CKD Flashcards
consequence of impaired kidney func
concept of CKD
what does CKD mean for patient?
renal function: 3 functions of the kidneys
- Homeostasis; regulates and maintains.
- > elimination of waste
- > water homeostasis
- > acid base homeostasis; need to pass enough H+ ions to prevent acidosis
- > electrolyte homeostasis
- > BP control
- Excretion of drugs and drug metabolites
- Metabolic/ Endocrine -> synthesis of hormones
what 3 hormones synthesised in kidney?
Vitamin D, Erythipoietin, Renin
what electrolytes does kidney control (homeostasis)?
K, Phosphate, Ca
How would you measure kidney function?
- what influences this?
serum creatinine (traditional measure) - influenced by gender, ethnicity, age, body mass, diet, excercise
relationship on graph between plasma conc and GFR?
- as kidney function declines, the creatinine levels increase (GFR increases)
- not sensitive to small changes
- non-linear relationship to kidney function
- doesn’t take long-term changes into account
How would you estimate the GFR?
- calculate from creatinine, age, gender, ethnicity
- better reflection of kidney function
- best measure for use in stable renal function
Is CKD irreversible or reversible?
irreversible and tends to progress
Stages of CKD?
CKD 1-5
CKD 5- worst, shows kidney failure of levels of 0-15 eGFR
CKD 4- Severe decrease in GFR ; 15-29; feeling tired and insulin doses and drug tablets
CKD 3- moderate CKD; 30-59
CKD2- kidney damage but mild; 60-89
CKD 1- kidney damage but normal GFR; >90
What occurs with CKD 5?
- end stage renal failure
- insufficient renal function to sustain life/health
- death
- there are renal replacement therapies are essential to prevent progression of kidney failure
3 possible treatments for CKD5?
end stage renal failure
- > haemodialysis
- > peritoneal dialysis
- > kidney transplantation
Who has CKD?
- common
- most of it unrecognised
- diabetes and renovascular disease lead to CKD and most common
- more common with older age
What are the risk factors for CKD?
- increased age
- hypertension (highest risk)
- diabetes
- smoking
- poor education
- drugs (NSAIDs)
6 possible Causes of CKD
- systemic diseases; diabetes, hypertension, atherosclerotic disease !!!
- immune mediated diseases; IPA nephropathy
- infectious diseases; HIV, HBV, HCV, TB
- genetic diseases; polycystic kidneys
- arterial disease; atherosclerosis
- obstruction; tumours, stones, fibrosis
With chronic glomerulonephritis, what happens to the glomeruli and tubules?
sclerosed glomeruli and atrophied tubules
What is the pathology of CKD? 3 steps
- thickening of BM; cap walls become weak, bleed and leak protein; slow blood flow
- mesangial expansion
- > hyperglycaemia stimulates increased matrix production by mesengial cells
- > stimulation of TGF-beta release
- glomerulosclerosis
- > due to intraglomerular hypertension or ischaemic damage
- high levels of sugarcane also make vessels to become narrow and clogged
Explain the vascular disease- renal artery stenosis
- low blood flow
- consequence of poor diet and diabetes
- both or one of the arteries leading to the kidneys becomes narrowed
- cant use an ACE inhibitor
- we want to constrict the afferent arterial to maintain BP and glomerular pressure
List the complications of CKD
- anaemia
- hypertension
- disturbed calcium
- CVD
- Bone disease
- immune suppression
- bleeding tendency
- treatment complications
4 types of obstructions that may occur?
stones
benign prostate
tumours: intrinsic/ extrinsic
fibrosis: narrow blood vessels
obstructio may cause hydronephrosis, what is it?
enlargement + swelling of kidney as build up of urine
why is anaemia a complication of CKD
lack of erythrop. production, loss of Fe absorption -> Fe deficiency
hyeprtension in CKD caused by result of?
RAAS system inactivation problem-
if not able to pass fluids properly -> urine poorly func kidneys = inc BP
What does the failure of fluid homeostasis lead to? (2)
inability to concentrate urine
- > loss of diurnal rhythm of urine excretion
- > limited rate of water excretion
- osmotic diuresis of surviving glomeruli
inability to excrete water load
- > dilutational hyponatraemia
- > oedema
- > hypertension
What is the treatment for fluid overload?
- diuretics (remove as much urine as possible, using working parts of kidney)
- salt restriction
- fluid restriction
if doesnt work then dialysis and transplant
What do electrolytes such as sodium do and cause?
- loss of nephrons reduces ability to excrete salt and water
- major cause of hypertension and fluid overload; damage to vessels and blood flow- heart struggles to pump blood around, enlarged
- sodium must be within normal range
- high or low sodium leads to confusion, fits, coma
What do electrolytes such as potassium do and cause?
- enormous functional reserve to excrete potassium
- severe hyperkalaemia when GFR <10ml/min
- due to:
- > excessive load
- > interference with potassium excretion; acidosis with volume contraction and diabetic nephropathy
What ECG changes are seen with hyperkalaemia?
- tall T waves
- long QRS interval
- long PR interval
- cardiac arrest
-> alterations in membrane excitability
what is the treatment to prevent hyperkalaemia and hypernatraemia?
- salt restriction
- K+restriction
- dialysis and transplants if all else fails; drugs that act as K+ binders (less effective than insulin dextrose) - bring K+ back into cells. dont fix but help manage hyperkal, risk of arrhythmias
whats meds should be stopped when trying to prevent hyperkalaemia and hypernatraemia?
ACEi and ARBS: increase K+.
dont remove K+ well: aldosterone antagonists.
K sparing diuretics: spironolactone
State the equation for the carbonic acid buffer system and how this system works
CO2 + H20 - H2CO3 - H+ + HCO3-
- increasing H+ due to failure to excrete acid leads to increase in HCO3- and so increase in CO2 and H20
the CO2 is removed by lungs to maintain pH
there is an accumulation of H+ acid
What are the effects of acidosis?
- increased respiratory drive; breathless
- chest pain
- confusion
- bone pain
- demineralisation of bone
What is the treatment for metabolic acidosis?
- sodium bicarbonate
IV/ caps/ tabs
OR… dialysis/transplant if fails
What do Vitamin D, renin and erythropoietin control?
Vitamin D- Ca metabolism
Erythropoietin- Hb production
Renin- control of blood production
what is hypertension? and what mechanisms occur?
- high BP
- accelerates decline of kidney function
- contributes to CV risk
mechanisms:
- sodium retention
- volume expansion
- RAS activation
- sympathetic nervous system activity
- endothelial dysfunction
What is the treatment for hypertension?
- salt restriction
- diuretics
- RAS blockade
- other antihypertensive med
What happens when excretory function reaches failure?
accumulation of toxic waste products
- > creatinine rises only after significant renal damage
- > nitrogenous waste retention occurs
- > urate retention then occurs
- > phosphate retention then will occur -> skin itching
what is the treatment for uraemia?
dialysis or transplantation
why is protein restriction not used as treatment for uraemia?
due to it causing malnutrition which weakens the individual further
what happens when drugs fail to be excreted?
- many drugs are usually excreted by the kidney but the metabolism of these drugs will be impaired by renal failure
- toxicity due to accumulation of the drug will lead to:
insulin-> hypoglycaemia opiates-> narcosis anitbiotics-> encephalopathy sedatives-> respiratory arrest digoxin-> cardiac arrythmias
treatment to prevent drug toxicity?
modify presc according to renal function
- adjust the dose when needed
- adjust the frequency when and if needed
Genatmicin etc. dec doses to prevent toxicity
explain the purpose of dialysis?
dialysis removes the waste products and excess body fluids from the individual when the kidneys are failing to excrete these substances
explain what is narcosis
it is when a patient is in a state of unconsciousness or arrested activity due to narcotics or chemicals in the body
What three diseases show the greatest risk of harm when a patient has all of them?
CKD, CVD, diabetes
Why does CKD progress?
major modifiable risk factors
- > uncontrolled underlying disease
- > hypertension
- > proteinuria
- > smoking
What is the treatment for the CKD?
- control underlying diseases
- treat hypertension
- ACEi/ARB
- stop smoking
4 main things that may cause harm in CKD patients?
K+ !!!! ALWAYS CHECK
acid
fluid
confusion/urea
CKD is the progressive loss of?
excretory renal function
- water
- electrolytes
- acid
- metabolites
- drugs
secretory renal function
- EPO
- Vit D
treatment of CKD (5)?
- if possible treat underling cause
- healthy lifestyle
- stop smoking
- good BP control
- reduce protein excretion
