer safety-net advice: “If you get a sudden severe headache, vomiting or changes in vision, go to A&E immediately.”
📌 Take-Home for PLAB 2
✅ Think pituitary if symptoms suggest hormonal imbalance + visual symptoms + fatigue
✅ Initial bloods can be done in GP; refer early if suspicion is high
✅ Know urgent features: visual loss, apoplexy, headache with vomiting
✅ Management depends on hormone excess and mass effect
✅ Effective communication and referral are key in PLAB 2 scenarios
📚 References:
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