Constipation (Case 23)
Case: A 67-year-old woman presents to the ED complaining of abdominal discomfort, decreased frequency of her bowel movements, and mild abdominal distension. She is clearly distressed in the ED, unable to find a comfortable position on the stretcher, and wincing with abdominal pain.
Irritable bowel syndrome (IBS)
Acute colonic pseudo-obstruction (Ogilvie syndrome)
When asked to see a patient for constipation, we first want to find out the patient’s definition of constipation. Has she not been able to move her bowels in days or is it just not as frequently or as comfortable as she would like? Most cases of constipation aren’t critical; however, a bowel obstruction or volvulus requires more urgent care. If she has not been able to move her bowels or pass any gas for days, she may need more immediate treatment. A thorough history is important, concentrating on alarm symptoms such as unintentional weight loss, rectal bleeding, or a recent or sudden change in bowel habits. Any surgical history should be reviewed, along with the patient’s medications, followed by a dedicated abdominal and rectal exam.
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Irritable Bowel Syndrome
IBS is a very common disorder characterized by abdominal pain, bloating, and altered bowel habits. The condition can affect both sexes at any age but is prominent in young females. Patients regularly experience abdominal cramping that is relieved with a bowel movement. The bowel habits can be either constipation-predominant or diarrhea-predominant in nature. Constipation-predominant patients usually experience chronic constipation with intermittent diarrhea or regular bowel movements. The pathophysiology of IBS remains unknown; however, hereditary and environmental factors probably play a role. Psychosocial dysfunction also contributes to IBS and its fluctuating symptoms.
Crampy abdominal pain, incomplete evacuation of bowels, bloating, gas (flatulence or belching), hard or lumpy stools, relief of abdominal discomfort with defecation.
The main diagnostic tool is the Rome III diagnostic criteria. This includes recurrent abdominal pain or discomfort at least 3 days a month for the last 3 months associated with two of the following: improvement with defecation, onset associated with a change in frequency of stool, or onset associated with a change in form (appearance) of stool.
Initially, constipation-predominant patients can be treated with fiber supplementation and psychosocial therapies, if emotional stress is a contributing factor. A bowel regimen in the form of a laxative, suppository, or enema may be needed if symptoms persist. Finally, specific medications that activate chloride channels or stimulate the release of serotonin can be used in refractory cases. See Cecil Essentials 34.
Colon cancer is a malignancy that usually arises from a long-standing polyp. The disease can be localized to the colon or can metastasize to other organs, most frequently the liver. Cancers in the proximal colon may present as iron deficiency anemia from a slow occult hemorrhage, while cancers in the distal colon can present with obstructive symptoms or with gross bleeding.
Symptomatic iron deficiency anemia, gross or occult blood in the stool, change in bowel habits (obstruction, diarrhea), unintentional weight loss, abdominal pain.
CT scans can sometimes demonstrate lesions in the colon and are necessary to evaluate for metastatic disease. Colonoscopy is the best diagnostic test to assess for colon cancer, and allows for definitive biopsy samples to be taken and examination of the entire colon; flexible sigmoidoscopy permits examination of only the rectum and distal colon.
Resection of polyps can usually be achieved endoscopically. Cancer resections generally require surgery, which can be performed by open or laparoscopic techniques. Radiation therapy is now used routinely for preoperative treatment of rectal cancer. When colon cancer is metastatic, chemotherapy is the treatment of choice. See Cecil Essentials 39, 57.
An impaction results from an accumulation of hardened stool, most frequently occurring in the rectum. This prevents the evacuation of stool, resulting in pain and constipation. This condition occurs more commonly in the elderly and those with chronic neuropathic disorders, from immobility, and in those on medications that alter colonic motility.
Inability to move bowels with straining, rectal pain, and pressure. Overflow diarrhea (encopresis) may occur; rectal ulcers may develop.
A fecal impaction can usually be diagnosed very easily with just a simple digital rectal exam. If the impaction is beyond the reach of a rectal exam, an obstruction series or abdominal radiograph will often demonstrate a mass of hardened stool. A CT scan can visualize and localize an area of impaction.
Manual digital disimpaction can be performed at the bedside or under general anesthesia, if necessary. Enemas, suppositories, and laxatives can be used to help break up and resolve an impaction. Following the resolution of an impaction, the patient should be given a fiber supplement and a bowel regimen containing a stool softener and possibly a stimulant or osmotic laxative to prevent further episodes. Narcotics and other medications possibly contributing to the problem should be eliminated to avoid repeat episodes.
Medications are an extremely common cause of constipation. Narcotics, calcium channel blockers, and anticholinergics are frequent culprits. The chronic use of these medicines requires an adequate bowel regimen and daily fiber supplementation to avoid recurrent issues with constipation.
Difficulty moving bowels, infrequent bowel movements, painful bowel movements, localized rectal bleeding from straining.
A thorough history is essential for diagnosing constipation due to medication administration. A complete review of the patient’s medication list is required. A detailed physical exam, along with appropriate radiologic testing, is essential to rule out any other etiology for the patient’s symptom of constipation.
The treatment of medication-related constipation can be as simple as removing the offending agent. The patient should at least temporarily be placed on a bowel regimen in the form of a fiber supplementation, stool softener, or laxative, depending on the severity of symptoms.
A volvulus is a twisting of the bowel upon itself, causing an obstruction, most commonly occurring in the sigmoid colon and cecum. Alterations in anatomic features have a role in this pathology. Left untreated, this condition can progress to ischemia and necrosis due to compromised blood supply.
Progressive abdominal distension and pain, nausea, inability to move bowels, and the absence of flatus.
An obstruction series or abdominal radiograph is a good initial test to evaluate for an obstruction, and a “coffee bean” or “bird’s beak” sign can be seen with a sigmoid volvulus. A CT scan of the abdomen and pelvis helps distinguish findings such as a volvulus and isolates the exact area of concern. A barium enema can also diagnose this condition but is used less often and is not as immediate or easily available.
If a patient presents with a sigmoid volvulus, an emergent endoscopic decompression should be performed, if possible, with a flexible sigmoidoscopy. Occasionally, a decompressive tube is left in place beyond the area of previous torsion. Following decompression, most patients need a sigmoidectomy to prevent a recurrent volvulus. See Cecil Essentials 35.
Acute Colonic Pseudo-obstruction (Ogilvie Syndrome)
Acute colonic pseudo-obstruction, also known as Ogilvie syndrome, presents as gross dilatation of the cecum and right hemicolon in the absence of an anatomic lesion causing an obstruction that can present as constipation. Trauma, neurologic conditions, surgery (abdominal/obstetric, cardiovascular, orthopedic), severe medical illness, metabolic imbalance (hypokalemia, hypocalcemia, hypomagnesemia), malignancy, and medications (narcotics, calcium channel blockers) all can predispose patients to this condition. Ogilvie’s is more commonly found in men over 60 years of age and is thought to be due to impairment in the autonomic nervous system.
Abdominal pain, nausea, vomiting, constipation and/or diarrhea, and significant abdominal distension.
On physical exam, the abdomen is distended and tympanitic, usually with bowel sounds present. An obstruction series or abdominal radiograph shows a dilated colon, more commonly from the cecum to the splenic flexure. This finding is also seen on a CT scan or barium enema, without evidence of distal obstruction.
Initial treatment involves supportive care with the correction of metabolic imbalances and the removal of precipitating factors, such as medications. An NG tube and/or rectal tube can be inserted for further symptomatic relief. Gentle enemas and stimulating suppositories can be utilized to help induce colonic motility. More aggressive pharmacologic therapy can be given with neostigmine or erythromycin; however, their efficacy is questionable, and each possesses its own side effects. Finally, endoscopic decompression is sometimes warranted if symptoms are severe or colonic dilation increases (11–13 cm). A decompressive tube can be left in the transverse colon to allow for continued treatment.