Morning Report: Cyanide Poisoning

CYANIDE POISONING

• Sources

1. 1. Ingestion – chemists, photographers, jewelers, lab techs have access to cyanide salts
   2. Smoke inhalation – release of cyanide from combustion of wool, silk, synthetic rubber
   3. Occupational exposure – many industrial processes involve CN (jewelers, mining, fumigation, photography)
   4. Medicinal sources – nitroprusside
   5. Food sources – pits of apricots, bitter almonds, cherry, peaches
   6. Smoking

• Pathophys – NO ATP!

1. 1. Inhibition of cytochrome a3 of ETC –> hydrogen unable to combine with oxygen at terminal end of chain –> no ATP can be made –> cellular hypoxia

• Clinical presentation

1. 1. CNS – HA, anxiety, agitation, confusion, lethargy, coma, seizure, “knocked down quickly”
   2. Cardiac – abnormalities of BP and HR
   3. Resp – tachypnea –> bradypnea
   4. Skin – cherry red skin color

• Diagnosis

1. 1. Bitter almond smell – only detected by 60% of pop
   2. Severe metabolic acidosis with increased AG and significant lactic acidosis (>7 mmol/L)
   3. VBG looks like ABG
   4. Unexplained coma and acidosis = THINK CYANIDE

• Tx

1. 1. Supportive care – ABCs
   2. Cyanide antidote kit
      • Amyl nitrite pearls

1. 1. 1. 1. Use until IV established
         2. Inhaled for 30 sec to 1 min
         3. Induces about 5% MetHb
   2. • Sodium nitrite

1. 1. 1. 1. Peds dose – 0.33 mL/kg
         2. Adult dose – 10 mL
         3. Infuse over 2-4 minutes
         4. Adv effects – vasodilation, hypotension, tachycardia
         5. Induces 7-14% MetHb
   2. • Sodium thiosulfate

1. 1. 1. 1. Peds dose: 1.65 mL/kg
         2. Adult dose: 50 mL
2. • • Mechanisms of kit
   1. 1. • Nitrite –> methemoglobinemia

1. 1. 1. 1. • CN has higher affinity for MetHb
            • MetHb of about 20-30% can be tolerated without sig adv effects
      2. • Thiosulfate
           • CN transferred from cyanomethemoglobin to thiosulfate –> thiocyanate –> peed out

3. Hydroxocobalamin

• • • MOA – chelates CN to form cyanocobalamin (vit B12) –> eliminated in urine
    • Dose
      • 2.5 gm for dilution in 100 cc NS

1. 1. 1. • Starting dose
           • Adult – 5 gram (2 vials)
           • Peds – 70 mg/kg
         • Give further doses of 5 gm (up to 15 gm total) recommended for incomplete or transient result
   2. • To know
        • Red color of hydroxocobalamin –> chromaturia and red skin for up to 2 weeks
        • Interferes with colorimetric lab tests; if given pre-hospital, EMS should draw labs first
        • Do not give in same IV as thiosulfate

4. So if concomitant CO and CN poisoning:

• • • Do not have nitrites – CO poisoning + MetHb = BADNESS
    • Suggested mgmt
      • Sodium thiosulfate +/- hydroxocobalamin
      • HBO

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• Bio
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Jay Khadpe MD

• Editor in Chief of "The Original Kings of County"
• Assistant Professor of Emergency Medicine
• Assistant Residency Director
• SUNY Downstate / Kings County Hospital

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