(SYNOPTIC) AKI & CKD Flashcards
What term has ‘acute kidney injury’ replaced?
Acute renal failure
How is AKI loosely defined?
An abrupt/ acute decline in kidney function
- e.g. glomerular filtration
Hours or days
What is the official definition of AKI? as in serum creatinine and urine volume
How much serum creatinine has increased from its baseline level over a set period of time
OR
How much urine volume has decreased over a set period of time
How is stage 1 of AKI defined?
(1) 1.5-1.9 times baseline SERUM CREATININE
(2) <0.5ml/kg/h of urine for 6-12 hours URINE OUTPUT
How is stage 2 of AKI defined?
(1) 2.0-2.9 times baseline SERUM CREATININE
(2) <0.5ml/kg/h of urine for ≥12 hours URINE OUTPUT
How is stage 3 of AKI diagnosed?
(1) 3 times baseline SERUM CREATININE
(2) Initiation of renal replacement therapy
(3) Anuria ≤12 hours
How many stages of AKI are there?
3 stages
How many classifications of AKI are there?
3
What are the classifications of AKI?
(1) Pre-renal
(2) Post-renal
(3) Intrinsic
What is pre-renal AKI?
Reduced blood flow to the kidney
What causes pre-renal AKI?
- Reduced BP
- Hypovalaemia (decreased blood volume)
- Dehydration
- GI bleed
- Sepsis
- Cardiac & liver failure
- Burns
- Medications
What is post-renal AKI?
Obstruction to outflow from the kidneys
What causes post-renal AKI?
- Benign prostatic hypertrophy (BPH)
- Prostate cancer
- Renal calculi
- Retroperitoneal fibrosis
- Medications
What is intrinsic AKI?
Damage to the functional tissues of the kidney
What causes intrinsic AKI?
- Acute interstitial nephritis
- Myeloma
- Rhabdomyolysis
- Immunological renal disease
- e.g. vasculitis/ medications
What is the most common classification of AKI?
Pre-renal
Why is it important to check blood creatinine levels?
- If rising, could indicate kidneys are not functioning correctly
- Determine sufficiency of kidney function
- Determine severity of kidney damage
- Monitor progression of kidney disease
How can GFR be calculated?
(1) eGFR (mL/min/1.73m^2)
2) Creatinine clearance (mL/min
What are disadvantages of using eGFR to estimate GFR?
- Does not account for a patient’s bodyweight
- Can dramatically underestimate the creatinine clearance in renal failure
- Not interchangeable between labs
How is creatinine clearance measured?
Cockcroft + Gault equation
What is the Cockcroft & Gault equation?
CrCl = [F(140-age) x weight] / serum creatinine
F = 1.04 in females and 1.23 in males
What is F in females?
1.04
What is F in males?
1.23
What is eGFR?
Estimated glomerular filtration rate
Calculated in labs
What are the units for eGFR?
mL/min/1.73m2
Which method of GFR calculation is more accurate?
Creatinine clearance
When must creatinine clearance be calculated, instead of eGFR?
Patients who:
(1) Are on DOACs
(2) Are on nephrotoxic drugs
(3) >75yrs
(4) Extremes of muscle mass
(5) Drugs that are highly renal excreted
(6) Narrow therapeutic index drugs
What is the action to be taken when eGFR or creatinine clearance is low?
(1) Establish if AKI or CKD
(2) Review all medications
- Change dose/ frequency
- Stop/ hold
(3) Does literature suggest dose changes?
What is CKD?
Abnormalities of kidney function for >3 months, with implications for health
What are some risk factors for CKD?
- Diabetes
- HTN
- Kidney disorders
- CVD
- AKI
- Infections (of urinary tract)
- HIV/ HepC
- Medications (lithium, NSAIDs, etc)
- Malignancy
- Age
- Family Hx of CKD
What are some prompts/ findings that will lead to checking for CKD?
(1) Persistent microalbuminuria
(2) Persistent proteinuria
(3) Persistent haematuria (exc. other sources)
(4) Ultrasound/ biopsy (imaging)
What are three main functions of the kidney?
(1) Homestasis: regulate the balance of fluids and electrolytes in the body, as well as the levels of certain hormones and waste products
(2) Hormone function: kidneys produce hormonones: e.g. renin, prostaglandins, EPO and calcitrol
(3) Metabolic function: efer to the role of the kidneys in regulating the levels of various substances in the body, including electrolytes, glucose, amino acids, and hormones
What are some clinical complications of CKD?
- Acidosis
- Anaemia
- Dyslipidaemia
- Fluid overload (less able to excrete water)
- Hyperkalaemia
- HTN
- Mineral & bone disorder
- Uraemia
ø Raised levels of urea in the blood
What is acidosis?
Inability of kidneys to maintain blood pH
CKD progresses - kidneys are less able to excrete H+ and reabsorb HCO3-
How is acidosis managed?
Long-term oral sodium bicarbonate
Sodium bicarbonate 1g TDS
When is 1g sodium bicarbonate TDS PO an appropriate treatment?
Acidosis
What is the acute treatment of metabolic acidosis?
IV sodium bicarbonate
What are some side-effects of acidosis?
Secondary increase in sodium retention
Be aware of fluid retention
What is renal anaemia?
Quality/ quantity of RBCs is below normal
What causes renal anaemia?
(1) Lack of circulating iron
(2) Lack of erythropoietin