Barium Studies: Principles & Contraindications
Overview
Barium sulfate is an insoluble heavy metal compound that is radio-opaque. Because it is chemically inert and poorly absorbed from the normal gastrointestinal tract, it has been used for decades as the standard positive oral and rectal contrast agent for fluoroscopic evaluation of the GI mucosa and motility.
Key Modalities
- Barium Swallow: Evaluates the pharynx and oesophagus. Best for esophageal webs, rings, strictures, and motility disorders.
- Barium Meal: Evaluates the stomach and duodenum. Often performed as a double-contrast study with effervescent granules.
- Barium Follow Through (FT): Assesses the small bowel for strictures, mucosal lesions, and transit time (e.g. Crohn's disease).
- Barium Enema: Evaluates the large bowel. Greatly supplanted by CT colonography, but historically used for colorectal cancer screening and stricture evaluation.
Contraindications
🚨Absolute Contraindications (DANGER)
Barium MUST NEVER be given when there is a suspected GI tract perforation. Barium extravasation into the mediastinum or peritoneum causes a severe, fibrotic, and often fatal chemical peritonitis/mediastinitis. In cases of suspected leak (e.g. post-op anastamosis check, perforated ulcer), a water-soluble contrast agent (like Gastrografin or Omnipaque) must be used instead.
Another relative contraindication is immediately proximal to an acute high-grade bowel obstruction, particularly in the colon, as barium can desiccate and worsen the obstruction, creating a concrete-like impaction.
Complications
While generally remarkably safe, distinct life-threatening and chronic complications can occur:
- Aspiration: Massive barium aspiration can cause a chemical pneumonitis. Small amounts of aspirated barium are usually cleared by mucociliary action, but can remain visible on CXR for years.
- Barium Peritonitis/Mediastinitis: Arises from perforation. Mortality ranges up to 50%.
- Intravasation: Very rare but highly fatal event where barium enters the portal or systemic venous system during an enema, resulting in severe pulmonary barium embolism.
- Bowel Impaction: Due to water absorption in the colon; patients should be advised to maintain high fluid intake post-procedure.
High Yield Facts
💡FRCR / MD Prep Pearl
Toxic megacolon and severe acute inflammatory bowel disease are ABSOLUTE contraindications to Barium Enema due to the exceedingly high risk of spontaneous toxic perforation during the procedure. Always review the abdominal X-ray prior to administering the enema.