Week 4 Flashcards
Which follows which - water or sodium?
Water follows sodium everywhere
What is sodium controlled by?
Mineralcorticoid activity
What does mineralcorticoid activity refer to?
Sodium retention in exchange for potassium and/or hydrogen ions
Which steroid has the most mineralcorticoid activity?
Aldosterone
What is water controlled by?
ADH
What two things does ADH act on renal tubules to cause?
- Water re-absorption and thus
2. Antidiuretic effect
What does increased ADH do to urine?
Concentrated urine - low ADH causes dilute urine
What type of urine osmolality does concentrated urine have?
High
Give two reasons why sodium might be low due to water high being too high?
Decreased excretion - SIAD
Increased intake
Give two reasons why sodium might be low due to too little sodium?
Increased sodium loss - Addisons, Gut and Skin
Decreased sodium intake
Give two reasons why sodium could be high due to too little water?
- Increased water loss in diabetes insipidus
2. Decreased water intake
Give some reasons why sodium could be high due to too much sodium?
- Some IV medications are given as sodium salts
What condition can present with a craving for salty foods and increased pigmentation in hand creases?
Addisons
What is the basic problem in addisons?
Adrenal insufficiency so cant make enough steroids, CANT retain sodium in kidneys, loses sodium in ECF and becomes dehydrated
In addisons - what does hypotension come from?
Decreased ECF
What causes excess pigmentation in addisons?
ACTH excess and degraded reveals protein inside called MSH
What is the basic problem in diabetes inspidisu?
Disruption of pituitary or stalk so cant secrete ADH from posterior pituitary
How do you treat diabetes inspidus?
Desmopressin
If you suspect adrenal insufficiency then what must you measure?
Cortisol and ACTH but if patient unwell then give sodium replacement
Name two non-trophic hormones secreted from anterior pituitary?
GH and prolactin
What pouch is the anterior pituitary derived from?
Rathke’s
Name three types of cell in the anterior pituitary histology?
- Acidophils
- Basophils
- Chromophobe
Name two acidophils in anterior pituitary and name their hormone?
Somatotrophs - GH
Mammotrophs - PRL
Name three basophils in anterior pituitary and name their hormone?
Corticotrophs - ACTH
Thyrotrophs - TSH
Gonadotrophs - FSH/LH
What is the condition where there is ischaemic necrosis of the anterior pituitary?
Sheehan syndrome
What syndrome are pituitary adenomas associated with?
MEN1
`What is the most common functional tumour in the pituitary?
Prolactinoma
Give three symptoms of prolactinomas?
Infertility, lack of libido and amenorrhoea
What type of pituitary problem can sarcoidosis, TB and haemorrhages cause?
Panhypopituitarism
What is a craniopharyngioma derived from?
Remnants of Rathke’s pouch
What are the three zones of the cortex in adrenal gland?
Zona glomerulosa
Zona Fasciculata
Zona Reticularis
What do the layers of adrenal cortex secrete?
Mineralocoreticoids - G
Glucocorticoids - F
Sex steroids - R
In the medulla of adrenal gland - what cells secrete catecholamines?
Neuroendocrine cells
Name an acute disease that leads to hypofunction of adrenocortical gland?
Waterhouse Friderichsen
What colour are adrenocortical adenomas?
Brown/yello
What syndrome can primary hyperaldosteronism cause?
Conn’s
Give three common causes of Addison’s?
Autoimmune
TB, HIV
Metastatic malignancyt
Name two adrenal medullary tumours?
Phaeochromocytoma
Neuroblastoma
Name a neoplasm derived from chromaffin cells of the adrenal medulla?
Phaechromocytoma
How do you lab diagnose phaeochromocytoma?
Detection of urinary excretion of catecholamines and metabolites
What is ohaeochromocytoma associatd with?
Secondary hypertension
Characteristically what do tumour cells do in phaeochromoxytomas?
Form nests (zellballen)
What two things is phaeochromoxytoma a feature of?
MEN1 ,2
What system regulates aldosterone?
Renin angiotensin system
How do you treat adrenal insufficiency such as addisons?
- Hydrocortisone as cortisol replacement
2. Fludrocortisone as aldosterone replacement
What is the commonest cause of secondary adrenal insufficiency?
Exogenous steroid use
What are the diferences between addisons and secondary adrenal insufficiency?
Skin pale - no increased ACTH
Aldosterone production intact
For secondary adrenal insufficiency - how is it managed?
Just hydrocortisone
hypertension + hypokalaemia =
Primary aldosteronism - conns
What drug works on the mineralcorticoid receptor to help in primary aldosteronsim ?
Spironolactone
How do you confirm aldosterone excess?
Measure plasma aldosterone and renin and express as ratio - if raised then do saline suppression test.
Name the commonest congenital adrenal hyperplasia?
21alpha hydroxylase deficiency - autosomal recessive
How do you diagnose congenital adrenal hyperplasia?
Basal 17-OH progesterone
What disease does genital ambiguity suggest in females?
Congenital Adrenal Hyperplasia
What condition do labile hypertension, postural hypotension, paroxysmal sweating, headache and feeling of impending doom suggest?
Phaeochromocytoma
What is an extra adrenal tumour called?
Paraganglioma
In a phaeochromocytoma what to chromaffin cells reduce chrome salts to?
Metal chromiim resulting in brown colour reaction
What is the classical triad for phaeochromocytoma?
Hypertension
Headache
Sweating
Give two medications for phaeochromocytoma?
phenoxybenzamine (alpha-blocker)
propranolol (beta-blocker)
What are medullary thyroid canacer, parathyroid hyperplasia nad bilateral phaeochromocytomas associated with?
MEN2
What inheritancd is Voin Hippel Lindau sndrome?
Dominant
In VHL syndrome - what does gene mutation lead to?
Accumulation of HIF proteins and stimulation of cellular proliferation
For type I diabetes diagnosis what does fasting BG have to be and what does random have to be?
Fasting over 7
Random over 11
How do you screen for congenital thyroid disease?
Guthrie test
With congenital thyroid disease -what does absence of thyroxine after 3 months lead to?
Cretinism
