Acute Kidney Injuries

How long is the delay with kidney injury?

48-72 hours

What is the creatinine level of a septic patient?

50% less than healthy

T/F urine output is the same as GFR?

False

What is the most common causes of acute kidney injury in dogs?

Toxic, infectious, other

What is the most common causes of acute kidney injury in cats?

Obstruction, unknown, infectious

What can cause acute kidney injury in a hospital?

Use of nephrotoxic drugs

Hemodynamic instability left untreated

Volume overload

What is a hemodynamic (pre-renal) acute kidney injury?

Renal hypoperfusion or excessive vasoconstriction

What can cause hemodynamic (pre-renal) AKI?

Hypovolemia

Decreased CO

Systemic vasodilation

Renal vasoconstriction due to Norepi, sepsis, hypercalcemia, drugs

What are the characteristics of hemodynamic AKI

Rapidly reversible once inciting cause is eliminated

How do you treat hemodynamic AKI?

Restoration of perfusion

What are causes of renal AKI?

Prolonged ischemia

Infectious dz

Toxins

Systemic disease

What are the phases of renal AKI?

Initiation/induction

Extension

Maintenance

Recovery

What happens during the initiation phase of renal AKI?

occurs immediately after the insult and pathologic damage to the kidneys occur

What happens during the extension phase of renal aki?

Ischemia, hypoxia, inflammation, cellular injury continues

What happens during the maintenance phase of renal AKI?

Clinical and laboratory findings may now by detected by an azotemia, uremia, oliguria, or anuria

What happens during the recovery phase of renal AKI?

Renal tubular repair occurs and azotemia improves. Marked polyuria may be seen

How long can recovery from a renal AKI take?

Days to weeks

How do you treat renal AKI?

Remove inciting cause

What are causes of obstructive AKI?

Urethral obstruction

Bilateral ureteral obstruction

Unilateral ureteral obstruction with a non-functional contralateral kidney

Rupture of any part of urinary system

What are the characteristics of obstructive AKI?

Rapidly reversible

How do you treat obstructive AKI?

Relive obstruction

Repair damage to the urinary tract

Remove urine

What are causes of obstructive aki?

Nephrotoxins

Ischemia

Infectious

Systemic inflammation

Neoplasia

Describe Grade 1 AKI grade

Non-azotemic AKI

• Documented AKI

• Progressive non-azotemic increase in creatine > 0.3mg/dL within 48 hours

• Oliguria or anuria over 6 hours

Describe Grade II AKI

Mild aki with a static or progressive azotemia

• Progressive azotemia with increase in creatinine > 0.3mg/dL within 48 hours

• Oliguria or anuria over 6 hours

What is the clinical description of grade III, IV, and V AKI?

Moderate to severe AKI with documented AKI increasing severity of azotemia and functional renal failure

What are the C/S of AKI?

Non-specific with short duration of illness

How is on physical exam of AKI?

Dehydration

Oral ulceration

Tongue tip necrosis

Hepatomegaly

What is USG with intrinsic AKI?

Isosthenuric

What is USG of a hemodynamic AKI?

Adequate

What can indicate PCT damage on a dipstick?

Glucosuria, proteinuria, ketonuria

What is the pH of urine during AKI?

Acidic

What can be found on microscopic analysis of urine of a AKI?

Casts

Crystals

Microorganisms

T/F you can get bilirubin and hemoglobin in the urine during AKI?

True

What can a leukocytosis tell you with AKI?

It might be infectious

What is on the biochemistry of an AKI?

Azotemia

Hyperphosphatemia

Hyperkalemia

Metabolic acidosis

Why can BUN be disproportionately increased compared to creatinine?

Skinny animal or GI bleed

Why can a cat have severe azotemia but still eat and has mild clinical signs?

Cat might have eaten a lily or urethral obstruction

Why can a patient have azotemia, metabolic acidosis, hyperkalemia, mild hyponatremia?, and hyperphosphatemia

Uroabdomen

Why can a patient have massive hypercalcemia, hyperphosphatemia, azotemia, and hyperproteinemia?

Anuria, oliguria, rupture or block

Why can a patient have azotemia, elevated liver enzymes, hypokalemia, thrombocytopenia?

Infectious

What does AKI with hypocalcemia and high anion gap metabolic acidosis point you too?

Ethylene glycol

What do you look for on a radiograph?

Size and shape of kidney

Presence of urolith

What can you look for on abdominal ultrasound?

Size and shape of kidney

Echogenicity

Cysts, masses, obstruction

What is pyelectasia?

Renal pelvis is dilated

What can cause pyelectasia?

PU/PD

Obstruction

Pyelonephritis

What is renal hyperechogenicity?

Denser in US

When do you get subcapsular fluid in the kidney?

Acute injury

Lymphoma

Leptospirosis

What is the first step to managing AKI?

Rule out things not directly related to kidney like urinary tract obstruction or rupture

What is the second step of diagnosing AKI?

Look if it is pre-renal AKI by

• Check blood pressure

• Test response to fluids and if no response in 8-12 hours than it is intrinsic AKI

How much fluid do you give initially when deciding if it is pre-renal AKI?

Use vitals to give the minimum because if you give too much you can make it worseH

After getting to a intrinsic AKI what do you need to do?

Specific testing to remove underlying cause with a prioritized differential diagnosis

What are some specific tastings you should do with renal AKI?

Bacterial culture, ethylene glycol, Lepto, RMSF, Lyme, Leishmania, Ehrlichia, Babesia, FNA

What are the parts of your treatment plan for AKI?

Specific therapy

Supportive therapy

What are the goals of fluid therapy?

DO NOT CAUSE FLUID OVERLOAD BUT

• Correct and maintain hydration

• Acid-base and electrolyte normal

What are the impacts of fluid overload?

Interstitial edema leading to impaired cellular oxygenation

Renal edema leading to increased parenchymal pressure and decreased GFR

Elevated blood pressure

Increased mortality

What fluid type do you want for AKI?

Buffered crystalloid solutions like Ringer’s lactate

What are the risks of saline for AKI fluid therapy?

Metabolic acidosis

Chloride load

Excess sodium

Increased workload on the nephrons leading to hypernatremia, hypervolemia, hypertension, and edema

What is the ROSE model?

Rescue

Optimize

Stabilize

De-escalate

What happens during the rescue phase?

Replace fluid deficits

Restore normal perfusion ASAP

Stop fluids after getting a response to prevent overload

How to you optimize fluids?

Decide if they are urinating too much, or little to keep a neutral fluid balance

What are your ins while doing fluid therapy for AKI?

IV fluids

Enteral nutrition

Catheter flushes

CRIs

What are the Outs of your fluid therapy for AKI?

Sensible losses

Insensible losses

Urine output

Feeding tube aspirations

How do you optimize fluid therapy?

Monitor body weight, BP, lactate, vitals, electrolytes, acid-base, BP

How do you stabilize during fluid therapy?

Use enteral routes

Can use antiemetics and gastroprotectans

When can you de-escalate fluid therapy for AKI?

Azotemia and body weight are stable on a fixed rate of IV and enteral fluids

How do you descalate fluid therpy?

Decrease fluid rate by 10-25% per day

Urine output decreases in line with the fluids and maintains a stable weight and perfusion

IV fluids can be tapered

Why do you give diuretics for AKI?

If there is persistent oliguria or anuria to manage fluid overload

Giving a diuretic will only help what?

Continue parenteral medication

Nutrition

What is renal replacement therapy?

Dialysis

Describe RRT

Identify need early to be effective

It will provide kidney vacationWEhat

What are the indications for RRT?

When consequences of azotemia are refractory to medical management

Fluid overload

Severe progressive intrinsic renal azotemia

Refractory hyperkalemia

Persistent oliguria/anuria

Severe persistent acid-base disturbances

What is the mortality for AKI?

About 50% with 60% of them getting chronic renal disease

What does polyuria do to the prognosis of AKI?

increases it