Pituitary Flashcards
Causes of Pituitary dysfunction
Tumours eg adenomas
Craniopharyngioma
Rare - granulomas, cysts and TB
Clinical presentation of Pituitary Tumourss
Headache - frontal or retroorbital Visual loss Superior temporal field loss or bitemporal hemianopia that progress to concentric visual field loss and blindnes Optic disc pale and atrophic Diabete insipidus Hypothalamic syndrome Hydrocephalus Nasal stuffiness or discharge Facial pain CSF rhinorrhoea Damage to CN 3, 4, 5 and 6 Raised ICP
Ix of pituitary tumor
Optic nerve damage - perimetry, visal acuity
Endocrine status - Hypopituitarism or overactivity eg prolactin or GH
Tumour mass - MRI
Tx of pituitary tumor
Medical
- If optic nerve compression - urgent dopaminergic agonist eg bromocriptine and somatostatin eg octreotide. Can shrink some.
Surgery
- Also need urgent decompression if optic nerve compressed otherwise if vision normal medical is often enough.
Radiotherapy
- reserved for if medical and surgery fail. Lots of damage to surrounding structures
Common causes of hypopituitarism
Pituitary and hypothalamic tumours eg primary or secondary Iatrogenic eg surgery or radiotherapy Idiopathic eg empty sella syndrome Rare - Cyst granulomas - Autoimmune eg lymphocytic hypophysitis - Vascular eg Sheehan's syndrome
Diabetes Insipidus
Is a symptom of hypothalamic damage. No ADH secretion. Symptoms Overwhelming thirst Polyuria over 4L a day Frequency Nocturia Ix - Usually obvious clinically. Otherwise water deprivation test.
Tx is desmopression - a synthetic ADH analogue
Symptoms of GH deficiency
Growth failure in children Lethargy Impaired well being Altered body composition Dyslipidaemia Osteoporosis
Symptoms of gonadotrophic deficiency
Amenorrhoea, infertility in women
Impotence and infertility in men
Difference between hypoadrenalism caused by ACTH definicency vs dysfunction of the adrenal gland
Patient does not become pigmented
Not aldosterone deficient
Symptoms of panhypopituitarism
Pale Hypotensive Impotent Weak Lethargic Collapse Hyponataemic fits due to cortisol and thyroxine defiency Tumour mass symptoms
Ix for pituitary underactivity
Static
- should have low pituitary hormones and low target gland hormones. Used for Thfyroid, Gonadotrophins
Dynamic
- GH and ACTH - Insulin stress testing - induced hypoglycaemia and wait for response
- GH - Arginine stimulation test.
Mx of hypopituitarism
Replace deficiency hormones - Coritsol. And thyroxine, GH in children. Sex steroid replacement. Intranasal or oral desmopressin.
In panhypopituitarism - Start steroids for a week prior to thyroxine to avoid increase metabolic rate causing hypoadrenal crisis. Start desmopressin without delay.
- Watch for hypoadrenal crisis if non compliant or illness. Treat with extra hydrocortisol. Need emergency bracelet and card.
Symptoms of Hyperprolactinaemia
Galactorrhoea
Menstral distrubance
Infertility in young woman
Causes - Microadenoma less then 1 cm or lactotroph hyperplasia.
Men - impotence and infertility. Usually PC later as not as sensitive to prolactin.
Causes of hyperprolactineamia
Primary - Tumour of pituitary or lactotroph hyperplasia
Secondary
- Intra or suprasellar tumour or granulomas that prevent inhibition of prolactin
- Drugs eg metoclopramide, phenothiazines, antidepressant, histamine H2 antagonists
- Endocrine: primary hypothyroidism, PCOS
- Systemic disease: Renal failure
- Chest wall/breast stimulation or disease
- Fitting
Physiological causes
- pregnancy
Breast feeding
Stress, anxiety
Sleep
Mx of hyperprolactinaemia
Exclude 2rd causes
MRI and pituitary functioning tests
Tx - Dopaminergic agonist 1st line cabergoline
Surgery and radiotherapy if failure of medical treatment
