Endocrine Pathology Flashcards
where does the pituitary gland sit?
In the sella turcica of the sphenoid bone
what hormones does the anterior pituitary produce?
growth hormone prolactin FSH LH TSH ACTH
what hormones does the pituitary hormone release?
ADH
oxytocin
what is a pituitary adenoma?
tumours derived from the glandular tissue of the anterior pituitary
what syndrome can pituitary adenoma’s be a part of?
MEN 1
why can a pituitary adenoma cause bitemporal hemianopia?
The tumour can compres the optic chiasm ‘vision is missing in the outer half of both fields’
what are the main mass effects caused by a pituitary adenoma?
bitemporal hemianopia
Diplopia
what size do functional adenomas of the pituitary tend to be at presentation?
very small because they will have been producing symptoms related to the endocrine pathology
what is a prolactinoma?
A pituitary adenoma causing excess production of prolactin
What is the most common type of pituitary adenoma?
prolactinoma
what is the presentation of prolactinomas in women of reproductive age?
Present with oligomenorrhoea or galactorrhoea
often present early so have small tumours
how do prolactinomas present in men and post menopausal women?
mass effects such as headache/visual disturbance
larger at presentation
what does an ACTH secreting adenoma present as?
Cushings syndrome
what does a GH secreting adenoma present as?
acromegaly
what causes the metabolic effects from having a GH pituitary aedenoma?
the increased IGF1
what is there a higher mortality in acromegaly?
high incidence of left ventricular hypertrophy and hypertension
what are the signs and symptoms of acromegaly?
- protruding supraorbital ridges
- enlarged nose
- coarse facial features
- headaches
- hypertension
- insulin resistance
- impotence
- degenerative joint disease
- peripheral neuropathy
- large hands and feet
- thicker skin
what are the three biggest causes of thyrotoxicosis?
Graves Disease
toxic multinodular goitre
functional thyroid adenoma
where is aldosterone secreted from?
aldosterone is a mineralocorticoid so comes from the zona glomerulosa
where is cortisol secreted from?
zona fasciculata
where are androgens secreted from?
zona reticularis
what does the adrenal medulla secrete?
catecholamines
what is cushings syndrome?
High levels of glucocorticoids
what are the signs of cushings syndrome?
poor hair growth moon face buffalo hump abdominal obesity poor healing bruising proximal myopathy hypertension striae osteoporosis
what is the common problem that presents in a patient with cushings?
weight gain
muscle weakness
what are the most common causes of cushings syndrome?
exogenous steroid use
why is important to bring patients off exogenous steroids slowly?
because the increased cortisol means the adrenal axis is downregulated meaning adrenal atrophy. coming off them slowly gives them a chance to increase production.
what are four causes of cushings syndrome?
- exogenous steroids
- ACTH secreting pituitary adenoma
- adrenal cortical adenoma
- Paraneoplastic syndrome
what is an ACTH secreting pituitary adenoma?
the adenoma secretes ACTH causing hyperplasia of the adrenal cortex as increased cortisol is made
Causes cushings disease
what is an adrenal cortical adenoma?
A tumour in the zona fasciculate which secretes cortisol causing cushings syndrome
what is paraneoplastic syndrome?
tumour cells that secreted ACTH
in paraneoplastic syndrome what is the most common tumour to secrete ACTH?
Small cell lung cancer
In an adrenal cortical adenoma what colour is the tumour compared to the adrenal cortex?
the same as the adrenal cortex
what is the equation for blood pressure?
Blood pressure = TPR x CO
what is the main determinant of cardiac output?
circulatory volume mainly on renal sodium
what are the causes of primary hyperaldosterism?
- aldosterone producing cortical adenoma
2. bilateral cortical hyperplasia
what Is conns syndrome?
there is an aldosterone producing adrenal cortical adenoma
what is the most common cause of primary hyperaldosteronism?
Conns syndrome
what are the effects of angiotensin II?
- Stimulates aldosterone release
- causes vasoconstriction
- stimulates ADH release
what is the effect of hyperaldosteronism?
- excess Na and water reabsorption
- vasoconstriction of arterioles
This things cause high blood pressure
what is the effect of high aldosterone on sodium and potassium levels?
Low potassium
High sodium
what is a phaeochromocytoma?
A neuroendocrine tumour of the adrenal medulla.
what is the colour of the phaeochromocytoma?
The tumour is the same colour as the medulla with a small cortex around the edge.
what is secreted from a phaeochromocytoma?
Catecholamines mainly aldosterone
what is the presentation of a phaeochromocytoma?
Normally patients have no symptoms but can have a throbbing headache, sweating and palpations.
why is it important to identify phaeochromocytomas?
they are a treatable form of hypertension
what is the specific investigation done for measuring catecholamines and metanephrines?
a 24 hour urinary collection
what percentage of phaeochromocytomas are familial and what syndromes?
10%
von hippel lindau, neurofibromatosis, MEN type 2
what germline mutation is in phaeochromocytomas?
SDH
what is the combination of low potassium and high aldosterone suggestive off?
high aldosterone levels
what is the effect of hyperparathyroidism on calcium levels?
they will be high
what type of genetic disorder are MEN 1 and 2?
autosomal dominant
what is MEN 2 due to?
a germline mutation in RET proto-oncogenes
