Hypopituitarism Flashcards by Rachel Glass

How big is the pituitary gland and how much does it weight?

Pea sized

0.5g

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Which hormones are secreted by the anterior pituitary gland?

Prolactin
FSH
LH
TSH
ACTH
GH
MSH

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Which hormones are secreted by the posterior pituitary gland?

Oxytocin

ADH

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Which hormones are secreted by the hypothalamus?

CRH
GHRH
GnRH
TRH
Somatostatin
Dopamine

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What is a hormone?

A substance, usually a peptide or steroid, produced by one tissue and conveyed by the bloodstream to another to effect physiological activity eg growth, metabolism

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How do you investigate for a hormone deficiency?

Stimulatory test

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How do you investigate for hormone excess?

Suppression test

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When should cortisol be tested for suspected adrenal insufficiency?

8am when it should be highest

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When should cortisol be tested for suspected Cushing’s?

12am when it should be lowest

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Name common causes of hypopituitarism

Surgical hypophysectomy
Compression by tumour
Pituitary radiotherapy
Sheehan syndrome
Empty sella syndrome
Metastatic tumours/granulomas

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What are the 9Is of hypopituitarism?

Invasive
Infarction
Infiltrative
Injury
Immunological
Iatrogenic
Infectious
Isolated
Idiopathic

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Give examples of invasive causes of hypopituitarism?

Pituitary adenoma

Craniopharyngioma

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Give examples of infarction causes of hypopituitarism?

Pituitary apoplexy

Sheehan syndrome

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Give examples of infiltrative causes of hypopituitarism?

Sarcoidosis

Haemochromatosis

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Give examples of immunological causes of hypopituitarism?

Autoimmune

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Give examples of iatrogenic causes of hypopituitarism?

Pituitary surgery

Radiation therapy

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Give examples of infectious causes of hypopituitarism?

Give examples of isolated causes of hypopituitarism?

E.g gonadotrophin deficiency
Kallman’s syndrome
Anorexia nervosa

Give examples of injury causes of hypopituitarism?

Trauma

What are the most common causes of hypopituitarism?

Macroadenomas

Followed by vascular

What is the classical fallout pattern of hypopituitarism?

Gonadal
GH
Thyroid
ACTH

Hypofunction of the pituitary gland results in?

2° hypogonadotrophic hypogonadism 
GH deficiency
2° hypothyroidism
2° hypoadrenalism
Incr/decr prolactin

What is hypogonadotrophic hypogonadism and how do these patients present?

Low LH, FSH, oestradiol, testosterone
Amenorrhoea in females
ED and decreased libido in males

What is GH deficiency and how do these patients present?

Low GH
Growth retardation
Dwarfism

What is hypothyroidism and how do these patients present?

Low/normal TSH Low T3 Low T4 Secondary hypothyroidism

What is hypoadrenalism and how do these patients present?

Low ACTH, cortisol | Secondary hypoadrenalism

Name signs of pituitary failure

``` Fine scalp hair Ocular palsies Wrinkling of skin Evidence of prev acromegaly/Cushing's Loss of body hair Pale, dry, fine skin Testicular atrophy Loss of mm bulk Plump w/ female distribution of fat Hypotension Galactorrhoea Niiple pallor Optic atrophy Temporal field defect Scar from prev pituitary surgery ```

What tests do you perform to test for anterior hypopituitarism?

ACTH deficiency - 8h00 cortisol / ACTH stimulation test / insulin tolerance test LH/FSH deficiency - serum LH/FSH/testosterone/oestradiol TSH deficiency - random serum T4, TSH (but TSH can be ↑/↓/N) Growth hormone deficiency - only investigate if GH replacement is considered - exercise / other stimulatory tests (eg glucagon)

What is empty sella syndrome?

Subarachnoid space extends into sella turcica -> filled with CSF -> remodelling Pituitary function normal but must be checked

What are causes of empty sella syndrome?

``` Congenital 2° to Sheehan syndrome Pituitary radiation Pituitary surgery Post pituitary adenoma infarction ```

What is pituitary apoplexy?

Rare Frightening syndrome of violent headache, visual and VN disturbances, mental confusion/coma/death from haemorrhage or infarction of pituitary gland Diagnosed on MRI findings

Causes of pituitary apoplexy?

Usually pituitary tumour DM Head trauma Anticoagulation therapy

How do you treat pituitary apoplexy?

High dose dexamethasone Trans-sphenoidal pituitary decompression Evaluate for deficiencies afterwards

What is Sheehan's syndrome?

Postpartum pituitary necrosis preceded by obstetric haemorrhage leadin to circulatory collapse Severe hypotension -> pituitary ischaemia

Which part of the pituitary gland does Sheehan's syndrome usually spare?

Posterior pituitary gland

How do patients with Sheehan's syndrome present?

Failure to lactate Loss of axillary + pubic hair Hypothyroidism Hypocortisolism

What is important in the treatment of hypopituitarism?

Always replace cortisol before T4

ACTH hormone replacement

Hydrocortisone 10mg am, 5mg noon 5mg evening Cortisone acetate 25mg am 12.5mg pm Prednisone 5mg am 2.5mg pm

TSH hormone replacement

L-thyroxine 0.075-0.15mg daily

FSH/LH hormone replacement

Males - testosterone enanthate 200mg IM every 2 weeks - testosterone skin patch 5mg/d Females - conjugated oestrogen 0.65-1.25mg qd for 25days - progesterone 5-10mg qd on days 16-25 - oestradiol skin patch 0.5mg every other day - menopausal gonadotropins - HCG

GH hormone replacement

Adults - somatotropin 0.3-1.0mg SC qd Children - somatotropin 0.02-0.05 mg/kg/day