Kidney disease 1 Flashcards
What are the functions of the kidney?
- regulation of bone metabolism
- regulation of red blood cell production
- regulation of blood pressure
- influence on blood pH and acid-base-metabolism
- excretion of metabolic waste products and water
Describe the range of renal patients
“Normal” renal function
Patients with various stages of impairment
Patients not yet having dialysis (pre-dialysis) but rapidly approaching
Patients requiring Renal Replacement therapy
Haemodialysis
Peritoneal dialysis
Transplantation
CKD: what is it? How common is it?
What is moderate to severe CKD associated with?
Treatment goals?
- Abnormal kidney function and/or structure
- Common
- Often unrecognised but often exists with other conditions eg diabetes or cardiovascular disease
- Moderate to severe CKD associated increased risk of other adverse outcomes
- Not all CKD progresses to end-stage kidney disease
It is detectable and easily tested
Treatment can prevent or delay progression and reduce complications
State markers of kidney disease
Albuminuria (ACR >3mg/mmol) Urine sediment abnormalities Electrolyte and other abnormalities due to tubular disorders Abnormalities in histology Structural abnormalities (imaging) History of kidney transplantation
GFR
What is it?
Normal value?
Indicative of?
- Glomerular filtration rate is the best measure of overall kidney function
- It is the composite function of all the nephrons
- -Normal ~100mls/min
- Result roughly indicates % of normal function
- Exact measurement difficult but can be estimated in the lab from serum creatinine, gender and age using a simple formula.
Creatinine-estimated GFR versus
NICE guidance
-Laboratories should report an estimate of GFR using a prediction equation and the serum creatinine
-Laboratories should use the Chronic Kidney Disease Epidemiology collaboration (CKD-EPI) creatinine equation to estimate GFRcreatinine
-Apply a correction factor for patients of African-Caribbean or African family origin ((eGFR x 1.159)
In extreme muscle mass
-decreased muscle mass will lead to overestimation and increased muscle mass under estimate GFR
Cystatin C-based GFR
What is it? When is it used?
-Laboratories report an estimate of GFR eGFRcystatinC and the serum cystatin C
-Used when an improved assessment of risk is needed
-Caution in patients with uncontrolled thyroid disease
-Used at initial diagnosis to confirm or rule out CKD in people with:
An eGFRcreatinine of 45-60ml/min/1.73m2 for >90 days and
No proteinuria or other marker of kidney disease
Urine dipstick tests
What are they? What do they detect?
What are they associated with?
- Basic test to shows kidney damage (presence and severity)
- Haematuria (blood in urine)
- Associated with more rapid decline in kidney function
- Proteinuria/ albuminuria (protein in urine)
- Ratio of protein or albumin to creatinine is measured.
- ACR recommended for people with diabetes
What is CKD? Prevalence?
What can it result in?
What complications can it cause?
Estimated to affects about 10% of the general population
Long term, often progressive loss of normal kidney function
May, (but does not always) result in end-stage kidney failure
Usually asymptomatic until renal function severely reduced
Commonly leads to cardiovascular disease (CVD) and other complications
As kidney function deteriorates, the incidence of complications increases eg anaemia, CVD, disordered bone mineral metabolism and calcification of blood vessels.
Risk factors for CKD (clinical conditions)
Diabetes Systemic Hypertension Acute kidney injury Cardiovascular disease Structural renal tract disease, recurrent renal calculi, prostatic hypertrophy Multisystem disease with potential kidney involvement, eg SLE Family history of end stage kidney disease Detection of haematuria Proteinuria Dyslipidaemia Smoking Obesity Alcohol consumption Low socio-economic status Drugs and herbs/analgesic abuse auto-immune disease/obstructive uropathy/stones
Unmodifiable risk factors for CKD
- old age
- male sex
- race/ethnicity
- genetic predisposition
- family history
- low birth weight
Clinical disease causes of CKD
Diabetes
Chronic (untreated) high blood pressure.
glomerulonephritis (inflammation of the kidney)
pyelonephritis (infection in the kidney)
polycystic kidney disease (an inherited condition where both kidneys are larger than normal due to the gradual growth of masses of cysts)
failure of normal kidney development in an unborn baby while developing in the womb
systemic lupus erythematosus (a condition of the immune system where the body attacks the kidney as if it were foreign tissue)
long-term, regular use of medicines, such as (non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen
blockages, for example due to kidney stones or prostate disease
Discuss the importance of early detection of CKD
Early detection of CKD and its complications can delay or prevent progression to ESRD
Early intervention
Blood pressure control
Glycaemic control for diabetes
Reduce proteinuria
Control of rate of kidney disease progression via:
Blood pressure
Drugs
- Ideally, blood pressure reading should be systolic below 140mmHg Target range 120-139mmHg) and diastolic below 90mmHg
- kidney disease, diabetes or a condition that affects heart and circulation, target blood pressure should be below 130/80mmHg.
- 3 or more anti-hypertensives usual
Choice of anti-hypertensive in CKD
Combinations not recommended
Monitoring requirements
Choice of agent:
Low cost renin angiotensin antagonist
Do not use combination of ACE and ARB
ACE inhibition/ A2RB/aldosterone blockade
Lower Bp, reduce proteinuria, preserve renal function
Measure serum potassium and estimate GFR before starting
Repeat after 1-2 weeks
Do not give if potassium >5mmol/l pre treatment
Stop if potassium on treatment is >6mmol/l
Diabetes control in CKD
Diabetes control
ADVANCE trial showed good glycaemic control can slow down progression of renal disease
Drugs to avoid
Avoid nephrotoxic drugs eg NSAIDs or at least annual check of renal function
Other meds to offer in CKD
Statins
Lipid recommendations in NICE CG181
Oral antiplatelets and anticoagulants
offer antiplatelet drugs to people with CKD for the secondary prevention of cardiovascular disease but note increased risk of bleeding
Link of CKD and CVD
Both may be consequences of same diseases eg diabetes, hypertension ,atherosclerosis
CKD may cause or exacerbate CVD eg anaemia,, oxidative stress, vascular calcification
CVD may cause or exacerbate CKD
Management and aims of CKD treatment
Definitive Diagnosis
Treatment/prognosis
Depending on the stage of CKD
Prevent or treat complications
Reduce the risk of cardiovascular events and death
Reduce the risk of progressing to end stage renal disease
Describe the 5/6 stages of drug treatment for CKD
Everyone - Screening for CKD, CKD risk reduction ↓ Stage 1&2: Normal/↓GFR, proteinuria Slow progression diagnosis and treatment ACE/ARB Strict BP control CVD risk reduction ↓ Stage 3 Moderate ↓GFR Slow progression, treat complications Stage 1&2 treatment PLUS Anaemia Acidosis Bone disease CVD risk ↓ Stage 4 Severe ↓GFR Treat complications Preparation for renal replacement therapy Stage 3 treatment PLUS Choice Vascular access Transplant workup Living donor ↓ Stage 5 ESRD Dialysis Transplant Conservative care
Compications of CKD
Renal anaemia
Mineral bone disease
Acidosis
Cardiovascular disease
Treatment of anaemia in CKD
Iron and Erythropoietin replacement
Serum ferritin 200-500micrograms/L
Iron - oral or iv
For people who are not receiving haemodialysis, consider a trial of oral iron before offering intravenous iron therapy. If they are intolerant of oral iron or target Hb levels are not reached within 3months offer intravenous iron therapy.
For people who are receiving haemodialysis, offer intravenous iron therapy. Offer oral iron therapy to people who are receiving haemodialysis only if:
intravenous iron therapy is contraindicatedor
the person chooses not to have intravenous iron therapy after discussing the relative efficacy and side effects of oral and intravenous iron therapy.
Folic acid (if low folate)
Vitamin B12 (if low B12)
Blood transfusions if symptomatic
ESA – erythropoesis stimulating agents eg aranesp®, eprex ®, mircera ®, neo-recormon ®
Causes of Anaemia in CKD
Causes: -uraemia increases the risk of GI bleeding, nausea and vomiting decrease appetite -Shortened life span of red blood cells -Chronic inflammation -Secondary hyperparathyroid disease amount of iron absorbed is decreased leading to low iron stores -Decreased erythropoietin (epo) production + impaired bone marrow response
Treatment of CKD-MBD
Disordered bone metabolism and osteoporosis
CKD-MBD – chronic kidney disease – mineral bone disorder
Systemic disorder – abnormalities in bone and mineral metabolism and extra- skeletal calcification
Patients with CKD may have deranged calcium, raised phosphate and increased levels of parathyroid hormone (secondary hyperparathyroid disease).
Vitamin D
treat deficiency
High phosphate can cause what?
Mineral- bone disease Premature death Calcification of major vessels High phosphate symptoms for patients Severe Itching Painful, gritty eyes
What are phosphate binders? Name the different types
What must be taken into consideration when using these drugs?
Calcium based
Calcichew (calcium carbonate) ,
renacet (calcium acetate)
Non-ionic/ non catonic / other binders
Renagel/ renvela (sevelamer)
Fosrenol (Lanthanum carbonate) Metal based
Velphoro (iron) , Magnesium
Metal based
Aluminium hydroxide * rarely used, Magnesium containing
Timing is everything!
Must be taken immediately before or with meals to ensure efficacy
Remember if binds phosphate, what about other drugs?
Pruritis
Cause in CKD patients
Treatment
Symptom control
Itch
Caused by high phosphate levels and/or uraemia
treatment:
low phosphate diet & phosphate binders. Efficient dialysis.
symptom control:
antihistamines & topical preparations
Hyperkalaemia
treatment
Treat by reducing potassium in diet
Correct any metabolic acidosis
Acidosis
GFR levels
Correct with
GFR <30mls/min/1.73m2 (GFR g4 or G5 and serum bicarbonate
Correct with oral sodium bicarbonate
Hypertension treatment in CKD
May require a number of agents to decrease blood pressure:
diuretics
beta blockers
Centrally acting agents
ACE inhibitors & Angiotensin II inhibitors
MHRA warning about using together so need to monitor patients very closely
Vasodilating drugs eg. calcium channel blockers
Ace inhibitors and A2R blockers use: What blood levels to expect?
Incidence of hyperkalaemia in different patients
When do we see this combination?
Expect a serum creatinine rise of up to 20% or decline in GFR of 15% on initiation
Potassium
Overall incidence of hyperkalaemia (K+>5.1mmol/l) is ~10%
Pts with no kidney disease or CKD 1-3 expect a rise of 0.5mmol/l
CKD 4 or 5 more prominent hyperkalaemia
See combination in
Difficult hypertension, proteinuria, diabetes
Diuretics in CKD
Examples and doses, RoA
Avoid which ones? Cautions?
frusemide , bumetanide
may require high doses eg 500mg frusemide
may be given by prolonged iv infusion
avoid thiazides if moderate to severe renal impairment (eGFR<20mls/min) as ineffective
Caution with potassium sparing diuretics eg spironolactone, amiloride unless careful monitoring of potassium, or patient has severe heart failure
Calcium channel blockers in CKD
Side effects
Often require maximum doses
Side effect of ankle swelling should not be confused with fluid overload especially with amlodipine
Difficult to control hypertensive patients may also require:
Centrally acting antihypertensives Moxonidine Methyldopa Minoxidil Nitrates Alfa and betablockers eg labetalol High dose diuretics
Nausea in CKD is often caused by what?
Treatment?
Caused by a build up of toxins
Treatment: anti-emetics metoclopramide cyclizine haloperidol (low dose) ondansetron
