Pituitary Gland Conditions

a) Posterior pituitary gland


Diabetes insipidus (DI)

This is a condition which leads to the production of much dilute urine (>3L/day) due to poor water reabsorption.

– It is split into 3 subtypes:

i) Central DI – This is a failure of the pituitary gland to produce ADH

Causes: Idiopathic (50%), congenital defect in ADH gene DIDMOAD + trauma/tumour


ii) Nephrogenic DI – This is an impaired renal response to ADH

Causes: Inherited genes, low K+, high Ca2+, Drugs (e.g. lithium, demeclocycline)


iii) Dipsogenic DI – This is producing large amounts of urine due to drinking too much water

Symptoms – These resemble those of losing water giving hypernatremia

– Polyuria + polydipsia (e.g. kids drinking bathwater) with risk of life-threatening dehydration

– Dilute urine and low specific gravity –> a high urine osmolality (> 700mOsm/kg) excludes DI


Diagnosis­ Blood tests show increased Plasma Osmolality, Decreased Urine Osmolality

Water deprivation test –> this tests ability of the kidney to concentrate urine

–> Patient empties bladder and is then deprived of water for 8 hours

–> Weighed hourly and urine collected every 2h – measure volume and osmolarity

–> After 8h, if urine osmolarity <600mOsmol/kg (dilute), give desmopressin

–> If osmolarity does not increase after 4h, then nephrogenic, otherwise neurogenic



– Central DI –> Desmopressin

– Nephrogenic DI –> Treat the cause + Bendroflumethiazide diuretic – acts as an anti-diuretic

SIADH syndrome

– This is a disease which leads to excessive ADH secretion


Often due to ectopic ADH production (e.g. small cell lung carcinoma)

– CNS trauma + Drugs (SSRIs, opiates, TCAs)


– Hyponatremia (low serum Na+ and low osmolarity) and low volume urine

– This leads to neuronal swelling and cerebral oedema giving rise to seizures, headache


Concentrated urine Na+ > 20mM, and >100mOsmol/kg with hyponatraemia (Na+<125mM)


– Water restriction

– Demeclocycline – an antibiotic which also reduces the sensitivity of the collecting duct to ADH

– ADH receptor antagonists – Vaptan drug family

b) Anterior pituitary gland


This is decreased secretion of anterior pituitary hormones.

– Most commonly affected hormone is GH –> FSH/LH –> TSH –> ACTH –> Prolactin


Causes – These occur at 3 levels

Hypothalamus – Kallman’s syndrome, tumour

– Pituitary stalk – Trauma, Carotid artery aneurysm

– Pituitary gland – Adenoma + apoplexy (bleeding of adenoma, haemorrhage of gland)

Sheehan syndrome

During pregnancy, the gland doubles in size but blood supply hardly increases

– Blood loss during parturition gives ischaemia and infarction of pituitary gland

– Patients get fatigued + have poor lactation

Empty Sella syndrome

In this condition, the arachnoid mater and CSF herniate into Sella compressing the pituitary

Kallman Syndrome

This condition occurs due to a failure of development of GnRH neurons derived from olfactory epithelium

– Gives anosmia (lack of smell) + cleft lip + colour blindness

– Low LH/FSH and low sex hormones cause delayed puberty and hypogonadism

– Height is usually normal or above average



Hypopituitarism gives many symptoms due to the effect on the corresponding hormones.



Different tests are carried out to work out which hormones are affected e.g. LH/FSH, IGF-1



Hormone replacement therapy

Pituitary adenoma

This is a benign tumour of the anterior pituitary cells.

– It can be a microadenoma (<1cm) or macro (>1cm)

– Can also be functional (hormone-producing) or non-functional (silent)

– Most common tumour is prolactin secreting –> non-functional –> GH secreting –> ACTH secreting


i) Non-functional tumours – these often present with mass effect due to structural compression

– Can cause bitemporal hemianopia –> compression of the optic chiasm

– Visual disturbances –> pressure on cavernous sinus pressing CN III, IV and VI

– Can cause hypopituitarism –> compression of normal pituitary tissue

– Early morning headaches, worse when lying down


ii) Functional tumours – these present with the features based on the type of hormone produced

– Usually prolactin, GH and ACTH producing – the others are very rare



– Pituitary blood profile (GH, prolactin, ACTH, FH, LH and TFTs)

– MRI provides visualization of pituitary gland enlargement

– Formal visual field testing



– If it affects hormones, treat accordingly

– Surgery – transphenoidal hypophysectomy or radiotherapy (residual/recurrent adenomas)


–  A benign tumour of the epithelial remnants of Rathke’s pouch

– This sits between the pituitary gland and the 3rd ventricle

– It presents as a supratentorial mass in a child or young adult, often leading to compression of the optic chiasm



(Children) Gives growth failure, and compression of structures

– Bitemporal hemianopia (lower quadrants worse)

(Adults) Amenorrhoea, loss of libido, DI, hyperphagia


– CT/MRI shows calcifications (as if derived from “tooth like tissue”)



– Surgical removal, but usually recurs after resection


This is the most common hormone disturbance on the pituitary



– Most often due to a pituitary adenoma increasing production

– Also due to reduced inhibition e.g. dopamine antagonists (Haloperidol, Domperidone)

– Pregnancy and raised oestrogen

– Polycystic Ovary syndrome

– Acromegaly (1/3 of patients)

– Primary hypothyroidism –> as TRH stimulates prolactin release



As well as direct effects on lactation, raised prolactin inhibits GnRH which decreases testosterone and oestrogen giving secondary effects like osteoporosis.




Amenorrhea – absence of menstruation

Erectile dysfunction

Infertility – due to Inhibition of GnRH

Loss of libido




– MRI visualisation of pituitary gland


Management :

– 1st choice is dopamine agonists to reduce secretion e.g. Bromocriptine/Cabergoline

– 2nd line is surgery


This is a condition caused by increased secretion of growth hormone from the pituitary

– Most often due to a pituitary adenoma


Symptoms: GH stimulates bone and soft tissue growth through IGF-1

– (Children) – gigantism due to increased bone growth

– (Adults) – enlarged hands, tongue, jaw and feet (increase shoes size)

– Acroparathesia – tingling in the extremities

– Pituitary tumour features (headache + hyperprolactinaemia)

– Excessive sweating and oily skin, due to sweat gland hypertrophy



– Growth of visceral organs leads to cardiomyopathy


– Secondary diabetes mellitus as GH induces gluconeogenesis

– Colorectal cancer



– 1st line is to check if Serum IGF-1 level is raised

Confirmation test is Oral glucose tolerance test –> Normally GH supressed to <2mu/L with glucose

– In acromegaly there is no suppression of GH

– MRI pituitary fossa to visualise tumour



– 1st line is transphenoidal surgery

Octreotide – somatostatin analogue, used as adjunct to surgery

Pegvisomant – GH receptor antagonist, given by subcutaneous injection

– Can use radiotherapy in older patients of if the methods above fail


Image 1 Craniopharyngioma: Hellerhoff / CC BY (https://creativecommons.org/licenses/by/3.0)

Image 2 Acromegaly: Philippe Chanson and Sylvie Salenave (https://creativecommons.org/licenses/by/2.0