Y2 IMBALANCES OF ELECTROLYTES, METABOLITES, HORMONES ETC. Flashcards
Symptoms of hyponatraemia.
- altered conscious.
- confusion
- nausea
- vomiting
- fitting
same as hypernatraemia
symptomatic hyponatraemia is?
life-threatening
loss/gain of Na+ is from the?
ECF only
Na+ is confined to the?
ECF
if ECF volume is too high?
kidneys excrete Na+ which is followed by water.
if ECF volume is too low?
kidneys retain Na+ to retain water
by what two mechanisms does hyponatraemia develop?
- reduced sodium
- increased water
how do you treat hyponatraemia?
- if due to too little sodium, give the patient sodium.
- if due to too much water, restrict fluids.
sodium is controlled by?
mineralocorticoid activity
how does mineralocorticoid control sodium?
sodium is retained in exchange for potassium +/or hydrogen ions.
which steroids have mineralocorticoid activity?
- aldosterone.
- cortisol.
excess mineralocorticoid activity causes?
sodium retention
+ thus water retention
little mineralocorticoid activity causes?
sodium loss
+ thus water loss
ADH is released?
by the posterior pituitary in response to stimuli.
ADH acts on the?
renal tubules
ADH acts on the renal tubules to cause?
water reabsorption - i.e. anti-diuresis.
increased ADH causes?
concentrated urine i.e. water retention
reduced ADH causes?
dilute urine i.e. water loss
the concentration of urine is assessed as?
urine osmolality
concentrated urine can be described in terms of osmolality as?
high osmolality
dilute urine can be described in terms of osmolality as?
low osmolality
another name for ADH?
arginine vasopressin
how does ADH cause water reabsorption?
countercurrent multiplication
in SIADH what is meant by inappropiate?
inappropiate with regards to the osmolal state
what may cause reduced H2O loss?
SIADH
symptoms of hypernatraemia?
- altered conscious.
- confusion
- nausea
- vomiting
- fitting
same as hyponatraemia
what causes hypernatraemia?
- increased Na+ intake
- reduced Na+ loss
- increased H2O loss
- reduced H2O intake
what are causes of increased Na+ intake?
- IV meds
- near-drowning
- malicious
what causes increased H2O loss?
diabetes insipidus
when water is lost, which compartment does the majority come from?
ECF
hypernatraemia is commonly seen in?
diabetic ketoacidosis.
- esp. if vomiting.
management of hypernatraemia?
- if due to too little water: give them some water.
- if due to excess sodium: give them a loop diuretic.
oedema is a sign of?
effective circulating vascular volume depletion.
- body secretes ADH and aldosterone to try and restore volume but most retained water just ends up in interstitial fluid, making the problem worse.
what can be inferred from a patient with oedema?
they have too much water and sodium
management of oedema?
loop diuretic e.g. furosemide
hyponatraemia, hyperkalaemia and hypoglycaemia are suggestive of ?
adrenal insufficiency
symptoms of hypercalcaemia?
- dehydration, confusion and polyuria (excessive thirst).
bones, groans, stones and psychic moans.
i.e. osteopenia/fractures, abdominal pain (pancreatitis, ulcers), renal stones, depression.
symptoms of hypocalcaemia?
- paraesthesia
- muscle cramps/weakness or tetany,
- fatigue
- bronchopasm or laryngospasm
- fits
signs of hypocalcaemia?
- chvostek’s sign (tap over facial nerve causes tetany).
- trousseau sign (carpopedal spasm -hands/wrist, feet/ankle)
- ECG: QT prolonged
