Session 11: Group Work Flashcards
Which patient characteristics can make serum creatinine an unreliable measure of kidney function and explain why.
Male
Big muscly
Black
Old
Female
Small
White
Which factors are considered in the calculation of an eGFR.
Serum creatinine
Size
Age
White or black
Sex
Why is eGFR an unhelpful test in AKI?
It assumes that the creatinine levels are relatively stable over a few days and not rapidly changing. THis is why eGFR is not valid in AKI.
What happens to urea in terms of filtration, reabsorption and secretion?
It is filtered and then 50% are reabsorbed in the PCT
More reabsorbed in the collecting duct of the medulla as well.
IT can go and be secreted back into the thin ascending limb again for recycling and working as an effective osmole
How will the serum urea levels be in
a - AKI due to volume depletion
b - malnutrition
c - upper GI bleed
A - high serum urea (low volume leads to more Na+ reabsorbed and therefore less urea that is being secreted)
B - lower serum urea (less urea produced from proteins)
C - High serum urea (blood digested into urea)
List symptoms that a patient may present with that are present if the kidneys are failing?
Hyperkalaemia
Uraemia
Malaise
Lethargy
Insomnia
Fatigue
Aches
Pruritus
Bone disease
Acidosis
Oliguria
Anuria
Oedema
What is the difference between oliguric and non-oliguric patients with AKI?
Oliguric don’t wee as much as non-oliguric.
Oliguria is defined as less than 500 ml of urine produced in 24 hours
What is pre-renal AKI and what might cause this?
Hypoperfusion such as hypovolaemia (septic or distributive shock)
Renal artery stenosis
NSAIDs
ACE inhibs
ARBs
What is post-renal AKI and what might cause this?
Obstruction of urinary tract
Kidney stones
Urinary calculi
Cancer of urinary tract
Define acute tubular injury (ATI)
Damage to the cells of the tubules and interstitium of the kidneys
An intrinsic kidney injury
What are the risk factors or possible causes of ATI?
Pre-renal casues
NSAIDS
Nephrotoxic durgs like antiobiotics (gentamicin)
Contrast
Myoglobin
Bilirubin
Smoking
Hypertension
Diabetes
What two blood chemistry values are reflective of the kidneys ability to excrete waste?
Serum creatinine
Urea
Describe the patient’s acid-base status and suggest why this has occurred in the patient.
Metabolic acidosis as well as respiratory acidosis.
Metabolic acidosis because of the breakdown of muscle in his left leg leading to lactic acidosis. Also renal failure leading to a failure to reabsorb bicarbonate.
He is also on opiates leading to hypoventilation and retention of CO2 leading to respiratory acidosis.
AKI due to rhabdomyolsysis is suspected in this case. What characteristic of this urine is suggestive of this diagnosis and what circumstance might have caused the rhabdomyolysis?
Very dark brown urine and haematuria.
Possible DVT or thrombophlebitis.
Possible compartment syndrome
Rhabdomyolysis is caused by muscle damage. What is released that causes AKI?
Myoglobin which is nephrotoxic
How would you confirm your diagnosis?
Creatine kinase
Serum creatinine
Explain the mechanisms that have led to a high K+ in this patient.
Suggest three different mechanisms that may be contributing to hyperkalaemia in this patient.
Low glucose leading to less insulin and therefore less K+ going into cells.
Cell breakdown leading to expelled K+
Acidosis which means that H+ is being transported into cells in exchange for K+
Na+ is spared in exchange for K+ in the kidneys
Does that patient’s creatinine result surprise you?
No the kidneys are shutting down and can’t fitler the serum creatinine.
There is also increased creatine kinase which will lead to more creatinine (increased muscle breakdown)
Would you expect his anion gap to be normal?
Increased due to lactic acidosis
What is the principle of managing patient’s with this condition?
Fluids
Insulin+glucose
Naloxone
What is the most likely cause of her AKI?
Hypoperfusion
What factors have contributed?
Low BP
Ace inhibs
NSAIDs
Diarrhoea + vomiting
Is her pulse rate higher or lower than you would expect?
Why?
Lower
Would have expected higher in order to compensate for the low BP
Why is the skin around her legs wrinkled?
Fluid depletion
Are her sodium and potassium what you would expect them to be?
Suggest and explanation for her electrolyte results.
Na+ should be low but the as there is only loss of Na and H2O and also only replacement of water.
K+ should be high in AKI but is rather low which might happen in diarrhoea and vomiting
What would be your initial management of this patient?
Are there any particular precautions in this case?
How would you minimise the risk of harm?
Fluid replacement with Na+ and K+
Stop bisoprolol, ramipril and furosemide
Watch out for heart failure
