9/14/2020 Paralytic ileus - EMCrit Project

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Paralytic ileus

September 14, 2020 by Josh Farkas

(https://emcrit.org/?attachment_id=478321)

CONTENTS

Basics (#basics)

Presentation (#presentation)

Differential diagnosis (#differential_diagnosis)

Investigations (#investigations)

Causes (#causes)

TreatmentGeneral measures (#treatment_–_general)

Opioid antagonists (#opioid_antagonists)

Prevention (#prevention)

Podcast (#podcast)

Questions & discussion (#questions_&_discussion)

Pitfalls (#pitfalls)

PDF of this chapter (https://emcrit.org/wp-content/uploads/2017/01/hyperthermia.pdf)  (or create customized PDF (https://emcrit.org/ibcc/about-guide/#pdf) )

basics

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Ileus is used in this chapter to refer to functional hypomotility of the small intestine (also known as “paralytic ileus” or “adynamic ileus”).  This isnot due to an anatomic obstruction of the small intestine (which is referred to as “small bowel obstruction”).

presentation

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presentation may include

TOC ABOUT THE IBCC TWEET US IBCC PODCAST

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Nausea, vomitingDistensionAbdominal pain (usually mild, may have a colicky quality)High gastric residual volumesAbsence of bowel movements for 3 days or more (30294835 (https://pubmed.ncbi.nlm.nih.gov/30294835/) )

di�erential diagnosis

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[Anatomic] small bowel obstructionColonic pseudo-obstruction (similar to ileus, but involves marked dilation of the colon)Bowel perforation

investigations

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(https://emcrit.org/?attachment_id=476881)

abdominal X-ray

Distended, gas-�lled loops of bowel are seen.Features differentiating ileus from small bowel obstruction are listed above.

CT scan

CT scan provides de�nitive imaging of the abdomen and pelvis.This is indicated if there is persistent uncertainty about the diagnosis.

causes

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sepsis

medications

Opioids and antidiarrheals (e.g., loperamide)Calcium channel blockersClonidineAlpha-adrenergic medicationsMedications with anticholinergic properties, for example:

Antipsychotics, tricyclicsAntihistaminesMuscle relaxants (e.g., baclofen, cyclobenzaprine, tizanidine)Parkinson's disease medications

electrolyte or metabolic abnormalities

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Hypokalemia, hyponatremia, hypomagnesemiaHypothyroidismHyperglycemiaUremia

abdominal pathology

Recent surgeryPeritonitis, appendicitis, cholecystitis, pancreatitisIntestinal ischemia

treatment – general

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general measures

Avoid other causative medications as able (see list above).If the patient is on opioids, these should be minimized and effects on the gut may be speci�cally counteracted (see section below(#treatment_-_antiopioid_therapies) on this).

Aggressive mobilization if possible.Treat any electrolytic abnormalities.

continuation of feeding?

Feeding will generally need to be held temporarily.  (However, if ileus is noted incidentally on X-ray and the patient is clinically toleratingfeeding clinically, then feeding should probably be cautiously continued with careful monitoring.)Once some time has passed and underlying factors have been addressed, feeding re-challenge may be attempted (often starting withliquids).Prolonged periods without enteral nutrition may promote ileus, so an overly conservative strategy to enteral nutrition could becounterproductive.

nasogastric tube drainage

Nasogastric drainage is not generally needed, nor evidence-based.Drainage may be used to palliate symptoms (e.g., intractable vomiting or uncomfortable distension).Avoidance of nasogastric tube drainage is one component of some protocols designed to facilitate early recovery after surgery (ERAS), witha goal of avoiding ileus. (28818187 (https://pubmed.ncbi.nlm.nih.gov/28818187/) )   There isn't high-level evidence here, but it's important to notethat nasogastric drainage may not promote normal gut functioning.  

pro-motility agents 

These are generally ineffective for ileus and not recommended.Erythromycin may tend to slow, rather than accelerate, transit through the small intestine! (30294835(https://pubmed.ncbi.nlm.nih.gov/30294835/) )

If there is marked dilation of the colon (i.e., ileus plus colonic pseudo-obstruction), then neostigmine may be considered (see chapter oncolonic pseudo-obstruction).

opioid antagonists

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#1:  limitation of opioids

Reduce the dose of opioids as much as possible.  This should involve the use of a multi-modal analgesia strategy that maximizes non-opioidanalgesics (e.g., acetaminophen and pain-dose ketamine infusions).It may be impossible to eliminate opioids altogether, but even a reduction in dose may be helpful.

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#2:  enteral naloxone

Enteral naloxone (i.e., naloxone delivered via feeding tube) acts predominantly on the gut.  First-pass metabolism should generally minimizesystemic effects, in the absence of liver disease. (22541841 (https://pubmed.ncbi.nlm.nih.gov/22541841/) )  This usually doesn't cause worseningpain or opioid withdrawal, but some increase in pain can occur at higher doses.Nuts and bolts:

Give 4-8 mg enteral naloxone per feeding tube, every six hours if needed (not intravenously). (12626983(https://pubmed.ncbi.nlm.nih.gov/12626983/) )  The intravenous formulation of naloxone may simply be administered via feeding tube.  It mightbe reasonable to start at 4 mg and then increase the dose to 8 mg if needed. (8800821 (https://pubmed.ncbi.nlm.nih.gov/8800821/) )Observe the patient following naloxone administration.  If an increase in pain does occur, this may be treated with a non-opioidanalgesic (e.g., pain-dose ketamine).Make absolutely sure NOT to administer the naloxone intravenously.  A bolus of 4-8 mg intravenous naloxone could induce withdrawaland severe pain.

Evidentiary basis:  Oral naloxone 8 mg q6hr has been demonstrated to improve tube feed tolerance, improve motility, and reduce the riskof aspiration pneumonia in an ICU setting. (12626983 (https://pubmed.ncbi.nlm.nih.gov/12626983/) )  This is only one study, but it's somewhatunique in that the drug was validated to work in critically ill patients and also improved a patient-centered endpoint.

(methylnaltrexone is currently not supported by evidence)

Methylnaltrexone is an opioid antagonist which functions peripherally, but does not cross the blood-brain barrier.  As such, it may antagonizethe effect of opioids on the gut, without increasing pain.Drawbacks of methylnaltrexone include high cost and lack of evidentiary basis among critically ill patients.

Evidentiary basis:  Methylnaltrexone was ineffective in the MOTION trial, a double-blind RCT evaluating whether it could improveconstipation among critically ill patients.  Some trends actually seemed to suggest increased bowel motility in the control group.  Mortalitywas higher within the methylnaltrexone group. (32016532 (https://pubmed.ncbi.nlm.nih.gov/32016532/) )

prevention

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Early feeding:  Early initiation of enteral nutrition and avoidance of long interruptions may reduce the risk of ileus.Aggressive mobilization.Balanced pain control, with avoidance of excessive opioids.Optimization of �uid balance and electrolytes.

podcast

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questions & discussion

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To keep this page small and fast, questions & discussion about this post can be found on another page here (https://emcrit.org/pulmcrit/hyperthermia/) .

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Don't assume that a nasogastric tube should be placed for any patient with ileus.  If possible, it may be preferable to avoid nasogastricdrainage.Avoid holding nutrition for long periods of time unnecessarily, as this may promote ileus development.

References

08800821.  Sykes NP. An investigation of the ability of oral naloxone to correct opioid-related constipation in patients with advancedcancer. Palliat Med. 1996;10(2):135-144. doi:10.1177/026921639601000208  [PubMed (https://pubmed.ncbi.nlm.nih.gov/8800821/) ]11779668  Liu M, Wittbrodt E. Low-dose oral naloxone reverses opioid-induced constipation and analgesia. J Pain Symptom Manage.2002;23(1):48-53. doi:10.1016/s0885-3924(01)00369-4  [PubMed (https://pubmed.ncbi.nlm.nih.gov/11779668/) ]12626983  Meissner W, Dohrn B, Reinhart K. Enteral naloxone reduces gastric tube re�ux and frequency of pneumonia in critical carepatients during opioid analgesia. Crit Care Med. 2003;31(3):776-780. doi:10.1097/01.CCM.0000053652.80849.9F  [PubMed(https://pubmed.ncbi.nlm.nih.gov/12626983/) ]22541841.  Smith K, Hopp M, Mundin G, et al. Low absolute bioavailability of oral naloxone in healthy subjects. Int J Clin Pharmacol Ther.2012;50(5):360-367. doi:10.5414/cp201646  [PubMed (https://pubmed.ncbi.nlm.nih.gov/22541841/) ]28818187  Vilz TO, Stoffels B, Strassburg C, Schild HH, Kalff JC. Ileus in Adults. Dtsch Arztebl Int. 2017;114(29-30):508-518.doi:10.3238/arztebl.2017.0508  [PubMed (https://pubmed.ncbi.nlm.nih.gov/28818187/) ]28828195  Vazquez-Sandoval A, Ghamande S, Surani S. Critically ill patients and gut motility: Are we addressing it?. World J GastrointestPharmacol Ther. 2017;8(3):174-179. doi:10.4292/wjgpt.v8.i3.174  [PubMed (https://pubmed.ncbi.nlm.nih.gov/28828195/) ]29720852  Ladopoulos T, Giannaki M, Alexopoulou C, Proklou A, Pediaditis E, Kondili E. Gastrointestinal dysmotility in critically illpatients. Ann Gastroenterol. 2018;31(3):273-281. doi:10.20524/aog.2018.0250  [PubMed (https://pubmed.ncbi.nlm.nih.gov/29720852/) ]30294835  Deane AM, Chapman MJ, Reintam Blaser A, McClave SA, Emmanuel A. Pathophysiology and Treatment of GastrointestinalMotility Disorders in the Acutely Ill. Nutr Clin Pract. 2019;34(1):23-36. doi:10.1002/ncp.10199  [PubMed (https://pubmed.ncbi.nlm.nih.gov/30294835/)

]30855322  Plummer MP, Reintam Blaser A, Deane AM. Gut dysmotility in the ICU: diagnosis and therapeutic options. Curr Opin Crit Care.2019;25(2):138-144. doi:10.1097/MCC.0000000000000581  [PubMed (https://pubmed.ncbi.nlm.nih.gov/30855322/) ]31061645  Harnsberger CR, Maykel JA, Alavi K. Postoperative Ileus. Clin Colon Rectal Surg. 2019;32(3):166-170. doi:10.1055/s-0038-1677003  [PubMed (https://pubmed.ncbi.nlm.nih.gov/31061645/) ]32016532.  Patel PB, Brett SJ, O'Callaghan D, et al. Methylnaltrexone for the treatment of opioid-induced constipation and gastrointestinalstasis in intensive care patients. Results from the MOTION trial. Intensive Care Med. 2020;46(4):747-755. doi:10.1007/s00134-019-05913-6 [PubMed (https://pubmed.ncbi.nlm.nih.gov/32016532/) ]

The Internet Book of Critical Care is an online textbook written by Josh Farkas (@PulmCrit), an associate professor ofPulmonary and Critical Care Medicine at the University of Vermont.

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