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Acute Abdominal Distension

38

 

Mohd. Talha Noor and Rakesh Kochhar

 

A 75-year-old male patient presented with respiratory distress after a road traffic accident. On examination, he was dyspneic. Computed tomography (CT) revealed features suggestive of massive hemothorax. He underwent urgent open thoracotomy following which his condition improved. On the third day of hospitalization, he developed acute onset abdominal distension. The percussion note over the abdomen was tympanic, and bowel sounds were sluggish. Abdominal X-ray revealed dilated bowel loops with multiple air-fluid levels. The serum sodium level was 139 mEq/L, and the serum potassium level was 2.6 mEq/L.

Abdominal distension in the ICU patients occurs due to many reasons. Acute colonic pseudo-obstruction is not an uncommon cause of acute abdominal distension in this setting. This is characterized by clinical features of large bowel obstruction but without any mechanical cause. Early recognition and appropriate management are critical in minimizing the morbidity and mortality from complications.

Step 1: Initial resuscitation and assessment

After initial resuscitation (Chap. 78), a detailed history should be obtained, and the patient should be carefully examined.

The bowel frequency, stool character, bowel sounds, abdominal distension and abdominal girth, and intra-abdominal pressure should be monitored (see the chapter 39).

M.T. Noor, M.D., D.M. (*) • R. Kochhar, M.D., D.M.

Department of Gastroenterology, Postgraduate Institute of Medical Education and Research, Chandigarh, India

e-mail: dr_kochhar@hotmail.com

R. Chawla and S. Todi (eds.), ICU Protocols: A stepwise approach,

305

DOI 10.1007/978-81-322-0535-7_38, © Springer India 2012

 

306

M.T. Noor and R. Kochhar

 

 

Crampy abdominal pain and exaggerated bowel sound suggest the presence of mechanical obstruction.

Ileus presents with abdominal distention and abdominal pain that is typically mild and poorly localized. Other features include hypoactive or absent bowel sounds, lack of passage of flatus and stool, intolerance of oral intake, and nausea and emesis. Physical examination reveals a distended, tympanitic abdomen; hypoactive bowel sounds; and mild, diffuse abdominal tenderness. The patient may exhibit signs of dehydration, such as tachycardia, orthostatic hypotension, poor skin turgor, and dry mucous membranes.

In critically ill patients, the possibility of a fecolith causing fecal impaction and obstruction should be kept in mind. Rectal examination should be performed with digital disimpaction if hard fecal matter is present.

Send for the following investigations immediately:

– Erect and supine abdominal X-ray

Abdominal X-ray shows a cutoff point in mechanical obstruction. Free air under the diaphragm must be looked for perforation. Gas seen till the rectum rules out distal bowel obstruction.

Stool for occult blood and C. difficile toxin.

Serum electrolytes.

Step 2: Make a diagnosis

The following conditions commonly present with acute abdominal distension in the

ICU:

Acute colonic pseudo-obstruction (ACPO)

Mechanical obstruction

Intestinal perforation

Ischemic bowel

Toxic megacolon

Inflammatory bowel disease

C. difficile colitis

ACPO can be associated with a number of medical conditions (Table 38.1), which should be looked for and corrected if present.

Correct important conditions:

Medications such as calcium channel blockers and narcotics can lead to paralytic ileus. These medications should be stopped or their dose should be reduced.

The presence of sepsis should be investigated, and samples for culture should be sent.

In elderly patients with risk factors such as hyperlipidemia, atrial fibrillation, and the presence of coronary artery disease, mesenteric ischemia should be excluded.

Rarely, endocrine disorders such as adrenal insufficiency, hypothyroidism and hypoparathyroidism can also lead to paralytic ileus.

38 Acute Abdominal Distension

 

307

 

 

Table 38.1 Common conditions associated with ACPO

 

Cardiovascular

Metabolic

Neoplastic

Posttraumatic

Heart failure

Alcohol

Disseminated

Femur fracture

Myocardial infarction

Electrolyte imbalance

Leukemia

Pelvic trauma

 

Liver/kidney failure

Retroperitoneal

Spinal cord injury

Drugs

Inflammation

Neurologic

Postsurgical

Antidepressants

Acute cholecystitis

Alzheimer’s

Cesarean

Antiparkinsonian

Acute pancreatitis

Multiple sclerosis (MS)

Hip surgery

Opiates

Pelvic abscess

Parkinsonian

Knee replacement

Phenothiazines

Sepsis

Spinal cord disease

Spinal cord injury

Respiratory problems

 

 

 

Mechanical vent

 

 

 

Pneumonia

 

 

 

Step 3: Do appropriate imaging with proper interpretation

Postoperative ileus must be differentiated from small bowel obstruction. Plain abdominal roentgenogram in ileus reveals pronounced small bowel dilatation but may reveal less pronounced large bowel dilatation.

Additional imaging, such as abdominal CT, may be necessary to exclude mechanical obstruction. Abdominal CT is up to 90% specific and sensitive in excluding bowel obstruction.

Step 4: Initial treatment (Fig. 38.1)

Continuous nasogastric decompression.

Correction of fluid and electrolyte disturbance.

Underlying conditions should be identified and aggressively treated.

Discontinuation of drugs that promote an ileus.

Metabolic disorders like diabetic ketoacidosis, if present, should be treated properly.

Step 5: Pharmacotherapy (Fig. 38.1)

The role of pharmacotherapy in the management of paralytic ileus is limited. However, the following drugs have shown some benefit:

Metoclopramide—cholinergic agonist and dopamine antagonist—induces phase 3 of interdigestive migrating motor complex. Dose should be 0.5 mg/kg/24 h intravenously or intramuscularly.

Alvimopan—selective mu-receptor opiate antagonist—antagonizes the gastrointestinal effects of nonselective opiates without affecting its central analgesic properties and enhances recovery of bowel function. Dose should be 6 mg orally.

Neostigmine—reversible acetylcholine esterase inhibitor—enhances the activity of the neurotransmitter acetylcholine at the muscarinic receptors. It is the firstline treatment for colonic ileus. It is used in dosages of 2.0 mg infused over

308

M.T. Noor and R. Kochhar

 

 

Acute massive colon dilatation

Exclude mechanical obstruction assess for ischemia/perforation

Conservative management for 24–48 hours Identify and treat reversible causes

No improvement Or

Cecum > 12 cm Distention > 6 days

IV neostigmine

 

Resolution

No improvement—Repeat dose

 

Colonoscopy with decompression tube

Yes

 

Percutaneous cecostomy

improvement

No

or surgery

Fig. 38.1 Algorithmic approach to ACPO

3–5 min. Atropine should be kept ready when it is done. EKG should be constantly monitored during infusion. Vital signs should be monitored for about 30 min after infusion. The patient should be kept in supine or semisupine position, and a bedpan should be provided. Randomized controlled trials (RCTs) have shown benefit.

Step 6: Colonoscopic decompression

Colonoscopy is required in some patients to rule out distal obstructive lesions, but its role for colonic decompression is controversial.

Its use has decreased after neostigmine has been accepted for treatment. Now it is resorted to if neostigmine fails.

This is done without any preparation, and attempt has to be made to use minimum insufflation and reach cecum.

Some centers use a decompression tube, which is kept inside to constantly decompress.

This is initially successful in 70–90% of patients, but 10–20% may recur. In such patients, the second decompression can be tried.

Step 7: Surgery

Surgery is rarely required in patients with persistent colonic dilatation in spite of colonoscopic decompression and in patients with peritonitis.

Surgery recommended in such cases is cecostomy or loop colostomy. If there is any nonviable bowel, it is resected. In patients who are unfit for surgery, percutaneous cecostomy just like percutaneous endoscopic gastrostomy is performed.

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