The special challenge of patients with diabetic ketoacidosis (Proceedings)

Pathophysiology

• Ketone bodies:  acetoacetate, beta hydroxybutyrate, acetone

• Oxidation of free fatty acids

• Mobilization of fatty acids from adipose tissue

• Shift from fat synthesis to fat oxidation in the liver

• Relative/absolute deficiency in insulin

• Mitigating factor

• elevation in glucose counter-regulatory hormones, especially glucagon

• glucagon:insulin ratio

• metabolic acidosis

• elevations in plasma free fatty acids and amino acid concentrations

• Hyperketonuria enhances osmotic diuresis and electrolyte loss into the urine

• Severe volume depletion

• Severe acidosis

• Pre-renal azotemia

Clinical presentation

• Previously diagnosed diabetes mellitus

• Previous clinical signs of diabetes mellitus

• Anorexia

• Vomiting

• Weight loss

• Tachypneic

• Tachycardic

• Lethargy

• Depression/obtundation

• Poor perfusion, weak pulses, pale mm

• Hypotension

Initial Diagnostic Assessment

• PCV/TS/AZO/DEX

• Na, K, UA (dipstick and S.G.), serum ketones

• Osmolality, blood gas

• CBC, Chemistry, Urinalysis, Urine culture

Diagnosis

• Hyperglycemia

• Glucosuria

• Ketonemia

• Ketonuria

Clinical Pathologic Abnormalities

• Elevated WBC +/- left shift if pancreatitis or underlying infection

• Elevated liver enzymes

• Icterus in some cats

• Azotemia, pre renal

• Sodium concentration normal/low

• Potassium concentration normal/low

• Acidosis

• Bacteriuria, pyuria

Treatment (in order of importance)

• Fluid Therapy

• Correct hypovolemia and poor perfusion

• Combat lactic acidosis

• Correct electrolyte abnormalities

• Preserve cardiac output and renal perfusion

• Dilute hyperglycemia

• 0.9% NaCl +/- potassium

• Potassium Replacement

Serum K (mEq/L)

KCl/L (mEq)

Maximum rate (mL/kg/h)

3.6-5.0

20

24

3.1-3.5

30

16

2.6-3.0

40

11

2.1-2.5

60

8

<2.0

80

6

• Insulin Therapy

• Rregular crystalline insulin

• 2.2 U/Kg/24 hr (dog); 1.1 U/kg/24 hr (cat) IV in separate IV bag

• CRI Insulin Therapy using Regular, Crystalline Insulin

Glucose (mg/dL)

Fluid

Insulin rate (2.2 U/kg in 250 ml) mL/hr

>250

0.9% NaCl

10

200-250

0.45% NaCl + 2.5% dextrose

7

150-200

0.45% NaCl + 2.5% dextrose

5

100-150

0.45% NaCl + 5% dextrose

5

<100

0.45% NaCl + 5% dextrose

Stop infusion

• Intermittent IM insulin technique with regular insulin

• 0.2 U/kg IM initially

• 0.1 U/kg IM hourly until blood glucose < 250 mg/dl

• Regular insulin SQ 0.5-1 U/kg q 4-6 hours after patient hydration achieved

• Bicarbonate Therapy

• Only give initially if pH < 7.0

• Otherwise wait to see if reperfusion will correct acidosis

• 0.1 x base deficit x BW(kg); add slowly over 2 hours – only 1/3    replacement amount to prevent overcorrection

• Phosphorous Therapy

• patients will often get hypophosphatemic within 1-3 days after initiation of therapy

• can cause myopathies, hemolysis, encephalopathy

• 0.01-0.03 mmol phosphate/kg/h over 6 hours and recheck

• Magnesium Therapy

• Often worsens with initial treatment

• 2.  Difficult to correct other electrolyte abnormalities until hypomagnesemia is addressed

• 0.75-1.0 mEq/kg/day IV in 5% dextrose for 24-48 hours

Initiation of Longer Acting Insulin

• Dehydration corrected

• Animal eating/drinking normally

• Electrolyte abnomralities corrected