Obstruction of the intestines is a common surgical emergency that requires prompt management. The catch with intestinal obstruction is that it needs to be differentiated into either small or large bowel obstruction, and then again to identify the underlying cause. This is important as the treatment differs for each cause. Due to the vast amount of information that the topic of intestinal obstruction entails, I will focus on large bowel obstruction and in the future do a case study on small bowel obstruction (when I can get my hands on an x-ray of one).

The most common causes of large bowel obstruction are colonic carcinoma, volvulus strictures/adhesions and intussusception. They each vary in presentation and are commonly found amongst different population groups such as intussusception is most common in infants and volvulus in institutionalized/psychiatric patients.

So what happened?

A 45-year-old slightly obese patient presented to the emergency treatment unit with symptoms of abdominal distension and crampy abdominal pain. She claimed to be in immense discomfort for the last 3 days and had not passed flatulence or stool. She had never previously experienced this pain before and came in for treatment as she could not bear the discomfort anymore.

So what did I do?

On history taking, she had no fever but felt nauseous even though she had not vomited. She denied any abnormal stool pattern prior to the 3 days but complained of bouts of tenesmus. She did not claim to experience any episodes of rectal bleeding or melaena, but had a loss of appetite, with no noticeable weight loss. She also had no significant past medical or surgical history and is not on any regular medication. Her father and her paternal grandmother both had colonic carcinoma but despite this, the patient had never undergone faecal occult blood testing or flexible sigmoidoscopy/colonoscopy. Her last menstrual period was 2 weeks ago.

On examination, her vitals were all stable (no fever or dehydration as well), but her pain was an 8/10 on the pain scale. Her abdomen was significantly distended and diffusely tender to touch. Percussion elicited resonant tones and bowel sounds were very active. No hernias were noted and both PV/PR examination were found to be normal.

After giving the patient analgesics, we had a strong suspicion of bowel obstruction and so proceeded with appropriate initial investigations to both rule out differentials and confirm our suspicions:

• Urine hCG – do not forget this! Any female patient of reproductive age admitted with abdominal pain MUST be investigated for pregnancy – trust no one!
• Full blood count
• ESR
• CRP
• Serum electrolytes
• S. Creatinine/B. Urea
• CEA – the tumour marker of choice for colorectal carcinoma
• Group & DAT – because the complications of bowel obstruction (perforation and bowel necrosis) may require blood transfusions
• Abdominal x-ray supine and erect – will definitely help differentiate between large and small bowel obstruction.
• Faecal Occult blood test – colon carcinoma is a common cause of intestinal obstruction in elderly individuals, but must always be ruled out.

The patient’s abdominal x-ray showed distended large bowel in the peripheries with haustra present (no coffee bean sign that is seen in volvulus). With the diagnosis now confirmed, it was important to find out the underlying cause of the obstruction.

X-ray of Large Bowel Obstruction – sent in by Dr. Jaya Roy Choudhury

The consultant was informed and the patient was kept on bed rest and nil by mouth. The mainstay of management is As the patient did not have vomiting, a nasogastric tube was not inserted (this is an essential part of managing small bowel obstruction). Fluid therapy was commenced to maintain hydration with intravenous fluid and appropriate electrolyte replacement as fluid loss and electrolyte imbalances are common problems with intestinal obstruction. The fluid requirement was guided by the use of an input/output chart – this is very important as proper fluid management will reduce operative risk. Anti-spasmodics (hyoscine butylbromide or buscopan) and domperidone were also given to reduce discomfort.

An urgent colonoscopy (the gold standard to diagnose colorectal cancer) was done and a rectosigmoid tumour was found to be the mischief maker. The tumour was found 15cm from the anal canal and a CT scan was also ordered. The urgent CT scan showed a complete single point of obstruction (as opposed to close looped obstruction) which required urgent surgery (an anterior resection was done). The CT was also used for staging purposes (metastases). CEA (carcinoembryonic antigen) which is a tumour marker for colon cancer was also found to be significantly raised.

The patient made a full recovery after surgery and the case was put towards a multidisciplinary meeting to discuss further treatment (chemo/radiotherapy) – yes, these exist in Sri Lanka, especially in the tertiary hospitals. My secondary care level hospital MDT meetings consisted of the surgeons, an oncologist, radiologist, histopathologist and the ward nurses/junior doctors – so it was small, but something better than nothing!

Discussion

If managed timely and effectively, patients with obstruction have approximately 20% mortality, unless a colonic perforation or bowel ischaemia occurs.

In this particular case, the tumour resulted in mechanical large bowel obstruction and bowel dilatation above the obstruction. This dilatation causes the mucosal lining to swell, thereby impeding blood flow and resulting in inappropriate fluid loss, electrolyte imbalances and the risk of infection due to bacterial translocation. Bowel obstruction is more common further down the intestine as contents become more solid. Absolute constipation (meaning nothing is going to pass through) and hence presents earlier in lower level obstructions than higher ones. Similarly, abdominal distension is more evident in lower level obstructions. Vomiting in large bowel obstruction is relatively rare and if it does occur, it comes in the form of faeculentvomiting.

Dukes staging used to be used for colorectal carcinoma staging, however, this has now been largely replaced by the TNM staging system.

P.s. did you know that volvulus typically is more prevalent in the elderly or psychiatric/institutionalized individuals? There is no clear reason as to why this happens, but it is thought that psychotropic drugs (which relax the gut), immobilization and chronic constipation (a common side effect of opiates) are to blame.

Ogilvie’s syndrome is also commonly seen and is acute colonic pseudo-obstruction that can occur due to a number of reasons including infection. Remember the name and you can impress your consultant!

Conclusions

A significant number of colorectal malignancies (primarily left side colon cancers) have been known to present with bowel obstruction and so it is an important differential diagnosis to keep in mind. Bowel obstruction is not uncommon and can virtually present in any age. The abdominal distension was a dead giveaway in this instance, but it may always not be this easy. Keep this diagnosis at the back of your mind and always remember that once a diagnosis is made, you need to find an underlying cause.

I am exceptionally sorry this article is so late! I have had an insane week of work and hence was more exhausted than I’ve been in a long time.