Acute kidney injury Flashcards
what does acute on chronic mean
refers to an acute injury suffered in addition to pre-existing chronic renal disease – the injury may or may not be related to the cause of pre-existing disease.
What are the 3 categories of acute kidney injury
Haemodynamic
Intrinsic renal
post renal
Describe how to resolve haemodynamic acte injury
correcting the underlying cause (often via fluids to restore renal perfusion)
list 3 common causes of Haemodynamic acute kidney injury
hypovolaemia
anaesthesia
use of NSAIDs
describe intrinsic renal injury
True renal damage – most commonly ischaemic /hypoxic or toxic in nature.
List 3 nephrotoxins that can cause intrinsic renal injury
NSIADs
Ethylene Glycol
Lillies (cats)
List 2 causes of post renal injury
urinary obstruction- blocked bladder
urinary leakage- uroabdomen
What are the 4 phases of AKI- intrinsic
phase 1- asymptomatic- towards end of this phase azotaemia begins to develop
Phase 2- hypoxia and inflammatory responses propagate renal damag
Phase 3- can last up to 3 weeks
Phase 4- recovery phase, can last weeks to months- Na lost and svere polyuria –> can lead to hypovolaemia- kidney trying to fix itself
What do you look for in the history that suggests AKI
Presence of a predisposing factor e.g. anaesthesia, toxin exposure
<1w history – anorexia, vomiting, PUPD, lethargy, diarrhoea.
List what we see on clinical exam with AKI
renal pain +/- palpable enlargment
jaundice
signs associated with fluid loss
signs associated with concurrent illness e.g. sepsis
If you see jaundice in an unvaccinated animal with renal pain and vomiting what should you think
Lepto
what do we tend to see on biochem with AKI
azotaemia
Hyperphosphataemia (relatively marked)
Hyperkalaemia – to a possibly dangerous level
hypocalcaemia
Elevated hepatic parameters in Lepto
what to we tend to see on urinalysis with AKI
Inappropriate USG- dilute when animal is dehydrated
Proteinuria
Glucosuria
what is the normal size of kidneys
Dogs – 5.5 - 9.1x Aortic Diameter
Cats – 3 – 4.3cm in length
when is peri-renal free fluid seen
lepto in dogs
or
lymphoma in cats
what should you test every dog with a possible AKI for
Lepto
because it is zoonotic
what do we see with lepto
renal damage
thrombocytopaenia
anaemia
electrolyte disturbances
25% of dogs get hepatic damage
75% get dyspnoea
Describe how to diagnose lepto
SNAP lepto antibody test- (needs antibodies to have been generated, so early false negatives)
so if tests neg and has suggestive clinical signs - send off blood/urine samples for PCR
Treatment of AKI
Fluid therapy
monitor urinary output, and fluid intakes - or via body weight
change fluid rate based on these - need to match losses
define oliguria
<1ml/kg/hr in the hydrated and perfused patient
define Anuria
little to no urine in the hydrated and perfused patient
when is dialysis (renal replacement therapy) indicated
for the non-responsive patient to fluid therapy or acute poisoning e.g. lilly/ethylene glycol toxicity in cats.
Very expensive so not used much
what is the complications associated with peritoneal dialysis
are moderate, including causing a septic abdomen.
what is a good first line AB for suspected urinary tract infection
TMPS- for E.coli
Could use amoxyclav but getting moved to second line
what is a good AB for lepto
doxycycline
why should we avoid ACE inhibitors in AKI animas
they try to reduce blood pressure but they reduce afferent renal blood flow
which will damage kidneys further
what is the prognosis of AKIs
depends on what problem is and the owner finances
Realistically – in the non-obstructive, non-infectious case, there is a 50/50 chance for a good outcome.
What is haemodynamic acute kidney injury
it is reduced renal blood supply
