Ileus: Clinical sciences

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Introduction0:00–0:54

Ileus is a functional obstruction of the intestines caused by reduced or absent peristalsis without evidence of mechanical blockage.
Both functional and mechanical obstructions present with similar signs and symptoms. So, before you diagnose ileus, you must first rule out a mechanical obstruction such as small bowel obstruction.
Ileus most commonly occurs after abdominal operations, which is referred to as postoperative ileus. However, it can also be caused by a wide variety of underlying medical conditions like heart failure, systemic infection, or medications such as opiates.
This is called a non-postoperative ileus.Alright, when assessing a patient with signs and symptoms suggestive of ileus, you must first perform an ABCDE assessment to determine if the patient is unstable or stable.

Unstable patients0:54–1:39

If the patient is unstable, start acute management immediately to stabilize their airway, breathing, and circulation. This means that you might need to intubate the patient, administer supplemental oxygen, obtain IV access, administer fluids, and monitor their vitals before continuing with your assessment.
Also, if your patient is postoperative, don’t forget to examine their surgical wounds!Now that we’re done with acute management of unstable patients, let’s get back to the ABCDE assessment and talk about stable patients.

Stable patients1:39–3:08

The first step here is to obtain a focused history and physical exam, as well as order labs like CBC, CMP, and lactate. In stable patients, the history typically reveals inability to tolerate oral intake, bloating, abdominal pain, and obstipation, with or without nausea and vomiting.
Here is a high-yield fact! You can suspect some causes of ileus based on history.
For example, remember to ask your patients about any recent abdominal operations or opioid usage. Both are common causes of reduced intestinal motility on their own; together they can lead to a prolonged state of intestinal paralysis.
Ok, let’s get back to the physical examination. The physical exam will often reveal abdominal distention, and sometimes abdominal tenderness on palpation.
On auscultation, bowel sounds might be reduced or absent. Finally, lab results might show electrolyte abnormalities such as hyponatremia or hypokalemia.
At this point, you can suspect ileus, but the differential diagnosis still includes mechanical obstruction, so let’s move on to imaging to differentiate the two.

SBO/mechanical obstruction3:08–4:13

To start, obtain an abdominal x-ray series. First, let’s consider possible abdominal x-ray findings that indicate a mechanical obstruction.
These may include small bowel dilatation with air-fluid levels; and absence of any gas in the colon and rectum. These findings are highly suggestive of mechanical obstruction, so you should call the surgical team for a consultation.Here’s a clinical pearl!
The surgical team may order an abdominal and pelvic CT with contrast to confirm the diagnosis. If there’s mechanical obstruction, CT may show evidence of a transition point, where the small bowel is distended to the place of obstruction but collapsed beyond.

Ileus4:13–4:38

Alright, now that mechanical obstruction is diagnosed, let’s go back to x-ray and talk about ileus. The x-ray might reveal small bowel dilatation without evidence of a transition point or mechanical obstruction.
Additionally, there could be gas present in the colon and rectum. Once you have confirmed on imaging that the patient has an ileus, it is important to return to the patient's history and identify whether they recently had a prior abdominal operation.

Ileus Non-postop4:38–5:56

If the answer is no, then your diagnosis is a non-postoperative ileus. The next step is to start supportive care which includes bowel rest, nasogastric tube placement for bowel decompression if the patient is having nausea and vomiting, IV fluid resuscitation, electrolyte repletion, as well as serial abdominal exams, and X-rays.
If the patient is able, encourage them to ambulate frequently, and possibly chew gum, too, as both can increase intestinal motility.
Next to supportive care, you need to do further workup to find the underlying cause of ileus. Potential medical causes of ileus can include heart failure; systemic infections, most commonly associated with UTI; metabolic abnormalities; and a variety of medications including opioids, recent chemotherapy or radiation.

Response assessment5:56–7:26

Over the next few days, continue supportive care and evaluate the patient frequently to determine if they have an adequate response to this management.
Listen for increased bowel sounds, look for evidence of improved bowel function such as bowel movements and flatus, and assess for reduced abdominal discomfort and reduced distention on physical exam and X-ray.
If this is the case, you can see if the patient tolerates a trial of oral or enteral nutrition. Don’t forget to treat the underlying cause as well.The vast majority of non-postoperative ileus patients respond to supportive care alone.
However, if there’s an inadequate response and they don’t improve, or even show signs of worsening like nausea, vomiting, abdominal distention and pain; repeat CT of the abdomen and pelvis with contrast to see if there is a new mechanical obstruction.
In these patients imaging typically shows small bowel dilatation with air fluid levels; evidence of a transition point, an obstructing lesion; or absence of gas in the colon and rectum.
If you see these findings, that’s a mechanical obstruction. Your next step is to call the surgical team for a consultation.

Ileus post-op7:26–8:47

Ok, let’s go back to the point where we identified an ileus on abdominal x-Ray. If your patient recently had an abdominal operation, then you can suspect postoperative ileus.
This is quite common, as the inflammation and neurohumoral response to physical manipulation of the bowel often results in temporary changes in bowel motility.As before, the next step is to start supportive care with bowel rest, nasogastric tube decompression, fluid and electrolyte repletion, serial abdominal exams and x-rays, and possible ambulation and gum chewing.
Additionally, be sure to avoid opiates in these patients as they can further reduce bowel motility. Now, if there’s an adequate response and they improve, the surgeon will give the patient a trial of oral or enteral nutrition and continue appropriate postoperative care.
However, there’s an inadequate response when the ileus persists longer than 72 hours, or if there is a concern for sepsis, or if the patient has worsening of symptoms such as nausea, vomiting, or abdominal pain and distention.

CTAP8:47–10:07

The next step in the workup of an unresolved or worsening ileus is to obtain a CT of the abdomen and pelvis with contrast to look for postoperative complications.
Here is a high-yield fact! Although a CT scan is your top choice and is available at most institutions, there are a couple of imaging alternatives to be aware of, just in case.
These include abdominal ultrasound, and a small bowel follow-through contrast study, both of which can help identify a mechanical obstruction.
Ok, now that you have obtained a CT scan, let’s talk about some possible findings. The CT may be relatively unchanged, and show dilated loops of the small bowel with no evidence of a transition point, abscess, or mechanical obstruction.
When you see this, you can confirm your diagnosis of postoperative ileus. Go ahead and continue supportive care and monitor for the return of bowel function.
When the patient begins to have consistent flatus or bowel movements, proceed with a trial of oral or enteral nutrition.
Now, let's talk about the results of CT that suggest postoperative complications. There are different types of postoperative complications that cause new mechanical or functional obstruction.

Postoperative complications10:07–11:02

On the CT scan, if you see a transition point, your patient likely has a small bowel obstruction. On the flip side, if you see a fluid collection next to newly anastomosed sections of the bowel, along with some associated free air, it might indicate a serious problem called an anastomotic leak.
Additionally, intra-abdominal infections like abscesses, or fluid collections like hematomas can disrupt bowel motility.
All of these postoperative complications require further management and treatment by the surgical team, who should be notified immediately.
Alright, as a quick recap… An ileus is a functional intestinal obstruction resulting from reduced or absent peristalsis, without evidence of mechanical blockage.

Review11:02–12:03

You can use an abdominal X-ray to differentiate an ileus from mechanical obstruction. If your x-ray indicates ileus, you will want to determine if the patient recently had an operation.
If not, it is a non-postoperative ileus; if yes, it is post-operative ileus. This distinction will help guide further management and workup, which may or may not include consulting your surgical team.
Remember, if your patient isn’t improving, or is worsening, get a CT of the abdomen and pelvis with contrast to re-evaluate for mechanical obstruction or possible postoperative complications.
And don’t forget to consult your surgical team,
Ileus: Video, Causes, and Symptoms | Osmosis