A common cause of abdominal pain

Small intestinal obstruction: a common cause of abdominal pain

Do you or someone you know have repeated episodes of abdominal pain? Hoping that it will go away?

Why not go for a check-up? An obstruction in the small intestine is a common cause of abdominal pain and could lead to more serious problems if left untreated. Dr Chan Hsiang Sui, general surgeon from Gleneagles Hospital and Mount Elizabeth Hospital, shares some facts about this oft overlooked medical condition.

The main function of our intestines or bowels is to digest the food that we eat and absorb the nutrients and water. Intestinal obstruction happens when the passage of food is blocked and the intestine is not able to perform its function. The obstruction can occur anywhere along the intestinal tract. It can be in the large or the small intestine, or even in the oesophagus or stomach. The most common cause of large intestinal obstruction is a cancer of the colon; while a small obstructed bowel can be due to many causes and where patients are frequently seen in the hospitals.

There are three types of small intestinal obstruction:

Partial obstruction is a condition where some of the food and gas are still able to pass through the intestinal tract

Complete obstruction means that nothing is able to pass through the tract

Strangulated obstruction indicates complete blockage, and affects the blood supply to a segment of the intestine - much like a heart attack. This may lead to gangrene or death of the affected segment and is a medical emergency that requires immediate surgery

The two types of causes of small intestinal obstruction:

Mechanical cause: In this type of obstruction, the stool moving through the intestine is physically blocked, similar to clogged plumbing. The most common mechanical cause is due to adhesions in the intestine. This can happen after abdominal or pelvic surgery where parts of the small intestine become stuck to itself or other organs, or the abdominal wall. When this happens, the intestine is not able to move freely in the abdominal cavity, forming a sharp bend that prevents the passage of food. Other possibilities include hernia or tumour due to cancer of the caecum (start of the large intestine), or spread of intra-abdominal cancers such as stomach or ovarian cancers.

Non-mechanical cause: Also known as pseudo-obstruction, there is no actual obstruction, and no movement of contents in the intestine. This is commonly seen after operations. It may also be due to ingestion of medicines to treat abdominal pain and discomfort, as well as anti-diarrhoea medication.

Symptoms can be segmented into two areas:

Upper half:

• Sudden onset of symptoms
• Pain in the upper abdomen
• Large volume of vomit, usually green in colour
• No abdominal distension (ballooning)

Lower half:

• Pain in the centre of the abdomen (around umbilicus)
• Gradual onset of symptoms
• Low volume of vomit which contains waste matter
• Generalised and gradual abdominal distension

For acute abdominal pain, you are advised to seek treatment at the Accident & Emergency Department or visit your doctor as soon as possible. Your doctor will take a detailed clinical history, do a physical examination and X-rays or carry out a Computed Tomography (CT) scan of a your abdomen before confirming if you are suffering from small bowel obstruction.

There are several types of treatment presented here in order of severity:

Conventional "Drip and suck"

Small intestinal obstruction is a serious condition and should be treated in the hospital. Most of the patients are dehydrated and the fluids need to be replenished with intravenous drips. It is also necessary to decompress the intestine. This is accomplished by inserting a nasogastric tube into the stomach, which alleviates distension and vomiting by sucking out the intestinal contents. Fortunately, most patients recover through this non-surgical method.

Laparoscopic or open surgery

If the patient's condition does not improve, or there are repeated episodes of obstruction, or if some portion of the intestine is suspected to be ischaemic or has died, surgery is necessary. Surgery is often done laparoscopically, using special equipment inserted through a few small incisions on the abdomen. This provides for faster recovery and lesser chance for recurrence of adhesions. If the procedure cannot be done laparoscopically, conventional surgery is used.

If the obstruction is due to adhesions, the affected areas should be freed from one another and placed back into the abdominal cavity carefully. Any hernia defect should be repaired. If there are multiple areas of narrowing due to deposits of cancer in various parts of the intestine, multiple bypasses of the areas of obstruction may be required.

Resection and removal of small intestine tracts

If the bowel is in danger of dying off or is gangrenous, resection of that segment of the intestine is needed. In cases where the adhesions are so dense that the affected areas cannot be separated, resection is also needed. Our small intestine varies from three to seven metres long. Only if it is absolutely necessary, large segments of the small intestine may be removed.

Recovery from surgery

The body is an amazingly adaptable machine. There may be some loose bowel movements after surgery, but generally there is no long-term nutritional problem. With time, the consistency of the stool and the frequency of the bowel movement will get back to normal. Until the bowel is able to adapt to its maximum capability, the patient may be given parenteral nutrition or fed intravenously. Patients who have had a large segment of their small intestines removed may however suffer from short bowel syndrome and require long-term parenteral (intravenous) nutrition for sustenance.

So the next time you or your loved ones have an acute abdominal pain, do not hesitate to seek medical help. Don't wait till it's too late!

Publication of article by courtesy of Dr Chan Hsiang Sui, General Surgeon from Gleneagles Hospital and Mount Elizabeth Hospital