Pituitary Disorders Flashcards
This deck covers
Hypersecretion disorders:
- Cushing’s Disease
- Hyperprolactinaemia
- Acromegaly
Hyposecretion disorders:
- Craniopharyngioma
- Infection
- Sheehan’s syndrome
- Cranial Diabetes Insipidus
What is Acromegaly?
- Excess production of Growth Hormone after the long bones fuse (i.e. in adults)
- Before long bones fuse is gigantism.
- In acromegaly there is excess growth hormone secondary to a pituitary adenoma in over 95% of cases.
How does acromegaly present?
Symptoms [7]
Signs [6]
Symptoms
- Rings and shoes no longer fitting
- Headaches
- Wonky bite
- Sweating, snoring (OSAS)
- Amenorrhea, reduced libido
- Galactorrhea
- Paresthesia
Signs
- Coarse facial features
- Increased growth of hands, jaw, feet
- Macroglossia, puffy lips, eyelids
- Scalp folds, skin darkening, acanthosis
- Goitre
- CTS
Remember features of a pituitary tumour: hypopituiraism, headaches, bitemporal hemianopia
What complications can arise from excess GH? [5]
What kind of follow up is required post-treatment of acromegaly? [5]
- Chiasmal Compression
- DM, Hypertension
- Cardiomyopathy
- Accelerated Osteoarthritis
- Colonic Polyps & adenoma > CRC
Follow up:
- Annual GH and IGF-1
- OGTT
- Visual field and vascular assessment
- BMI
- Photos
How would you test someone for Acromegaly? [4]
Treatment options [3]
- Visual Field Testing (chiasmal compression –> Bitemporal Hemianopia)
- Screen potential patients for IGF-1 Elevation - also used in monitoring of patients
- Confirm diagnosis with an OGTT if IGF-1 unequivocal. Acormegaly is diagnosed with GH suppressed.
- MRI for pituitary tumour
Treatment
- Transphenoidal resection
- Somatostatin analogues OCTREOTIDE monthly IM (inhibits GH)
- GH receptor antagonist PEGVISOMANT, OD S/C.
- Bromocriptine has been superceded.
- External irradiation following failed surgical/medical tx in older patients.
What is Cushing’s Disease? [2]
Excessive Glucocorticoids [1] due to the excessive ACTH [1] release from pituitary
Presentation Cushing’s disease
Symptoms [6]
Signs [8]
Symptoms:
- Easy bruising, Acne
- Mood change
- irregular periods
- Recurrent Achilles tendon rupture
- Increased hair growth
- Swelling, weight gain
Signs:
- DM
- HTN, HF due to Na retention
- Thin purpuric skin, pink striae
- Proximal myopathy, atrophy
- Osteopororsis
- Facial mooning & plethora, pendulous breasts, abdomen
- Edema, central obesity, supraclavicular fat, buffalo neck hump
- Virilisation (masculinization)
What are the various causes of Cushing’s? [6]
ACTH dependant:
- Pituitary Tumour ‘Cushings disease’
- Ectopic ACTH (SCLC)
ACTH independent:
- Adrenal adenoma 5-10% producing cortisol
- Adrenal carcinoma is rare
- CCS therapy
- Carney complex
- Micronodular adrenal dysplasia
Pseudo-Cushing’s: alcohol excess, severe depression
Cushing’s disease investigation algorithm
Tests to confirm Cushing’s syndrome:
- Overnight dexamethasone suppression test
- 1mg oral at midnight then serum cortisol at 8am - 24h urine cortisol
Localisation test
1. Paired morning & midnight ACTH-Cortisol
- If ACTH undetectable > ACTH-independent
- If ACTH detectable > ACTH dependent
2. High dose dexamethasone suppression test
8mg
What can cause hyperprolactinaemia?
Split into 3 categories - give at least 2 eg of each
Physiological
- Pregnancy
- Lactation/stress
- Stress
Pharmacological
* Dopamine antagonists or DA depleting
* Oestrogens (doesn’t include OCP)
* Antidepressants
Pathological
* Primary hypothyroidism
* Pituitary tumour
Give an example of each drug (DA depleting and DA antagonist) that causes hyperprolactinemia
How do we classify prolactinoma that also influences the treatment that it receives? [2]
Neuroleptics eg chlorpromazine
Anti-emetics eg metoclopramide
A microprolactinoma is <10mm
A macroprolactinoma is >10mm
How does hyperprolactinaemia present in women [3] and men [6]
Women:
- Galactorrhoea
- Menstrual irregularity
- Infertility
Men:
- Impotence
- Visual field abnormalities
- Headache
- Extraocular muscle weakness
- Other pituitary malfunction
- Eventual galactorhea
Men present later due to less obvious early warning symptoms
Investigation [2]
How do you manage hyperprolactinaemia? [1]
Test Serum PRL
Elevated? –> Pituitary MRI
Treat with dopamine agonist Cabergoline
What is the primary management for all pituitary tumours?
Compare to this to the management of prolactinomas and give a reason for this difference [2]
- Transphenoidal surgery to remove it +/- radiotherapy
- Dopamine agonists - bromocriptine, cabergoline (1xweekly) can shrink prolactinomas.
- Surgery is usually not indicated due to high response rate
What are the signs of hypopituitarism? [5]
What are 2 signs specific to hypopituitarism in children
Tiredness, Weight gain, Depression Lost libido, Impotence Menstrual problems Skin pallor Reduced body hair
Children: reduced linear growth, delayed puberty
What is Cranial Diabetes Insipidus?
How does CDI present? [2]
What are the dangerous sequelae? [2]
No vasopressin means huge amounts of urine [1] and consequent thirst [1]
Risk of dehydration [1] & hypokalemia [1]
What causes CDI? [4]
Cranial DI - NO secretion of ADH
Nephrogenic - decreased sensitivity to ADH
Gestational DI - degradation of vasopressin by placental vasopressinase
Primary polydipsia - primary defect in osmoreg of thirst
How do we test for CDI? [3]
Water deprivation test [1] - deprive fluids for 8h [1] then introduce desmopressin 2mcg [1]
- Cranial DI: responds to ADH causing increase serum osmolality (kidneys are responsive)
- Nephrogenic DI: unable to respond to ADH, kidneys dont respond. Urine osmolality stays low.
What could a pituitary tumour press on? [2]
- Optic chiasm
- Cavernous sinus nerves
Causes of pituitary hypofunction [4]
Craniopharyngioma
Trauma
Infection - TB, sarcoidosis
Sheehan’s syndrome
Management of cranial DI
Mild cases [1]
Main rx [1]
Monitoring [1]
Emergency management [5]
If mild, drinking water can do the trick [1]
Physiological replacement of desmoproressin [1]
Measure serum sodium 1-3 monthly for high Na
Emergency mx:
- ABCDE
- Urgent U&E, serum and urine osmolality, monitor urine output
- Fluids: hypernatremic 0.9% saline with aim of reducing Na no more than 12 mmol/L per day
- Desmopressin
In testing for acromegaly, why is it not wise to rely on random testing of Growth Hormone?
- GH: DO NOT rely on random testing as secretion is pulsatile and levels in acromegaly can overlap with normal pulsations and GH is also elevated in stress, sleep, puberty and pregnancy
Mx Cushing's disease: Iatrogenic Cushing's disease Adrenal adenoma Adrenal carcinoma [3] Ectopic ACTH Severe ACTH associated
- Stop CCS
- Cushing’s disease: transphenoidal excision of pituitary adenoma
- Adrenal adenoma: adrenalectomy
- Adrenal carcinoma: adrenalectomy, RT, adrenolytic drugs (mitotane)
- Ectopic ACTH: surgery
- Severe ACTH associated psychosis - intubation, mifepristone, etomidate
Cushing’s disease vs syndrome [2]
Cushing’s Disease - pituitary source of ACTH
Cushing’s Syndrome - ACTH independent ie adrenal tumor or exogenous CCS
What is the effect of pegvisomant on Acromegaly
very effective - decreases IGF-1 levels in 90% of patients to normal
doesn’t reduce tumour volume therefore surgery still needed if mass effect
Hypopituitarism causes [5]
- congenital empty sella
- pressure from pituitary tumours
- post-irradiation
- post-surgery
- pituitary infarction
Hypopituitarism Investigations
- Baseline bloods - 09.00 hours cortisol, LH/FSH, oestradiol, testosterone, TSH and fT4, prolactin
- Insulin tolerance test ITT or glucagon test to confirm GH and ACTH reserve
- Hypoglycaemia and glucagon should cause increase in cortisol and GH where pituitary is functioning
- GnRH stimulation is rarely used to assess gonadotrophins.
Management of hypopituitarism
- Hormone replacement therapy is essential.
- ACTH deficiency is treated with hydrocortisone replacement in a regime similar to that in adrenal insufficiency (e.g. 10 mg on waking, 5 mg at midday and 5 mg at 18.00 hours)
- Similarly, the resulting secondary hypothyroidism is treated with levothyroxine and gonadotrophins with oestrogen or testosterone.
- It is important to replace or confirm ACTH reserve before commencing thyroxine as the resulting increase in metabolism could otherwise precipitate an Addisonian crisis.
690 - In adults, replacement of GH (subcutaneously) will often relieve symptoms of low mood and fatigue.
Water deprivation test & post- DDAVP test
What is the diagnosis if
Urine osmolality after water deprivation remains <300
Post desmopressin test, the urine osmolality is >600
Cranial DI
Water deprivation test & post- DDAVP test
What is the diagnosis if urine osmolality after water deprivation is <300
Post desmopressin is <300
Nephrogenic DI
Water deprivation test & post- DDAVP test
What is the urine osmolality result for psychogenic polydipsia for post-water deprivation and post-desmopressin
Both remain >400
