Chronic kidney disease Flashcards
Define CKD
a reduction in kidney function, characterised by a reduction in GFR, which is not reversible and may be progressive
What is a normal adult 2-kidney GFR?
120ml/min/1.73m^2
How is CKD staged?
CGA
Cause
Glomerular stage
Albuminuria stage
Markers of kidney disease
GFR<60
albuminuria/haematuria
electrolyte abnormalities due to tubular disorders
structural/histological abnormalities
kidney transplantation
How long does kidney damage have to last to be CKD?
> 3 months (more than one blood test/urine sample)
or expected to last >3 months (transplant, polycystic kidneys etc)
How are pre-renal, renal and post-renal AKIs treated?
pre-renal = good perfusing pressure (fluids) and oxygen delivery
renal = remove nephrotoxins, treat inflammation
post-renal = ensure free urinary flow
CKD causes
diabetes
hypertension
renovascular disease
reflux disease
obstructive uropathy
autosomal dominant polycystic kidney disease
glomerulonephritis
unknown
CKD management (1,2,3a)
identify cause - US, biopsy, urine dip
treat cardiovascular risk factors - BP, DM, smoking, weight, activity, salt, proteinuria
monitor progression
What is the blood pressure target in CKD?
systolic below 140
diastolic below 90
if diabetic or ACR>70:
- systolic below 130
- diastolic below 80
Why are ACE-is/ARBs used in CKD?
block angiotensin 2
dilate efferent arteriole
reduce GFR but increase tubular blood flow
How much is creatinine allowed to rise on ACE-is/ARBs?
<30% is acceptable
What is normal rate of GFR decline after 40?
1ml/min/year after 40
CKD management (3b,4)
ongoing risk factor management
non-glomerular functions start to be relevant (iron-erythropoietin balance, calcium-phosphate balance)
tubular function can start to decline (low potassium diet, oral bicarbonate)
Complications of CKD
anaemia of CKD
mineral bone disorder of CKD
salt and water, acid-base disorders
uraemia
disease-specific complications
When should EPO replacement be considered in CKD?
if circulating iron stores are well replaced (ferritin 200-500, TFsat >20%) and Hb still low
EPO side effect
hypertension
What happens to phosphate in CKD? What effects does this have?
hyperphosphataemia
tubular function declines, phosphate builds up
high phosphate lowers calcium
parathyroid responds to low calcium –> 2ndry hyperparathyroidism
eventually 3rdry parathyroidism
Uraemia symptoms
GI disturbances
uraemic encephalopathy
pericarditis
leg cramps
restless legs
mood and sleep disturbance
gout
fatigue, lethargy
CKD management (5)
prepare for RRT
close monitoring of progression
may need fluid ration - can start to get problems with salt and water
What are the options for renal replacement therapy?
haemodialysis
peritoneal dialysis
transplantation (cadaveric waiting list/planned living donor)
How can you help to preserve veins in haemodialysis/end-stage renal failure patients?
no bloods/cannulae from elbow to wrist
avoid subclavian lines if possible
never use HD line or fistula for bloods/access
Dialysis drawbacks
only replace glomerulotubular functions of kidney and incompletely at that
returns you to GFR of ~15
poor at clearing phosphate
not a great quality of life
When to start dialysis in CKD?
creatinine stops being useful measure in CKD 5
guided by sx or intractable biochemistry:
- unmanageable salt-water/potassium
- nausea, vomiting, weight loss, protein malnutrition
- uraemic encephalopathy
When should dialysis not be started in CKD?
conservative management is appropriate for many frail elderly/unwell patients
symptom management:
- low protein diet
- fluid rationing
- antihistamines for pruritis
- antiemetics for nausea
Stage 1 CKD criteria
eGFR>90 but other tests have detected signs of kidney damage
Stage 2 CKD criteria
eGFR 60-89
and other signs of kidney damage
Stage 3a CKD criteria
eGFR 45-59
Stage 3b CKD criteria
eGFR 30-44
Stage 4 CKD criteria
eGFR 15-29
Stage 5 CKD criteria
eGFR <15
