Hydrogen peroxide poisoning: an unusual cause of portal venous gas

Abstract

Hydrogen peroxide (H₂O₂) is an oxidizing agent found in many household products. It is a clear liquid at room temperature, allowing it to be mistaken for water if unlabelled. Ingestion of H₂O₂ can have serious sequelae even in low volumes and concentrations.We present a case study of H₂O₂ poisoning and discuss the pertinent radiographical findings.

Summary

Hydrogen peroxide (H₂O₂) is an oxidizing agent found in many household products. It is a clear liquid at room temperature, allowing it to be mistaken for water if unlabelled. Ingestion of H₂O₂ can have serious sequelae even in low volumes and concentrations. We present a case study of H₂O₂ poisoning and discuss the pertinent radiographical findings.

Clinical presentation

A healthy 21-year-old male unintentionally ingested approximately one mouthful of 3% H₂O₂ stored in his relative’s refrigerator. He presented to the emergency department with vomiting and pain in his mouth, throat and epigastrium. He was tachycardic (100 beats min⁻¹) and mildly hypertensive (155/100 mmHg) but not hypoxic (SpO₂ 97% on room air). A clinical examination revealed dysphonia with mild erythema and oedema of the oropharynx and uvula; the abdominal and respiratory examinations were otherwise unremarkable. Blood and biochemical investigations were also normal.

Imaging findings

A CT scan was performed to exclude gastrointestinal perforation, which demonstrated pneumatosis and mucosal thickening throughout the stomach and proximal duodenum, as well as extensive portal venous gas (Figures 1–3).

Figure 1.

Axial portal venous phase CT image showing gastric mucosal thickening with portal venous gas.

Figure 3.

Coronal portal venous phase CT image showing gastric mucosal thickening and pneumatosis with portal venous gas.

Figure 2.

Axial portal venous phase CT image showing gastric mucosal thickening and pneumatosis (arrow).

Treatment

The patient was intubated owing to concerns for developing airway involvement and gastrointestinal perforation, and conservative treatment with intravenous piperacillin/tazobactam 4.5 g four times daily and intravenous pantoprazole infusion at 8 mg hour⁻¹ was commenced prior to transfer to a tertiary intensive care unit.

Outcome

An upper endoscopy performed 3 days after the ingestion was normal, with no evidence of mucosal injury. A repeat CT scan at this time revealed interval partial resolution of the bowel wall thickening and complete resolution of the pneumatosis and portal venous gas (Figure 4). The patient was discharged 3 days after presentation on oral pantoprazole and antibiotic therapy, and made a full recovery.

Figure 4.

Coronal CT image with intravenous and oral contrast showing interval resolution of pneumatosis and portal venous gas.

Discussion

H₂O₂ is an oxidizing agent that is available in concentrations ranging from 3% to 90%.¹ It is found in numerous household products, including disinfectants, hair dyes, bleaches and stain removers. It is a clear, colourless liquid at room temperature,² allowing it to be mistaken for water if unlabelled, as in this case. Recently, H₂O₂ has also been sold for consumption in small volumes following promotion of its purported natural health benefits,³ despite multiple documented fatalities from its ingestion² and no evidence to demonstrate health benefits of any kind. Upon contact with the enzyme catalase in the gastric mucosa, H₂O₂ undergoes rapid decomposition into oxygen and water (2H₂O₂ → 2H₂O + O₂ + heat).⁴ If the amount of oxygen liberated exceeds the maximum solubility of blood, bubbles migrate through the epithelial interstices and gas embolism may occur, manifesting as pneumatosis³ or gas within the portal venous system,⁵ brain⁶ and coronary arteries.⁷ Toxicity is also caused by direct caustic injury to the gastric mucosa, resulting in gastritis and potential rupture, as well as cytotoxicity from lipid peroxidation.¹ This particular case is unusual because gas embolism usually only occurs with ingestion of the stronger 35% H₂O₂ solution, with only a few other published case reports of portal venous gas following ingestion of the 3% solution. ^8,9

Learning points

1. Ingestion of H₂O₂, a common household item, can have serious sequelae even in low volumes and concentrations.

2. Radiographical findings may include gastritis, pneumatosis, perforation and portal venous gas.