What is wrong?

February 12, 2011

This EMR specimen has been pinned up up-side-down . The flat polyp had just been resected from the sigmoid colon. As the polyp is being mounted on a polystyrene board, the patient begins to complain of abdominal discomfort. Can you tell why?

To the inexperienced, a therapeutic colonic perforation is easily missed.  The enclosed video demonstrated the classical appearance of a perforation.   In most cases, the patient remains comfortable for a period before vague abdominal pains develop.  The patient is different to the usual wind-like low abdominal discomfort, relieved by passing wind which most patients suffer for a few hours after their examination.  The pain of a perforation is continuous, rapidly worsening and occasionally pleuritic. 

It is my own practice, after colonic polypectomy, to explain to the patient what type of discomfort is to be expected and what are the symptoms of a delayed perforation or significant late bleeding.  Naturally, all patients are also given a copy of their colonoscopy report, a written information leaflet about their polypectomy or EMR procedure together with 24hour contact numbers (including my own mobile number). 

After all resections, I scrutinise the specimen for the tell-tale disk of muscle propria which indicates that the resection has been too deep.  In this image, you can clearly see a paler disc-like area in the centre of the up-side-down specimen.  

The video shows the corresponding EMR procedure.  The lesion is a serrated adenoma which hasn’t lifted very well due to previous sampling.  For this reason, I have selected a very stiff snare, pressing it firmly onto the lesion.  The cutting was taking rather too long and, anticipating a perforation, I had the clips ready.  In the video clip you can see how I turn the EMR specimen over in the colon to confirm the presence of a muscle propria disk. 

The defect is closed endoscopically, the patient was commenced on intravenous antibiotics and admitted for overnight observation.  Provided that the patient remains completely well and apyrexial, I can be persuaded to discharge younger patients the following day.  However, when to discharge depends on your local policies, the opinion of your colorectal surgeons and the age and comorbidities of your patient. 

In my care, these patients never have an abdominal X-ray or CT scan.  The reason for this is that the scan will usually show either local air or air in the peritoneum.  As the defect has been clipped shut, the decision to operate is now clinical rather than radiological.   Should the patient deteriorate, surgical repair should be carried out as early as possible and preferably within a few hours. 

When patients develop “perforation-like” pain within the endoscopy unit following an EMR, I will usually re-intubate and close the complete mucosal defect with clips.   Surprisingly, the pain very quickly settles after the perforation is closed endoscopically.  However, patients who develop pain after discharge from the endoscopy unit, usually have an abdominal CT to distinguish a perforation from a “post-polypectomy syndrome”.  If there is radiological evidence of a full thickness perforation, immediate surgery is scheduled.



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