Acute Kidney Injury Flashcards
What does acute kidney injury imply?
That there is an abrupt reduction in kidney function but they still have the ability to compensate for something. They can heal!
What can AKI cause?
A. Inability to maintain fluid
B. Electrolyte imbalances
C. Acid-base imbalance
D. Azotemia
The purpose of fluid therapy is to maintain these so the kidneys can heal
What are the three parts of azotemia?
Pre-renal, Renal, and Post-renal
What can cause Pre-renal azotemia?
Dehydration
Urine will be hypersthenuric (USG > 1.035) which means the kidney is working!
What can cause renal azotemia?
Damage to the nephrons - many causes
Urine will be isosthenuria (USG 1.008 - 1.012) which means its not concentrating.
What can cause post-renal azotemia?
Urinary outflow obstruction
How can you localize azotemia to pre, renal, and post?
A urinalysis with USG.
What must you also consider with isosthenuric or gray zone urine?
It could be:
1. Pre-renal azotemia superimposed on an inability to concentrate urine due to some other cause.
2. Anything that causes PU/PD
What are the four stages of AKI pathophysiology?
- Initiation
- Extension
- Maintenance
- Recovery
What happens during initiation of AKI?
There is an insult to compromise kidney function like ischemia, a toxin, infection, obstruction, etc. that damages the tubular cells.
Often no clinical signs
What happens during the extension phase of AKI?
Original insult is amplifies with more hypoxia and an inflammatory response develops. Duration is 1-2 days.
Renal tubular cells undergo necrosis
What happens during the maintenance phase of AKI?
GFR will bottom out and lasts 1-2 weeks.
Renal blood flow returns to normal with repair of the cells. The tubules begin to be repaired and polarity reestablished
What happens during the recovery phase of AKI?
GFR rises and may fully recover.
May be residual CKD
Cellular repair continues with polyuria
Lasts weeks to months
Does the IRIS AKI grading scale correlate with prognosis?
No! The grade I-V system only shows the degree of injury by measuring creatinine levels and other parameters
What etiologies can cause AKI?
Ischemia, toxins, infection, neoplasia, obstructions
Most common is undetermined!
What can cause ischemia?
Shock, Hypotension, Thromboembolism or infarction
Know that toxins can cause AKI. What is the specific toxin that can cause Fanconi syndrome?
Chicken jerky treats
What is acquired Fanconi syndrome and what are the classic findings associated with it?
Damage strictly to the proximal tubules
Findings include:
1. Hypophosphatemia
2. Glucosuria
3. Acidosis
4. Normal to low blood glucose
5. Hypokalemia
6. Azotemia
What types of infection can cause AKI?
- Pyelonephritis
- Feline infectious peritonitis
- Leptospirosis
- Prostatitis
What types of neoplasia can cause AKI?
- Lymphoma
- Adenocarcinoma
- Sarcoma
- Nephroblastoma
What types of obstruction can cause AKI?
- Calculi
- Mucous plugs
- Dried blood
- Tumors
- Urethral/ureteral strictures
Can anemia be seen with AKI?
Possibly if there is acute GI hemorrhage, but more commonly its only in the chronic disease
With AKI, what chemistry values would be seen?
Azotemia from a lack of BUN/Cre filtering, hyperphosphatemia, elevated SDMA, possibly hyperkalemia but could go either way
What does uremia cause in AKI, and why is it present?
There is a lack of filtering of the nitrogenous waste products
Signs include nausea, vomiting, anorexia, uremic breath and oral ulcerations
