Chronic Kidney Disease Flashcards
Common causes of chronic kidney disease
diabetic nephropathy chronic glomerulonephritis chronic pyelonephritis hypertension adult polycystic kidney disease
Serum creatinine may not provide an accurate estimate of renal function due to
differences in muscle.
For this reason, formulas were developed to help estimate the glomerular filtration rate (estimated GFR or eGFR).
What formula is used to estimated gfr and what variables does it look at
Modification of Diet in Renal Disease (MDRD) equation, which uses the following variables: serum creatinine age gender ethnicity
What factors affect gfr result?
pregnancy
muscle mass (e.g. amputees, body-builders)
eating red meat 12 hours prior to the sample being taken
CKD may be classified according to
GFR
Describe the stages of CKD?
1 Greater than 90 ml/min, with some sign of kidney damage on other tests (if all the kidney tests* are normal, there is no CKD)
2 60-90 ml/min with some sign of kidney damage (if kidney tests* are normal, there is no CKD)
3a 45-59 ml/min, a moderate reduction in kidney function
3b 30-44 ml/min, a moderate reduction in kidney function
4 15-29 ml/min, a severe reduction in kidney function
5 Less than 15 ml/min, established kidney failure
dialysis or a kidney transplant may be needed at which stage of CKD?
5
Usually chronic kidney disease is asymptomatic and diagnosed on routine testing
true
Aims of CKD management?
Slow the progression of the disease
Reduce the risk of cardiovascular disease
Reduce the risk of complications
Treating complications
How do you reduce risk of complications in CKD?
Exercise, maintain a healthy weight and stop smoking
Special dietary advice about phosphate, sodium, potassium and water intake
Offer atorvastatin 20mg for primary prevention of cardiovascular disease
What is the A Score? What does it include?
The A score is based on the albumin:creatinine ratio:
A1 = < 3mg/mmol A2 = 3 – 30mg/mmol A3 = > 30mg/mmol
The patient does not have CKD if they have which scores?
score of A1 combined with G1 or G2. They need at least an eGFR of < 60 or proteinuria for a diagnosis of CKD.
Complications of CKD?
Anaemia Renal bone disease Cardiovascular disease Peripheral neuropathy Dialysis related problems
Investigations for CKD?
Estimated glomerular filtration rate (eGFR) can be checked using a U&E blood test. Two tests are required 3 months apart to confirm a diagnosis of chronic kidney disease.
Proteinuria can be checked using a urine albumin:creatinine ratio (ACR). A result of ≥ 3mg/mmol is significant.
Haematuria can be checked using a urine dipstick. A significant result is 1+ of blood. Haematuria should prompt investigation for malignancy (i.e. bladder cancer).
Renal ultrasound can be used to investigate patients with accelerated CKD, haematuria, family history of polycystic kidney disease or evidence of obstruction.
When should you refer to a specialist?
NICE suggest referral to a specialist when there is:
eGFR < 30
ACR ≥ 70 mg/mmol
Accelerated progression defined as a decrease in eGFR of 15 or 25% or 15 ml/min in 1 year
Uncontrolled hypertension despite ≥ 4 antihypertensives
Roughly outline how should you treat complications of CKD?
Oral sodium bicarbonate to treat metabolic acidosis
Iron supplementation and erythropoietin to treat anaemia
Vitamin D to treat renal bone disease
RRRT in end stage renal failure
The majority of patients with chronic kidney disease (CKD) will require more than two drugs to treat hypertension.
true
Which hypertension drugs are particularly helpful in proteinuric renal disease
ACE inhibitors
Which drugs reduce filtration pressure?
ACE inhibitors
these drugs tend to reduce filtration pressure a small fall in glomerular filtration pressure (GFR) and rise in creatinine can be expected
When using ACEi in hypertension NICE suggest that a decrease in eGFR of up to ?% or a rise in creatinine of up to ?% is acceptable
decrease in eGFR of up to 25% or a rise in creatinine of up to 30% is acceptable
A rise greater than this may indicate underlying renovascular disease.
When using ACEi in hypertension any rise in creatinine should prompt what
careful monitoring and exclusion of other causes (e.g. NSAIDs)
Other than ACEi, what other drug is useful in CKD?
Furosemide
Furosemide is useful as a anti-hypertensive in patients with CKD, particularly when
the GFR falls to below 45 ml/min
guidelines suggest a lower cut-off of less than 30 ml/min
What is a benefit of furosemide in hypertension and CKD?
lowering serum potassium
High doses of furosemide in hypertension and CKD are usually required
true
When should you consider stopping furosemide?
If the patient becomes at risk of dehydration (e.g. Gastroenteritis) then consideration should be given to temporarily stopping the drug
Patients with chronic kidney disease (CKD) may develop anaemia due to a variety of factors, the most significant of which is
Reduced erythropoietin levels
What kind of anaemia do you usually get in CKD?
normochromic normocytic anaemia
Anaemia in CKD predisposes to the development of
left ventricular hypertrophy
left ventricular hypertrophy is associated with a three fold increase in mortality in renal patients
true
normochromic normocytic anaemia and becomes apparent when the GFR is less than
35 ml/min
other causes (other than reduced erythropoietin levels) of anaemia should be considered if the GFR is > 60 ml/min
true
Causes of anaemia in renal failure?
Reduced erythropoietin levels - the most significant factor
Uraemia can lead to - reduced erythropoiesis due to toxic effects of uraemia on bone marrow, anorexia/nausea
reduced absorption of iron
Reduced red cell survival (especially in haemodialysis)
Blood loss due to capillary fragility and poor platelet function
Stress ulceration leading to chronic blood loss
NICE guidelines suggest a target haemoglobin of what in CKD
10 - 12 g/dl
In CKD Many patients, especially those on haemodialysis, will require IV iron
true
In anaemic CKD patients, what should be carried out before administering erythropoiesis-stimulating agents?
determination and optimisation of iron status
Examples of erythropoiesis-stimulating agents?
erythropoietin and darbepoetin
When should ESA’s be used? (CKD anaemia)
‘who are likely to benefit in terms of quality of life and physical function’
Proteinuria is an important marker of chronic kidney disease, especially for
diabetic nephropathy
NICE recommend using the albumin:creatinine ratio (ACR) in preference to the protein:creatinine ratio (PCR) when identifying patients with proteinuria as it has greater sensitivity
true
For quantification and monitoring of proteinuria, PCR can be used as an alternative, although ACR is recommended in diabetics.
Urine reagant strips are the most senstive test for proeinuria
Urine reagent strips are not recommended unless they express the result as an ACR
How do you collect an ACR sample?
by collecting a ‘spot’ samples of urine (avoids the need to collect urine over a 24 hour period in order to detect or quantify proteinuria)
should be a first-pass morning urine specimen
if the initial ACR is between 3 mg/mmol and 70 mg/mmol, this should be confirmed by a subsequent early morning sample.
If the initial ACR is 70 mg/mmol or more, a repeat sample need not be tested.
How do you interpret ACR results?
‘regard a confirmed ACR of 3 mg/mmol or more as clinically important proteinuria’
In terms of proteinuria, when should you refer to a nephrologist?
a urinary albumin:creatinine ratio (ACR) of 70 mg/mmol or more, unless known to be caused by diabetes and already appropriately treated
a urinary ACR of 30 mg/mmol or more, together with persistent haematuria (two out of three dipstick tests show 1+ or more of blood) after exclusion of a urinary tract infection
consider referral to a nephrologist for people with an ACR between 3-29 mg/mmol who have persistent haematuria and other risk factors such as a declining eGFR, or cardiovascular disease
Which medications are key in management of CKD? When would these be used?
ACE inhibitors (or angiotensin II receptor blockers) are key in the management of proteinuria
they should be used first-line in patients with coexistent hypertension and CKD
if the ACR > 70 mg/mmol they are indicated regardless of the patient’s blood pressure
Basic problems in chronic kidney disease for bone disease?
Low vitamin D (1-alpha hydroxylation normally occurs in the kidneys) leads to low calcium
High phosphate due to reduced secretion
Secondary hyperparathyroidism: due to low calcium and high serum phosphate = more parathyroid hormone.
This leads to increased osteoclast activity. Osteoclast activity lead to the absorption of calcium from bone.
What are the manifestation of bone disease in CKD?
Osteitis fibrosa cystica (aka hyperparathyroid bone disease)
Osteomalacia (softening of bones)
Osteoporosis (brittle bones)
Osteosclerosis (hardening of bones)
Osteomalacia occurs due to increased turnover of bones without adequate calcium supply.
Osteoporosis can exist alongside the renal bone disease due to other risk factors such as age and use of steroids.
Osteosclerosis occurs when the osteoblasts respond by increasing their activity to match the osteoclasts by creating new tissue in the bone, however due to the low calcium level this new tissue is not properly mineralised.
high phosphate level ‘drags’ calcium from the bones, resulting in osteomalacia
true
What lab results do you get in bone disease in CKD?
low calcium: due to lack of vitamin D
high phosphate (‘drags’ calcium from the bones, resulting in osteomalacia)
secondary hyperparathyroidism: due to low calcium, high phosphate and low vitamin D
What is the aime of Chronic kidney disease: mineral bone disease management
reduce phosphate and parathyroid hormone levels.
Overview of Chronic kidney disease: mineral bone disease management
reduced dietary intake of phosphate is the first-line management
phosphate binders
vitamin D: alfacalcidol, calcitriol
parathyroidectomy may be needed in some cases
In bone disease management aluminium-based binders are less commonly used now
true
What types of phosphate binders can you use in CKD?
aluminium-based
calcium-based binders
sevelamer
What problems can you get with calcium binders
problems include hypercalcemia and vascular calcification
What is Sevelamer and how does it work?
a non-calcium based binder that is now increasingly used binds to dietary phosphate and prevents its absorption
also appears to have other beneficial effects including reducing uric acid levels and improving the lipid profiles of patients with chronic kidney disease
The human leucocyte antigen (HLA) system is the name given to the major histocompatibility complex (MHC) in humans. It is coded for on?
chromosome 6.
class 1 antigens include?. Class 2 antigens include ?
class 1 antigens include A, B and C. Class 2 antigens include DP,DQ and DR
when HLA matching for a renal transplant the relative importance of the HLA antigens are as follows?
DR > B > A
Describe the 10 yr survival for cadaveric vs living donor transplants
60% for cadaveric transplants
70% for living-donor transplants
In renal transplant what are the post op complications?
ATN of graft
vascular thrombosis
urine leakage
UTI
Hyperacute rejection occurs within
minutes to hours
Hyperacute rejection occurs due to?
pre-existing antibodies against ABO or HLA antigens
an example of a type II hypersensitivity reaction
What does hyperacute rejection lead to?
widespread thrombosis of graft vessels → ischaemia and necrosis of the transplanted organ
How do you treat hyperacute rejection?
no treatment is possible and the graft must be removed
Acute graft failure occurs within?
< 6 months
What causes acute graft failure?
usually due to mismatched HLA. Cell-mediated (cytotoxic T cells)
other causes include cytomegalovirus infection
How do you treat acute graft failure?
may be reversible with steroids and immunosuppressants
When does chronic graft failure occur?
> 6 months
What causes chronic graft failure?
both antibody and cell mediated mechanisms cause fibrosis to the transplanted kidney (chronic allograft nephropathy)
recurrence of original renal disease (MCGN > IgA > FSGS)
How does ciclosporin work?
inhibits calcineurin, a phosphotase involved in T cell activation
Tacrolimus has a
lower incidence of acute rejection compared to ciclosporin
true
What are the advantages and disadvantages of tacrolimus vs ciclosporin?
less hypertension and hyperlipidaemia
however, high incidence of impaired glucose tolerance and diabetes
How does Mycophenolate mofetil (MMF) work and what are its side effects?
blocks purine synthesis by inhibition of IMPDH
therefore inhibits proliferation of B and T cells
side-effects: GI and marrow suppression
How does Sirolimus (rapamycin) work and what are its side effects?
blocks T cell proliferation by blocking the IL-2 receptor
can cause hyperlipidaemia
How do monoclonal antibodies work and what are 2 examples?
selective inhibitors of IL-2 receptor
daclizumab
basilximab
Patients on long-term immunosuppression for organ transplantation require regular monitoring for complications such as
Cardiovascular disease - tacrolimus and ciclosporin can cause hypertension and hyperglycaemia. Tacrolimus can also cause hyperlipidaemia. Patients must be monitored for accelerated cardiovascular disease.
Renal failure - due to nephrotoxic effects of tacrolimus and ciclosporin/graft rejection/recurrence of original disease in transplanted kidney
Malignancy - patients should be educated about minimising sun exposure to reduce the risk of squamous cell carcinomas and basal cell carcinomas
Around 10% of those with CKD will go on to develop renal failure
true
renal failure is defined as?
glomerular filtration rate of less than 15ml/min
For patients with renal failure, the management options are
renal replacement therapy (RRT), to take over the physiology of the kidneys, or conservative management, which will be palliative.
several types of renal replacement therapy includes?
haemodialysis
peritoneal dialysis
renal transplant
The decision about which RRT option to pick should be made jointly by the patient and their healthcare team, taking into account the following
predicted quality of life
predicted life expectancy
patient preference
co-existing medical conditions
What is the most common form of renal replacement therapy?
Haemodialysis
What is haemodyialysis?
regular filtration of the blood through a dialysis machine in hospital
haemodialysis regimen?
Most patients need dialysis 3 times per week, with each session lasting 3-5 hours.
At least 8 weeks before the commencement of treatment, the patient must undergo surgery to create an arteriovenous fistula, which provides the site for haemodialysis. Most commonly this is created in the lower arm.
Some patients may be trained to perform home haemodialysis so that they do not have to regularly attend hospital.
What is peritoneal dialysis?
filtration occurs within the patient’s abdomen.
Dialysis solution is injected into the abdominal cavity through a permanent catheter.
The high dextrose concentration of the solution draws waste products from the blood into the abdominal cavity across the peritoneum.
After several hours of dwell time, the dialysis solution is then drained, removing the waste products from the body, and exchanged for new dialysis solution.
What are the two types of peritoneal dialysis?
Continuous ambulatory peritoneal dialysis (CAPD)
Automated peritoneal dialysis (APD)
What does Continuous ambulatory peritoneal dialysis (CAPD) that is different from PD
each exchange lasting 30-40 minutes and each dwell time lasting 4-8 hours. The patient may go about their normal activities with the dialysis solution inside their abdomen
What does Automated peritoneal dialysis (APD) that is different from PD
dialysis machine fills and drains the abdomen while the patient is sleeping, performing 3-5 exchanges over 8-10 hours each night
Renal transplantation involves the receipt of a kidney from either a live or deceased donor.
tru
The average wait for a kidney in the UK is 3 years, though patients may also receive kidneys donated by cross-matched friends or family.
tru
What does renal transplant involve?
donor kidney is transplanted into the groin, with the renal vessels connected to the external iliac vessels. The failing kidneys are not removed. Following transplantation, the patient must take life-long immunosuppressants to prevent rejection of the new kidney.
Complications of haemodialysis?
Site infection, Stenosis at site
Endocarditis, hypotension, cardiac arrhthmia, air embolus
anaphylaxis to sterilising agents
Disequilibration syndrome
Complications of peritoneal dialysis?
Peritonitis, Sclerosing peritonitis Catheter infection, Catheter blockage Constipation Fluid retention Hernias Back pain Malnutrition
Peritoneal dialysis causes hypoglycaemia
FALSE
hyperglycaemia
Complications of Renal transplantation?
DVT / PE Opportunistic infection Malignancies Bone marrow suppression Recurrence of original disease Urinary tract obstruction Cardiovascular disease
Which malignancies are you in particular risk of in renal trsansplant?
lymphoma and skin cancer
The average life expectancy of a patient with renal failure that does not receive renal replacement therapy is
6 months.
The symptoms of renal failure that is not being adequately managed with RRT are:
breathlessness, swelling
General: fatigue, pruritus, poor appetite, insomnia, weakness, weight gain/loss
GI: abdominal cramps, nausea
CNS: cognitive impairment, anxiety, depression, headaches
sexual dysfunction
muscle cramps
Peritoneal dialysis (PD) is a form of renal replacement therapy. It is sometimes used for whom
It is sometimes used as a stop-gap to haemodialysis or for younger patients who do not want to have to visit hospital three times a week.
Which type of PD is most commonly used? How many exchanges does this involve?
Continuous Ambulatory Peritoneal Dialysis (CAPD), which involves four 2-litre exchanges/day.
In PD peritoninits whihc bacteriaare most common
coagulase-negative staphylococci such as Staphylococcus epidermidis is the most common cause. Staphylococcus aureus is another common cause
