Pituitary Disease Flashcards
How are benign adenomas categorised based on size?
Microadenoma < 1 cm
Macroadenoma > 1 cm
What are the 6 hormones released from the anterior pituitary?
- ACTH
- FSH
- GH
- LH
- Prolactin
- TSH
Release of these hormones is controlled by the hypothalamus
What are the two hormones released from the posterior pituitary?
ADH
Oxytocin
How can the clinical features of pituitary adenomas categorised?
- Mass effects (visual disturbances and headaches)
- Endocrine effects (symptoms relate to the hormone which is in excess)
What are the different types of pituitary adenomas?
- Prolactinoma
- ACTH secreting adenoma (presents as Cushings)
- GH secreting adenoma (presents as acromegaly)
- FSH+LH secreting adenoma
- TSH secreting adenoma
What is Prolactinoma?
- Excess prolactin release due to adenoma
- Prolactin release from anterior pituitary is usually inhibited by dopamine release from the hypothalamus
- Clinical presentation depends on age and gender
What is the clinical presentation of Prolactinoma?
=> For women of reproductive age:
- Oligomenorrhoea
- Galactorrhoea
=> For men and post menopausal women:
- Erectile dysfunction
- Reduced facial hair
- Galactorrhoea
- Osteoperosis
- Headaches and visual disturbances
What are the causes of hyperprolactinaemia?
- Adenomas (Prolactinoma)
- Pregnancy
- Oestrogens
- Stress
- Acromegaly
- Primary hypoparathyroidism
- PCOS
- Compression of pituitary stalk causing disinhibition of prolactin
- Drugs (dopamine antagonists, SSRIs, phenothiazines)
What are the investigations is suspected Prolactinoma?
- Prolactin levels (First line)
- Pregnancy tests
- Blood tests (TFTs, U&Es)
- MRI (to determine location and size) Gold standard
What is the management Prolactinoma?
=> Medical - Dopamine agonists:
BROMOCRIPTINE, CABERGOLINE
=> Surgery to resect adenoma in cases of failed medical therapy
What is involved in the normal secretion of GH?
- GHRH released from hypothalamus acts on anterior pituitary
- Anterior pituitary releases GH which acts on liver
- Liver releases IGF-1
- Increased secretion of GH presents as acromegaly
Excess secretion of GH leads to acromegaly
What is the clinical presentation of Acromegaly?
- Big hands, face and jaw
- Coarse face
- Big tongue
- Wide space between teeth
- Puffy lips, eye lids and skin
- Dark skin
- Carpal tunnel signs
- Increased sweating
- Headache, backache
- Visual field defects
What are the complications of acromegaly?
- Hypertension
- Heart failure (LV hypertrophy)
- Obstructive sleep apnoea
- Cardiomyopathy
- Carpal tunnel syndrome
- Proximal myopathy
- Colorectal cancer
- Panhypopituitarism
- Resistance to insulin (therefore can cause diabetes)
What are the investigations in suspected acromegaly?
=> Bloods
- IGF-1 is first line investigation
=> OGTT
=> Pituitary MRI
What is the management of acromegaly?
=> Surgery (1st line) - as acromegaly can causes structural heart problems
=> If surgery fails: somatostatin analogues (GHIH) - eg Octreotide
=> If GHIH fails, then GH antagonists (Pegvisomant) or radiotherapy
