Disease Profiles: Pituitary Disorders Flashcards by Evie Brown

Define a pituitary macro-adenoma

Adenomas >1cm

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Describe the use of GH antagonists in the management of acromegaly

SC injection, blocks GH activity with an 85% response rate (but tumour size does not decrease)

Last line as very expensive

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Describe the clinical presentation of hypopituitarism

Depend on the specific hormone deficiency, age of onset, the rate at which hypopituitarism develops, and the underlying cause of hypopituitarism

If caused by intra/parasellar masses (e.g. pituitary macroadenomas, craniopharyngiomas) can present with headaches and visual field defects (bitemporal hemianopia)

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Is pituitary adenoma which produces ACTH more likely to be a micro or macroadenoma?

Microadenoma (Cushing’s, bilateral adrenocortical hyperplasia)

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Craniopharyngiomas are derived from the remnants of _______ pouch

Rathke’s

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Define a pituitary micro-adenoma

Adenomas <1cm

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Describe the findings in a GTT suppression test which would indicate acromegaly

GH unchanged/no suppression or paradoxical rise following oral glucose challenge (normally GH suppresses after glucose)

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Name the hormone replacement for TSH deficiency

Levothyroxine

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A subset of pituitary adenomas behave aggressively and enlarge more rapidly. Name two features which indicate an aggressive lesion.

Lots of mitotic figures and p53 mutations

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Name the Ur/serum osmol ratio which would indicate diabetes insipidus

< 2

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Describe the management of diabetes insipidus

Desmospray (nasally) or desmopressin oral tablets

Desmopressin IM injection - generally reserved for emergency or post pituitary surgery

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Describe the clinical presentation of GH excess

Giant (before epiphyseal fusion)

Thickened soft tissues - skin, large jaw, sweaty, large hands

Snoring/sleep apnoea (thickened nasopharynx)

Hypertension, cardiac failure

Headaches (vascular)

Diabetes mellitus

Local pituitary effects - visual fields, hypopituitarism

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Define hypopituitarism

Inadequate production of one or more pituitary hormone as a result of damage to the pituitary gland and/or hypothalamus

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Name 4 pathological causes of hyperprolactinaemia

Hypothyroidism, stalk compression e.g. due to pituitary adenoma, damage to stalk, prolactinoma

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How is a water deprivation test to investigate diabetes insipidus performed?

Patients stop drinking water for 2–3 hours before the first measurement

Check serum and urine osmolarities hourly for 8hr, then 4hr after giving DDAVP

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What would be the consequence of ↓ TSH production (hypopituitarism)?

Secondary hypothyroidism

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How would you investigate a prolactinoma (pituitary adenoma producing prolactin)?

Serum prolactin (raised)

MRI pituitary

Visual fields - bitemporal hemianopia

Other pituitary hormone tests to assess whether other hormones are being affected

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Name the dynamic test used to assess the adrenal axis

Synacthen test

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What are the two classes of diabetes insipidus?

Cranial (central) and nephrogeneic

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Describe the management of a craniopharyngioma

Usually resection + radiotherapy

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Describe the principle of management for hypopituitarism

Hormone replacement and treatment of underlying cause

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What does growth hormone (GH) stimulate?

Skeletal and soft tissue growth

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What would be the consequence of ↓ LH/FSH production (hypopituitarism)?

Hypogonadism

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Hyper__________ may cause galactorrhoea and hypogonadism, including amenorrhoea

Hyperprolactinaemia

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Name the hormone replacement for diabetes insipidus (ADH deficiency)

Desmospray (nasal) or desmopressin tablets

Pituitary macroadenomas can cause pressure _______ of normal surrounding cell tissue

Atrophy

Name 4 physiological causes of hyperprolactinaemia

Breastfeeding, pregnancy, stress, sleep

Name the most common causes of panhypopituitarism

Most commonly caused by pituitary tumours, surgery or radiotherapy

What would be the consequence of ↓ ADH production (hypopituitarism)?

Diabetes insipidus

Define hyperprolactinaemia

Abnormally high levels of prolactin in the blood

GH deficiency in children leads to ______ \_\_\_\_\_\_\_

Growth retardation

How can a pituitary macroadenoma cause visual field defects?

Compression of the optic chiasma

Name a long term side effect of somatostatin analogues in the management of acromegaly

Gallstones (inhibit gallbladder contraction)

What would be the consequence of ↓ ACTH production (hypopituitarism)?

Hypoadrenal

Define nephrogenic diabetes insipidus

Characterised by renal resistance to ADH

Describe the aquired causes of cranial (central) diabetes insipidus

Idiopathic (often autoimmune), tumours, trauma, infiltrations (sarcoidosis), infections

What is the consequence of a functioning pituitary adenoma which produces GH in an adult?

Acromegaly

Define panhypopituitarism

Refers to deficiency of all anterior pituitary hormones

Hypo\_\_\_\_\_\_\_ causes weight gain, slowness of thought and action, dry skin, cold intolerance, constipation and potentially bradycardia and hyperthermia

Hypothyroidism

How can a pituitary macroadenoma cause panhypopituitarism?

Can cause infarction

Define cranial (central) diabetes insipidus

Occurs when there is insufficient levels of circulating ADH

Describe the use of somatostatin analogues in the management of acromegaly

Monthly injections which selectively act on somatostatin receptor subtypes (highly expressed on GH-secreting tumours) Shrink tumour (reexpands after stopping treatment) Can be used before surgery to relieve symptoms or after surgery if GH levels fail to be normalised

What is a craniopharyngioma?

Benign tumour which typically arises in the sellar/suprasella region

In hypopituitarism, what percentage of pituitary cells must be damaged before the patient becomes symptomatic?

\>80%

How could you identify cranial diabetes insipidus from a water deprivation test?

If Ur/serum osmol ratio is low and improves after DDAVP then it is due to cranial DI (not nephrogenic)

Name the condition that results from GH excess in children (before epiphyseal fusion)

Gigantism

Name 2 consequences caused by secondary hypothyroidism, hypoadrenalism, hypogonadism and GH deficiency

Tiredness/general malaise, reduced quality of life

Why might you consider GH replacement for adults with hypopituitarism?

Improve work capacity and psychological well-being

How would you investigate a craniopharyngioma?

CT/MRI

Describe the use of dopamine agonists in the management of acromegaly

PO, act on D2 receptors, work on 10-15% of patients, increased efficacy if co-secreting prolactin

How would you investigate diabetes insipidus?

Obtain baseline values then perform a water deprivation test

What would be the consequence of ↓ GH production (hypopituitarism)?

Growth failure

Describe the typical presentation of a female with hyperprolactinaemia

Generally present early with features of hyperprolactinamia: * Galactorrhoea (30-80%) * Menstrual irregulatity (25%) * Decreased libido * Ammenorrhoea * Infertility

Describe the clinical presentation of posterior hypopituitarism

Diabetes insipidus - polyuria, polydipsia

Define diabetes insipidus

Kidneys are unable to concentrate urine

How does a functioning pituitary adenoma present?

Depends on hormone produced, prolactin is most common but can also produce FSH/LH, GH and ACTH

Name the visual field defect caused by a pituitary adenoma compressing on the optic chiasma

Bitemporal hemianopia

Name the dynamic test used to assess the adrenal and GH axes

Insulin Tolerance Test (glucagon stimulation test if ITT contraindicated)

Describe the growth of a craniopharyngioma

Slow growing, often cystic, may calcify

Name the hormone replacement for ACTH deficiency

Hydrocortisone

How would you investigate hypopituitarism?

Basal tests for relevant axis of the hypothalamo-pituitary system - LH/FSH, TSH, T4, prolactin, IGF-1 (GH axis), cortisol, Na+ Dynamic tests - synacthen test (adrenal), ITT (adrenal, GH), arginine and GH-releasing hormone (GH) MRI if a hormone deficiency is identified to identify pituitary adenomas

Describe the clinical presentation of a craniopharyngioma

Headaches and visual disturbances Can cause pituitary hypofunction → hormonal imbalances Children may have growth retardation

What is a pituitary adenoma?

Benign tumour derived from cells of anterior pituitary

Name 3 short term side effects of somatostatin analogues in the management of acromegaly

Flatuence, diarrhoea, abdominal pains

Hypo\_\_\_\_\_\_\_\_\_\_ causes mild hypotension, hyponatreamia and CV collapse

Hypoadrenalism

Name the two peaks of incidence for the development of a craniopharyngiomas

5-15 years, 6th-7th decades

Name the most common cause of hypopituitarism in adults

Nonfunctioning pituitary macroadenomas

List 3 side effects of dopamine agonists

Have the least side effects of alternatives Can cause N+V, low mood/depression, and may cause fibrosis of heart valves/retroperitoneal fibrosis

How would you investigate acromegaly/gigantism?

GF1 - age and sex matched, nearly always raised Gold standard - GTT suppression test Others - visual field, imaging to check adenoma size, pituitary function tests for other hormones

Describe the prognosis of a craniopharyngioma

Excellent prognosis (especially if \<5cm) Following radiation, SSC may develop (but rare)

How would you investigate hyperprolactinaemia?

Serum prolactin raised Excluse physiological and drug causes then investigate pathological ones: * Visual fields - bitemporal temianopia * Exclude primary hypothyroidism * Assess anterior pituitary function * MRI pituitary

How does a non-functioning pituitary adenoma present?

Mass effects e.g. headache, visual field defects

Describe the management of a pituitary adenoma

Transphenoidal surgery Replace hormones

Which type of drugs can cause hyperprolactinaemia?

Any drugs which reduce dopamine will reduce inhibition of prolactin so increase prolactin levels - dopamine antagonists, antipsychotics, antidepressants etc.

Pituitary micro-adenomas are much less ________ than macroadenomas

Aggressive

What is the consequence of a functioning pituitary adenoma which produces GH in a child?

Gigantism

Name the condition that results from GH excess in adults

Acromegaly

Name the hormone replacement for sex steroid deficiency

HRT/oest/prog pill for female Testosterone for males

List 3 causes of nephrogenic diabetes insipidus

Idiopathic, familial and renal disease

Which type of Multiple Endocrine Neoplasia is associated with the formation of pituitary adenomas?

MEN1

What most commonly causes GH excess?

Nearly always due to a GH-secreting pituitary adenoma

Hypo\_\_\_\_\_\_\_\_ leads to loss of libido, loss of secondary sexual hair, amenorrhoea and erectile disfunction, and eventually osteoporosis

Hypogonadism

Describe the management of acromegaly

Excision - transphenoidal approach Radiotherapy +/- pharmacological treatment indicated when pituitary surgery fails to normalise

Describe the pathophysiology of pituitary carcinoma

Rare, account for \<1% of pituitary tumours Often functional (prolactin or ACTH usually) Metastasise late after multiple recurrences

Describe the clinical presentation of diabetes insipidus

Polydipsia Polyuria with dilute urine

Describe the familial causes of cranial (central) diabetes insipidus

Isolated in most cases, can occur as part of DIDMOAD

Describe the clinical presentation of longstanding panhypopituitarism

Gives the classic picture of pallor with hairlessness ('alabaster skin')

Name the dynamic test used to assess GH insufficiency

Arginine and growth hormone releasing hormone test

Describe the management of prolactimonas

Dopamine agonists normalise prolactin and shrink tumour in majority of cases - surgery rarely considered because of this

Name the two groups of causes of cranial (central) diabetes insipidus

Familial (rare) Acquired

Describe the typical presentation of a male with hyperprolactinaemia

Impotence, generally present late with stuctural symptoms from a pituitary tumour - visual loss, headaches, anterior pituitary malfunction

Which form of malignancy is associated with GH excess?

GH excess can result in the formation of colon polyps and colon cancer - may be presenting feature