Intestinal Obstruction, Paralytic Ileus and Pseudo-Obstruction
Essentials
Identify and treat acute mechanical intestinal obstruction immediately. The treatment of imminent strangulation is particularly urgent (see also acute abdomen Acute Abdomen in the Adult.
In paralytic ileus start conservative treatment as soon as possible.
In strangulation rotation of the intestine stops local circulation
Paralytic ileus
Surgery, partial paralysis
Nowadays the goal is to start enteral nutrition soon after surgery.
Severe systemic disease (e.g. infection, particularly septicaemia)
Severe trauma
Intractable constipation in the elderly may have characteristics of both mechanical obstruction and paralytic ileus.
Possible aetiological factors include poisonings, neurological diseases and metabolic disorders.
Colonic pseudo-obstruction (Ogilvie's syndrome)
Marked dilatation and air filling (megacolon) may be associated with any disease affecting the general condition, surgery (heart and hip operations in particular), or medication suppressing intestinal motility. No septic symptoms suggesting a toxic megacolon.
Symptoms and signs
Mechanical obstruction
Abdominal pain is colicky, and at first paroxysmal.
In strangulation the pain becomes continuous and increase. The general condition of the patient deteriorates subsequently, and symptoms of peritoneal irritation develop. A complete ileus develops, the patient has bouts of fever, and inflammatory markers in the blood are elevated.
Vomiting is an early symptom in proximal obstruction, and a late symptom or totally absent in colonic obstruction.
Abdominal distension is marked in colonic obstruction.
In the colic phase, bowel sounds are frequent and high-pitched.
In the later ileus phase, bowel sounds become quiet.
Paralytic ileus
Bowel movements cease (no defecation or passing of air).
The abdomen becomes distended.
Bowel sounds are absent.
Splashing may sometimes be heard when the abdomen is pushed from the side while the patient is lying supine.
There is no pain or the pain is mild and diffuse, not colicky.
Colonic pseudo-obstruction
The abdomen distends and there are no bowel movements; pain is only mild.
The whole length of the colon is distended in plain abdominal x-ray, without signs of obstruction. Clearly infectious symptoms suggest a toxic megacolon, which usually should be operated on emergency basis.
Investigations
Auscultate the bowel and palpate the abdomen repeatedly (observe tenderness and splashing).
CT scan is increasingly used in primary diagnostics.
If CT scan is not performed, plain x-ray of the abdomen is carried out with the patient in an upright position or, if the patient's general condition is poor, lying on one side.
Air-filled, distended bowel loops or fluid levels confirm the diagnosis and give a clue to the level of the obstruction.
A large amount of impacted faeces can often be seen in the x-ray.
Always look for free air in the abdominal cavity (under the diaphragm in an upright x-ray). Detecting free air is an indication for immediate surgical consultation.
Carry out infection tests (CRP) in paralytic ileus if the cause is not evident. Remember abdominal infections (pancreatitis, cholecystitis).
A CT scan with contrast medium enhancement performed at a hospital helps in distinguishing between total and partial obstruction and in assessing the condition of the bowel wall and circulation. In a follow-through examination, Gastrografin® contrast medium (diatrizoic acid) stimulates bowel movements and may resolve a partial obstruction.
Treatment
Choosing the place of treatment
If intestinal obstruction or ileus is suspected the patient should be evaluated during the first visit on a hospital emergency department, with the exception of severe constipation that can be treated in a primary care unit or at an outpatient clinic.
Patients with good general condition with paralytic ileus or mild mechanical obstruction can be treated at a community hospital if the aetiology is known (old adhesions, constipation).
A patient with painful obstruction should be referred to a surgical unit. It is particularly important to recognize strangulation, which can cause perforation of the necrotic bowel.
Fluid therapy
Both mechanical and paralytic ileus is associated with fluid retention in the bowel and (in severe cases) peritoneal cavity, resulting in dehydration and salt loss.
Infuse isotonic saline; initially 2 000-4 000 ml, and thereafter guided by peripheral circulation, urine output, signs of dehydration, and serum sodium and potassium levels. Avoid overloading.
Relieving the bowel
Do not give fluid or food perorally before the obstruction has become resolved or bowel motility has resumed and bowel sounds are present in paralytic ileus.
Nasogastric tube is useful in proximal obstruction but not necessarily in paralytic ileus if the patient is not vomiting.
Empty the bowel and remove air with a rectal tube if the abdomen is distended.
Motility-reducing drugs, such as anticholinergics and opioids, should be discontinued, if possible.
The treatment of colonic pseudo-obstruction consists of decompressing the colon with a rectal tube, or if necessary, by suction with a colonoscope (or sigmoidoscope).
0.5-2 ml of neostigmine + glycopyrronium combination drug (containing 2.5 mg of neostigmine and 0.5 mg of glycopyrronium per millilitre) intravenously may be helpful. Bradycardia caused by neostigmine can be treated with an additional dose of glycopyrronium or with atropine. Respectively, tachycardia caused by glycopyrronium can be treated with a corresponding dose of neostigmine.
Surgery is contraindicated in pseudo-obstruction.
Treating the underlying cause
The underlying cause, such as infections, should be treated properly in paralytic ileus.
Indications for surgical treatment of mechanical obstruction: imminent strangulation, incarcerated hernia, volvulus, suspected intestinal perforation, radiologically confirmed total obstruction, a primary disease requiring surgery (e.g. an obstructing tumour)