033 Regulation of fluid electrolyte balance Flashcards
What will produce neural stimulation of thirst?
Increase of osmolality by 3%
If osmolality increases by 5mOsm/kg (2%), how much will AVP secretion increase by?
35%
Which receptor is responsible for pressor action of AVP?
V1
Which receptor is responsible for antdiuretic action of vasopressin?
V2
What are the short term and long term regulators of water balance and blood volume?
Aldosterone: long term regulator
AVP: short term regulator
What is mineralcorticoid escape?
When there is mineralcorticoid excess, AVP can adjust, but this might result in hypokalaemia, resulting in muscle weakness and fatigue
How do you treat diabetes insipitus?
If its cranial - synthetic vasopressin
If its nephrogenic - low salt diet, thiazide diuretics, and K+ replacement. Possibly also given with amiloride.
Why might it be dangerous to give someone who ran a marathon water? and what would you give them instead?
They will have increased vasohypersecretion and may have hypervolaemia and fatal hyponatremia
Explain liddles syndrome
Overexpression of ENAC because it is not properly degraded by ubiquiton proteosome. There is a change in the PY motif so it is not recognised by E3 ligase.
What are the symptoms of Liddle’s syndrome
Hypertension
Low plasma renin activity
Metabolic alkalosis due to hypokalaemia
Asymptomatic in children
How would you treat Liddle’’s syndrome
Amiloride
Spironolactone is not effective
Name AVP receptor antagonists
Vaptans
