What Is Causing This Man’s Bowel Obstruction?

A 77-year-old male with multiple medical problems including recent hospitalization for pneumonia and chronic obstructive pulmonary disease (COPD) exacerbation presented to the emergency department complaining of right flank pain and decrease in bowel movements.

History

The patient had a past medical history that included hospitalization for pneumonia and COPD with exacerbation. He was diagnosed with stage 3 chronic kidney disease, COPD, and questionable lung mass versus infiltrate. His cardiac history includes coronary artery disease (status post-coronary artery bypass graft), peripheral artery disease, a history of transient ischemic attack, and a history of pulmonary embolism off coumadin currently (status post-right hemi colectomy secondary to acute colonic ischemia resulting in gangrene). 

The patient has osteoarthritis, a history of bladder and prostate cancers (status post-iliac stent), abdominal aortic aneurysms (status post right common femoral endartectomy), and dyslipidemia. 

The patient is married. He is a former smoker with no current or history of alcohol abuse. He is retired.

Physical Examination

The patient appeared comfortable and in no apparent distress. He had no rashes or jaundice. He recorded a temperature of 98.9°F, pulse of 96 beats per minute, respiratory rate of 18 breaths per minute, blood pressure of 125/74 mm Hg, and oxygen saturation 96%. 

His head, eyes, ears, nose, and throat exam showed a normal oropharynx, no enlarged lymph nodes, and no jugular venous distension. His lungs noted vesicular breath sounds, but no wheezing or rales. The S1 and S2 heart sounds were normal. He is mildly tachycardia and a murmur was noted. 

His abdomen was soft, diffuse abdominal pain on superficial palpation, decreased bowel sounds, and no rebound tenderness or guarding.

His extremities had trace pedal edema. There was no cyanosis or clubbing. 

Neurologic exam showed no focal deficits. 

His current medications include oxycodone/acetar, clopidogrel, albuterol sulfate aerosol, tiotropium bromide, metoprolol, vitamin D3, amlodipine, aspirin, doxazosin, doxycycline, gabapentin, niacin, pravastatin, prednisone, and tramadol. 

Laboratory Tests

An initial series of the abdomen (Figures 1a and 1b) showed an obstruction, which was confirmed in a follow up CT of the abdomen (Figures 2a and 2b) that showed retention of barium. Past medical history revealed a double contrast barium study that was ordered 1 month prior for the evaluation of peptic ulcer disease (PUD). The results showed no mucosal abnormality in esophagus, stomach, or proximal duodenum; the evaluation of the distal esophagus was limited due to lack of distension. 

Figures 1a and 1b. (a) Retained barium contrast is seen in the left lower quadrant. The dilated loops of large and small bowel are identified. (b) Decreasing collection of high-density barium in the sigmoid colon. Persistence of markedly distended air and fluid filled viscous in the left upper abdomen, almost certainly a markedly distended stomach.

Diagnosis

Bowel obstruction caused by retained contrast. 

Discussion 

Barium sulfate is a type of contrast medium that is opaque to x-rays. It is used to diagnose different pathologies, such as achalasia, esophageal stricture, ulcers, tracheoesophageal fistula, and schatzki ring. A common concern with imaging studies is radiation exposure; as seen in this case, an overlooked concern of barium studies could be obstruction. Risk versus benefit should be considered before ordering these tests. 

Barium swallow is contraindicated in patients with any suspicion of esophagus perforation, bowel obstruction, severe constipation, and pregnancy.¹ There have been at least 2 cases reported where patients with partial small bowel obstruction had a conversion to full obstruction when barium was used.² In patients who require an upper GI study with prior history of constipation, water-soluble contrast (eg, diatrizoic acid and iohexol), are relatively safe to use. 

Diatrizoic acid has been proven safe in patients with partial small obstruction³ and noted to reduce obstruction completely is some studies.⁴ Note: The concentration of water-soluble contrast should be titrated when used for fluoroscopic and plain radiographic visualization.⁵ Though diatrizoic acid can be used in patients with severe constipation or bowel obstruction, its use might be limited if the patient is at risk for aspiration. It is a water-soluble contrast media used to look for GI leaks and preferred over barium as it is less likely to cause peritoneal complications. 

The risk of aspiration is almost similar with the use of either lipid-soluble (low- and high-density barium) or water-soluble (diatrizoic acid and iohexol) contrast agents. The pneumonitis resulting from aspiration can be fatal at times and may require mechanical ventilation.⁶ There have been recorded cases of death related to aspiration with both contrast agents.^7-9 

Aspiration of barium sulphate is not expected to cause severe lung injury due to its relatively nonirritant matter. However, acute inflammation can lead to acute respiratory failure leading to death.⁶ Diatrizoic acid has been reported to induce pulmonary edema and fatal respiratory failure after aspiration in adults.⁹ Cardiac arrests have occurred even with aspiration of small doses of 50 mL of contrast.¹⁰ 

Iohexol, on the other hand, is a low osmolar, nonionic, iodinated water-soluble contrast agent. The osmolality of iohexol ranges from 322 mOsm/kg—approximately 1.1 times that of blood plasma—to 844 mOsm/kg, almost 3 times that of blood; inspite of these numbers, it has one of the lowest osmolality when compared to other water-soluble agents.¹¹ 

In an experimental study of 24 lab rats, equal numbers were intratracheally injected 0.15 mL of 1 of the 3 agents: full-strength or 3% diatrizoic acid or iohexol. The results: The rats who received the full-strength diatrizoic acid died instantly, while 3% diatrizoic acid or iohexol were not fatal; iohexol produced more alvelolar edema than 3% diatrizoic acid.¹² 

Figures 2a and 2b. Retained barium contrast is again seen in the left lower quadrant. The dilated loops of large and small bowel are identified. 

Outcome of the Case

Treatment with lactulose and phosphate enema did not relieve the obstruction in our patient. He underwent colonoscopy to remove the barium impaction. 

Aspiration risk should be taken into account on all patients undergoing contrast studies to prevent pneumonitis secondary to aspiration. In patients with a history of severe constipation and obstruction that require upper GI studies, water-soluble contrast is an option to avoid complications such as bowel obstruction. Diatrizoic acid can generally be used for the same purposes as barium sulphate with the exception of the visualization of mucosal diseases. For disease such as PUD, upper endoscopy is the gold standard and should be used. In patients where perforation of upper GI tract is questioned, water-soluble contrast should be used with fluoroscopy; if no leak is identified, then a single barium esophagram should be used.^13,14 Patients who have barium swallow studies should be advised to have adequate oral intake to clear the barium in their intestine to avoid complications as seen in our patient. Iohexol, with its low osmolality and lower level of damage on aspiration, is a better choice for investigating the upper GI series.

Bensson Samuel, MD, PG Dip, is the medical director of inpatient services at War Memorial Hospital in Sault Ste Marie, MI.

Berhanu Geme, MD, is a gastroenterologist at St. Luke’s University Hospital and Health Network in Bethlehem, PA.

Jennifer Axelband, DO, is a critical are attending at St. Luke’s University Hospital and Health Network and an associate clinical professor at Temple University School of Medicine, both in Bethlehem, PA. 

Alden Smith, BA, is a medical student at Temple University School of Medicine in Bethlehem, PA.

References:

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