L8: Renal Failure Flashcards
What are the 5 key roles of the kidneys
Elimination of waste products, control of fluid balance, control of minerals, regulation of acid-base balance and production of hormones
What is definition of AKI vs CKD
AKI: decrease in GFR over the course of hours to days
- manifested in accumulation of waste products
- increased risk of CKD, mortality, but potentially reversible
CKD: abnormalities of kidney structure or function present for 3 or more months
- decrease in GGFR over wks/mo/yrs,
How do you stage AKI (3 stages) - two factors and what are the ranges
Serum Creatinine:
1) 1.5-1.9x baseline
2) 2.0-2.9x baselines
3) 3x baseline
Urine output (usually only measured in post surgery)
1) <0.5ml/kg for 6-12 hrs
2) <0.5ml/kg for >12 hrs
3) <0.3ml/kg for >24hrs or anuria for >12 hrs
What are the 5 risk factors for AKI and what do you do if you have an at risk patient
- age >65 yrs
- CKD
- Chronic conditions - eg. DM, CHF etc
- Polypharmacy: 5+ drugs
- Specific meds: diuretics, NSAIDS, ACEi / BP medications
Need to monitor renal function in 1’ practice, - reviewing medications to prevent overtreatment
- make sick day plan to stop meds if dehydrated
What are the steps in recognising and responding to types of AKI
- Determine cause:
- Pre-renal: affecting blood supply
- Renal: within the kidney
- Post-renal: Drainage problems - Determine investigation (after history + exam)
- blood test, USS/CT imaging, renal biopsy if sus of intrarenal
3.Review meds:
any new, potential exacerbations/ accumulation: reduce dose of drugs renally excreted
- Fluids: determine if fluid overloaded/dehydrated/euvolemic and treat
- Review to see if response- repeat tests
What are the different ways to measure GFR
- Inulin clearance: (gold standard, bc it is neither resorbed nor secreted into the tubule)
GFR: volume of urine/time x conc of inulin in urine / conc of inulin in blood
- Measure how fast the kidney clears an isotope from blood: eg. Cr EDTA requires time and several blood samples Or taking pictures of the uptake of isotope into the kidney
- Creatinine produced by muscle metabolism and freely filtered at the glomerulus (ESTIMATED GFR)
= urine creatinine x urine volume / plasma creatinine x time period
What are some problems with using Creatinine clearance (4)
- Creatinine is also secreted in small amounts by the tubules thus CrCl tends to overestimate GFR
- There is a need to standardise for body size, muscle mass, gender
- moderate-> severe CKD also confounds interpretation of CrCl
- In GFR in end-stage renal disease, there is increased extra-renal excretion of creatinine + decreased muscle mass
so GFR can be overestimated
How is CKD classified - related to renal prognosis based on two measures and the ranges
-Polycystic kidney disease : autosomal dom, structural abnormality with preserved function
1stly based on cause
- eGFR category ml/min/1.73m^2
- > 90
- 60-90
- 30-59
- 15-29
- <15
- Albuminuria mg/mmol
A1 <3
A2 3-30
A3 >30 (severely increased)
What are the 6 risk factors for CKD and 4 primary causes
- Older
- Man
- Maori, Pacific
- Low income
- Obesity
- Smoking
Causes:
- Diabetic nephropathy
- Glomerulonephritis
- Hypertensive nephrosclerosis
- Polycystic kidney disease
what are the 2 factors that cause progression of CKD
Lack of control of primary causes leads to progression of CKD to end stage renal disease
- Despite 1’ disease, 2ndary factors develop which are likely to contribute to progression
How can progression of CKD be slowed down
- Managing diabetes
- Lowering BP
- Reducing Proteinuria
- Avoid nephrotoxins
=weight loss, salt restriction, alcohol moderation, moderate protein restriction
=RAAS inhib: ACEi, A2Rb
=Symp inhib,
=diuretics, aldosterone antagonists
-Reducing Ca : P less than 4.5 mmol2/L2
= limiting dietary phosphate
=Phosphate binders: aluminum hydroxide and Calcium carbonate
What are 5 other things you need to treat/monitor in someone with CKD
- Prone to dehydration and volume overload: optimise fluid balance
- Supplement 1,25 OH vit D and EPO
- Monitor for Normochromic normocytic anaemia: responds to supranormal iron or EPO
- Lack of excretion of non-organic acids leads to metabolic acidosis: give oral sodium bicarb
- Uraemia : due to organ dysfunction in CKD 4, 5 = loss of appetite, fatigue, anorexia etc
What are the main treatment options for ESKD
- Conservative:no treatment
Balance in quality of life vs quantity of life gained.
Prediction of survival based on comorbidities - serum albumin eGFR
- Dialysis : if can’t get transplant
a) peritoneal: emptying several times a day but can stay at home/travel
b) haemodialysis: 4.5 hours sessions 3 days a week
-renal transplant:
deceased or live onor.
