What is fecal impaction?
Fecal impaction (FI) is a serious condition in which a hardened stool gets stuck in the large intestine (colon), often resulting in the inability to pass stool. It often happens in people who have chronic constipation issues.
Treatment involves clearing out the stool mass. Without prompt treatment, FI can lead to intestinal wall ulcerations or perforations (holes in the intestinal wall) and even life-threatening infections and death.
FI can affect anyone but is more common in children, the elderly, people with reduced mobility (paralyzed or confined to bed), patients in long-term care facilities, or patients with severe neuropsychiatric disorders.
If you have not been able to pass stool for at least 4 days, you should seek urgent medical attention.
Most common symptoms
Many people with fecal impaction still pass stool. In these cases it’s mostly liquid stool, and the stool generally passes around the impacted fecal matter in the intestines. —Dr. Adam Pont
Symptoms may depend on where the stool mass is located. You may have abdominal pain and your abdomen may be swollen. You may be able to feel a hard mass (the hardened stool) in your lower abdomen if you press it with your hand. If the hard stool is close to your anus, you may be able to feel the hard stool if you insert your finger inside.
You might be nauseous or even vomit. In other cases, liquid stool can get past the hardened stool mass causing liquid diarrhea or even incontinence (inability to control bowel movements).
- Inability to pass stool for at least 4 days.
- After 4 (or more) days of not being able to pass stool, sudden liquid diarrhea, possibly with trouble controlling bowels.
- Abdominal pain.
- Swollen abdomen.
- Hard mass in the abdomen that you can feel when pressing down.
- Hard mass of stool in the rectum that you can feel when sticking a finger in your anus.
Other symptoms you may have
- Nausea and vomiting.
- Rectal bleeding.
- Fever, chills, lightheadedness/dizziness, or sudden extreme worsening of abdominal pain. (These symptoms might happen if the mass pokes a hole in your intestinal wall.)
- Agitation or confusion, especially in the elderly or those who can’t describe symptoms.
Is impacted stool an emergency?
It’s almost always an urgent situation. If you have not been able to pass any stool for at least 4 days (not including sudden development of uncontrollable liquid diarrhea), you should go to the ER for further evaluation and treatment.
However, if you also have severe “alarm” symptoms, you should call 911. These severe symptoms include:
- Sudden, severe abdominal pain
- Rectal bleeding
- Difficulty breathing
- New lightheadedness/dizziness, especially when standing up or sitting up
Causes of fecal impaction
Fecal impaction is often caused by untreated chronic constipation. As you get constipated, stool may start to collect in the colon. Because the colon takes water and salts out of stool, this stool collection may harden. This can disrupt the normal movements of the colon that push stool through, causing more stool to get stuck and potentially causing an obstruction.
Your colon can stretch to accommodate a large amount of stool. However, there comes a point when the mass of stool is too large to pass. Sometimes liquid stool will work its way around the mass. Stool pressing on the intestinal wall also causes inflammation that may cause liquid secretion by intestinal wall tissue. This looks like watery diarrhea.
In extreme cases, the stool mass may injure the intestinal wall, causing bleeding, or breaking through it (perforation). These situations can be life-threatening and require emergency care.
Treatment for fecal impaction
I have seen patients with a mass of impacted fecal matter larger than a full-term fetus, and we were successful in significantly reducing the mass with only oral laxatives and enemas. —Dr. Pont
Once FI is confirmed by your doctor (usually after a series of X rays or an abdominal CT scan), they will confirm that you are not bleeding from your colon and do not have a hole in your colon (perforation). Treatment involves disimpaction (breaking up the stool mass) and then evacuation (removing the stool mass).
If the stool is in your rectum (the part of your large intestine right inside the anus), your doctor will try to take it out manually. They will insert a lubricated, gloved finger into your anus to break up the mass.
Enema and laxatives
The next step may be to evacuate the stool with a combination of enemas and oral laxatives. An enema is an injection of fluid into the rectum. Rectal enemas are usually given first.
That is followed by an oral laxative (usually polyethylene glycol). How long this takes depends on the size of the stool mass.
If these methods are unsuccessful (for instance, if the impacted stool is beyond the reach of an inserted finger), the doctor (a gastroenterologist) may do a colonoscopy to look for the cause of the blockage. This is when a thin tube with a light and a lens at the end is inserted through the anus to examine the colon. If the stool blockage is found, the doctor may use the colonoscope to attempt to dislodge the stool blockage. A colonoscopy is generally done under sedation in a hospital.
If manual (or colonoscope-assisted) disimpaction is successful, surgery is usually not required. Surgery is usually only needed if the impacted stool has caused a perforation (hole) in your intestine.
When the impacted stool is completely cleared out, your doctor may start you on a laxative regimen to prevent constipation and another impaction. They may also suggest further testing or procedures to look for underlying conditions. If you are taking a medication (such as opioid painkillers) that causes constipation, you may need to stop taking it or adjust the dose.
Almost every patient I have seen with fecal impaction has been in some way mentally incapacitated—usually by dementia. Most of my advice is more likely to be something that I’m telling a family member or health care proxy. —Dr. Pont
Underlying constipation can lead to FI. People most at risk include:
- People with certain neurological disorders such as multiple sclerosis or Parkinson’s disease
- People with severe psychiatric illness
- Residents of long-term care facilities
- People with spinal cord injuries or limited mobility.
- People with abnormal gut anatomy or who have had surgery on the colon or anus.
- People taking certain medications, like opioid painkillers
- Having a very low-fiber diet or dehydration may increase the risk.
- People with metabolic disease such as hypothyroidism
Fecal impaction in children
Chronic constipation is common in children and they are also at risk of FI. Risk factors in children include:
- Stool withholding behavior (consciously holding in stool for reasons including being afraid or unwilling to poop in certain situations).
- Low-fiber diet.
- Abnormalities of the anus.
- Hirschsprung’s disease—a congenital neuromuscular disease that affects the colon and causes problems passing stool.
- Spinal cord injuries.
- Certain medications.
Children with fecal impaction are usually treated with oral laxatives, enemas, or suppositories.
The best way to prevent fecal impaction is to recognize and treat constipation symptoms. This includes being aware of your medications can cause constipation, and talking with your doctor if you begin to notice constipation symptoms. Increasing fiber intake and drinking plenty of water may help prevent FI recurrences.
Dr. Pont is currently a fellow in Gastroenterology at New York Presbyterian Hospital/Columbia, where he also completed his residency in Internal Medicine. Dr. Pont received his medical degree and PhD at the New York University School of Medicine. He earned his BS in Biological Systems Engineering at the University of Nebraska-Lincoln.