Urinary Session 11 Flashcards
What happens to renal tissue in CKD?
Replaced by extracellular matrix and fibrosis in response to tissue damage
What can be used in addition to eGFR to assess renal function?
Albumin-creatinine ratio
What proportion of nephrons need to be working in a kidney in order for renal function to be sufficient?
2%
What is the aetiology of CKD?
Immunologic - glomerulonephritis Infection - chronic pyelonephritis Genetic - polycystic kidney, Alport's Obstruction and reflex nephropathy Hypertension Vascular - vasculitis, arteriosclerosis, IHD Systemic disease - DM, myeloma Idiopathic
What are the commonest causes of CKD?
Diabetes
Idiopathic
Which cause of CKD gives rise to an exception to the common histological appearance of CKD?
Polycystic kidney
What is the pathogenesis of CKD regardless of aetiology?
Loss of renal parenchyma and tubules with formation of scar tissue and infiltration by inflammatory cells
How does the incidence of CKD change relative to staging?
Decreases as staging increases
What is associated with CKD pts who inexorably worsen?
CVS morbidity and mortality, often before GFR decrease requires dialysis
Does early recognition and intervention cure CKD?
No, delays rate of decline and delays need for dialysis but most pts decline anyway
When does mortality start to increase in CKD?
Once eGFR has decreased by 25%
What is chronic kidney disease?
Irreversible +/- progressive loss of renal function over a period of months to years
What investigations are used in CKD to define the degree of impairment?
BP Urine dipstick Serum creatinine Inulin clearance Cr EDTA clearance Iohexol clearance Creatinine clearance eGFR
What is proteinuria proportional to in CKD?
Development of end-stage renal disease therefore more protein –> steeper decline in eGFR
Does a serum creatinine level within the normal range of 80-120 micromoles per litre always indicate normal renal function?
No, depends on renal function and muscle mass which is affected by age, sex and with city
Why are inulin, Cr EDTa and iohexol clearance impractical measures of renal function in CKD?
Must be IV, need time in hospital and use of radiation is unpopular
Why is creatinine clearance not a good assessment of renal function in CKD?
Impractical, inaccurate and time consuming (must be done over 24 hr period)
Can eGFR be used to assess a child’s renal function?
No, adults only
How can the cause of CKD be assessed?
Autoantibody screen for lupus/myeloma Complement, Ig, ANCA for vasculitis, CRP levels Serum/urine proprotein electrophoresis US for size and hydronephrosis CT, MRI Biopsy
When is the kidney biopsied in CKD?
If kidneys are normal size and there is no obvious CKD cause
What are the possible complications of CKD?
Metabolic acidosis
Normocytic and normochromic anaemia
Metabolic bone disease
How does CKD lead to metabolic acidosis?
Diseased kidney cannot regain HCO3- –> loss of HCO3- —> decreased HCO3-/CO2 ratio –> decreased pH in blood
What are the consequence of metabolic acidosis in CKD?
Muscle function impairment
Decreased bone mass
Worsened renal function decline
What is the Tx for metabolic acidosis in CKD?
Oral NaHcO3- tablets
How does CKD cause anaemia?
Decreased EPO production and increased resistance –> decreased RBC survival –> blood loss
What is renal osteodystrophy?
Sclosis of vertebral end plates and erosion of terminal phalanges
How does CKD cause metabolic bone disease?
Decreased GFR –> increased phosphate retention
–> decreased calcium levels –> increased PTH –> osteitis fibrosa cystica
Decreased GFR –> decreased activation of vitamin D –> osteomalacia –> increased PTH and non-bone calcification
How is metabolic bone disease in CKD treated?
Supplements
What potentially modifiable risks can be targeted in management of CKD?
Smoking Obesity Lack of exercise Tx DM and hypertension In proteinuria use ACEI/ARBs and consider lipid lowering Tx
When is renal replacement therapy used to manage CKD?
Native renal function decreases and can no longer support health
What symptoms indicate renal replacement therapy with dialysis in CKD?
Uraemic symptoms Acidosis Pericarditis Fluid overload Hyperkalaemia
What is end-stage renal failure?
When death is likely without renal replacement therapy
What is the numerical definition of ESRF?
eGFR
What are the S/S of ESRD?
Tiredness Difficulty sleeping Difficulty concentrating SoB and oedema due to volume overload N+V/reduced appetite Restless legs and debilitating cramps Pruritis Sexual dysfunction with decreased fertility Increase in number of infections
What causes an increase in number of infections in ESRD?
Impaired cellular and humoral immunity
What is the effect of CKD in water/salt handling when GFR is small but the solute load is the same?
Osmotic diuresis due to impaired maximum concentrating ability and reduced response to ADH –> nocturia
What is the effect of CKD on renal water/salt handling when the volume of filtrate is reduced?
Impaire ability of kidney to excrete substances –> decrease in max urine volume
Why do 80-85% of CKD pts have altered water/salt handling?
They are hypertensive and are taking anti-hypertensives/diuretics/fluid restricted
Why might muscle or bone pains be felt in acid abase balance and electrolyte disturbances due to CKD?
Acidosis –> hyperphosphataemia and decreased 1-alpha-calcidiol –> bone breakdown
Acidosis –> muscle wasting
If there a definitive threshold in the accumulation of waste products and onset or uraemic symptoms?
No
Why do most drugs need dose altering in CKD/ESRD pts?
Decreased metabolism +/- elimination
Increased sensitivity without impairment of elimination –> increased likelihood of S/E
What are the advantages of using haemodialysis for renal replacement therapy?
Less responsibility for Tx
Days off between dialysis sessions so can forget illness
What are the disadvantages of haemodialysis Tx?
Travel and waiting time
Restriction of dialysis times
Big restriction of fluid and food intake
Unsightly fistulas which start at wrist so difficult to cover
Why is home/nocturnal haemodialysis considered better than in hospital?
Gives more dialysis hours –> better large molecule clearance –> pt fells better and needs less supportive Tx but requires second person to be present due to haemorrhage risk
Describe the process of haemodialysis.
Arterial access drains into machine, pressure is monitored throughout and blood pumped round. Anticoagulant is added, then blood flows in opposite direction to diasylate within the dialyzer to exchange solutes. Processed blood returned to venous system
How does the K+ concentration of diasylate fluid in haemodialysis compare to that of blood?
Lowe than you want in blood returning to body so it moves out in dialyzer
What are the contraindications for haemodialysis?
Failed vascular access
Heart failure due to machine decreasing preload
Coagulopathy
What complications arise as a result of haemodialysis?
Lines –> infection, thrombosis, venous stenosis
AVF –> thrombosis, bleeding, access failure, steal syndrome causing an ischaemic hand
CVS instability
Felling chronically unwell
Accumulation of co-morbidities
Does peritoneal dialysis require more or less supplementary Tx (additional tablets and injections) than haemodialysis?
Fewer
What are the advantages of permit penal dialysis?
Self-sufficient
Less fluid and food restrictions
Fairly easy to travel with
Renal function better preserved initially
What is in the diasylate fluid in peritoneal dialysis?
Sugar or polymer
What are the disadvantages of peritoneal dialysis?
Frequent daily exchanges or overnight
Responsibility
No days off from illness
What are the contraindications for peritoneal dialysis?
Failure of peritoneal membrane e.g. due to scar from surgery
Adhesions, hernia, stoma
Pt or carer cannot connect/disconnect
Obese or large muscle mass due to reduced SA/volume
What complications are associated with peritoneal dialysis?
Peritonitis (typically experienced once ever 20 months) Site infections Ultrafiltration failure Leaks into scrotum or diaphragm Development of hernia
What is the difference between continuous ambulatory peritoneal dialysis and ambulatory peritoneal dialysis?
Continuous = 4-5 bags per day whereas other is overnight
What are the three different methods of kidney transplant currently available?
Live donor
Deceased after brain death (DBD)
Deceased after circulatory death (DCD/non-heart beating)
What are the advantages of kidney transplant for renal replacement therapy?
Decreased mortality and morbidity in comparison to dialysis
Better QoL
What are the disadvantages of kidney transplant as a renal replacement therapy?
Peri-operative risk (mortality highest for 3 months after)
Malignancy risk
Infection risk
Diabetes and hypertension risk from additional medication required
Describe the process of kidney transplant.
Pt on waiting list –> accrues points based on age and waiting time –> tissue match by blood group(ABO) and MHC class I(HLA)–> attach new kidney to iliac arteries
What morbidity does transplant medication cause due to its side effects?
Diabetes Hypertension GI ulceration Decreased WCC and platelets Steroid S/E
Which type of kidney transplant has the best average transplant life?
Live related donor
What is the numerical definition of kidney failure?
eGFR
How long does dialysis prolong life for in pts >70 y.o. with ESRD and significant CVD co-morbidities?
~2 years
Why do some pts >70 y.o. with ESRD and significant co-morbidities choose not to have dialysis?
Can survive a substantial length of time (although
Which co-morbidities confer a particularly poor outcome for elderly dialysis pts?
CVD
How does the mortality of ERSD pts compare to age matched pts without ERSD?
It is higher
When do pts die from ERSD?
If dialysis access is not possible otherwise CVD cause in dialysis or malignancy in transplant pts
What is the average life expectancy for a pt aged 25-29 with incident ERSD?
18 years from diagnosis
What is the average life expectancy for an incident ERSD pt aged 75 years?
3 years from diagnosis
Why might muscle or bone pains be felt in acid abase balance and electrolyte disturbances due to CKD?
Acidosis –> hyperphosphataemia and decreased 1-alpha-calcidiol –> bone breakdown
Acidosis –> muscle wasting
If there a definitive threshold in the accumulation of waste products and onset or uraemic symptoms?
No
Why do most drugs need dose altering in CKD/ESRD pts?
Decreased metabolism +/- elimination
Increased sensitivity without impairment of elimination –> increased likelihood of S/E
What are the advantages of using haemodialysis for renal replacement therapy?
Less responsibility for Tx
Days off between dialysis sessions so can forget illness
What are the disadvantages of haemodialysis Tx?
Travel and waiting time
Restriction of dialysis times
Big restriction of fluid and food intake
Unsightly fistulas which start at wrist so difficult to cover
Why is home/nocturnal haemodialysis considered better than in hospital?
Gives more dialysis hours –> better large molecule clearance –> pt fells better and needs less supportive Tx but requires second person to be present due to haemorrhage risk
Describe the process of haemodialysis.
Arterial access drains into machine, pressure is monitored throughout and blood pumped round. Anticoagulant is added, then blood flows in opposite direction to diasylate within the dialyzer to exchange solutes. Processed blood returned to venous system
How does the K+ concentration of diasylate fluid in haemodialysis compare to that of blood?
Lowe than you want in blood returning to body so it moves out in dialyzer
What are the contraindications for haemodialysis?
Failed vascular access
Heart failure due to machine decreasing preload
Coagulopathy
What complications arise as a result of haemodialysis?
Lines –> infection, thrombosis, venous stenosis
AVF –> thrombosis, bleeding, access failure, steal syndrome causing an ischaemic hand
CVS instability
Felling chronically unwell
Accumulation of co-morbidities
Does peritoneal dialysis require more or less supplementary Tx (additional tablets and injections) than haemodialysis?
Fewer
What are the advantages of permit penal dialysis?
Self-sufficient
Less fluid and food restrictions
Fairly easy to travel with
Renal function better preserved initially
What is in the diasylate fluid in peritoneal dialysis?
Sugar or polymer
What are the disadvantages of peritoneal dialysis?
Frequent daily exchanges or overnight
Responsibility
No days off from illness
What are the contraindications for peritoneal dialysis?
Failure of peritoneal membrane e.g. due to scar from surgery
Adhesions, hernia, stoma
Pt or carer cannot connect/disconnect
Obese or large muscle mass due to reduced SA/volume
What complications are associated with peritoneal dialysis?
Peritonitis (typically experienced once ever 20 months) Site infections Ultrafiltration failure Leaks into scrotum or diaphragm Development of hernia
What is the difference between continuous ambulatory peritoneal dialysis and ambulatory peritoneal dialysis?
Continuous = 4-5 bags per day whereas other is overnight
What are the three different methods of kidney transplant currently available?
Live donor
Deceased after brain death (DBD)
Deceased after circulatory death (DCD/non-heart beating)
What are the advantages of kidney transplant for renal replacement therapy?
Decreased mortality and morbidity in comparison to dialysis
Better QoL
What are the disadvantages of kidney transplant as a renal replacement therapy?
Peri-operative risk (mortality highest for 3 months after)
Malignancy risk
Infection risk
Diabetes and hypertension risk from additional medication required
Describe the process of kidney transplant.
Pt on waiting list –> accrues points based on age and waiting time –> tissue match by blood group(ABO) and MHC class I(HLA)–> attach new kidney to iliac arteries
What morbidity does transplant medication cause due to its side effects?
Diabetes Hypertension GI ulceration Decreased WCC and platelets Steroid S/E
Which type of kidney transplant has the best average transplant life?
Live related donor
What is the average transplant life for a DCD kidney transplant?
What is the average transplant life for a DCD kidney transplant?
How long does dialysis prolong life for in pts >70 y.o. with ESRD and significant CVD co-morbidities?
~2 years
Why do some pts >70 y.o. with ESRD and significant co-morbidities choose not to have dialysis?
Can survive a substantial length of time (although
Which co-morbidities confer a particularly poor outcome for elderly dialysis pts?
CVD
How does the mortality of ERSD pts compare to age matched pts without ERSD?
It is higher
When do pts die from ERSD?
If dialysis access is not possible otherwise CVD cause in dialysis or malignancy in transplant pts
What is the average life expectancy for a pt aged 25-29 with incident ERSD?
18 years from diagnosis
What is the average life expectancy for an incident ERSD pt aged 75 years?
3 years from diagnosis
How does the mortality rate of RRT pts compared to an age matched population compare between pts aged 30-34 and 85+?
30-34 = 25x greater 85+ = 2.7x greater
How long is the typical wait for a suitable kidney transplant?
3 years for deceased donor but longer for ethnic minorities
