chronic kidney disease Flashcards
Functions
What is the function of the kidneys
Homeostasis ones
Homeostasis ones
* Water/ fluid
* Electrolytes
* Acid-Base
* Blood pressure
* Elimination of waste
* Excretion of drugs & drug metabolites
Functions
What are the endocrine/metabolic functions of the kidneys
synthesis of hormones
* Vitamin D
* Erythropoietin
* Renin
Assessing kidney function in clinical practice
what is the gold standard of kidney functioning measurements
Exogenous filtration markers
* E.g. inulin, 51Cr-EDTA
* Require injection or infusion
* Require multiple sample collection, so it’s quite intrsuive
Endogenous Filtration Markers
* E.g. urinary clearance of creatinine
* Requires accurate timed urine collection
-matched serum sample
- need time and mutiple samples again
only use methods when there is uncertentity about kidney functions, not used in clincial practise as much
How do we measure kidney function in clinical practise
- Serum creatinine
- use it to estimate GFR
- not a linear relationships
- for example when kidney function is very good will lead to big chnages in egfr
- when kidney function is low big changes in creatnine shows up as small changes in egfr
creatnine breakdown from mucsles
What factors can affect creatanine
the non renal ones
creatnine: breakdown of muscles, muscle mass effects it
Non-renal determinants of serum creatinine include
- Age
- Sex
- Ethnicity
- Body habitus
- Diet
ethnicty has been dropped from the equations
For example a 20 year old with 100 serum cretanien has the egfr of 80 compared to 80 year old female with the same creatanine has 40 eGFR
Proteinuria
What do injured, inflammed glomeurli/kidneys leak
Proteins
Proteinuria
How do we quantify proteinuria
measure total amount: proudce 24hr urine sample, (and you’ll see the amount of protein proudced over 24 hours)
Measure ratio to reference analtye
we use an albumin to creatinine ratio. to assess how much protein would be in someones urine if done over 24 hours
CKD
What is CKD
defined as abnormalties of kidney structure and function that has been there for over 3 months
CKD
What if someone has normal kidney function, can they still have CKD
Yes
if they have protein in urine, or blood, or if they have scarring (seen on ultrasound)
some of these can point to glomeruli
Stage 1
What happens in stage 1 of CKD
when someone’s eGFR is over 90 ml per minute (that means they have normal function)
*if they have proteinuria, or blood then they have CKD stage 1
normal is about 120 ml per minute
btw when eGFR increases your confiedence decreases
Stage 2
What is stage 2 classified as
eGFR is between 60-90 ml per minute
as we get older, eGFR reduces anyway
To call it CKD you need to have something
Stage 3
What is Stage 3 CKD
30-60ml per minute (eGFR)
at that point you have CKD with reduced kidney function (mild-moderate)
Stage 3
What is the difference between stage 3a and b
stage 3a: 45-59
stage 3b: 44-30 (see the complications of CKD)
stage 4
What is stage 4
Severe kidney impairement
eGFR less than 30
What happens in stage 5
eGFR is less than 15
atp you start dialysis, or do transplant
CKD
People can progress through the stages of CKD
what does this mean for the kidneys
it means there’s an irreverisble loss of nephrons
- so loss of renal filtration function
Stage 5
What are the types of renal replacment therapies
Haemodialysis
Peritoneal dialysis
Kidney transplantation
CKD
How else can we classify CKD
the amount of proteinuria present
A1 - normal (no proteinuria)
A2 -significant proteinuria
A3 - severe proteinuria (about half a gram of protein a day)
A3: either have signgficant CKD, or an inflamtorty disease of kidney
Proteinuria
Why is it important to know if someone has proteinuria
- can help determine the cause
- risk of death
can end up doing a biposy to determine cause
Renal disease
What are the imporant risk factors are there
population wise, medical disease, social factors, lifestyle
- Age
- Social deprivation
- Black or South Asian ethnicity
- Hypertension
- Diabetes
- Smoking
Causes of Chronic Kidney Disease
What are the common causes of CKD
- Diabetes
- Hypertension
- Genetic
- Glomerulonephritis
- other reasons
Diabetic nephropathy
What is Diabetic nephropathy characterised by
like what will the person present with
proteinuria
What is the pathology of diabetic nephropathy
thickening of basement membrane
* mesangial expansion
* hyperglycaemia stimulates increased matrix production
by mesangial cells
* stimulation of TGF-b release (causes fibrosis)
* glomerulosclerosis
* due to intraglomerular hypertension or ischaemic damage
* essentially lose filtration power
hyperglycemria: increase filtration due to dilation of afferent ateriole, but you get increase glomerular pressure, causes damage with time
Diabetic Nephropathy
True or flase
there is a correlation between diabetic retinopathy and Diabetic
Nephropathy
True
What is the natural history of diabetic
nephropathy
cba check the lecture slides
Diabetic nephropathy
How do we treat diabetic nephropathy
Treat underlying disease
* Good blood sugar control (diet & medications)
Reduce proteinuria
* use ACE inhibition & SGLT2 inhibitor
Limit cardiovascular risk
* Control blood pressure
* Treat hyperlipidaemia
*Stop smoking, etc.
Hypertensive nephropathy
What is hypertensive nephropathy
When yo get glomerular hypertension
intermial thickiening of blood vessles
* leads to narrowing of blood vessels
* and glomerular ischaemia
* end up with proegessive CKD and firbosis due to hypertension
Glomerular hypertension causes injury and sclerosis over prolonged
periods
Renal atery stenosis can cause CKD
what is it?
find answer
Glomerulonephritis
What is glomerulonephritis
immune-mediated injury to glomeruli
Glomerulonephritis
What can cause glomerulonephritis
- IgA nephropathy (most common one)
- maybe associated with infection (e.g streptococcus, HIV)
- can be part of systemic disease process (e.g. systemic lupus erythematosus, vasculitis)
Glomerulonephritis
How do we diagnose glomerulonephritis
usually there may be blood and or protein in urine
and they don’t have oher reaosns to cause this
Autosomal dominant polycystic kidneys
What is polycystic kidneys
when cyst on the kidneys
the cysts replace kidney tissue so reduces function
can cause pain
- if they repture (cause haemturia)
Polystsic kidneys
When can someone get autosmal domianat polycystic kidneys and when can someone get autosomal reccessive polycystic kidneys
Reccessive: manifest in childhood
Dominant: adulthood
Causes
What else can cause CKD not mentioned
- Medications (NSAIDs, chemotherapy, others)
- Recurrent urinary tract infection
- Urinary outflow obstruction (bladder obstruction, cause of that bengin hyperplastic prostate)
- Trauma
- Interstitial nephritis
- Recurrent/ persistent acute kidney injury
Consequences of impaired kidney function
What are the complications related to CKD
- increased mortality (3)
- cardiovascular disease & hypertension (3)
- Altered drug handling (3)
- Anaemia(4)
- Vitamin D, phosphate & parathyroid disturbance(4)
- Acidosis(4)
- Hyperkalaemia(4)
- Fluid retention (5)
- Uraemia (5)
brackets allude to stages
CVS risks in CKD
What are the tradional risks factors of CVS in CKD
- Diabetes
- Hypertension
- Dyslipidaemia
- Smoking
Dyslipidaemia & Smoking share some risk factors
Cardiovascular risk in CKD
What are the non classical risks
- Endothelial dysfunction
- Inflammation
- Oxidative stress
- Catabolic state
how they think CKD affects CVS mortality
Cardiovascular risk in CKD
What are the CKD related risks
- Fluid retention
- Anaemia
- Hyperparathyroidism
- Vascular calcification
Why is hypertension important when it comes to ckd
- can accelerates decrease of kidney function
- Can contribute to cardiovascular risk
- (stroke, myocardial infarct,
heart failure)
Hypertension
What are the mechanims that hypertension can contribute to CKD
like who can HT cause CKD
- Sodium retention
- Volume expansion
- Renin-angiotensin-system activation
- Sympathetic nervous system activation
- Endothelial dysfunction
How do we manage hypertension
- Moderate salt intake
- Renin-angiotensin system blockade
- diuretics
- Other anti-hypertensive
medications
PTH
Parathyroid hormone mechanism
and how does this affect the kidney
- Low calcium
- stimulates parathyroid
- stimulates PTH
- PTH acts on kidney to stimulate kidney to activate vitamin D
- VD acts on gut to increase calcium absoption
- increases serum calcium
- increased calcium serum which acts on parathyroid to stop PTH
if blocked
* there wil be cnstant sectreiton of PTH
* bone resoption to increase calcium
* can end up with 2nd or 3rd hyperparathyroodism
Mineral bone disease
How do we manage mineral bone disease?
- Correct Vitamin D deficiency if present (colecalciferol, ergocalciferol)
- Supplement activated Vitamin D (alfacalcidol, calcitriol)
- Control high phosphate levels (dietary restriction, phosphate binders)
- Offer calcimimetics (use drugs to stop producing PTH)
- Last resort: parathyroidectomy
Anaemia
How can anaemia impact people’s lives
Impaired quality of life
* reduced exercise capacity
* impaired cognition
* increased risk of Left Ventricular
Hypertrophy
* increased CV disease in patients with CKD and anaemia compared to those with CKD without anaemia
Anaemia
How do we treat CKD with anaemia
- Correct iron deficiency if present
- Recombinant erythropoietin
don’t give blood tranfusion all the time because of iron overload,
also don’t want to sensitise patients if they are going to recieve transplant
Bicarbonate -carbonic acid buffer
What happens during with the bicarbonate - carbonic acid buffer system during CKD
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3 -
There is adFailure to excrete acid (H) in CKD
so increase ↑ H+ -→↑H+.HCO3 → ↑CO2 +↑H2O means increased co2 and water
This is removed by lungs to maintain pH
Metabolic Acidosis
What is the impact of Metabolic Acidosis
Impact
* Increased respiratory rate
* Acute – life-threatening metabolic dysfunction
* Chronic - loss of bone and muscle mass
How do we manage metabolic acidosis
Management
* Sodium bicarbonate
* Dialysis (or transplantation)
Hyperkalaemia
True or false
the body has little reserve of pottassium
False
it has a large functional reserve to excrete potassium
with severe hyperkalaemia happens when GFR decrease 10ml/min
Hyperkalaemia
Why do people with hyperkalemia
Excessive load
* Interferance with potassium excretion
* acidosis with volume contraction
* diabetic nephropathy
Hyperkalaemia
What can happen when pottassium goes outside normal range
life threatning
you can get
- Alterations in membrane excitability
- cardiac arrythmias
Can see ECG changes
* Tall T waves
* Long QRS interval
* Long PR interval
* Cardiac arrest
hyperkalaemia
How do we manage hyperkalaemia
- restricting dietry pottassium
- Potassium binders (not used in CKD in clincial practise as much)
- dialysis
Sodium and fluid retention
what happens when there is failure of fluid retention
- can’t conc urine
- inablity to excrete water load (so can have dilutional hyponatraemia, oedma, hypertension)
Sodium & fluid retention
What can high levels of sodium lead to
Confusion, fits and coma
for normal neurological function, sodium needs to be in normal rnage
Sodium & fluid retention
What can the loss of nephrons reduce
ablity to excrete salt and water
which can cause hypertension and fluid overload
Fluid overload
How do we manage fluid overload?
Intake (dietry)
* Reducing/restric salt
* Reducing/restrict Fluid
Output
* Diuretics
* Dialysis or transplant
Uraemai
What is it
When urea is high
aren’t clearing toxins that well
may mainain nitrogenous waste, and things like urate, phosphate TNF alpha
can affect peoples brains
What are the consequences of uraemia
life threatning ones
Encephalopathy
Pericarditis
Pericarditis: inflammation of oericardium, can bleed into it, bled into tight space which can compress the heart, and you can get cardiac tampondae
Encephalopathy: twiching because uranmic (indication to start dialysis)
Drugs
Drugs are metabolsied and excreted by the kidneys
What is the consequnce of impaired renal clearance
Can get toxicity from high drug levels
and
prolonged action (since they aren’t being cleared)
Drugs
What adverse effects can opiates accumliating cause
Reduced consciousness & respiratory arrest
Drugs
What adverse effects can antoboitics not being cleared cause
Encephalopathy
can affect brain function
Drugs
What adverse effects can lithium accumliating cause
Vomiting, tremors, confusion
Drugs
What adverse effects can digoxin accumliating cause
arrthymias
