Chronic kidney disease Flashcards
What is chronic kidney disease?
Reduced GFR and/or evidence of kidney damage over a long period of time
How is GFR assessed?
24 hour urine collection (creatinine clearance)
eGFR (serum creatinine, age, sex & race)
Creatinine is a product of the breakdown of what?
Muscle
What are the drawbacks of eGFR?
Not sensitive over 60ml/min
Over estimates if muscle mass low
Under estimates if muscle mass high
Only valid is serum creatinine is stable (not acute illness)
When might we want to directly measure GFR with nuclear medicine?
Screening for kidney donation
Very high or low muscle mass
Describe the stages of CKD
Stage 1 - GFR >90 with evidence of kidney damage
Stage 2 - GFR 60-90 with evidence of kidney damage
Stage 3 - GFR 30-60 (A- 45-60 B- 30-44)
Stage 4 - GFR 15-30
Stage 5 - GFR
What do we mean by “evidence of kidney damage”?
Proteinuria
Haematuria
Abnormal imaging
How common in CKD?
Mild CKD is fairly common especially in the elderly
Why does CKD staging matter if most people don’t progress to severe disease?
Must identify those at risk of progression through the stages
Increased CVS risk is important in patient health
Who is likely to progress to severe CKD? Why?
Those with proteinuria (more protein - faster progression) Younger patients (longer to progress)
What are the common causes of CKD?
Diabetes mellitus Hypertension Vascular disease (renal artery stenosis, large vessel disease, etc) Chronic glomerulonephritis Reflux nephropathy Polycystic kidneys
How does CKD present?
Asymptomatic until GFR
How is CKD managed?
Slow progression
Manage CVS risk
Treat complications
Prepare for replacement therapy
How can progression of renal disease be slowed?
Reducing proteinuria - control BP with ACE/ARB +/- spironolactone
Glucose control
Smoking cessation
How do ACE/ARBs characteristically affect the kidney when they are started? What is the risk of this? How is this monitored?
Initially reduce GFR –> risk of hyperkalaemia
Blood test a week or so post starting drugs
How might you reduce CVS risk in patients with CKD?
Smoking cessation
BP control
Statins (stage 4)
What are the complications of CKD?
Anaemia
Bone disease
Why is anaemia a complication of CKD?
Erythropoietin (stimulates RBC formation) production declines in CKD
If a CKD patient has anaemia what must be measured?
Iron
Vitamin B12
Folate
Can all be other causes of anaemia
How is anaemia of CKD treated?
IV iron
If iron doesn’t work weekly/fortnightly SC injection of erythropoietin
What is the target haemoglobin in CKD anaemia?
105-125 g/dl
If giving erythropoietin for CKD what else must be given?
Iron (as stores depleted)
How is vitamin D metabolised in the kidney?
Hydroxylated
What happens to vitamin D metabolism in CKD?
Reduced calcium absorption –> secondary hyperparathyroidism
Serum phosphate raised (advanced disease) –> increases PTH secretion
Hyperplasia of all parathyroid glands occurs in CKD. T/F
True
Explain tertiary hyperparathyroidism and its main complication
Autonomous production of PTH even when serum calcium normal –> hypercalcaemia
What is the sequelae of CKD bone disease?
Severe bone disease (pain & imaging changes) uncommon
High phosphate and calcium –> calcification of vessels and heart valves
How is bone disease in relation to CKD managed?
Alfacalcidol (hydroxylated vit D) Adjustment of phosphate intake in diet Phosphate binders (bind to phosphate in gut to reduce absorption)
Name three phosphate binders
Calcium carbonate
Calcium acetate
Sevelamer
Name three types of renal replacement therapy
Haemodialysis
Peritoneal dialysis
Kidney transplant
What is the best form of dialysis access? How long does it take to mature?
Arteriovenous fistula
6 weeks
Why is an operation needed in peritoneal dialysis? How long does it take to mature?
Insertion of cannula
1-2 weeks
How long must people be able to live to be considered for a transplant?
At least 5 years
When is conservative management indicated over dialysis?
Older patients with multiple co-morbidities
Symptom control still given
