10 CKD Flashcards
Why is serum creatinine not used to measure kidney function?
because it does not respond to small changes in kidney function
doesn’t offer a good comparison between people
Why is eGFR used to measure kidney function?
It is the best measure in stable kidney function
Can be used to compare between people
What is CKD?
Chronic kidney disease
either
eGFR < 60ml/minute/1.73m2
or
kidney damage…
must be present for at least 3 months
What is the eGFR range for stage 1?
kidney damage with normal GFR
at least 90
What is the eGFR range for stage 2?
mild kidney damage
60-89
What is the eGFR range for stage 3?
moderate kidney damage
30-59
What is the eGFR range for stage 4?
severe damage
15-29
What is the eGFR range for stage 5?
kidney failure
less than 15
How might stage 5 CKD be treated?
haemodialysis
peritoneal dialysis
transplant
What are the groups of causes of CKD?
Systemic diseases immune mediated diseases infectious diseases genetic diseases arterial diseases obstruction
What sorts of systemic diseases might cause CKD?
diabetes
hypertension
What sorts of immune mediated diseases might cause CKD?
membranous nephropathy
IgA nephropathy
What sorts of infectious diseases might cause CKD?
HIV
HBV
HCV
TB
What sorts of genetic diseases might cause CKD?
Polycystic kidneys
cystinosis
what sort of arterial diseases might cause CKD/?
atherosclerosis
What sorts of obstructions might cause CKD?
tumours
stones
fibrosis
What would you see down the microscope in chronic glomerulonephritis?
scleroses glomeruli
atrophied tubules
What proportion of those with diabetes experience renal disease?
40%
What is the pathology of nephropathy?
BM thickens
mesangial expansion
glomerulosclerosis
What facilitates mesangial expansion?
hyperglycaemia stimulates increased matrix production by mesangial cells
stimulation of TGF-beta release
What facilitates glomerulosclerosis?
intraglomerular hypertension or ischaemic damage
What might cause vascular disease?
renal artery stenosis stones benign prostate tumours fibrosis
How can CKD lead to a failure of fluid homeostasis?
inability to concentrate urine (early)
and then, an inability to excrete water load (dilution hyponatraemia, oedema hypertension)
How might we treat fluid overload?
diuretic
decrease fluid intake
less salt
if all else fails dialysis or transplant
How does nephropathy cause hypertension?
inability to excrete salt and water
What can sodium inbalance lead to?
confusion, fits, coma
How can interference with Potassium excretion cause very low GFR?
acidosis with volume contraction
diabetic nephropathy
What effect does hyperkalaemia have on ECGs?
What might this cause?
tall T waves
Long QRS interval
long PR interval
Cardiac arrest
What treatment is there for hyperkalaemia and hypernatraemia?
eat fewer bananas and crisps
What is the basis of the carbonic acid buffer system?
a failure to secrete acid pushes the PoE to the right, meaning more CO2 has to be removed by the lungs to balance pH
What are the symptoms of metabolic acidosis?
breathlessness
chest pain
confusion
bone pain (demineralisation)
How would you treat metabolic acidosis?
sodium bicarbonate
otherwise dialysis/transplant
What effect does renal failure have on calcium homeostasis?
less GI calcium absorption
hyperparathyroidism
hyperphosphataemia
ectopic clacification
How might you treat the effects of renal failure on calcium homeostasis?
active form of Vit D (we can’t activate it)
calcium supplements
phosphate restriction
phosphate binders
if fails parathyroidectomy
How would you treat renal anaemia?
recombinant Epo
What are the mechanisms of renal hypertension?
sodium retention volume expansion RAS activation Sympathetic NS activity endothelial dysfunction
causes over-production of renin, not under-production
How would you treat renal hypertension?
less sodium and water
take BP tablets
diuretic
RAS blockade
What happens in a failure of excretory function?
creatinine rise (only after significant damage)
retention of nitrogenous waste
retention of urate
retention of phosphate
How would you treat Uraemia?
dialysis or transplant
you could restrict protein intake although this cause malnourishment
What might happen if the kidney fails to excrete insulin?
hypoglycaemia
What might happen if the kidney fails to excrete opiates?
narcosis
What might happen if the kidney fails to excrete antibiotics?
encephalopathy
What might happen if the kidney fails to excrete sedatives?
respiratory arrest
What might happen if the kidney fails to excrete digoxin?
cardiac arrhythmia
How would you treat drug toxicity in renal disease?
lower the dose!
Why does CKD progress?
uncontrolled underlying disease
hypertension
proteinuria
smoking
How do you limit the progression of CKD?
treat underlying disease
stop smoking
ACEi / ARB block renin angiotensin system to stop protein leaking
What are the characteristics of hyperparathyroidism?
browns tumour
rugger jersey vertebrae
