Chronic Kidney Disease Flashcards
definition of chronic kidney disease
GFR<60ml/min for >90 days
causes of CKD
diabetes
hypertension
glomerulonephritis
cystic kidney disease
renovascular disease
what is the equation for calculating creatinine clearance
cockcroft and gault equation
men
GFR = ([140-age] x LBW x 1.22)/creatinine
women
GFR = ([140-age] x LBW x 1.04)/creatinine
LBW = lean body weight
what does the MDRD equation calculate
eGFR
what type of urine sample is required for creatinine clearance test
24 hour
is serum creatinine a good marker of renal function
no
what are the creatinine clearance/GFR values for the five stages of CKD
Stage 1 - 120-90
Stage 2 - 89-60
Stage 3 - 59-30
Stage 4 - 29-15
Stage 5 - 15-0
what is required for the diagnosis of CKD
stage 1 and 2 - abnormal ultrasound/radiology or biopsy or hypertension or proteinuria in addition to moderately reduced GFR
stage 3 to 5 - only need low GFR
strategies for prevention of progression of CKD
control of BP (renin-angiotensin system inhibition)
reduce proteinuria (RAS inhibition)
if diabetes - optimise glycaemic control (SGLT2 inhibitors)
what two markers indicate prognosis of CKD
GFR
albuminuria
is proteinuria a marker or a cause of CKD
both
what happens when too much protein passes through the renal filter into the tubule
tubule cells are overloaded and die
macrophages try to repair the damage which leads to scarring and fibrosis
how do ACEis help prevent progression of CKD
cause vasodilation of the efferent arteriole
which mean less protein passes through the filter into the tubule
so the tubular cells don’t get overloaded
so there is less fibrosis
what drug should be avoided in those with CKD
NSAIDs
contrast (when GFR <30)
gentamicin
phosphate enemas
how does drug dosing change in CKD
many drugs need to be given at lower doses
what drugs need to be given in lower doses in those with CKD
many but especially chemotherapy and antibiotics
where can you get info on drug dosing in CKD
BNF
what percentage of elderly patients have CKD
> 25%
complications of end stage kidney disease
hypertension which can lead to:
left ventricular hypertrophy
stroke
end organ damage - e.g. eyes and kidneys
what are the BP treatment goals in CKD
130/80
or 125/75 in diabetes or proteinuria
what effect does good hypertension control have on GFR compared to uncontrolled hypertension
uncontrolled - GFR will decrease much more rapidly
treatment of hypertension
low salt diet
exercise
reduce alcohol
reduce smoking
drugs (ACEi, ARB, BB, CCB, alpha blockers)
what ion is it important to monitor in CKD
K+
at what GFR is hyperkalaemia common
<25
when might hyperkalaemia occur in GFR>25
diabetes
type 4 renal tubular acidosis
ACEi use
high K diet
what commonly happens to K levels in stage 5 CKD patients
hyperkalaemia
what are the management options for hyperkalaemia
reduce K+ dietary intake
potassium binders - short term as expensive
name foods high in K
‘student diet’
orange juice
bananas
beer
wine
coffee
chocolate
crisps
nuts
baked potatoes
chips
beans
what is the cause of acidosis in CKD
animal protein in food
and inability to acidify urine
what is the cause of acidosis in CKD
animal protein in food
and inability to acidify urine
treatment of acidosis in CKD
sodium bicarbonate replacement
what type of anaemia is normally seen in CKD patietns
normochromic normocytic anaemia
causes of aneamia in CKD patients
decrease response of erythropoetin to hypoxic stimulus of the kidney
RBCs surviving for less time
iron deficiency
blood loss - dialysis, blood samples
hyperparathryoidism
B12 and folate deficiencies
treatment for anaemia in CKD
for those with Hb <10.5 and and adequate iron stores they should be on Epo
how does CKD cause renal osteodystrophy
kidneys can hydroxylate vit D
so Ca not absorbed as much from diet
which can lead to osteomalacia/rickets
also low Ca prompts PTH to increase - secondary hyperPTHism
increases Ca phosphate resorption from bones
causing bone disease
kidneys can’t get rid of excess phosphate
foods with high phosphate
meat
dairy
scones
treatment of rneal osteodystrophy
phosphate restriction
vitamin D therapy
monitor PTH
parathroidectomy may be required
what are the consequences of hyperphosphataemia
vessel calcification which leads to
- non compliant vessels
- systolic hypertension -> left ventricular hypertrophy
- diastolic hypotension -> myocardial ischaemia
calciphylaxis (ulceration)
calcification of joints
what type of vascular calcification occurs due to hyperphosphataemia
medial
(within wall of blood vessel and encircling whole width)
intimal calcification is atherosclerosis
what is calciphylaxis
when calcium accumulates in small blood vessels of the fat and skin tissues which causes blood clots, painful skin ulcers and may cause serious infections that can lead to death
what happens to risk of death when on haemodialysis`
increases significantly
25 yo on haemodialysis has same irks of death as a healthy 75 yo
why are CKD patients at risk of malnutrition
decreased protein intake due to dietary restrictions
decrease appetite
low albumin possibly due to inflammation and infection
is low protein diet beneficial in end stage kidney disease
no
who should you refer to the renal clinic
those with a rapid increase in creatinine or hypertension
stage 3 CKD with hypertension, proteinuria, haematuria or rising creatinine
stage 4/5 CKD who are suitable for treatment
late stage signs of kidney disease if not already been picked up (should be picked up earlier than this though)
what type of dialysis can be done at home
peritoneal
what does peritoneal dialysis involve
draining used dialysate solution from peritoneal cavity
filling with new solution
allowing the cleaning to happen
repeating
what creatinine clearance value should you start dialysis
9-14
