Pituitary disorders Flashcards
Multiple Endocrine Neoplasia
Functioning hormone tumours in multiple organs
All autosomal dominant
MEN 1
Pituitary adenoma: prolactin or GH
Parathyroid adenoma/ hyperplasia
Pancreatic tumours: gastrinoma or insulinoma
MEN 2
Thyroid medullary carcinoma
Adrenal phaeochromocytoma
A) Hyperthyroidism
B) Marfanoid habitus
Hypopituitarism causes
Hypothalamic:
Kallmann’s syndrome
Tumour
Inflam, infection, ischaemia
Pituitary Stalk:
- Trauma
- Surgery
- Tumour (e.g. craniopharyngioma)
Pituitary:
- Irradiation
- Tumour
- Ischaemia: apoplexy, Sheehan’s
Kallmann’s syndrome
anosmia + GnRH deficiency)
Features of hypopituitarism
Hormone Deficiency:
GH: (linked with insulin like GF) - central obesity, atherosclerosis, ↓CO,
LH/FSH:
M: ↓libido, ED, ↓hair
F: ↓libido, amenorrhoea, breast atrophy
TSH: hypothyroidism
ACTH: Secondary adrenal failure
Prolactin excess
Ix for hypopituitarism
Basal hormone tests Dynamic pituitary function test - Insulin → ↑ cortisol + ↑ GH - GnRH → ↑ LH/FSH - TRH → ↑T4 + ↑ PRL
MRI brain
Tx of hypopituitarism
Hormone replacement
Treat underlying cause
Pituitary tumours
Microadenoma: <1cm
Macroadenoma: >1cm
Pathology of pituitary tumours
Pathology
Many are non-secretory
~50% produce PRL
Others produce GH or ACTH
Mass effects of pituitary tumours
Headache
Visual field defect: bitemporal hemianopia
CN palsies: 3, 4, 5, 6 (pressure on cavernous sinus)
Diabetes insipidus
CSF rhinorrhoea
Hormone effects of pituitary tumours
PRL → galactorrhoea, ↓libido, amenorrhoea, ED
PRL → ↓GnRH → ↓LH/FSH
GH → acromegaly
ACTH → Cushing’s Disease
Ix for pituitary tumours
MRI
Visual field tests
Hormones: PRL, IGF, ACTH, cortisol, TFTs, LF/FSH
Suppression tests
Mx of pituitary tumours
Medical:
- Replace hormones
- Treat hormone excess
- Increased prolactin treated with dopamine
Surgical: Trans-sphenoidal excision
- Pre-op hydrocortisone
- Post-op dynamic pituitary tests
Radiotherapy: sterotactic
Craniopharyngeoma
Originates from Rathke’s pouch
causes growth failure in children
Causes of hyperprolactinaemia
Excess pituitary production:
- Pregnancy, breastfeeding
- Prolactinoma (PRL >5000)
- Hypothyroidism (↑TRH)
- Disinhibition by compression of pituitary stalk
- Pituitary adenoma
- Craniopharyngioma
- Dopamine antagonsists: Antiemetics: metoclopramide
Antipsychotics
Symptoms of hyperprolactinaemia
Amenorrhoea Infertility Galactorrhoea ↓ libido Erectile dysfuction Mass effects from prolactinoma
Ix of hyperprolactinaemia
Basal PRL: >5000 = prolactinoma
Pregnancy test, TFTs
MRI
Mx of hyperprolactinaemia
1st line: Dopamine agonist- Cabergoline or bromocroptine
- inhibits PRL secretion and ↓ tumour size
2nd line: Trans-sphenoidal excision
- If visual or pressure symptoms don’t response to medical Rx
Acromegaly
Excess growth hormone:
Pituitary adenoma in 99%
- Hyperplasia from GHRH secreting carcinoid tumour
- GH stimulates bone and soft tissue growth through ↑IGF1
Presentation of acromgealy
- Amenorrhoea, ↓libido
- Headache
- Snoring
- Sweating
- Arthralgia, back ache
- Carpal tunnel (50%)
Signs; Huge hands Face: - Prominent supraorbital ridges - Wide nose and big ears - Macroglossia - Widely-spaced teeth
Other
- Puffy, oily, darkened skin skin
- Proximal weakness + arthropathy
- Pituitary mass effects: bitemporal hemianopia
Ix and Rx for acromegaly
Ix:
- ↑IGF1
- ↑ glucose, ↑Ca, ↑PO4
- Visual fields and acuity
- MRI brain
Rx
- 1st line: trans-sphenoidal excision
- 2nd line: somatostatin analogues
- 3rd line: GH antagonist
- 4th line: radiotherapy
Diabetes Insipidus presentation
Severe polyuria + polydipsia
Hypernatraemia: lethargy, thirst, confusion, coma
Cranial diabetes inspidus causes
Idiopathic: 50% Tumours Trauma Vascular: haemorrhage (Sheehan’s syn.) Infection: meningoencephalitis Infiltration: sarcoidosis
Insult causes decreased ADH release
Nephrogenic diabetes insipidus
Receptors are not sensitive to ADH therefore less aquaporins are expressed and less water is absorbed
Ix for diabetes insipidus
Bloods: U+E, glucose
Urine and plasma osmolality
Exclude DI if U:P osmolality >2
Find cause: MRI brain
Mx of diabetes insipidus
Desmopressin - ADH analogue
Nephrogenic - treat cause
