Fecal impaction: Clinical sciences

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Introduction0:00–0:30

Fecal impaction occurs when a hard mass of compacted stool in the colon cannot be voluntarily evacuated. It usually results from chronic constipation and is highly associated with elderly, immobile, and institutionalized patients because of their reduced ability to sense and respond to the increasing burden of stool.
If left untreated, fecal impaction can lead to complications like bowel ulceration and perforation. When assessing a patient with signs and symptoms suggestive of fecal impaction, first perform an ABCDE assessment to determine if the patient is unstable or stable.

Unstable patient0:30–2:23

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, obtain IV access, administer fluids, and monitor their vitals before continuing with your assessment.
Next, obtain a focused history and physical exam, as well as labs such as CBC, CMP, and lactate. History might reveal chronic constipation, bloating, abdominal pain, and possibly opioid usage.
Physical exam typically shows abdominal distension and signs of peritonitis, such as diffuse tenderness to palpation, guarding, and rebound pain.
On digital rectal examination, you’ll usually notice a large, hardened mass of stool in the rectum and possibly rectal bleeding.
Finally, labs may show leukocytosis, lactic acidosis, or anemia. In some patients, you might also notice electrolyte abnormalities like hypercalcemia, hyperkalemia, or hypermagnesemia which might actually be the cause of their constipation; or hypernatremia due to dehydration from excessive vomiting.
Alright, if you see these signs and symptoms, suspect fecal impaction. Okay, your next step is to start supportive care.
Initiate IV fluid resuscitation, electrolyte replacement, broad-spectrum antibiotics, and bowel rest. Additionally, if the patient has nausea and vomiting, place a nasogastric tube to decompress the bowel.
However, if the patient has severe anemia, be sure to provide a blood transfusion. Alright, once the supportive care is initiated, you should order an abdominal x-ray and CT, which will help you make a diagnosis.

Stercoral perforation2:23–3:10

On x-ray, you will typically see a large stool burden overlying the rectum, with or without proximal colonic distention.
CT findings may include evidence of bowel ischemia, such as pneumatosis or portal venous gas. Now, if you see pneumoperitoneum in the setting of a patient who has stercoral colitis, then you should suspect secondary stercoral perforation.
This is when an unresolved impacted fecal mass, or fecaloma, causes pressure necrosis, and ultimately, the necrotic bowel perforates.
If you notice any of these signs, go ahead and call a surgical consultation for an emergent laparotomy. Now, let’s go back to abdominal x-ray and CT.

Stercoral ulcer bleed3:10–3:58

If you see a large colonic stool burden without any signs of ischemia or perforation, and especially if the patient is having active rectal bleeding, proceed with lower endoscopy, which can be both diagnostic and therapeutic.
After the impacted stool is removed, endoscopy will show an irregular, bleeding mucosal ulceration, whose contour correlates to nearby impacted feces.
If this is the case, you can diagnose a stercoral ulcer leading to acute lower GI bleed. Initial treatment includes injectant, thermal, or mechanical endoscopic hemostasis.
Then, continue supportive care, transfuse blood products as needed, and make sure to treat underlying causes. Okay, now that unstable patients are taken care of, let’s return to the ABCDE assessment and talk about stable patients.

Stable patient3:58–5:39

Your first step here is to obtain a focused history and physical exam, as well as labs like CBC, CMP, and lactate. Stable patients also report chronic constipation, bloating and abdominal pain, as well as possible nausea and vomiting.
Don’t forget to ask about common risk factors such as opioid or anticholinergic medication usage, hypothyroidism, history of functional immobility or institutional care, and any prior neuropsychiatric diagnoses.
Here’s a high-yield fact! Although fecal impaction is related to constipation, patients may present with other forms of bowel and bladder dysfunction.
It is not uncommon for patients to have urinary tract infections, urinary incontinence, or even paradoxical diarrhea when watery stools leak past the solid impaction.
On the flip side, a physical exam often reveals abdominal distention, and sometimes abdominal tenderness to palpation. If the patient is thin, and the impaction is bulky enough, you may even be able to palpate a left lower quadrant mass!
The key finding of fecal impaction is a large rectal stool burden during the digital rectal examination. But remember, in some cases the impaction may be too proximal to feel, so don’t rule it out based solely on the rectal exam!
Finally, labs might show electrolyte abnormalities like hypercalcemia, hyperkalemia, hypermagnesemia, or hypernatremia. At this point, go ahead and obtain an abdominal x-ray.

Imaging5:39–6:08

This typically shows a large burden of stool in the colon and rectum. The intraluminal stool has a soft tissue mixed-density appearance, due to its mixture of solid and gas components.
Sometimes, you might see radiopaque fecaliths, which are hard calcified fecal masses. At this point, diagnose fecal impaction and initiate supportive care.Okay, as before, supportive care includes IV fluid resuscitation, electrolyte replacement, bowel rest, and nasogastric tube placement for bowel decompression if the patient is having nausea and vomiting.

Supportive care6:08–7:30

Next, perform manual disimpaction to address and relieve the fecal impaction.Okay, here’s a clinical pearl for you! To perform manual disimpaction, insert a gloved and lubricated finger into the patient’s rectum, and break up stool with a scissoring motion.
Then, with your finger slightly bent, gently perform a circular sweeping motion, before extracting your finger with pieces of stool from the rectum.
Keep in mind that there can be liquid stool and gas under pressure behind the impacted stool, so disimpaction can result in an explosive release of the backed up liquid stool and gas.Alright, now that the patient’s impaction has been relieved, let’s talk about the next steps.
Since fecal impaction is the end result of constipation, make sure to initiate a maintenance bowel regimen. This regimen can include laxatives, stool softeners, and enemas.
You can implement it either orally, rectally, or both, depending on the patient. Additionally, provide the patient with supplemental fiber and, if they are able, make sure they are drinking enough water.
Continue serial abdominal exams and x-rays, and treat any underlying causes. Okay, now that supportive care is initiated, let’s talk about possible outcomes.

Response assessment7:30–8:27

Over the next few days, continue supportive care and evaluate the patient frequently to assess their response to treatment.
If the patient is improving, you’ll notice bowel movements and reduced abdominal discomfort and distention on your physical exam.
Serial abdominal x-rays should show significantly improved stool burden. If this is the case, go ahead and restart oral or enteral nutrition, but continue the other supportive care measures, and treat underlying causes.The vast majority of fecal impaction patients respond to supportive care alone.
However, if they don’t improve, or if they show signs of worsening like new leukocytosis, fever, or hemodynamic changes, as well as worsening abdominal pain and distention, or complete obstipation, order a CT of the abdomen and pelvis with IV contrast to diagnose the condition and possibly find the underlying cause.
Let’s consider some possible CT findings in patients who were unresponsive to supportive management or worsened clinically.

Stercoral colitis8:27–9:00

Okay, let’s say the CT scan shows a large stool burden, with or without colonic dilatation, in addition to mural thickening and pericolonic fat stranding.
These signs are concerning for colitis, and in the setting of fecal impaction, you can diagnose stercoral colitis. If this is the case, continue supportive care including bowel rest and IV fluid, and make sure to start the patient on broad-spectrum antibiotics.

Large bowel obstruction9:00–9:29

Lastly, let’s go back to CT imaging to discuss one more possibility to keep in mind. You might find colonic dilation and evidence of a new mechanical obstruction from another cause, such as a tumor.
For example, a tumor can lead to fecal impaction when the enlarging mass narrows the bowel lumen and stool cannot pass. If you find any evidence of mechanical large bowel obstruction on imaging, call a surgical consultation for further management and treatment of underlying causes.
Alright as a quick recap… A patient with fecal impaction can present as stable or unstable. Unstable patients should be assessed with an abdominal x-ray and CT.

Review9:29–10:36

If you see signs of ischemia or perforation, call the surgical team for a consultation. However, if you don’t see these signs, continue with lower endoscopy, which can both diagnose and treat the patient.
On the other hand, stable patients should be evaluated with an abdominal x-ray and treated with supportive care, such as manual disimpaction, the initiation of a bowel regimen, IV fluid, electrolyte repletion, and possible bowel rest and decompression.
If they respond to treatment, proceed with restarting oral or enteral nutrition, and continue to treat underlying causes.
If they don’t respond to treatment or worsen, order a CT of the abdomen and pelvis. If you see evidence of stercoral colitis, continue supportive care, including bowel rest and IV fluids, and start antibiotics.
On the other hand, if the patient has evidence of a new mechanical large bowel obstruction on imaging, call the surgery team for a
Fecal impaction: Video, Causes, and Symptoms | Osmosis