Ethanol, Xylitol, and Methylxanthines Flashcards

1
Q

Diets containing __________ have caused ethanol toxicosis in calve, lambs, and pigs due to yeast fermentation in the GI tracts

A

Glucose (18-60%)

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2
Q

What is the distribution of ethanol?

A

Distributed widely including CNS

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3
Q

How is ethanol metabolized?

A

Hepatic alcohol dehydrogenase —> acetaldehyde
Aldehyde dehydrogenase —> aldehyde
-> acetyl CoA -> CO2 -> water

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4
Q

What is the MOA of ethanol?

A
CNS depression as ethylene glycol and propylene glycol 
Vasodilation as acetaldehyde
Acidosis from acetate
Diuretics - ethanol inhibit ADH 
Irritation of mucous membranes
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5
Q

Clinical signs seen in acute toxicosis due to ethanol poisoning?

A
CNS depression 
Abnormal behaviour -> vocalization, excitement, and disorientation 
Hypothermia, tremor and ataxia 
Congested mucous membranes 
Polydispia and dehydration 
Death from respiratory failure
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6
Q

Laboratory diagnosis for ethanol toxicosis?

A

Blood alcohol levels (>1-1.5g/L)

Hypoglycemia

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7
Q

Treatment for ethanol and methanol toxicosis ?

A

Methanol - fomepizole and ethanol

Emetic in recent ingestion, and gastric lavage

Supportive and symptomatic treatment
- Iv injection of thiamine
Naloxone can antagonize CNS depression

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8
Q

What is xylitol?

A

Sugar alcohol that tastes like surgar

Used as substitute in gums, and, and diabetic diets

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9
Q

What is the MOA of xylitol ?

A

Potent promoter or insulin release in dog —> hypoglycemia and hypokalemia

Large dose can cause liver failure, GI hemorrhage and DIC

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10
Q

Clinical signs of xylitol toxicity?

A

Weakness, ataxia, collapse, seizure, vomiting, diarrhea, icterus, and intestinal hemorrhage (within 12-24hrs)

Liver failure and DIC within 48hrs

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11
Q

Laboratory diagnostics associated with xylitol toxicity?

A

Hypoglycemia
Elevated liver enzymes

Liver failure causes

  • hypoglycemia
  • hyperglobulinemia
  • moderate to severe elevations of serum activity of liver enzymes
  • hyperphosphatemia
  • prolonged clotting times and thrombocytopenia
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12
Q

Treatment of xylitol toxicity?

A

Induce vomiting
50% dextrose followed by continuous IV infusion until blood glucose returns to normal

Response in usually within 12-24 hours

Oral feeding of sugar or sugar-containing meals is prophylactic before clinical signs appear

Fluid therapy
Antibiotics with acute liver fialure
Antacids and GI protectants in acute hepatic failure

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13
Q

What are the methylxanthine alkaloids?

A

Caffeine, theophylline, and theobromine

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14
Q

Metabolism and excretion of methylxanthines?

A

Met in liver
Ex in bile > enterohepatic recycling
Ex in urine as unchanged metabolites

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15
Q

What is the MOA of methylxanthine?

A

Competitive inhibition of adenosine
Inhibition of phosphodiesterase - Increased cAMP
Release of catecholamine from adrenal
Inhibit Ca sequestration in SR -> entry into cardiac and skeletal muscle

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16
Q

Clinical signs of methylxanthine toxicosis?

A
Restlessness
Hyperactivity 
PU/PD 
Urinary incontinence 
Vomiting
Tachycardia
Hypertension 
Weakness
Ataxia
Diarrhea
Cardiac arrhythmia 
Seizure 
Hyperthermia
17
Q

Treatment of methylxanthine toxiciosis?

A

Early decontamination - induction of vomiting
Supportive for cardiac and neurological signs
IV fluid therapy
Diazepam IV to treat seizures, muscle tremors, and hyperactivity

Monitor ECG
B blocker for tachyarrythmias
Atropine if bradycardia