Acute Kidney Injury

Question 1

What does acute kidney injury imply?

Answer 1

That there is an abrupt reduction in kidney function but they still have the ability to compensate for something. They can heal!

Question 2

What can AKI cause?

Answer 2

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

Question 3

What are the three parts of azotemia?

Answer 3

Pre-renal, Renal, and Post-renal

Question 4

What can cause Pre-renal azotemia?

Answer 4

Dehydration

Urine will be hypersthenuric (USG > 1.035) which means the kidney is working!

Question 5

What can cause renal azotemia?

Answer 5

Damage to the nephrons - many causes

Urine will be isosthenuria (USG 1.008 - 1.012) which means its not concentrating.

Question 6

What can cause post-renal azotemia?

Answer 6

Urinary outflow obstruction

Question 7

How can you localize azotemia to pre, renal, and post?

Answer 7

A urinalysis with USG.

Question 8

What must you also consider with isosthenuric or gray zone urine?

Answer 8

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

Question 9

What are the four stages of AKI pathophysiology?

Answer 9

1. Initiation
2. Extension
3. Maintenance
4. Recovery

Question 10

What happens during initiation of AKI?

Answer 10

There is an insult to compromise kidney function like ischemia, a toxin, infection, obstruction, etc. that damages the tubular cells.

Often no clinical signs

Question 11

What happens during the extension phase of AKI?

Answer 11

Original insult is amplifies with more hypoxia and an inflammatory response develops. Duration is 1-2 days.

Renal tubular cells undergo necrosis

Question 12

What happens during the maintenance phase of AKI?

Answer 12

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

Question 13

What happens during the recovery phase of AKI?

Answer 13

GFR rises and may fully recover.

May be residual CKD

Cellular repair continues with polyuria

Lasts weeks to months

Question 14

Does the IRIS AKI grading scale correlate with prognosis?

Answer 14

No! The grade I-V system only shows the degree of injury by measuring creatinine levels and other parameters

Question 15

What etiologies can cause AKI?

Answer 15

Ischemia, toxins, infection, neoplasia, obstructions

Most common is undetermined!

Question 16

What can cause ischemia?

Answer 16

Shock, Hypotension, Thromboembolism or infarction

Question 17

Know that toxins can cause AKI. What is the specific toxin that can cause Fanconi syndrome?

Answer 17

Chicken jerky treats

Question 18

What is acquired Fanconi syndrome and what are the classic findings associated with it?

Answer 18

Damage strictly to the proximal tubules

Findings include:
1. Hypophosphatemia
2. Glucosuria
3. Acidosis
4. Normal to low blood glucose
5. Hypokalemia
6. Azotemia

Question 19

What types of infection can cause AKI?

Answer 19

1. Pyelonephritis
2. Feline infectious peritonitis
3. Leptospirosis
4. Prostatitis

Question 20

What types of neoplasia can cause AKI?

Answer 20

1. Lymphoma
2. Adenocarcinoma
3. Sarcoma
4. Nephroblastoma

Question 21

What types of obstruction can cause AKI?

Answer 21

1. Calculi
2. Mucous plugs
3. Dried blood
4. Tumors
5. Urethral/ureteral strictures

Question 22

Can anemia be seen with AKI?

Answer 22

Possibly if there is acute GI hemorrhage, but more commonly its only in the chronic disease

Question 23

With AKI, what chemistry values would be seen?

Answer 23

Azotemia from a lack of BUN/Cre filtering, hyperphosphatemia, elevated SDMA, possibly hyperkalemia but could go either way

Question 24

What does uremia cause in AKI, and why is it present?

Answer 24

There is a lack of filtering of the nitrogenous waste products

Signs include nausea, vomiting, anorexia, uremic breath and oral ulcerations

Question 25

What values would be consistent on a urinalysis in an AKI?

Answer 25

Isosthenuria, proteinuria, glucosuria, hematuria, pyuria, bacteriuria (may not be seen), and casts

Question 26

What are some potential diagnostics besides UA for AKI?

Answer 26

Radiographs, abdominal ultrasound

Biopsy not used and FNA for renal lymphoma

Question 27

What are the 4 parts of fluid therapy in AKI?

Answer 27

1. Initial volume needs if hypotensive (resuscitation?)
2. Replace what was lost - % dehydration
3. Maintenance - about 50 ml/kg/day
4. On going losses from V/D/Urine

Question 28

What is the most important thing about measuring a patients urine output?

Answer 28

It cannot be measured until the hydration status has been corrected. Ex. Make sure they aren’t dehydrated.

Question 29

What does urine output measurement tell you?

Answer 29

Whether they are anuric (bad prognosis), oliguric, or polyuric

Question 30

Treatment for AKI:
What to give to convert a patient from oliguria to non-oliguria?

Answer 30

They MUST be rehydrated first
A. Furosemide
B. Diltiazem
C. Mannitol
D. Fenoldopam

Question 31

Treatment for AKI:
Which anti-emetics should be given?

Answer 31

Maropitant, Ondansetron, Metoclopramide CRI

Question 32

Treatment for AKI:
Which gastroprotectants?

Answer 32

Omeprazole and pantoprazole

Do NOT give famotidine. Fagotista-DON’T

Question 33

Why is it important to monitor how much blood you take from an AKI patient?

Answer 33

They have a decreased ability to heal and regenerate. You don’t want to make them anemic