Renal handling of solutes and renal stones Flashcards
What are kidney stones?
Precipitated salts which grow into calci
Urolithiasis
In urinary tract
Nephrolithiasis
In kidney
Nucleation
Ions come together in CD
Aggregation
Crystals aggregate in renal pelvis
Renal colic
pain associated with kidney stone - lower back pain, nausea and vomiting, intermittent pain
5 types of kidney stones
- Calcium-containg stones (calcium oxalate (alkaline/acidic) and calcium phosphate(alkaline))
- Magnesium ammonium phosphate - alkaline conditions
- Uric acid stones - acidic conditions
- Cystone stones - acidic conditions
- Xanthine stones
Risk factors for calcium stones
- Calcium supplements
- Calcium antacids
- Foods high in oxalates - spinach, pecans, peanuts
Risk factors for magnesium ammonium phosphate stones
- Women, UTIs
- Alkaline environment favours crystal formation
Risk factors for urate stones
- High uric levels in blood plasma (hyperuricemia)
- Probenecid - increased urate excretion
- Not visible on x-rays
Treatment for kidney stones
- Tamsulosin is a alpha1a antagonist to dilate ureter
- Keterolac is NSAID
- Hydromorphone or morphine is opioid for pain
- Zofran for vomiting
Shock wave lithotripsy
- High frequency ultrasound targets stone
- Breaks it up
Uteroscopy
- Medium stones
- General anaesthesia
- Ureteroscope to visualise stone
Percutaneous nephrolithotomy
- Hole into back at kidney level
- Camera inserted
- Visualise stone
- Pulverised using ultrasound
prevention of kidney stones
- Lots of fluids
- Limit oxalates and calcium supplements
- Decrease nondairy animal protein
- Decrease sodium
- Decrease fructose and sucrose
- Increase potassium
- Increase phytates
- Apple cider vinegar
How do thiazide diuretics prevent kidney stones?
stop sodium-calcium symporter in DCT so decreases intracellular sodium and increase sodium movement into cell by anti-porter so more calcium reabsorbed
What do SGLT2 cotransporters move?
Na+ anf glucose
When is acetazolamide used?
Altitude sickness
What is empahglifloxin
Reversibly inhibits sodium-glucose co- transporter 2 (SGLT2) in the renal proximal convoluted tubule to reduce glucose in diabetics
Which substances does empaglifloxin move?
Cl-, K+, water, amino acids out of lumen and H+ in
Which substances does acetazolamide move?
HCO3-
What is the purpose of the countercurrent principle?
Maintains hypertonic interstitial
What happens in ascending LOh
Reabsorbs solutes but no water - creates hypertonic medulla
Which substances does the NKCC2 cotransporter and loop diuretics move and where
Na+, Cl-, K+ out of lumen
Which molecules determine the paracellular voltage and what is this
Ca2+ and Mg2+ moving out - voltage is 8mV
Why is the inside of the cell positive?
Backleak of potassium through cells
PTh effect on calcium
Stops it being excreted
What happens to glucose concentration in PCT?
Falls to 0
What happens if we block SGLT2
Blocking SGLT2 so urinate sugar in diabetics - line would be less steep
Concentration would increase in descending limb and then stay constant in rest of LOH
In DCT concentration would steeply increase
Characteristics of calcium oxalate crystals
radio-opaque
Small and numerous
Can form in any urine
Characteristics of calcium phosphate crystals
Radio-opaque
Small and numerous
Form in alkaline conditions - hyperparathyroidism
Characteristics of magnesium crystals
radio-opaque
alkaline urine
Staghorn
Characteristics of uric acid crystals
High purine diets, malignancies and metabolic defects
Radio-lucent
Acidic urine
Small, numerous, stag horn
Characteristics of cystine and xanthine crystals
Metabolic defects
Soft and waxy
Faint on x-ray
especially in children
Function of ANP
ANP counteracts aldosterone
ANP released in response to increased intravascular volume
What are type A and B cells
Type A and B are both intercalated cells
Type A cells like to get rid of Hydrogen ions into tubular lumen and hold onto bicarb - correct acidosis
pCO2 increases due to hyperventilating
Type B cells hang onto hydrogen and get rid of bicarb
What is spironolactone
Aldosterone antagonist - sodium/chloride potasisum exchange
Impact of aldosterone and ANP on tubule
Move sodium and chloride out and potassium in
Impact of aldosterone on tubule
Moves HCO3- and K+ out and H+ in
