Pituitary disorders Flashcards
(104 cards)
1
Q
the pituitary gland is known as
A
the conductor of the endocrine audience
2
Q
Poster pituitary is derived from
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brain- neuroectoderm (nerve cells)
3
Q
features of the PP
A
fast acting- neurological
4
Q
what does the PP release
A
Vasopressin (ADH) and oxytocin (produced in the hypothalamus)
5
Q
Anterior pituitary is an
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up growth of gut- hormone producing and secreting
6
Q
hormones secreted by the AP
A
- growth hormone (GH)
- prolactin (PRL)
- follicle-stimulating hormone (FSH)
- luteinizing hormone (LH)
- adrenocorticotropic hormone (ACTH)
- thyroid-stimulating hormone (TSH)
7
Q
Disorders of the pituitary are rare, and can manifest themselves as
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either an over or under secretion of pituitary hormone.
8
Q
Clinical presentation of pituitary tumours
A
1. Mass effect of tumour on local structure- visual loss, headache
2.Abnormality in pituitary function – hypo or hyper-secretion
9
Q
A
10
Q
A
11
Q
most common pituitary tumour
A
Most commonly caused by pituitary adenoma- a benign pituitary tumour.
12
Q
most pituitary tumours are
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non functioning (do not produce any hormone) but can cause inadequate production of one or more pituitary hormone due to the physical pressure of the growing tumour on glandular tissue
13
Q
symptoms of non-functioning tumour
A
Headaches
Visual loss
Nausea and vomiting
14
Q
Functioning tumour (hyper-secreting)
A
Rarer
Clinical symptoms dependent on which pituitary hormone they are over-secreting and its systemic effects
15
Q
investigations required if pituitary tumour is suspected
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- MRI scan
- Assessment of visual field
- Blood tests measuring hormone levels
16
Q
picture of a nonrmal pituitary and its interactions with local structures
A
17
Q
upwards (superior) growth of pituitary tumour causes
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visial field loss due to compression on the optic chiasm
18
Q
how would an upwards (superior) growth of pituitary tumour effect vision
A
bitemporal hemi-anopia
19
Q
Sideways (lateral) growth of pituitary gland
A
would cause pain, double vission and left sided eye compressive problems
20
Q
what cause a tumour to be hypo-functioning
A
pressure on gland by adenoma
21
Q
hyper- functioning tumour
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hypersecreting adenoma
22
Q
When a tumour blocks the hypothalamic-pituitary access… which hormones will decrease
A
Hormones that decrease (due to being under positive control of hormones produced in the hypothalamus)
- GH
- LH/FSH
- TSH
- ACTH
23
Q
When a tumour blocks the hypothalamic-pituitary access… which hormones will increase
A
Hormones that will increase (due to be under under negative control of hormones produced in the hypothalamus)
- Prolactin (positive control by dopamine)
24
Q
cause of hypopituitarism
A
- Most commonly caused by a pituitary adenoma putting pressure on the pituitary glandular tissue.
- Tumour could be blocking hypothalamic control of the pituitary
- causes a progressive loss of anterior pitutiary function
- posterior pit usually only affected if the tumour also affects hypothalamic function (secretion of ADH and oxytocin normally unaffected)
25
ADH deficiency
May occur from a hypothalamic tumour or pituitary tumour that has ended up in the hypothalamus.
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Symptoms of ADH deficiency
* Dilute urine
* Dehydration
* Increased thirst
* Diabetes insipidus
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GH deficiency
Loss of GH
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GH deficiency hard to diagnose
Can be hard to diagnose because GH is released in a pulsatile fashion
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symptoms of GH deficiency in adults
Adults (adenoma)
* Decreased exercise tolerance
* Decreased muscle tone
* Increased body fat
* Reduced sense of wellbeing
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symptoms of GH deficiency in children
Children (idiopathic- specific mutations and autoimmune may be linked)
Short stature in children- can be treated with GH manufactured by recombinant DNA technology
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Gonadotrophin deficiency
LH and FSH deficiency
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symptoms of Gonadotrophin (LH and FSH) deficiency: general
* Delayed puberty in children
* Loss of secondary sexual characteristics in adult
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symptoms of Gonadotrophin (LH and FSH) deficiency: female
* Reduced libido
* Infertility
* Oligomenorrhea
* Amenorrhea
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Oligomenorrhea
- infrequent menstrual periods
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Amenorrhea
- absence of periods
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symptoms of Gonadotrophin (LH and FSH) deficiency: male
* Reduce libido
* Impotence
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Impotence
- inability to achieve erection of orgasm)
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TSH and Adrenocorticotropic hormone deficiency
Late features of pituitary tumours
* TSH and ACTH deficiency
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TSH deficiency
* Low thyroid hormones
* Symptoms:
* Cold
* weight gain
* tiredness
* slow pulse
* low T4 and non-elevated TSH
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ACTH deficiency
* Low cortisol
* Symptoms:
* Tired
* dizzy
* low BP
* low sodium
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sumamry of hypopituitarism
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hyperpituitarism
Caused by a hypersecreting pituitary adenoma
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three hormoens most commonly saffecte dby hyperpituitarism
Prolactin
GH
ACTH
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two rarer hormones affected by hyperpituitarism
TSH
LH/FSH
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prolactin excess
Most common form of pituitary disorder.
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most common cause of prolactin excess
prolactinoma
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what is classes as a large tumour
macro-adenoma = \>1cm
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other causes of prolactin excess
## Footnote
Pregnancy
Suckling
Stress
Exercise
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symptoms of prolactin excess
Galactorrhoea (milky nipple discharge)
Gynecomastia (proliferation of male breast glandular tissue)
Hypogonadism (low testosterone symptoms)
Amenorrhea (absence of period)
Erectile dysfunction
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Galactorrhoea
(milky nipple discharge)
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Gynecomastia
(proliferation of male breast glandular tissue)
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Hypogonadism
(low testosterone symptoms)
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MOA of prolactin
* Increased conc of plasma prolactin increases negative feedback on the hypothalamus
* Increase in production of dopamine to try and bring prolactin back within normal limits
* This decreases release of GnRHà diminished sex hormone production
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prolactin excess treatment
Treated with drugs not an operation- Dopamine receptor agonist (dopamine inhibits prolactin e.g. bromocriptine)
Never send patients for surgery until prolactin is known
Make sure pt isn’t pregnant
Surgery (rare)
Radiotherapy (rare)
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GH excess cause
Large growth-hormone secreting pituitary adenoma
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symptoms of GH excess
Headaches
Visual field defects
Cranial nerve palsies
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signs of growth hormone excess
Broad nose
Coarse facial features
Thick lips
Prominent superorbital ridge
Enlarged hands and feet
Greasy skin
Excessive sweating
Deepening of voice
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in children GH excess is
gigantism
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in adults GH excess is
acromegaly
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MOA of GH excess
* Systemic effects are through both the direct actions of GH and through the stimulation of local IGF-1 production
* Usually takes years to develop
* GH antagonises insulin --\> diabetes mellites can occur. Increased IGF-1 associated with cancer
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GH excess treatment
* Surgery to remove adenoma
* Radiation or drug therapy
* E.g. somatostatin analogues, GH receptor antagonists
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ACTH stands for
Adrenocorticotropic hormone
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ACTH excess is the cause of
cushings syndrome
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symptoms of cushins syndrome
Hyperglycaemia
Hypertension
Purple striae
Abdominal obesity
Buffalo hump
Moon-shaped face
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summary of hyperpituitarism
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Hyperprolactinaemia caused by
Prolactinoma
prolactin \> 5,000 then high prolactin
is likely to be due to active prolactin secretion (prolactinoma)
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prolactin is under **tonic inhibitory control by**
dopamine
anything blocking the stalk will lead to prolactin disinhibition (increase in prolactin)
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prolactin directly inhibits ...... secretion
LH
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If prolactin \< 5,000
the high prolactin might be due to disinhibition (‘stalk effect’) rather than active prolactin secretion
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Biochemical assessment of pituitary disease types
Basal blood tests
Dynamic blood tests
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basal blood tests sufficient
* **Thyroid axis**
* T4
* TSH
* **Gonadal axis**
* LH, FSH
* Testosterone (men)
* Oestradiol (women)
* **Prolactin axis**
* Serum prolactin
74
* **HPA**
* 0900 cortisol
* **GH axis**
* GH/IGf-1
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Dynamic assessment of HPA and GH axes types of tests
stimulation and suppression test
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stimulation tests used for
suspected hormone deficiency
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supression test used in
suspected hormone excess
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test for suspected adrenal axis deficiency
* Direct stimulation of adrenals by ACTH (synACTHen test )
* Response to hypoglycaemic stress (insulin stress test)
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test for suspected adrenal axis excess
Supress ACTH axis with steroids **(dexamethasone suppression test)**
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test for suspected GH axis deficiency
Response to hypoglycaemic stress (insulin stress test)
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test for suspected GH axis excess
Supress GH axis with glucose load (glucose tolerance test)
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Radiological assessment of pituitary disease
Using MRI
83
Specific conditions caused by Pituitary disorders
Acromegaly
Cushing’s disease
Diabetes insipidus
Pituitary apoplexy
84
Acromegaly
“large extremities’
* Acromegaly is a rare condition where the body produces too much growth hormone, causing body tissues and bones to grow more quickly.
* Over time, this leads to abnormally **large hands and fee**t, and a wide range of other symptoms.
* Acromegaly is usually diagnosed in adults aged 30 to 50 but can affect people of any age. When it develops before puberty, it's known as "gigantism".
85
cause of acromegaly
GH-secreting pituitary tumour- can be visualised using a PET scan
86
symptoms of acromegaly
* Swollen hands and feet
* Tiredness and difficulty sleeping
* Gradual changes in facial features
* Brow
* Lower jaw
* Nose getting larger
* Teeth become more space
* Numb ness and weakness in hands caused by a compressed nerve (carpal tunnel syndrome)
87
long term complications of acromegaly
* Long term complications
* Premature CVS death
* Increase risk of colonic tumour
* Increase risk of thyroid cancer
* Disfiguring body changes may be irreversible
* Hypertension
* Diabetes
88
Biochemical tests to confirm acromegaly
* OGTT with GH response
* Failure to supress GH\<1ug/:
* Elevated IGF-1
* Growth hormone day curve – elevated mean GH
89
acromegaly treatment
* Surgical removal of tumour (through nose)
* Medical treatment
* Reduce GH secretion:
* Dopamine agonist- bromocriptine
* Somatostatin analogues- octreotide
* Block GH receptor- pegvisomant
* Radiotherapy
* External beam- multiple short bursts over several weeks
* Gamma knife
* High conc over single time
90
examples of acromegaly
91
cushings syndrome caused by
ACTH (adrenocorticotropic hormone) pituitary tumour
92
classical changes in appearance of Cushings disease patients
* Round pink face with round abdomen
* Skinny and weak arms and legs
* Thin skin and easy bruising
* Red stretch marks (striae) on abdomen
* High bp and diabetes
* Osteoporosis.
93
cushings disease vs cushings syndrome
* CD caused by pituitary tumour
* CS may be caused by other pathologies
* Adrenal tumour
* Ectopic ACTH
* Steroid medication
94
Examples of cushings disease
95
what does insipidus mean
large quantities of pale urine
96
how many types of diabetes insipidus
* Cranial DI
* Nephorgenic DI
* Dispogenic DI
* Gestational DI
97
cranial DI
* Lack of ADH (p.pituitary)
* ADH usually decreases urine output to increase BP by increasing reabsorption of water in the kidneys
98
causes of cranial DI
Inflammation
Infiltration
Malignancy
Infection
99
nephrogenic DI
Vasopressin resistant kidney disease
100
symptoms of diabetes insipidus
* Large quantities of pale (insipid) urine
* Extreme thirst due to fluid loss
101
consequences of untreated DI
Severe dehydration
Very high sodium levels (hypernatremia)
Reduced consciousness, coma and death
102
treatment of DI
* Cranial DI responds well to synthetic vasopressin (ADH)
* Desmopressin nasal spray, tablets or injection
*
103
Pituitary apoplexy
‘Apoplexy’ is the old-fashioned word for stroke
* Sudden vascular event in a pituitary tumour
* Haemorrhage
* Infarction
104
clinical presentation of pituitary apoplexy
Sudden onset of headache
Double vision
Visual field loss
Cranial nerve palsy
Hypopituitarism (cortisol deficiency)
