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Intestinal Obstruction

 

Ileus

 

What is an intestinal obstruction?

An intestinal obstruction (ileus) may affect the small and the large bowel. It is a disturbance affecting the flow of the chyme, in most cases for mechanical reasons. But what does this mean? A section of the small or large bowel is obstructed from the inside or the outside, so that the chyme cannot pass. This obstruction can be complete (ileus) or incomplete (subileus). From the inside, a mechanical barrier can be either caused by a growing tumour or by swallowed objects (often happening with children). As the bowel is a soft hose, it can be closed by pressure from the outside, too. Frequently, this is caused by adhesive bands, which pass through the abdominal cavity and in which the mobile small bowel can quickly get entangled. This is called an adhesion ileus; it usually affects patients who have suffered prior surgery as these may lead to the formation of such adhesive bands. The second form of a mechanical ileus is the strangulation ileus, which normally also affects the mobile small bowel. In this case, the loops of the small bowel literally rotate around their own axle, thus disrupting the blood supply of the bowel. This results in a deficient supply of oxygen of the intestinal tissue and in a blockage of the chyme. The small bowel also may get wedged into the hernial sac of various intestinal hernias, which may also cause an ileus. The large bowel, however, fixed to the peritoneum in many places, is most frequently affected by a disturbance of passage. It is caused by a tumour, which either grows within the large bowel or presses on it from the outside. Beside the already mentioned mechanical causes, a paralysis of the intestinal musculature can also be the reason for an ileus. This means that the typical periodical and spontaneous movements of the bowel come to a halt, the chyme cannot be transported onwards, and an obstruction is the result. This may be caused by grave metabolic disorders, generalized bacterial infections, abdominal trauma, or consequences of great abdominal surgery. But why is the ileus so dangerous? It is solely the obstruction of the chyme that causes an excessive distension of the intestinal wall, no matter at which section of the bowel or for what reason. This triggers a series of reactions in the body, which are described in the following text and which ultimately cause the dangerous "ileus disease": the excessive extension of the intestinal wall caused by congestion leads to a circulatory disturbance in the section, which triggers an oxygen deficiency in the tissue. This is why the bowel stops its movements and the number of bacteria rises drastically, which again discharge certain toxic substances. After these occurrences, the intestinal wall - if one considers it as a "barrier" - is weakened in various respects. The bowel and the intestinal wall now fill with liquid. In an abnormal redistribution, the liquid had been withdrawn from the blood vessels before, thus causing a circulatory debility in the patient. Moreover, the toxic substances of the bacteria can now penetrate the weakened barrier of the intestinal wall, then reach the blood circulation and - through complicated mechanisms - produce a shock, which may also affect other organs (kidneys, lungs, etc.).

How do I recognize an ileus?

"The day began like every other. After breakfast, I went to work. After lunch, I suddenly had an attack of spasmodic pains in the stomach, which stopped and then came again. In the afternoon, I could only sit folded-up on my chair, so that my boss sent me home. When I arrived, I had bouts of vomiting several times. My stomach was more and more bloated and the pain increased. Only when I was lying with my legs pulled up, I felt a little better. A friend, who came to visit me in the evening, took me to the hospital right away."

This description contains many complications, which a patient with an imminent ileus will report: the main symptoms are vomiting (possibly in bouts) and strong intermittent pain in the abdomen. In many cases, the abdomen is strongly bloated and very sensitive to pressure. Depending on the location of the obstruction, the patients may have no stools and no discharge of gas any more. A question frequently asked is why there are spasmodic colics. As soon as the bowel is blocked for some reason or other, it tries to react against this obstacle with all possible strength, which causes the colicky pains. In case of a paralytic ileus, however, the paralysis occurs quickly: "There is dead silence in the abdomen", which means that the doctor cannot hear any bowel sound through his stethoscope any more.

Necessary clarifications and diagnostic possibilities

The above-mentioned complaints may occur in very different manifestations and sequences, depending on which section of the bowel is affected by an obstruction. Patients with an ileus of the small bowel more often complain about colicky pains in the abdomen and about vomiting. Normally, an ileus of the large bowel first causes significantly irregular stools before pains in the abdomen occur. Therefore, the doctor must first carry out an exact questioning of the patient to rule out other diseases. In the case of an intestinal obstruction, it is of primary interest to know the exact time when the pains began, the type of pain (dull, pungent, colicky spasms), whether the patient had to vomit, and when he had his last stool. Further, he should be asked about prior operations of the abdomen (appendectomy, uterectomy, gall bladder operation, other operations of the bowel or stomach) and about other general sicknesses. After this, further examinations are carried out:

Examination of the abdomen with the hands: Through it, an inflated abdomen becomes obvious, reacting on pressure with acute pain. Furthermore, the doctor looks for abnormal swellings when he palpates the abdomen. A very important step in the examination is the auscultation of the abdomen with a stethoscope to assess the bowel sounds. By lightly tapping with the fingers on the abdomen, aggregations of air can be recognized. In case of an increasing intestinal obstruction, first so-called highly pitched bowel sounds are heard, later also duller tones. When a mechanical ileus has lasted for a longer period of time and during its transition to a paralytic ileus, bowel sounds are no more audible. For the surgeon, kind and quality of the bowel sounds are a very important indication of an ileus.

Rectal examination: The examination of the rectum is a must in all cases of acute abdominal complaints. Pains and possibly blood at the fingerstall are quite unspecific, however, and occur also in connection with other diseases of the bowel or abdomen.

Abdomen plain X-ray:An X-ray of the abdomen with the patient standing and lying is a simple examination that provides a lot of information about an intestinal obstruction. In the picture, one looks for fluid levels and so-called extra-intestinal air in the abdomen. If such fluid levels can be found, it is an almost certain indication of an actual intestinal obstruction. By assessing the localization of the fluid level, it can be estimated about where the bowel is obstructed. The so-called "standing" intestinal loops are another typical indication of an ileus. The intestinal obstruction causes gas to collect before the barrier, the intestinal loops get inflated, and the X-ray picture conveys the impression as if they were standing upright in the abdomen.

Ultrasound:An ultrasound of the abdomen offers a fast possibility to answer the following questions as to affected intestinal loops: Are they filled with liquid? Is the intestinal wall swollen? Are there still spontaneous movements of the intestinal loops?

Application of contrast medium: If there is the suspicion of an ileus of the small bowel without strangulation, an oral application of a water-soluble contrast medium can be tried. On the one hand, this medium has a laxative effect. On the other hand, an X-ray picture can be made after a certain time to assess whether the liquid has moved on to the large bowel in adequate time. Thus, the location of the obstruction can be determined more exactly.

Blood tests:A blood test can contribute to clarify the cause of the intestinal obstruction. The laboratory results can only show certain causes, but not the intestinal obstruction as such.

CT examination: If the cause of the intestinal obstruction cannot be found with the above mentioned examinations or if the palpitation of the abdomen shows a swelling, a CT examination can be carried out as complementary diagnostics in certain cases.

Only in an overview of clinical history and of the results of various examinations, the surgeon can answer the most important questions: Is it an intestinal obstruction of the small or the large bowel? Is the obstruction mechanical or paralytic? Is it complete or partial? Does the patient suffer from another, so far unidentified disease (tumour, inflammation, intestinal hernia)? Does he have to operate the patient immediately, or can he wait with the operation whereas the patient stays under strict supervision?

How is an acute intestinal obstruction treated?

Has the diagnosis of an acute intestinal obstruction been confirmed - without considering the type of ileus - the following essential measures are taken: As all patients suffer from a grave disturbance of the fluid balance, but have to go with an empty stomach at the same time, they are first provided with a great intravenous access: A soft plastic tube is inserted through a big needle into a central blood vessel. This central venous catheter is either installed at the collarbone or at the neck. Thus, the patients receive the necessary liquid, trace elements, and medication (e.g. antibiotics). As most of the patients have already vomited, a gastric tube is installed. This is a thin plastic tube, which is inserted through the nose and the gullet into the stomach. In this way, the accumulated liquid can be drained off into a bag from the stomach and the bowel. These two measures, gastric tube and infusion, are only meant to safeguard a stabile blood circulation, but they have no curative effect concerning the intestinal obstruction. Patients with an advanced ileus sometimes also have to be treated at the intensive care unit. How does the treatment continue?

In case of a paralytic ileus (i.e. non- mechanical), the above mentioned measures are taken, and attempts are made to eliminate the basic disease. The procedure is preferably non-surgical in this case, except in the case of a serious superdistension of the bowel. In this case, a special operation has to be carried out to relieve the bowel.

The mechanical ileus is often caused by adhesions in the abdomen and affects mostly the small bowel as it is rather mobile in the abdomen. Mechanical obstructions in the large bowel are usually caused by a tumour. In both cases, surgical intervention becomes necessary to remove the obstruction and to restore the continuity of the bowel. For the treatment of intestinal obstructions, open surgery is the preferred choice. Depending on the condition of the patient, a laparoscopic operation can also be considered. However, one often has tochange over to open surgery because the focus of trouble cannot be properly spotted, or a laparoscopic correction of the problem is too difficult. Depending on the location of the intestinal obstruction (upper, middle, or lower abdomen), a vertical incision in the middle of the abdomen is made to access. Afterwards, all layers of the intestinal wall are carefully severed. The edges of the incision are then tightly stretched with several retractors, so that the organs of the abdomen become freely visible. Now, the whole abdomen can be searched for the cause of the intestinal obstruction. As a rule, the strongly inflated loops of the bowel in front of the obstruction (adhesive band or tumour) catch the surgeon's first attention. Behind the obstruction, the so-called "hungry colon", the poststenotic distal colon, is often found. At this place, the bowel is completely empty and very thin as no food has passed through it for quite some time. Has the place of obstruction been located, the reason for it can easily be found out. In most cases, there are simple adhesions which result in an angulation or strangulation of the bowel. The adhesions are severed with a sharp pair of scissors, and bleedings are stopped with a few stitches. As soon as the bowel has been freed from the adhesions, its vitality has to be tested in order to find out whether the bent section of the bowel is still functional. If the bowel moves when touched, it is still functioning. Further criteria for its vitality are its colour and the blood circulation. If colour and mobility of the bowel are fine after the mobilization of the adhesions, the abdomen can be sutured again, layer by layer. Clamped sections of the bowel, which are badly supplied with blood, take on a blue colour. If the bowel does not turn rosy after the obstruction has been removed, it has to be assumed that the relevant section of the bowel is dead, so that it has to be excised. For this purpose, the bowel is severed above and below the dead section and then closed with a special linear stapling device. The resulting two blind ends are stitched together again with two running sutures. Then, a check follows in order to find out whether there is any bleeding, and two drains are laid. Finally, the abdominal wall is closed layer by layer.

What happens after the operation?

After surgery, the patients are normally observed and monitored at the intensive care unit for 1 - 2 days. Especially the intake of liquid is closely checked and constantly corrected. The patient receives sufficient pain killers and, if necessary, antibiotics. A leakage of the suture of the bowel accompanied by the escape of enteral contents was a frightening complication after such an operation in the past. Fortunately, this has become very rare due to advanced surgical techniques and suture materials. Still, it is important to check the functioning of the bowel once or twice per day. This can be done by auscultating the abdomen. After every abdominal surgery, the bowel may "go on strike" during the first few days. It is so to speak “offended” and refuses its service of transportation. This reaction is quite normal and disappears a few days after the operation. When the bowel starts functioning again, the patient can try to drink small quantities of tea/water. If the stomach drain does not discharge any more gastric juice, or only very little, it can be removed. The quantities of liquid can now be increased every day and food ingestion can begin with soup, mashed potatoes with sauce, finely cut food, and finally normal food. The sutures can be removed on the 10th day after the operation, and the patients may go home within 8 days if the recovery is favourable.

What has to be paid attention to in future daily life?

Many patients ask the doctor what they could do to prevent another intestinal obstruction. A mechanical ileus cannot be prevented in any way. Every open operation, including the one to treat an intestinal obstruction, may sometimes again cause adhesions in the abdomen. After such an operation, the patients can lead an entirely normal life, they can eat and drink without restrictions and they can go exercising. In the case of a recurrence of complaints like pain or retention of stool, the patients should consult their doctor in due time. If an intestinal obstruction is the consequence of a different basic illness (tumour, diverticulitis, Morbus Crohn), the basic illness has to be treated at the same time.

History

Already in antiquity, the symptoms of an intestinal obstruction were known to the Greek doctors. They called this disease "Ileus", which comes from the Greek word eileos “eilein - to compress". They chose this name because in the case of an intestinal obstruction, the contents of the bowel cannot be transported onwards, being blocked because of some obstacle in the front.

 

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