By the time a case of inpatient constipation gets to Melissa Latorre, MD, MS, it's usually been a problem for some time, and the consequences of clinicians' failure to move can be serious for patients.
“We want to remember that constipation can kill,” she told attendees at the annual meeting of the American College of Gastroenterology, held in Philadelphia in October. “Constipation increases the luminal wall pressure leading to ischemia, ulceration, and ultimately, perforation, peritonitis, and death.”
To help reduce risk for those complications, Dr. Latorre, director of inpatient services for gastroenterology at New York University Langone's Tisch Hospital and Kimmel Pavilion in New York City, offered some “pro tips” for diagnosing and treating inpatient constipation.
It's an increasingly common problem, she reported, citing a study published in the American Journal of Gastroenterology in 2014. “The primary diagnosis of inpatient constipation is on the rise. Since 1997, there's been about 120% increase in this diagnosis,” Dr. Latorre said.
Despite frequent exposure to the problem, physicians are still not treating it adequately, she noted. “Ineffective laxatives, such as docusate sodium, continue to be the most commonly prescribed.”
Dr. Latorre recommended a more proactive approach. “Be aggressive upfront with getting patients to have bowel movements,” she advised. “Ditch the PRNs . . . A lot of times [orders are] written for laxatives, but they're all PRN, and they're in effect getting none. So we've decided to start to combat this to provide laxatives standing, with an opt-out policy to hold if the patient has had more than two bowel movements or is having diarrhea.”
The presence of diarrhea does not rule out constipation, however, Dr. Latorre warned. Another of her pro tips is “Don't be fooled by diarrhea,” as it may be overflow. On the other hand, once you're treating a patient for constipation, diarrhea can be a good thing. “It's important to warn providers and patients that diarrhea is desired upfront. We're trying to get these patients over the hump of their constipation,” she said.
In her treatment algorithm for constipation, Dr. Latorre divided therapies by whether they are applied from above or below. She also advised physicians to think of inpatient constipation treatment like chemotherapy, with induction and maintenance regimens. “This is more from experience; the data is very limited,” she cautioned.
From above, in the induction phase, she recommends an osmotic laxative such as polyethylene glycol, 17 g in 8 ounces of water, either two or three times a day, or colonoscopy prep if the patient can tolerate it. “I don't advise the use of fiber or lactulose upfront, as the symptoms of bloating can be exacerbated,” she said. Similarly, oral stimulants can increase the pain and distension that patients are already feeling.
“For diet, I don't mind making patients NPO, especially since they are having nausea. A lot of times we see them have emesis and aspiration and later suffer consequences as a result of that, so I tell them that this is in their best interest, and once we get them better, then we'll let them eat,” Dr. Latorre said. For patients whose symptoms include nausea, emesis, or distension, a nasogastric tube may be considered.
From below, the induction phase can include manual maneuvers and suppositories. “Glycerin may help to soften the stool and bisacodyl may help with rectal motility,” she said. “After the first bowel movement, I get them some enemas to help clean more proximally—mineral oil or tap water.”
Once bowel movements have become reliable, pull back on the rectal therapy, she recommended. That's also when patients get to eat again (after they've tolerated a clear liquid diet) and the treatment moves into a maintenance phase.
This phase includes providing fiber, water or IV fluids, and oral laxatives, in addition to optimizing the patient's underlying medical condition, she said. If the patient is taking opioids, opiate-receptor antagonists may also be helpful.
“It's important to be aware of overlap,” Dr. Latorre said. “Many patients can have functional constipation in addition to opioid-induced constipation, and these can be our most vulnerable patients in the hospital.”
Opioid-induced and other causes
Multiple opiate-receptor antagonists have been approved by the FDA, but they may not all be available to prescribe in the hospital. “At my institution, we have only methylnaltrexone on our formulary, in the subcutaneous form,” she said.
Another challenge with these drugs is the risks they carry. “It's important to remember that these medications have an FDA warning for GI [gastrointestinal] perforation in patients with opioid-induced constipation and advanced illness with conditions that affect structural integrity of the digestive tract,” said Dr. Latorre.
Given this concern, she suggests these medications be administered in consultation with a gastroenterologist. “A lot of the providers aren't adept at checking for the structural integrity or don't feel comfortable, don't look at the imaging. That, at our institution, initially resulted in cases of perforation, which now have been reduced,” she said.
Several of her tips focused on reducing the risk of such adverse outcomes for patients. She encouraged clinicians to always risk-stratify constipation into urgent and emergent cases.
“What I consider urgent constipation is someone who is symptomatic, with bloating, nausea, has bowel distension, and is impacted. On the more emergent spectrum is someone who is symptomatic with emesis, pain, bowel dilation, or even colitis,” Dr. Latorre said.
Other patients at high risk include those who don't actually have constipation. “You'll be consulted for a patient with constipation, but the reality is that it's a more severe diagnosis that requires even more emergent evaluation, assessment, and diagnosis,” she said.
Such “fatal mimickers” include small-bowel obstruction, large-bowel obstruction, acute pseudo-obstruction, volvulus, toxic megacolon, and perforation.
“The similarities are that patients will have abdominal distension, they'll have abdominal pain, a paucity of bowel movements and gas, nausea, bloating, fullness, and emesis,” said Dr. Latorre. “The differences are they'll manifest with toxicity. There'll be a leukocytosis and elevated lactate, altered mental status. There's often hemodynamic compromise, in the form of tachycardia, tachypnea, hypoxia, and fever.”
Radiologic imaging and physical exam signs can also help distinguish these diagnoses from constipation. “Symptoms can be rapidly progressive,” she said. “Remember to risk-stratify patients and be mindful of alternative life-threatening diagnoses.”
If patients have recently had surgery, ileus will likely be considered in the diagnosis of their constipation.
“This is an inhibition of digestive propulsion that can affect all parts of the GI tract,” said Dr. Latorre. “It results in delayed recovery, prolonged hospitalization, and increased costs. It often occurs in the postoperative state.”
For four days after surgery, ileus is considered physiologic and normal, she explained. “Thereafter, it's considered pathologic, if two or more of the following are present: nausea, vomiting, inability to tolerate diet over the prior 24 hours, absence of flatus in the preceding 24 hours, abdominal distension, radiologic evidence.”
There are common misconceptions about the location of ileus. “We often see it in the small bowel and it's often thought that it only occurs in the small bowel, but it can occur anywhere,” said Dr. Latorre.
Most treatment is supportive and should include IV fluid, electrolyte repletion (especially potassium and magnesium), mobilization as tolerated, and nutritional support, she advised. “For symptomatic relief, I often recommend anti-emetics or laxatives,” she said.
Any drugs that might be causing the problem (e.g., narcotics) should be reversed, and GI decompression might be appropriate for some patients.
There are also two pharmaceutical options. Alvimopan is FDA-approved to accelerate upper and lower GI recovery following a partial small-bowel resection with primary anastomosis. “So a very specific population,” said Dr. Latorre, who noted that it also carries a black box warning about the risk of myocardial infarction.
The other choice is neostigmine, which is approved for acute pseudo-obstruction and large-bowel ileus. “It's also important to closely monitor patients for severe bradycardia and bronchospasm when neostigmine is used,” she said.
There's also one very safe and cheap therapy option. “Chewing gum has some reported benefits,” Dr. Latorre noted.