chronic kidney disease

what is chronic kidney disease (CKD)

slowly-developing progressive and irreversible loss in kidney function that can occur over months or years

difference between CKD and AKD (acute kidney disease)

AKD is reversible whereas CKD involves irreversible damage

in CKD, reduction of kidney function must be present for over 3 months

what are the causes/factors that increase risk of CKD

• increasing age - 65+

• family history

• african-caribbean or south asian ethnicity

• kidney infections - less common

• inflammation (glomerulonephritis) - less common

• urinary blockages

• prolonged use of certain meds like NSAIDs

• long term conditions like diabetes

• heart disease

• obesity (BMI>30)

• high cholesterol/ high fat diet

• high blood pressure

symptoms of CKD

• high blood pressure

• changes in urinary frequency e.g. particularly at night

• changes in appearance of urine

• leg/ankle/hand oedema

• tiredness/lack of energy

• erectile dysfunction

• weight loss/poor appetite

• muscle cramps

• headaches

• shortness of breath

• nausea and vomiting

• metabolic taste in mouth

as the kidney function progressively declines, what happens to:

• symptoms

• size of kidneys

• symptoms worsen gradually

• shrink in size the more damaged they become

how is CKD classified

5 stages:

• stage 1 = mildest

• stage 5 = severe with poor life expentency if left untreated

  • end-stage kidney disease

describe the GFR in early stage kidney failure

GFR may be normal or higher:

• >90 for stage 1

• 60-89 for stage 2

how might early kidney failure develop

due to changes in blood flow to parts of kidney caused by local damage or blockages (e.g. kidney stones) could affect renal function

true or false: in early stage kidney failure, there is no obvious symptoms and blood/urine tests can be normal

true

when looking at blood/urine tests/kidney function tests, what indicates middle stage kidney failure

• abnormal levels of waste products in blood

• GFR may be decreased → 30-59 for stage 3

what symptoms does the patient experience with middle stage kidney failure

• increase in urine freq

• increased BP

• weakness, fatigue and shortness of breath

in middle stage kidney failure, what increases the risk of cardiovascular disease

increased BP

why might patient with middle stage kidney failure feel weak, tired and shortness of breath

because anaemia may develop as erythropoetic function of kidney decreases

what is the GFR in later stage kidney failure

15-29 for stage 4

what are the symptoms in later stage kidney failure

• increased BP

• increased urination freq

• increased tiredness/reduced appetite

what is the GFR for end-stage kidney disease

GFR < 15 for stage 5

true or false: in end-stage kidney disease, kidney function is reduced to 20-25% of its capacity

false - reduced to 10-15%

what happens in end-stage kidney disease

• waste products are not adequately filtered

• excess water not removed

what treatment options can be given to end-stage kidney disease

• dialysis

• kidney transplant

how is CKD diagnosed

by carrying out routine screening of patient with recognised risk of developing kidney problems

creatinine blood tests are used to identify CKD - what is creatinine

normal waste product produced from creatine generated from muscle metabolism

why does higher blood levels of creatinine indicate a lower GFR

because normally in a healthy functioning kidney, creatinine is transported through bloodstream to kidneys where most of it is filtered out and disposed of it in urine

what is the normal blood creatinine levels in:

• males

• females

• males: 59-104 μmol/L

• females: 45-84 μmol/L

what does blood creatinine levels > 104μmol/L in males or 84μmol/L indicate

severe kidney impairment - need for dialysis

what is creatinine clearance

amount of creatinine passed in the urine over 24hrs

does low or high creatinine clearance indicate CKD

low

normal creatinine levels are 500-2000 mg/24hr

what are creatinine levels used to calculate

eGFR (mL/min)

estimate for GFR

what is the formula used to calculate eGFR

what are the types of blood/urine tests for kidney function

• urea blood and urine tests

• albumin blood and urine tests

• [high/low] blood urea indicates kidney dysfunction - why

• high because urea is normally excreted in the urine

what is the normal urine urea level

165-583 mmol/24hr

what is albumin

major protein synthesised by liver which makes up 55-60% of total plasma protein

importance of albumin

many hormones, drugs and other molecules are carried in the bloodstream bound to albumin from which they must be released to exert biological activity

is albumin blood levels high or low why there is renal dysfunction

low albumin blood levels because it is excreted in urine cause hypoalbuminemia

true or false: the urine albumin to creatinine ratio (ACR) is used as a kidney function marker

true

• ACR ratio < 30mg/g = abnormal or normal

• ACR > 30mg/g = abnormal or normal

• ACR ratio < 30mg/g = normal

• ACR > 30mg/g = abnormal → indicates early sign of kidney disease

why are urine dipstick tests not used anymore

urine dipstick tests are used to measure presence of protein in urine but not used due to unoptimal sensitivity and specificity

why is hyperkalaemia an indication of kidney damage

• what is it

• how can it occur

• what are the symptoms

• normal levels

• high potassium levels

• when GFR < 20-25 - kidneys have very reduced ability to excrete K+

• malaise, cardiac arrhythmias

• 3.5-5mmol/L

why is hyperphosphatemia an indication of kidney damage

• what is it

• how can it occur

• what are the symptoms

• normal levels

• high phosphate levels accumulating in blood

• due to reduced urinary phosphate excretion when GFR is decreased

• increased risk of CVD, itching

• 0.81-1.45 mmol/L

why is hypocalcaemia an indication of kidney damage

• what is it

• how can it occur

• what are the symptoms

• normal levels

• deficiency of calcium in blood

• calcitroil is active metabolite of vitamin D synthesised in kidney under control of parathyroid hormone (PTH) - this conversion is compromised when kidney function is impaired

• CKD causes increase PTH levels which results in excessive resorption of Ca2) from bones → increased risk of bone fractures

why is metabolic acidosis an indication of kidney damage

• what is it

• how can it occur

• what are the symptoms

• normal levels

• low plasma pH level < 7.35 and low HCO3- level

• due to blood accumulation of sulphates, phosphates and uric acid, decreased NH4+ from proximal tubule cells alter enzyme acitivity

• normal levels of serum bicarbonate is 22-29mmol/L

what causes iron deficiency anaemia (indication of kidney damage)

caused by reduction in renal erythropoietin synthesis

what is urine sediment abnormalities (indication of kidney damage)

urine sediments are red blood cells, cellular debris, fat and filtered proteins present in urine

these are the different imaging tests:

• renal ultrasonography

(only answer the ones about the ones in bold)

what does this screen for

• screens for kidney abnormalities, size, obstruction (stones) and tumours

(only answer the questions about the one in bold)

these are the different imaging tests:

• renal ultrasonography

• retrograde ureteroscopy

how is this performed

performed by inserting cystoscope into urethra and bladder → then injection of x-ray contrast medium through catheter into ureter and imagaging

true or false: retrograde ureteroscopy are useful for diagnosing renal stones

true

(only answer the questions about the one in bold)

these are the different imaging tests:

• renal ultrasonography

• retrograde ureteroscopy

• CT scanning - uses computer-processed x-rays

why is there an allergy issue involving CT scans

because a dye is given to patient before the CT scan - dye contains iodine so always ask patients first if they are allergic to iodine

what imaging technique can be used in patients who cannot receive I/V contrast agents (iodine)

MRI scanning - uses powerful magnets and computer-processed radio waves

(only answer the questions about the one in bold)

these are the different imaging tests:

• renal ultrasonography

• retrograde ureteroscopy

• CT scanning - uses computer-processed x-rays

• x-ray scanning

what do x-rays reveal

opaque kidney stones

(only answer the questions about the one in bold)

these are the different imaging tests:

• renal ultrasonography

• retrograde ureteroscopy

• CT scanning - uses computer-processed x-rays

• x-ray scanning

• renal radionuclide scanning

how does this work

uses MAG3 or DMSA chelated with ^99mTc (gamma emitter) to confirm renal blood flow so is used for screening for renal artery stenosis

treatment of CKD

next couple of flashcards

what conditions do patients with CKD have a higher risk of developing

atherosclerosis and cardiovascular disease e.g. heart disease like hyperlipidaemia

true or false: there is no specific medicine for CKD management - it is more focused on preventing cardiovascular events and minimising further decline in renal function stage 5

true

treatment of CKD aims to control blood pressure - how

• ACEIs e.g. ramipril, enalapril

• ARBs (angiotensin II receptor antagonists) e.g. valsartan, losartan

• monitoring serum K+ to check for hyperkalaemia

treatment of CKD aims to treat hyperlipidaemia - what med is used for this

statins e.g. atorvastatin

treatment of CKD aims to control oedema - what med is used for this

treated with loop diuretic e.g. furosemide

what is used to correct vitamin D deficiency

calcitriol replacement therapy

what can be given to reduce fatigue

treatment with i/v iron and erythropoeitin which normalises Hb

why are phosphate binders given

controls serum phosphate in CKD patients

when CKD patient reaches stage 5, renal replacement therapy is required - what does this involve

• haemodialysis or peritoneal dialysis

• renal transplant

what is haemodialysis

method whereby waste products (e.g. creatinine and urea) and free water which build up in the blood can be removed in absence of adequate kidney function

how often is haemodialysis carried out per week

3 times a week

how is haemodialysis set up

what is the main objective in haemodialysis

patients blood is pumped through dialyser and continuously fed with saline dialysate solution, ‘cleans’ it and then pumps it back into patients circulation

the dialyser consists of 2 compartments

• blood

• dialysate

separated by semi-permeable membrane

what drives the fluid from the blood from one compartment to another through the membrane

pressure gradient

what allows for the multiple use of dialyser by the same patient

the autoclean facility disinfects dialyser membrane and compartments

features of intensive home haemodialysis

what is peritoneal dialysis

• uses patients peritoneal ‘barrier membrane’ across which excess body fluids and dissolved waste substances are exchanged by osmosis/diffusion from blood into peritoneal dialysis solution

• fluid is introduced through permanent catheter in abdomen and drained after every night

what is the peritoneal membrane

transparent serous membrane lining walls of abdominal cavity and enclosing digestive organs in abdomen

• any fluid that escapes peritoneal capillaries into abdominal cavity is reabsorbed back into circulation via lymphatic