Hydrazine toxicity
Revision as of 19:56, 1 October 2019 by ClaireLewis (talk | contribs)
Background
- Clear, colorless liquid that has an ammonia-like odor
- Powerful reducing agent that is highly reactive
- Exposure to metal oxides makes it highly exothermic and combustible
- Used in rocket fuels, missile fuels, aircraft emergency power unit fuel (notably the F-16)
- Used in chemical manufacturing (intermediate for insecticides/herbicides/dyes, polymerization catalyst for making plastics, used to manufacture sodium azide [air bag propellant], used to make isoniazid and fluconazole
Toxic Dose
- OSHA limit 1 ppm in air for 8-hour workday
- NIOSH recommends 0.03 ppm in air for 2-hour period
- Odor threshold 3.7 ppm in air
Routes of Exposure
- Inhalation
- Skin contact / absorption (rapid within 30 seconds of contact)
- Ingestion
Mechanism of Action
- Hydrazine + ketone/aldehyde = hydrazones + B6 = hydrazones of pryidoxine
- "consumes" B6 in body
- functional B6 deficiency results
- Metabolism of hydrazine produces free radical intermediates
- Inhibits pyridoxine kinase as well as glutamic acid decarboxylase which results in decrease production of GABA neurotransmitter
Clinical Features
- Short term inhalation exposure may cause:
- Cough, oropharyngeal/pulmonary irritation
- Pulmonary edema
- CNS Depression, seizure, tremor
- Long term inhalation exposure:
- Above, plus may cause liver and kidney damage
- Ingestion
- Nausea/vomiting
- Uncontrollable shaking, seizure, nerve inflammation/polyneuritis, coma
- Contact exposure
- Dermatitis, chemical burns
- If absorbed systemically, can -> hemolytic anemia, methemoglobinemia
Differential Diagnosis
Evaluation
Management
Mild to Moderate Exposure
- Ensure patient has been decontaminated
- Irrigate eyes with normal saline or water if exposed
- Treat chemical burns if present
- Monitor pulmonary status
- Monitor for development of methemoglobinemia
Severe Exposure
- Seizures - pyridoxine 25 mg/kg IM or IV up to 5 grams plus benzodiazepine
- Respiratory distress - secure airway and assist ventilation
- Methemoglobinemia - initiate oxygen therapy, give methylene blue if patient is symptomatic; Methylene blue dose 1 mg/kg IV over 5 to 30 minutes repeat dose may be given 1 hour after first if symptoms persist
- Consider hemodialysis and acidification of urine if member has severe CNS depression
- Hypoglycemia treat with D10 and thiamine
Disposition
- Home in cases of mild skin exposure without burns
- Observation for patients with inhalation or ingestion exposure for at least 12 hours to ensure no serious symptoms develop
- Admit patients with CNS symptoms or persistent pulmonary/gastrointestinal symptoms