Chronic Kidney Disease Flashcards
Chronic Kidney Disease (CKD) is usually asymptomatic and is diagnosed post abnormal urea & electrolyte results. Late-stage undetected disease may be symptomatic.
What are the features of late stage CKD?
Oedema e.g. ankle swelling, weight gain
Polyuria
Lethargy
Pruritus - secondary to uraemia
Anorexia => weight loss
Insomnia
N&V
Hypertension
What are the causes of CKD?
Diabetic nephropathy
Chronic glomerulonephritis (following streptococcal URTI, Hep B/C, HIV)
Hypertension
Adult polycystic kidney disease
Nephrotoxic drugs i.e. ACE-i, aminoglycosides, AIIRAs, bisphosphonates, diuretics, lithium, NSAIDs)
What is CKD?
CKD = reduction in kidney function or structural damage present for more than 3 months
Kidney damage may cause:
=> fluid & electrolyte imbalance, proteinuria, haemturia
How is CKD diagnosed?
Usually incidental finding of:
- Raised serum creatinine and/or serum eGFR of less than 60mL/min1.73m2
- Proteinuria >3mg/mmol
- Persistent haematuria (2/3 urine dipstick tests shows 1+ or more of blood) after excluding UTI
- Urine sediment abnormalities i.e. RBC, WBC or granular casts and renal tubular epithelial cells
What are the initial investigations for suspected CKD in primary care?
- Arrange blood tests for serum creatinine and eGFR
=> advice the person does not eat meat for the last 12 hours before the test
=> if eGFR <60mL/min/1.73m2, repeat within 2 weeks
=> if eGFR remains <60mL on repeat, with no evidence of sudden deterioration in renal function suggesting AKI, repeat eGFR within 3 months - Arrange early morning urine sample to measure albumin:creatinine ratio (ACR)
=> ACR between 3-70mg/mmol => repeat test within 3 months
=> >70mg/mmol => significant proteinuria so repeat not needed - Arrange urine dipstick for haematuria
=> if 1+ or more on dipstick, arrange mid stream urine sample (MSU) to exclude UTI - Check nutritional status, BMI, BP and HbA1c and lipid profile to assess for CVD risk factor
Diagnosis of CKD id persistent reduction in renal function
=> eGFR <60mL/min/1.73m2 lasting for at least 3 months
=> classify CKD to determine risk of disease progression and ongoing management
*Arrange for serum creatinine, eGFR, urinary ACR and urine dipstick testing annually if person has not been diagnosed with CKD but has ongoing risk factors
How is CKD (stages 3-5) classified?
CKD:
STAGE 1: GFR >90ml/min with some signs of kidney damage i.e. U&E, proteinuria
STAGE 2: GFR 60-90ml/min with some signs of kidney damage
STAGE 3a: GFR 45-59ml/min and a moderate reduction in kidney function
STAGE 3b: GFR 30-44ml/min and a moderate reduction in kidney function
STAGE 4: GFR 15-29ml/min and a severe reduction in kidney function
STAGE 5: GFR <15ml/min, established kidney failure - dialysis or a kidney transplant needed
Urinary ACR
A1: Normal to mildly increased <3mg/mmol
A2: Moderately increased 3-30mg/mmol
A3: Severely increased >30mg/mmol
Explaining CKD to a patient:
=> CKD is a long term condition where the kidneys aren’t working as well as they used to.
=> It is a common condition associated with getting older but many other things can cause it such as high BP, diabetes, kidney infection / inflammation, medications
=> It is more common in south asian origin / black
=> CKD can get worse over time and eventually kidneys stop working, however, many people with CKD are able to live long lives.
=> There are usually no symptoms in the early stages and it may be incidentally diagnosed on a blood test or urine test
=> Symptoms at an advanced stage can include tiredness, swollen ankles, N&V, blood in your urine
=> tests to diagnose CKD is a blood test and urine test => these tests look for high levels of particular substance assoc. with kidneys which tell us how well your kidney is working. The blood test and urine test helps us stage the CKD
There is no cure for CKD but treatment can help relieve symptoms and stop it getting worse.
=> lifestyle changes
=> medicine to control high BP and cholesterol
=> dialysis which replicates the function of your kidney and may be important at an advanced stage
=> kidney transplant at advanced stage
=> Regular check ups to monitor condition
How is CKD progression monitored?
a) Confirmed diagnosis of CKD => monitor disease progression and assoc. complications
b) Underlying causes and risk factors for disease progression influence frequency of monitoring
c) Monitor renal function by checking serum creatinine and eGFR with urinary albumin:creatinine ratio to identify accelerated progression
=> a sustained decrease in eGFR of 25% or more form baseline and a change in CKD category within 12 months
d) To assess rate of progression, repeat the serum eGFR 3x over 3 months
=> assess for any reversible cause
=> arrange renal tract USS to identify structural cause and arrange referral
e) If a person has or is at risk of AKI, monitor for 2-3 years after the episode even if serum creatinine back to baseline
Referral:
=> arrange an urgent 2-week referral if there is isolated persistent haematuria and a urological cancer is suspected
=> refer if accelerated progression of CKD as defined above
=> ACR of >70mg/mmol unless proteinuria due to diabetes and managed properly
=> Urinary ACR of >30mg/mmol with persistent haematuria without UTI
=> Hypertension uncontrolled despite at least 4 drugs used
=> Suspected complication of CKD i.e. decline in nutritional status/malnutrition and persistent hyperkalaemia, renal anaemia, renal mineral bone disorder or persistent metabolic acidosis
How is CKD with hypertension managed?
Confirmed CKD = regular follow ups depending on clinical judgement
Urinary ACR or >30mg/mmol assoc. with hypertension => ACE-i or ARB i.e. lisinopril or losartan (do not prescribe ACE-i and ARB together)
Urinary ACR of <70mg/mmol, aim for BP <140/90mmHg
Urinary ACR of >70mg/mmol, aim for BP <130/80mmHg and arrange referral to nephrologist
Hypertension uncontrolled on 4 anti-hypertensive drugs => nephrology referral
*Furosemide = useful anti-hypertensive in CKD + helps lower potassium
Proteinuria = important marker of CKD, especially for diabetic nephropathy.
How is proteinuria managed in CKD?
What is the frequency of follow-ups/monitoring required?
How is ACR sample collected?
What are the NICE recommendation for referral?
- ACE-i (or ARB) first line
=> used in patients with coexistent hypertension and CKD, if ACR >30mg/mmol
=> if ACR >70mg/mmol, ACE-i indicated regardless of patient’s BP\
- eGFR Stage 3 => Annual follow-up but if A3 (>30mg/mmol) => 2x/year
eGFR Stage 4 => 2x/year follow-up but if A3 (>30mg/mmol) => 3x/year
eGFR Stage 5 => 4 or more / year follow up
- ACR sample = first urine sample of the morning
=> if initial ACR between 3 and 70 mg/mmol then repeat early morning sample again
=> if initial ACR >70mg/mmol, repeat sample not needed
=> NICE = ACR of >3 mg/mmol is clinically important proteinuria
- NICE for referral
=> ACR of >70mg/mmol unless known diabetes
=> ACR of >30mg/mmol with persistent haematuria (2/3 dipstick with 1+ of blood) after excluding UTI
=> ACR between 3-29mg/mmol with persistent haematuria and other risk factors i.e. declining eGFR / CVD
Anaemia in CKD:
CKD anaemia significantly due to reduced erythropoietin levels - normochromic normocytic anaemia. This is apparent with GFR <35ml/min.
Anaemia in CKD predisposes to left ventricular hypertrophy
Other causes of anaemia in CKD: => reduced erythropoiesis due to toxic effects of uraemia on bone marrow => reduced absorption of iron => anorexia/nausea due to uraemia => reduced RBC survival
Management:
Target haemoglobin of 10-12g/dl
Optimise iron status prior to administering erythropoiesis-stimulating agents (ESA) => many patients, esp on haemo-dialysis, require IV iron
Bone disease in CKD
CKD => low vit D (1-alpha hydroxylation occurs in kidneys),
=> high phosphate,
=> low calcium due to lack of vitamin D, high phosphate
=> secondary hyperparathyroidism due to low calcium, high phosphate and low vitamin D
Clinical manifestation:
=> Osteomalacia due to low vit D
=> Osteosclerosis
=> Osteoporosis
Kidneys excrete phosphate => phosphate high in CKD
High phosphate and low vit D = osteomalacia
Aim is to reduce phosphate and parathyroid hormone levels
=> reduce dietary intake of phosphate (first line)
=> phosphate binders
=> vit D: calcitriol, alfacalcidiol
=> parathyroidectomy
Prevention of deterioration + Self Management advice
- Information, advice and support
=> Kidney Care UK charity with a national telephone support help-line
=> NHS patient leaflet
2. Healthy lifetyle => Stop smoking => Drink in moderation => Healthy BMI => Eating a healthy, low protein and salt diet => Regular exercise
