Chronic Kidney Disease Flashcards
What are the 3 general functions of the kidney?
homeostasis
metabolic/endocrine
excretion of drugs and drug metabolites
What are the metabolic/endocrine functions of the kidneys?
Vitamin D
EPO
RAAS
What are the homeostatic functions of the kidneys?
elimination of waste water volume electrolytes acid-base blood pressure
How is kidney function measured?
traditionally via serum creatinine
What is serum creatinine influenced by?
Is it sensitive to small changes in function?
sex, ethnicity, age, body mass, diet, exercise
No
What is eGFR?
calculated from creatine, age, sex, ethnicity,
better reflection of kidney function
best measure for use in stable renal function
What is the definition of chronic kidney disease (CKD)?
irreveserrible and progress kidney disease
What are the stages of CKD, defined by eGFR?
Stage 1 >90 Stage 2 >60 Stage 3 >25 Stage 4 >15 Stage 5 <15
What is the prognosis of Stage 5 CKD without treatments?
What are the treatments?
Insufficient renal function to sustain life/health
–> death
haemodialysis, peritoneal dialysis, kidney transplantation
What patients are likely to have CKD?
diabetes, hypertension, multiple drugs especially NSAIDs, elderly
- other causes are genetic e.g. polycystic kidney disease or rare e.g. vasculitis or both
How is CKD related to socio-economic status?
mean GFR decreases with increased deprivation
What are the risk factors associated with CKD?
age, hypertension, diabetes, smoking and poor education
black and into-asian populations
What are the 6 classifications of CKD causes?
- systemic diseases - diabetes, hypertension
- immune mediated diseases - membranous nephropathy, igA nephropathy
- infectious diseases - HIV, HBV, HCV, TB
- genetic diseases - polycystic kidneys, cystinosis
- arterial diseases - atherosclerosis
- obstruction - tumours, stones, fibrosis
What are the histological signs of CKD?
chronic glomerulorephritis
sclerosed glomeruli, atrophied tubules, replaced by scar tissue
What is the pathology of diabetic nephropathy?
- thickening of basement membrane
- mesangial expansion: hyperglycaemia stimulates increased metric production by mesangial cells, stimulation of TGF-b release
- glomerulosclerosis: due to intraglomerular hypertension or ischaemic damage
What are 9 complications of chronic kidney disease?
anaemia hypertension disturbed calcium/phosphate homeostasis cardiovascular disease bone disease abnormal handling of drugs immune suppression bleeding tendency complications of treatment
What are the two aspects to failure of fluid homeostasis and what does this lead to?
Inability to concentrate urine - loss of diurnal rhythm of urine excretion - osmotic diuresis of surviving glomeruli - limited rate of water excretion Inability to excrete water load - dilution hyponatraemia - oedema - hypertension
What is the treatment for fluid overload?
diuretics
salt restriction
fluid restriction
dialysis
transplantation
How is sodium affected and what are the consequences of this?
- loss of nephrons reduces ability to excrete salt and water
- major cause of hypertension and fluid overload
- sodium must be within normal range for normal neurological function
- high or low sodium levels leads to confusion, fits and coma (CNS dysfunction)
How is potassium affected and what are the consequences of this?
- enormous functional reserve to excrete potassium
- severe hyperkalaemia when GFR <10ml/min
Due to: - excessive load
- interference with potassium excretion
- acidosis with volume contraction
- diabetic nephropathy
What are the consequences of hyperkalaemia?
How does the ECG trace change?
- alterations in membrane excitability
- cardiac arrhythmias
ECG changes - tall T waves
- long QRS interval
- long PR interval
- cardiac arrest
What is the treatment to prevent hyperkalaemia and hypernatraemia?
salt restricition
potassium restriction
dialysis
tranplant
What are the symptoms of metabolic acidosis?
increased respiratory drive --> SOB chest pain confusion bone pain demineralisation of bone
What is the treatment for metabolic acidosis?
sodium bicarbonate
dialysis/transplant
What 3 hormones are produced in the kidney and what are they responsible for?
vitamin D - calcium metabolism
erythropoietin - RBC production
renin - blood pressure control
When is PTH released?
What are its effects?
Low Ca2+
PTH release
activates Vit D in kidneys
increases bone resorption
What classical cases are there for hyperparathyroidism and hyperphosphataemia?
brown tumours
rugger jersey spine
both due to demineralisation of bone
What is ectopic calcification?
calcium deposits in soft tissue due to high PTH levels in kidney disease
What treatment prevents bone disease and ectopic calcification?
active Vit D replacement
phosphate restriction
phosphate binders
calcimimetics
parathyroidectomy
What is the impact of renal anaemia?
impaired quality of life - reduced exercise capacity - impaired cognition transfusion requirement - iron overload - blood-borne infection risk of left ventricular hypertrophy increased CV disease in patients with CKD and anaemia vs those with CKD without anaemia
What is the treatment more renal anaemia?
recombinant EPO
What are the mechanisms for renal hypertension?
sodium retention volume expansion RAS activation sympathetic NS activity endothelial dysfunction
What are the consequences of hypertension?
accelerates decline of kidney function
contributes to cardiovascular risk (stroke, MI, heart failure)
What is the treatment for hypertension in CKD?
salt restriction
diuretics
RAS blockade
other antihypertensives
What are the consequences of failure in excretory function?
accumulation of toxic waste products
- creatinine rises only after significant renal damage
- retention of nitrogenous waste
- retention of urate
- retention of phosphate
What is the treatment for uraemia?
dialysis or transplantation
why not protein restriction? –> malnutrition
What are the consequences of the accumulation of the following?
- insulin
- opiates
- antibiotics
- sedatives
- digoxin
- hypoglycaemia
- confusion/narcosis
- affect brain function, encephalopathy
- respiratory arrests
- cardiac glycoside used to treat AF –> causes arrythmias
What is the treatment to prevent drug toxicity?
modify prescription
change drug type/dose
What are the major modifiable risk factors in CKD?
uncontrolled underlying disease
hypertension
proteinuria
smoking
