hydrogen peroxide poisoning

introduction

hydrogen peroxide is an oxidising agent that is used in a number of household products, including general-purpose disinfectants, chlorine-free bleaches, fabric stain removers, contact lens disinfectants and hair dyes, and it is a component of some tooth whitening products.
hydrogen peroxide causes toxicity via three main mechanisms:
- corrosive damage - particularly if concentrated solutions > 35%
- oxygen gas formation
  - 30 mL of 35% hydrogen peroxide yields 3.5 L of oxygen
- lipid peroxidation

ingestion of 35% solutions can be lethal in adults and children
sinus tachycardia, lethargy, confusion, coma, convulsions, stridor, sub-epiglottic narrowing, apnoea, cyanosis and cardiorespiratory arrest may ensue within minutes of ingestion
excessive generation of oxygen within the GIT may result in:
- foaming at the mouth with potential to obstruct resp. tract or cause pulmonary aspiration or laryngospasm
- painful gastric distension with belching
- potential for hollow viscus rupture
- arterial gas embolism
  - this may cause stroke (CVA)
- venous gas embolism
  - this may cause intravascular foaming following absorption which can seriously impede right ventricular output and produce complete loss of cardiac output
GIT irritation via direct cytotoxic effect
- blistering of the mucosae and oropharyngeal burns
- nausea, vomiting, haemorrhagic gastritis, haematemesis

nil orally
contaminated skin should be washed with copious amounts of water
skin lesions should be treated as thermal burns
affected eyes should be irrigated immediately and thoroughly with water or 0.9% saline for at least 10-15 minutes
consider NGT if gastric distension
early aggressive airway management is apparently critical in patients who have ingested concentrated hydrogen peroxide, as respiratory failure and arrest appear to be the proximate cause of death.
endoscopy should be considered if there is persistent vomiting, haematemesis, significant oral burns, severe abdominal pain, dysphagia or stridor
endotracheal intubation, or rarely, tracheostomy may be required for life-threatening laryngeal oedema

most inhalational exposures cause little more than coughing and transient dyspnoea, inhalation of highly concentrated solutions of hydrogen peroxide can cause severe irritation and inflammation of mucous membranes, with coughing and dyspnoea.
shock, coma and convulsions may ensue and pulmonary oedema may occur up to 24-72 hours post exposure.