[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Conditions](https://durgical.com/en/conditions/) › Hypopituitarism (incl. Sheehan syndrome and pituitary apoplexy)

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# Hypopituitarism (incl. Sheehan syndrome and pituitary apoplexy)

The pituitary makes too little of one or more hormones. Causes include tumours, surgery and bleeding after childbirth; it needs lifelong hormone replacement.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Pituitary gland](https://durgical.com/en/anatomy/pituitary-gland/)
- [Hypothalamus](https://durgical.com/en/anatomy/hypothalamus/)
- [Sella turcica](https://durgical.com/en/anatomy/sella-turcica/)
- [Optic chiasm](https://durgical.com/en/anatomy/optic-chiasm/)
- [Cavernous sinus](https://durgical.com/en/anatomy/cavernous-sinus/)
- [Sphenoid sinus](https://durgical.com/en/anatomy/sinus-of-sphenoid-bone/)

## In embryology

- [Pituitary gland: Rathke pouch and the neurohypophysis](https://durgical.com/en/embryology/pituitary-gland-rathke-pouch-and-the-neurohypophysis/)

## Why it happens

- [Infarction: red vs white, and what decides the damage](https://durgical.com/en/general-pathology/infarction-red-vs-white-and-what-decides-the-damage/)
- [The hypothalamic–pituitary system: overview](https://durgical.com/en/physiology/the-hypothalamic-pituitary-system-overview/)
- [Maternal physiological changes in pregnancy](https://durgical.com/en/physiology/maternal-physiological-changes-in-pregnancy/)
- [Pituitary: adenohypophysis and neurohypophysis](https://durgical.com/en/histology/pituitary-adenohypophysis-and-neurohypophysis/)

## What it is

Partial or complete loss of anterior (and sometimes posterior) pituitary hormone secretion, from disease of the pituitary itself or of the [hypothalamus](https://durgical.com/en/anatomy/hypothalamus/). Sheehan syndrome is ischaemic necrosis of the pituitary after severe postpartum haemorrhage; pituitary apoplexy is sudden haemorrhage or infarction of a pituitary tumour.

## Who gets it

Uncommon but under-diagnosed. Pituitary adenomas and their treatment are the leading cause. Sheehan syndrome is rare where obstetric care is good, but it remains relevant in Latin American settings where postpartum haemorrhage is still a major cause of maternal morbidity.

## Causes

- Pituitary adenomas and their treatment (surgery, radiotherapy)
- Sheehan syndrome after massive postpartum haemorrhage
- Pituitary apoplexy
- Traumatic brain injury and subarachnoid haemorrhage
- Other sellar masses (craniopharyngioma), infiltrative or inflammatory disease (hypophysitis, sarcoidosis, haemochromatosis) and infections
- Congenital or genetic deficiencies; long-term glucocorticoids suppress the ACTH [axis](https://durgical.com/en/anatomy/axis/)

## Risk factors

- Known pituitary macroadenoma
- Cranial radiotherapy or pituitary surgery
- Postpartum haemorrhage with hypotension
- Moderate to severe head injury

## Pathophysiology

Loss of trophic hormones leads to secondary failure of the target glands. The gland enlarges in pregnancy without a matching increase in blood supply, so hypotension from haemorrhage can infarct it (Sheehan). In compressive lesions, GH and gonadotropins are usually lost first and ACTH and TSH later; ACTH loss is the most dangerous because cortisol is essential in stress.

## Classification

- Panhypopituitarism or isolated or partial hormone deficiencies
- Primary (pituitary) or secondary (hypothalamic)
- Acute (apoplexy, Sheehan) or chronic

## Symptoms and signs

- ACTH deficiency: fatigue, weakness, low blood pressure, nausea, hypoglycaemia; no hyperpigmentation
- TSH deficiency: features of hypothyroidism (cold intolerance, weight gain, constipation)
- Gonadotropin deficiency: amenorrhoea, infertility, low libido, loss of body hair
- GH deficiency: short stature in children; reduced muscle mass and energy in adults
- Sheehan syndrome: failure of lactation and of menses to return after delivery
- Posterior pituitary involvement: polyuria and thirst (diabetes insipidus)

## Red flags

- Thunderclap headache, vomiting, visual loss or ophthalmoplegia (pituitary apoplexy)
- Hypotension, shock or hypoglycaemia in a patient with known pituitary disease (adrenal crisis)
- Severe hyponatraemia with confusion or seizures
- Postpartum woman who cannot breastfeed and is weak and hypotensive

## Diagnosis

**Clinical**
Look for low levels of target hormones together with low or inappropriately normal pituitary hormones. Visual fields and eye movements are examined.

**Tests**
Morning cortisol (with a stimulation test if borderline), free T4 with TSH (TSH is low or normal, so TSH alone misses central hypothyroidism), LH, FSH with testosterone or oestradiol, IGF-1, prolactin, sodium and plasma and urine osmolality.

**Imaging**
Pituitary MRI; CT is useful in the emergency when apoplexy is suspected.

## Differential diagnosis

- Primary adrenal insufficiency (high ACTH, hyperpigmentation)
- Primary hypothyroidism (high TSH)
- Functional hypothalamic amenorrhoea or anorexia nervosa
- Lymphocytic hypophysitis (often in late pregnancy or postpartum)
- Subarachnoid haemorrhage or meningitis when headache is sudden

## Goal of treatment

Replace each missing hormone, prevent adrenal crisis, and treat the underlying cause.

## Treatment

**Acute**
Suspected apoplexy or adrenal crisis: intravenous hydrocortisone and fluids without waiting for results; urgent neurosurgical evaluation if vision is threatened.

**Medical**
Hydrocortisone replacement, given before levothyroxine when both are deficient (thyroid hormone first can precipitate adrenal crisis); sex steroids or gonadotropins for fertility; GH in selected patients; desmopressin for diabetes insipidus.

**Surgical**
Transsphenoidal decompression for apoplexy with visual compromise or for the causative tumour.

**Follow-up**
Free T4 (not TSH) to adjust thyroid replacement; education on increasing glucocorticoid in illness, a medical alert identification and emergency injectable hydrocortisone.

## Complications

- Adrenal crisis and death if unrecognised
- Hyponatraemia
- Infertility, osteoporosis and increased cardiovascular risk
- Permanent visual loss after apoplexy

## Prognosis

Usually permanent, but with appropriate replacement and education most people live normally. Undiagnosed or untreated ACTH deficiency is the main cause of avoidable death.

## Prevention

- Prevention and prompt treatment of postpartum haemorrhage
- Testing pituitary function after pituitary surgery, cranial radiotherapy or significant head injury

## Test yourself

Think of the answer, then tap the question to see it.

## In panhypopituitarism, which hormone is replaced first, cortisol or thyroid hormone?

Cortisol (hydrocortisone) first; giving thyroid hormone first can precipitate an adrenal crisis.

## What is Sheehan syndrome?

Ischaemic necrosis of the enlarged pituitary after severe postpartum haemorrhage, classically presenting as failure to lactate and absent menses.

## How is thyroid replacement monitored in central hypothyroidism?

By free T4, because TSH is low or inappropriately normal and does not reflect the dose.

## Why is there no hyperpigmentation in secondary adrenal insufficiency?

ACTH (and the related melanocyte-stimulating peptides) is low, not high as in primary adrenal failure.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/conditions/hypopituitarism/)

## Related conditions

- [Pituitary adenoma](https://durgical.com/en/conditions/pituitary-adenoma/)
- [Prolactinoma (hyperprolactinaemia)](https://durgical.com/en/conditions/prolactinoma/)
- [Postpartum haemorrhage](https://durgical.com/en/conditions/postpartum-haemorrhage/)
- [Adrenal insufficiency](https://durgical.com/en/conditions/adrenal-insufficiency/)
- [Adrenal crisis](https://durgical.com/en/conditions/adrenal-crisis/)
- [Hypothyroidism](https://durgical.com/en/conditions/hypothyroidism/)
- [Diabetes insipidus (central and nephrogenic)](https://durgical.com/en/conditions/diabetes-insipidus/)
- [Male hypogonadism](https://durgical.com/en/conditions/male-hypogonadism/)
- [Hypoglycaemia (including insulin-induced)](https://durgical.com/en/conditions/hypoglycaemia/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Hypopituitarism](https://medlineplus.gov/ency/article/000343.htm) (MedlinePlus Medical Encyclopedia (U.S. National Library of Medicine), 2025).

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Source: https://durgical.com/en/conditions/hypopituitarism/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/hypopituitarism/