Pneumobilia as a complication of accidental ingestion of methyl ethyl ketone peroxide

Objective: Methyl ethyl ketone peroxide (MEKP) is a colorless, odorless organic compound used in industrial processes as a catalyst, in diluted solution (30–60%). When ingested, MEKP causes direct caustic injuries by oxygen free radical production. With metal ions, MEKP readily forms alkyl and/or peroxyl radicals inducing lipid peroxidation of digestive tract and liver. Massive ingestion of MEKP may induce acute liver failure, which is the major cause of death. Finally, during MEKP decay, various organic acids are formed, e.g. formic acid, which induce acidosis and optic neuropathy. Symptoms of acute MEKP poisoning include gastrointestinal burns and bleeding, esophageal and gastric perforation, severe metabolic acidosis, rapid hepatic failure, rhabdomyolysis and respiratory failure. As with all peroxides, MEKP may produce high volumes of oxygen which could lead to gastrointestinal distension. Case report: A 47-year-old man was admitted to the Emergency Department of Monfalcone Hospital, after ingesting a liquid from an unlabeled bottle which was mistaken for water but contained MEKP 60%. On admission he had severe epigastric and chest pain. Vital signs were normal. No oral lesions were present but he experienced vomiting and drooling. Intravenous fluids, atropine 0.5mg, metoclopramide 10mg, morphine 10mg and pantoprazole 80mg (followed by 2 g in 24 hours), were administered. Chest and abdomen computerised tomography (CT) scan, performed after discussion with the Florence Poison Control Center, showed a massive pneumobilia associated with distention of jejunum-ileus because of oxygen production. Esophagogastroduodenoscopy (EGDS) was performed to assess the severity of the caustic injury. Esophageal mucosal oedema (grading 1 Zargar’s score) and several gastric necrotic areas (grading 3a) were present. The duodenum revealed few scattered superficial erosions. The surgeon decided for non-surgical treatment of pneumobilia and gastric injuries. The patient underwent orotracheal intubation and was transferred to an intensive care unit. Two days later, endoscopic examination was performed. Pneumobilia spontaneously recovered in 6 days. The patient was discharged after 15 days and EGDS follow up was prescribed. Conclusion: Pneumobilia, typically visualized as a large air confluence within the central portion of the liver, can be a complication of endoscopic or surgical procedures involving the biliary tract. To our knowledge, this is the first case of MEKP-induced pneumobilia. The patient developed local damage but limited systemic effects with a favorable outcome. Therefore, MEKP could be lethal upon ingestion and intoxicated patients should be followed for the risk of unexpected organ injury.