Pituitary Disorders Flashcards
What are pituitary disorders most commonly caused by ?
Pituitary adenoma , a benign pituitary tumour. Most of these tumours are non functioning , meaning that they do not produce any hormone themselves , but cause an inadequate production of one or more pituitary hormones due to the physical pressure of the growing tumour on the glandular tissue.
What are functioning pituitary tumours ?
Also known as hyper-secreting tumours , they are much rarer. And their clinical symtposms are dependant on which pituitary hormone they are over secreting.
What are common symptoms of pituitary adenoma ? ( non-functioning )
Headaches
Visual problems
Nausea
Vomiting
What is hypopituitarism ?
Most commonly caused by a pituitary adenoma putting pressure on the pituitary glandular tissue
There is a progressive loss of anterior pituitary function.
What hormones are most commonly affected first in hypopituitarism ?
Growth hormone
LH
Follicle stimulating hormone
Why is the secretion of oxytocin and ADH normally unaffected in hypopituitarism?
Because the posterior pituitary gland is normally only affected if the tumour also affects the hypothalamic function or if an inflammatory process is involved
What are the. Sytmpksmof GH deficiency?
Decreased exercise tolerance
Decreased muscle tone
Increased body fat
Reduced sense of well-being
If GH is released in a pulsatile fashion
Is GH deficiency hard or easy to diagnose ?
Very hard to diagnose
The common cause of GH deficiency in adults in pituitary adenoma , what is it in children ?
Idiopathic - unknown cause
Outline the effects GH deficiency has on fetal development , child development
- Has little effect on fetal development
- From aged 1-mid teens , GH deficiency can result in poor growth and short stature. This results in Pituitary dwarfism.
What hormones come under gonadotropin?
LH and FSH
What are the consequences of a deficiency in Gonadotrophin?
Can result in lack of libido , infertility and oligomenorrhea ( infrequent menstruated period ) , the absence of menustration in women
in men : decreased libido , cause impotence ( inability to achieve an erection)
What symptoms of TSH deficiency?
Feeling cold
Weight gain
Bradycardia
Symptoms of Adrenocorticotropic hormone deficiency
Tiredness
Low blood pressure
Dizziness
What can ADH deficiency result from ?
Hypothalamic tumour or pituitary tumour that has extended up into the hypothalamus
Other causes include cranial radiotherapy
Autoimmune infiltration
Infections such as meningitis
Symptoms of ADH deficiency
Dehydration
Increased sensation of thirst
Excess secretion of dilute urine
What does hyperpitutarism usually caused by ?
Hypersecreting pituitary adenoma
What are the three most commonly affected hormones affected in hyperpituitarism ?
Prolactin
GH
ACTH
What is hyperprolactinaemia ? And what is it most commonly caused by ?
The most common form of pituitary disorder. Most commonly caused by a prolactinoma - a pituitary adenoma that secretes prolactin.
Other causes are pregnancy , suckling , stress and exercise.
What are symptoms of hyperprolactinaemia?
- Galactorrhoea - spontaneous flow of milk from the breast which is unassosiated with just nursing or childbirth.
- Gynecomastia : male breast tissue increases in size , this is non cancerous tissue.
- Hypogonadism : diminished function of the gonadotropin hormones which results in less sex hormones due to testes / ovaries not functioning properly.
- Erectile dysfunction
- Amenorrhea : abscence of menustration
Why patients with hyperprolactinaemia often have a decreased production in sex hormones ?
This is because the increased concentration of plasma prolactin increases negative feedback on the hypothalamus causing an increase in the production of dopamine ( prolactin release inhibiting hormone ) .
However the increased dopamine levels decrease the release of GNRH ( gonadotropin releasing hormone )
What is the first line of treatment for someone with hyperlipidaemia?
Dopamine receptor agonist which is usually sufficient in most cases.
What is the cause of GH excess ?
Large growth hormone secreting pituitary adeonmas
What are local mass effects of GH. Excess ?
Headaches
Visual field defects
Cranial nerve palsies
What are systemic effects of excess GH ?
Broad nose , thick lips , enlarged hands & feet , excessive sweating , deepening of the voice
In childhood , this can result in gigantism.
While in adults , acromegaly occurs ( large hands , feet & lower jaw ).
Why does diabetes develop with excess GH ?
Antagonises insulim - meaning several metabolic conditions such as diabetes mellitus can occur.
How are prolactinomas treated ?
With tablets - not operations.
Biochemical tests to confirm acromegaly ?
Elevated IGF-1 level
Elevated mean GH
How to treat patients with acromegaly ?
- Surgical removal of tumour
- Reduce GH secretion using dopamine agonist.
- Block GH receptor
- Radiotherapy
What is cushings disease ?
Associated with an increase in ACTH
.
What are classical changes in appearance in people with cushings disease ?
Round pink face with round abdomen
Skinny and weak arms and legs
Thin skin and easy bruising
Red stretch marks ( striae) on abdomen
High blood pressure and diabetes
Osteoporosis
What is the difference between cushings disease and Cushing’s syndrome ?
Cushings disease is due to a pituitary tumour whereas Cushing syndrome is due to other pathologies.
What is diabetes insipidus
There are different forms of diabetes insipidus
One is cranial DI which is where there is ADH deficiency pituitary disease.
Another form is nephrogenic DI : where kidney cells are resistant to ADH.
What are the consequences of untreated diabetes insipidus?
Severe dehydration
Very high sodium levels which could lead to hypernatraemia
Reduced consciousness , coma , death
How is cranial diabetes insipidus treated ?
Responds brilliantly to synthetic vasopressin
What is pituitary apoplexy?
Apoplexy is an old fashioned word for stroke. Often caused by a sudden vascular event in a pituitary tumour. This can be caused by bleeding in the tumour ( haemorrhage ) or blood supply cut off ( infaraction )
What is clinical presentation of pituitary apoplexy ?
Double vision
Sudden onset headache
Visual field loss
Cranial nerve palsy
Hypopituitarism ( cortisol deficiency most dangerous )
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