kidney tests and diseases Flashcards
(42 cards)
what is the hierarchy of kidney function tests from low to high?
- serum- urea
- 24hr creatinine clearance
- serum creatinine
- EGFR estimated from serum creatinine
(this is done using the EPI, MDRD or cockcroft-gault formulas) - direct GFR measurement is the most accurate
what is the relationship between plasma creatinine and GFR?
- creatinine has poor sensitivity for GFR and it only starts to rise once 50% of the glomeruli are lost
- so if EGFR is raised then it means GFR has already halved
what happens to potassium levels if your kidneys are not functioning well?
you get hyperkalaemia
as kidney function decreases the kidneys cannot filter out the potassium
what is normal EGFR?
90 or higher
an EGFR above 60 is okay for those above 60
an EGFR below 60 is abnormal
what is normal serum urea level?
2.5 – 7.8 mmol/L
what is the normal serum creatinine level?
60 to 110 micromoles per liter (μmol/L)
what is the na+ range?
133-146mmol/L
what is the K+ range?
3.5-5.3mmol/L
what is the mg2+ range?
0.7-1mmol/L
what are the major intracellular cations and anions ?
- potassium
- magnesium
anions:
protein
ATP
what is are the major extracellular anions and cations?
cations:
- sodium
anions:
- chloride and bicarbonate
what is the effect of insulin potassium?
insulin increases the activity of the sodium/potassium ATPase so more potassium enters inside the cells- increasing intracellular potassium concentration, so decreasing the serum potassium levels
what is the normal range for creatinine kinase?
30-170iu/l
what happens to potassium during metabolic alkalosis?
the PH of the ECF increases, so hydrogen ions move from inside cells to the extracellular fluid to try to balance the PH.
the charges need to be balanced so the positive hydrogen leaving the cell is swapped fora positive potassium entering the cell
this results in hypokalaemia
what happens to potassium during metabolic acidosis?
hydrogen leaves extracellular fluid and enters the cells. The hydrogen is swapped for a potassium which results in hyperkalaemia
what does albuminuria suggest?
nephropathy
what is the best method to evaluate albuminuria?
measure the albumin to creatinine ratio
what are the different types of stones that can form?
- > calcium oxalate
- > calcium phosphate
- > uric acid
- > cystine
- > struvite
what is renal tubular acidosis?
Renal tubular acidosis (RTA) is a medical condition that involves an accumulation of acid in the body due to a failure of the kidneys to appropriately acidify the urine.
what are causes of calcium oxalate stone formation?
urinary factors: - high urine calcium - high urine oxalate - high urine citrate dietary factors: - low calcium diet - low potassium - low fluid intake - high oxalate diet - high animal protein intake
what causes calcium phosphate stones to form?
renal tubular acidosis
what is the cause of uric acid crystal formation?
if uric PH is <5.5
this can be due to chronic diarrhoea, gout, diabetes and obesity
what is the cause of cystine crystal formation?
occurs when someone has cystinuria- genetic condition where too much cystine is excreted
struvite stones cause?
made from magnesium ammonium phosphate
- caused by UTI by proteus and klebseila as they increase urease and increase Ph making it favourable for precipitation
