Week 4 - F - Chronic Kidney disease - more depth Flashcards
What is chronic kidney disease?
It is a reduced glomerular filtration rate and/or kidney damage associated with decreased urine creatinine over a long time
Why does creatinine overestimate the glomerular filtration rate?
This is because it is also secreted by the tubules
Creatinine is a product of muscle breakdown What people will therefore produce more creatinine?
Muscular people will therefore produce more creatinine
For white/Asian males: GFR = 186 x creatinine (mg/dl)-1.154 x Age-0.203 Correction factor for women, and for black race What is this equation known as?
This is knwon as the MDRD4 equation and allows you to calculate the glomerular filtration rate level
What are the four factors taken into account in the MDRD4 equation?
Serum creatinine Age Race Sex
Occasionally it is appropriate to measure the GFR instead of the eGFR What would be used to do this?
Would use inulin
What are 3 things that can account for evidence of kidney damage?
This would be proteinuria, haematuria (in absence of lower tract urinary cause) and abnormal imaging
What are the stages of chronic kidney disease? Also give the approximate prevalance of each stage?
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At what age does the glomerular filtration rate start to decrease and what is the rate at which it decreases?
• After the age of 40, GFR declines by about 0.75ml/min/year
Patients with what in their urine are more likely to progress to worse stages of CKD?
Patinets with proteinuria
What are common causes for chronic kidney disease?
Diabetes Hypertension Glomerulonephritis - commonly IgA
Patient presents and on ultrasound has multiple fluid filled cysts and hypertension What is this disease that can predispose to chronic kidney disease?
Polycystic kidney disease
When do symptoms of a reduced GFR actually begin to show?
Symptoms do not begin to show until late where the GFR reaches around 20ml/min
What are some of the symptoms of chronic kidney disease?
• Non-specific – tiredness, poor appetite, itch, sleep disturbance • Impaired urinary concentrating ability – nocturia Also can have a uraemic tinge to the skin - slightly yellow
Principlesof treating CKD: Slow progression Reduce cardiovascular risk Identify and treat complications of CKD Prepare for renal replacement therapy What drug is given to reduce cardiovascular risk and slow progression?
An ACEI is given to slow the progression - this reduces proteinuria and reduces the blood pressure
Why is there hypertension in chronic kidney disease? What is the target blood pressure?
Hypertension due to salt and water retention as kidneys are not excreting at the rate they should be Target BP - 130/80
What substances may increase in the blood due to a decreased filtration rate?
Hypernatraemia Hyperkalaemia Hyperphosphataemia Anaemia
What is the condition known as whee there is damage to the bone secondary to chronic kidney disease?
Renal osteodystrophy - happens because the chronic kidney disease cause secondary hyperparathyroidsim increasing the turnover of bones to restore calcium levels and therefore bones become weak
What are non pharmalogical factors in treating CKD? (ie what are the dietary controls)
Diet control, monitor blood glucose and stop smoking No salt diet, decrease intake of phosphate rich foods
Apart from stopping smoking, how else are the cardiovascular risks treated?
By potentially giving a statin if cholesterol is high and STOP SMOKING
How does anaemia arise in chronic kidney disease?
Anaemia arises as the kidneys are failing to produce erythropoeitin, this stops the stimulation of red blood cell formation in bone marrow leading to anaemia
What do you have to make sure is not causing the anaemia in CKD?
Check the: Iron Vitamin B12 and folate deficiency
What can be used to treat the anaemia in chronic kidney disease?
Intravenous iron - if this doesnt work Then give EPO (erythropoetin)
Vitamin D hydroxylated in the kidney Impaired in CKD Leads to reduced calcium absorption, leading to secondary hyperparathyroidism In advanced CKD, serum phosphate rises – also increases PTH secretion What can the seconday hyperparathyroidism cause?
This can cause tertiary hyperthyroidism which will be autonomous PTH secretion even when calcium is normal so - high PTH, high calcium, weak bones
What is the treatment for a hypocalcaemia and for the hyperphosphataemia??
Vitamin D analogues (alfacalcidol) and Ca supplements decrease bone disease and hyperparathyroidism. Can also try phosphate binders
Patinets with chronic kidney disease can also become acidotic and have oedema What can be given for both?
Acidotic - give sodium bicarbonate - be careful in hypertension and giving sodium Oedema - give loop diuretics and remember to restrict sodium and fluid intake
Principles: Slow progression Reduce cardiovascular risk Identify and treat complications of CKD What was the final prinicple for managing CKD if it needs to happen?
Prepare patient for renal replacement therapy
Most patients are ‘medically’ suitable for haemodialysis or peritoneal dialysis What GFR roughly does this discussion come up at with patients and what is the step protocol?
When the GFR hits roughly 20ml/min Buckman six step protocol to give the patinet the bad news Make sure to inform the patinet properly
What are the two types of dialysis available?
Hameodialysis and peritoneal dialysis
How does the patinet get ready fr haemodialysis?
Arteriovenous fistula (AVF) is best form of access AVF needs 6 weeks to mature after formation Refer to vascular surgeons when GFR about 15ml/min
Actual dialysis starts arounds <5-10 eGFR (dialysis provides an actual eGFR of about 10-12 ml/min/1.73m2)
What can be given for peritoneal dialysis?
Peritoneal dialysis – operation needed to insert catheter Catheter can be used after 1-2 weeks
What is the treatment of choice for end stage renal failure?
Renal transplantation
When can patinets with chronic kidney disease be listed on the cadaveric list for a kidney?
Patients can be listed for cadaveric transplantation when within 6 months of dialysis
When is conservative managment usually chosen in a patient?
When they are elderly and choose not not to have dialysis Instead opt for symptom and control and erythropoetin for the anaemia
What eGFR should NSAIDs be avoided in?
CKD 4 (Avoid if eGFR less than 30 mL/minute/1.73 m2)
