hyponatraemia Flashcards
where are Vasopressin and oxytocin made
paraventricular nucleus and supraoptic nucleus
where are vasopressin and oxytocin transported to
to the posterior pituitary in the axoplasm of the neurons
how much of body water is extraceullar fluid
1/3 total body water 14L
how much of body water is intraceullar fluid
2/3 total body water 28L
components of extracellular fluid
Intravascular fluid ¼ ECF 3.5L
Interstitial fluid ¾ ECF 10.5L
describe water excess feedback loopcom
- ingestion of water -> decrease plasma osmolarity -> increase cellular hydration ->
- decrease thirst -> decrease water intake
- decrease vasopressin secretion -> increase urine water excretion by kidney
decrease total body water
describe water deficit feedback loop
- water loss -> increase plasma osmolarity -> decrease cellular hydration ->
- increase thirst -> increase water intake
- increase vasopressin secretion -> decrease urine water excretion by kidney
increase total body water
what is the release of vasopressin (ADH) controlled by
- Osmoreceptors in the hypothalamus controls release day to day
- Baroreceptors in brainstem and great vessels release ADH in emergencies
units for osmolality
concentration per kilo
compare osmolality and osmolarity in plasma
in plasma very similar to osmolarity but concentration slightly different.
what causes cranial diabetes insipidus (DI)
lack of vasopressin
other causes of cranial diabetes insipidus (DI)
Idiopathic
Trauma
Tumours
Genetic
Vascular – aneurysms, infarction
Management of cranial DI
- Treat any underlying condition
- Desmopressin
Tablets
Nasal spray
Injection
what is sodium level in hyponatreamia
serum sodium <135mmol/l
what is sodium level in severe hyponatreamia
serum sodium <125mmol/l
