test results Flashcards
How are sodium levels regulated
urinary loss decreased - aldosterone
increased - natriuretic peptides
ADH release - reducing loss
thirst control
where in the nephron accounts for 65-70% of Na loss
proximal tubule
Ref Range - Na
135-145 mmol/l
symptoms hypernatraemia
CNS dysfunction - lethargy, confusion, irritability, seizures, weakness
Dehydration - dry mouth, oliguria, tachycardia
symptoms hyponatraemia
decreased ability to think, headaches, balance issues
causes hyponatraemia
SIADH
excess sweating
liver failure (due to increased blood volume)
kidney disease
causes hypernatraemia
dementia (thirst mechanism impaired)
diarrhoea and vomiting
diabetes
Ref Range K
3.5-5.5mmol/l
Symptoms hypokalaemia
vague - weakness, tiredness, cramping, N+V constipation, cramps
palpitations,hypotension
polyuria, thirst
depression, psychosis, delirium
causes hypokalaemia
N+V+D, furosemide, laxative, Mg deficiency (Mg needed to absorb K)
DKA - potassium excreted with negatively charged ketones
poor diet, malnutrition, illness, alcohol abuse
Insulin use
B agonist use
Drugs which increase K loss through kidney
Penicillin
diuretic
gentamicin
fludrocortisone
Drugs which encourage K loss from cells
verapamil
theophylline
pseudoephedrine
K level to stop heart beating
> 6.5mmol/l
treatment of hyperkalaemia
cation residues bind and excrete
IV glucose
nebulised salbutamol
haemodialysis
Calcium gluconate may be given to prevent cardiac effects
Drug causes hyperkalaemia
ACE Trimethoprim NSAIDS K sparing diuretic digoxin non-specific B-Blockers
other causes hyperkalaemia
trauma, burns
haemolysis
insulin deficiency
dietary intake
Urea ref range
1.7-7.1mmol/l
Urea levels in the plasma do not rise or fall with GFR because
50% of filtered urea is reabsorbed in proximal tubule
What do we find out from urea levels
hydration status
liver function
kidney function
causes of high urea
dehydration
kidney dysfunction
high protein diet
GI bleed
causes of low urea
overhydration
hepatic impairment
pregnancy
low protein diet
creatinine ref ranges
men 60-110 mmol/l
women 45-90 mmol/l
causes raised creatinine
trimethoprim - blocks tubular secretion of creatinine
rhabdomyolysis
high protein diet
reduction in GFR
when to use CrCl or GFR
eGFR used to stage kidney disease
CrCl for dosing adjustments in renal impairment
