A case of polyposis?

April 25, 2011 By: Bjorn Rembacken

What is the diagnosis?

This is the sigmoid colon in a 55 year old man undergoing colonoscopy to investigate a recent change in bowel habit.  On the video you can see that the mucosa is covered with what appears to be numerous polyps.  What is the diagnosis?

The clue is that when the nodules are pricked with a needle, they seem to deflate somewhat! 

The patient has pneumatosis intestinalis.  There are two forms of the disease: Primary idiopathic pneumatosis intestinalis (which is said to constitute some 15 - 20% of cases although I don’t think that there is reliable data on this) and secondary to conditions such as Chronic Obstructive Pulmonary Disease or end-stage ischaemic colitis, often associated with gas in the portal system.  In infants, the condition is associated with necrotizing enterocolitis.

In the benign idiopathic condition, the patient is asymptomatic and the multiple thin-walled cysts, about 1 cm in size, develop in the colon or small intestine.  The gas pockets are then incidental findings at endoscopy or X-ray.   In the published literature many conditions have been linked with the condition.  However, many of these associations probably reflect the numerous indications for the endoscopy at which the pneumatosis was detected, (rather than being a cause for the condition). I have only seen the primary condition myself on two occasions.  In both cases, the cysts were confined to the colon (more on the left than the right side) and the patient symptoms could not be explained by the pneumatosis.  Treatment of the pneumatosis therefore did not seem to be relevant.

There are several aetiological theories for the condition:
Mechanical: Luminal gas entering the through a defect in the mucosa. 
Pulmonary: increased intra-thoracic pressure allows air to dissect along vessels in the mediastinum and retroperitoneum eventually ending up in the wall of the intestines.  However gas has not been found outside of the intestinal wall in the condition.
Bacterial: The presence of an unknown gas producing bacterial species which creates small pockets of gas within the intestinal wall. 

Treatment with high flow oxygen and metronidazole have been described although the real question is – apart from patients moribund from an ischaemic colitis, when does the condition require treatment?

About the author

Bjorn Rembacken is at Leeds Teaching Hospitals NHS Trust, Leeds, UK. He was born in Sweden and qualified from Leicester University in 1987. He undertook his postgraduate education in Leicester and in Leeds. His MD was dedicated to inflammatory bowel disease. Dr Rembacken was appointed Consultant Gastroenterologist, Honorary Lecturer at Leeds University and Endoscopy Training Lead in 2005. Follow Bjorn on Twitter @Bjorn_Rembacken



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