Flashcards in Renal Deck (216)
What enzyme is bicarbonate regeneration in the proximal convoluted tubule dependent on and what drug inhibits this enzyme?
Inhibited by acetazolamide
Why do you get acidaemia in kidney disease and how may you compensate for this?
Failure to regenerate bicarbonate
Respiratory compensation - tachypnoea to blow off CO2
How does carbonic anhydrase help in the regeneration of bicarbonate?
For bicarbonate to pass into the podocyte from the filtrate it must be neutral
In filtrate converted to H20 and CO2 so it can pass through the podocyte membrane
When in the cell carbonic anhydrase converts CO2 + H2O back to bicarbonate
How is Na+, K+, Cl- and H2O absorbed in the ascending limb of Henle?
Through a K+,2Cl-, Na+ co transporter using the Na+ gradient set up by Na+/K+ATPase and water then follows
Where is the site of action of loop diuretics such a furosemide, what could this lead to the development of?
Act on the K+,2Cl-,Na+ co transporter in the ascending limb of Henle
Could lead to the development of hyponutraemia
What is reabsorbed at the cortical collecting duct and how?
Na+ (with Cl-, H20) is reabsorbed in exchange for K+
This is controlled by aldosterone
How do potassium sparing diuretics such as spironalactone work and what do they increase the riskl of?
Block the absorption of Na+ in exchange for K+
High risk of hyperkalaemia
What is diabetes insipidus and what can it cause?
Central failure to secrete ADH
or a peripheral resistance to ADH
Large volume of water output - polyuria
What 2 things can hyponatraemia lead to?
Confusion and fits
What are the 3 types of AKI?
Pre renal AKI, Intrinsic AKI, Post renal AKI
Over what time period would a reduction in kidney function be considered AKI rather than CKD?
Abrupt reduction in kidney function occurring over hours to weeks
With a SCr increase of >26umol/L or SCr increase >1.5 to 1.9 fold from baseline what stage AKI is this?
With a SCr increase of >3 fold from baseline or >354 umol/L what stage AKI would this be?
With a SCr increase of >2-2.9 fold from baseline what stage kidney disease would this be?
If a patient commenced on renal replacement therapy what stage AKI would this be?
If a patient produced 6 consecutive hours what stage kidney disease would this be considered to be?
If a patient produced 12 hours what stage kidney disease would this be?
If a patient produced 24 hours or was anuric for 12 hours what stage kidney disease would this be considered to be?
What does pre renal AKI refer to?
AKI due to inadequate blood flow to perfuse the kidneys
What are the causes of pre renal AKI? 5
2) Severe sepsis (vasodilation)
3)Vomiting and diarrhoea
4) Over diuresis with diuretics
5) Burns (excessive fluid loss through the skin)
What does intrinsic AKI refer to?
Intrinsic renal disease where there is structural damage to the renal tissue (glomeruli/tubules/interstitium) - most intrinsic AKI cause blood and our protein to leak out through the kidney which can be detected using a urine dipstick
What are some causes of intrinsic AKI? 5
1) Nephrotoxic medication
2) Interstitial nephritis
5) Tubulo nephritis
Name 4 nephrotoxic drugs/ substances?
2) Contrast media
What does post renal AKI refer to?
Post renal AKI is caused by obstruction to the renal tract, this can be anywhere from the renal pelvis to the urethra
What 8 things could cause post renal AKI?
1) Retroperitoneal fibrosis
2) Renal stone disease
3) Bladder carcinoma
4) Prostatic enlargement
5) Cervical carcinoma
6) Intra Abdominal hypertension
7) Urethral stricture
8) Obstructed urinary catheter
What is hydronephrosis?
Large kidneys on ultrasound
What 3 features may first present in AKI?
1) Symptoms suggesting uraemia
2) Raised serum creatinine
3) Decreased urine output
What are the risk factors for AKI? 9
1) Age >75
3) Cardiac failure (decreased renal perfusion)
4) Atherosclerotic peripheral vascular disease
5) Liver disease (hepato renal failure)
6) DM (diabetic nephropathy)
7) Nephrotoxic medications (NSAIDs, ACE-I, ARBs Gentamicin)
8) Sepsis (vasodilation - reduced perfusion pressure)
9) Hypovolaemia (eg. vomiting/diarrhoea lose water and reduce volume of blood)
Why may prostatic disease lead to AKI?
Post renal AKI, compressing the urethra