UMEM Educational Pearls - Toxicology

Category: Toxicology

Title: Cyanide

Keywords: cyanide, poisoning, hydroxycobalamin (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto, MD (Emailed: 7/8/2007) (Updated: 10/18/2021)
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Cyanide Presents with arterialization of venous blood (venous blood draw looks like ABG) Reason: o Hemoglobin is not able to offload oxygen o CN poisons cytochrome c oxidase preventing conversion of oxygen to water and thus production of ATP Old antidote: sodium thiosulfate New antidote: hydroxycobalamin binds CN producing cyanocobalamin (Vit B12) When you give it expects a dip in pulse because of its blue color. Remember CN will give you a beautiful 100% pulse all the way to death. Lee J, et al. Potential interference by hydroxocobalamin on cooximetry hemoglobin measurements during cyanide and smoke inhalation treatments. Ann Emerg Med. 2007 Jun;49(6):802-5. Epub 2007 Jan 8.

Category: Toxicology

Title: Hydrofluoric Acid (HF)

Keywords: hydrofluoric acid, hypocalcemia, burn (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto, MD (Emailed: 7/8/2007) (Updated: 10/18/2021)
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Hydrofluoric Acid (HF) Used in glass etching, brick/porcelain cleaning and available in hardware stores Death has been reported after JUST 2-3% body surface area exposure! Systemic toxicity: hypocalcemia, hyperkalemia and hypomagensemia Local effects: paucity of skin findings with tremendous pain Treatment: skin decontamination, correct electrolyte abnormalities and topical calcium gel for local pain Mayer TG, GrossPI. Fatal systemic fluoride due to hydrofluoric acid burns. Ann Emerg Med 1985; 14: 149-153.

Category: Toxicology

Title: Toxic Alcohols

Keywords: Ethylene glycol, methanol, toxic alcohol (PubMed Search)

Posted: 7/14/2007 by Fermin Barrueto, MD (Emailed: 7/8/2007) (Updated: 10/18/2021)
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Toxic Alcohols Unexplained anion gap metabolic acidosis => give fomepizole (antidote) Hypokalemia, hypocalcemia, elevated creatinine => think ethlylene glycol Visual disturbances => think methanol Ketosis without acidosis and high osmol gap => think isopropanol If osmol gap is >70; high specificity for a toxic alcohol ingestion

Category: Toxicology

Title: Valproic acid toxicity

Keywords: Valproic acid (PubMed Search)

Posted: 10/16/2014 by Hong Kim, MD, MPH (Emailed: 10/18/2021)
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Valproic acid (VPA) is often used to treat seizure disorder and mania as a mood stabilizer. The mechanism of action involves enhancing GABA effect by preventing its degradation and slows the recovery from inactivation of neuronal Na+ channels (blockade effect).

VPA normally undergoes beta-oxidation (same as fatty acid metabolism) in the liver mitochondria, where VPA is transported into the mitochondria by carnitine shuttle pathway.

In setting of an overdose, carnitine is depleted and VPA undergoes omega-oxidation in the cytosol, resulting in a toxic metabolite.

Elevation NH3 occurs as the toxic metabolite inhibits the carbomyl phosphate synthase I, preventing the incorporation of NH3 into the urea cycle.

Signs and symptoms of acute toxicity include:

  • GI: nausea/vomiting, hepatitis
  • CNS: sedation, respiratory depression, ataxia, seizure and coma/encephalopathy (with serum concentration VPA: > 500 mg/mL)

Laboratory abnormalities

  • Serum VPA level: signs of symptoms of toxicity does not correlate well with serum level.
  • NH3: elevated
  • Liver function test: elevated AST/ALT
  • Basic metabolic panel: hypernatremia, metabolic acidosis
  • Complete blood count: pancytopenia

Treatment: L-carnitine

  • Indication: hyperammonemia or hepatotoxicity
  • Symptomatic patients: 100 mg/kg (max 6 gm) IV (over 30 min) followed by 15 mg/kg IV Q 4 hours until normalization of NH3 or improving LFT
  • Asymptomatic patients: 100 mg/kg/day (max 3 mg) divided Q 6 hours.

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Category: Toxicology

Title: Opioid Prescription Drug Abuse - The Pattern of Abuse

Keywords: opioids, toxicology (PubMed Search)

Posted: 11/20/2014 by Fermin Barrueto, MD (Emailed: 10/18/2021) (Updated: 10/18/2021)
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The pattern of prescription drug abuse continues to center around semisynthetic opioids like oxycodone and hydrocodone. Federal regulations have now raised hydrocodone to a schedule II drug like oxycodone. Despite efforts, the slope for natural and semisynthetic opioids remains steep.  The ED measures of education, limit prescriptions for acute pain, minimize number of days/pills prescribed and utlize the prescription drug monitoring program are some basics that can assist you in better prescribing habits.

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Category: Toxicology

Title: Opioid Prescription Drug Abuse - The Pattern of Abuse

Keywords: opioids, toxicology (PubMed Search)

Posted: 11/20/2014 by Fermin Barrueto, MD (Emailed: 10/18/2021) (Updated: 10/18/2021)
Click here to contact Fermin Barrueto, MD

The pattern of prescription drug abuse continues to center around semisynthetic opioids like oxycodone and hydrocodone. Federal regulations have now raised hydrocodone to a schedule II drug like oxycodone. Despite efforts, the slope for natural and semisynthetic opioids remains steep.  The ED measures of education, limit prescriptions for acute pain, minimize number of days/pills prescribed and utlize the prescription drug monitoring program are some basics that can assist you in better prescribing habits.

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Category: Toxicology

Title: Spider bite

Posted: 9/5/2019 by Kathy Prybys, DO (Emailed: 10/18/2021) (Updated: 10/18/2021)
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Question

A 3 year old is bitten by a spider on his right ear which is causing him intense pain, tachycardia, and muscle cramping. Identify the spider.  What is the treatment?

 

 

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Category: Toxicology

Title: Hydrofluoric Acid Burns

Keywords: hydrofluoric acid, burn, chemical burn, HFA, calcium gluconate (PubMed Search)

Posted: 9/5/2010 by Dan Lemkin, MD, MS (Emailed: 10/18/2021) (Updated: 10/2/2010)
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Hydrofluoric acid is a weak acid used primarily in industrial applications for glass etching and metal cleaning/plating. It is contained in home rust removers. Although technically a weak acid, it is very dangerous and burns can be subtle in appearance while having severe consequences.

Hydrofluoric acid burn

Wilkes G. Hydrofluoric Acid Burns. Jan 28, 2010. 
http://emedicine.medscape.com/article/773304-overview

  • 2 mechanisms that cause tissue damage*
    • corrosive burn from the free hydrogen ions
    • chemical burn from tissue penetration of the fluoride ions
  • Clinical features*
    • Cutaneous burns - absent findings to white-blue appearance
    • Pulmonary edema
    • Hypocalcemia, hyperkalemia, hypomagnesemia
  • Treatment*
    • Decontaminate by irrigation with copious amounts of water.
    • With any evidence of hypocalcemia, immediately administer 10% calcium gluconate IV.
    • Cutaneous burns:
      • Apply 2.5% calcium gluconate gel to the affected area. If the proprietary gel is not available, constitute by dissolving 10% calcium gluconate solution in 3 times the volume of a water-soluble lubricant (eg, KY gel). For burns to the fingers, retain gel in a latex glove.
      • If pain persists for more than 30 minutes after application of calcium gluconate gel, further treatment is required. Subcutaneous infiltration of calcium gluconate is recommended at a dose of 0.5 mL of a 5% solution per square centimeter of surface burn extending 0.5 cm beyond the margin of involved tissue (10% calcium gluconate solution can be irritating to the tissue).
        • Do not use the chloride salt because it is an irritant and may cause tissue damage.

*Extracted from emedicine article.

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Category: Toxicology

Title: Octreotide for Pediatric Sulfonylurea Poisoning

Keywords: octreotide, sulfonylurea (PubMed Search)

Posted: 4/12/2013 by Bryan Hayes, PharmD (Emailed: 10/18/2021) (Updated: 4/13/2013)
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Methods: A large retrospective case series evaluated 121 children under 6 years old with hypoglycemia from a sulfonylurea ingestion.

Results:

  • In addition to dextrose, patients who received octreotide had a median of zero hypoglycemic episodes after octreotide (compared to 2 before treatment, p < 0.0001).
  • Median blood glucose concentrations after receiving octreotide were also higher (62 mg/dL vs 44, p < 0.001).
  • Most required only 1 dose of octreotide with no reported adverse effects.


Authors' Conclusion: Octreotide administration decreases the number of hypoglycemic events and increases blood glucose concentrations in children with sulfonylurea ingestion.

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