para>42% of patients in a geriatric ward with fecal impaction (1)
Prevalence
- 60% of patients with fecal impaction have a history of chronic constipation (2).
- In North America, the prevalence of constipation among the general population is 2-27%.
- Constipation is more common in females, non-whites, and people of lower socioeconomic status (3).
- 78% of all children with encopresis have fecal impaction (4).
- In children, encopresis is 3 times more common in boys than girls (4).
ETIOLOGY AND PATHOPHYSIOLOGY
- Age-related degenerative changes of the enteric nervous system, colonic hypomotility, and age-related anatomic changes of the lower GI tract contribute to delayed gut transit time and decreased stool water content.
- The rectosigmoid colon dilates to accommodate fecal material, which is not pliable enough to pass through the anal canal (5).
- Impacted stool may exist as a single mass (stercolith) or as a composite of small, rounded fecal particles (scybalum).
- Poor diet
- Inadequate fiber, water, and caloric intake all contribute to impaction.
- Medication side effect (6,7)
- Stimulant laxatives
- Opiate analgesics
- Anticholinergics
- Diuretics
- Calcium channel blockers
- Aluminum (sucralfate, antacids)
- Iron
- NSAIDs
- Neurogenic disorders
- Hirschsprung disease
- Chagas disease
- Autonomic neuropathy
- Multiple sclerosis
- Spinal cord injury (13%) (8)
- Cauda equina
- Parkinson disease
- Alzheimer disease (9)
- Metabolic disease
- Hypothyroidism
- Hyperparathyroidism
- Diabetes mellitus
- Electrolyte disturbances
- Hypokalemia
- Hypercalcemia
- Hypermagnesemia
- Anatomic abnormalities
- Anorectal stenosis
- Neoplasm
- Megarectum
- Painful rectal conditions inhibiting voluntary defecation (anal fissure, hemorrhoids, fistulas)
- Psychological comorbidities
- Depression
- Anxiety
- Anorexia nervosa
- Immobility (1% of hospitalized patients) (10)
- Pelvic floor dysfunction or dyssynergia
- Irritable bowel syndrome, constipation predominant
- Idiopathic
- Fecal impaction of the cecum may be seen in cystic fibrosis.
Genetics
In the absence of known syndrome (e.g., Hirschsprung disease, no clear genetic link)
RISK FACTORS
- Institutionalization
- Prior history of fecal impaction
- Constipation
- Psychogenic illness
- Immobility, inactivity
- Pica
- Chronic renal failure
- Urinary incontinence
- Cognitive decline, disability
- Heavy metal ingestion or exposure
- Poor toileting habits
- Excessive seed consumption (common in Middle Eastern cultures), leading to rectal seed bezoars
- Medication (opioids in particular)
Pediatric Considerations
Habitual neglect of urge to defecate may promote impaction.
GENERAL PREVENTION
- Maintain adequate hydration.
- Maintain high-fiber diet (11)[C].
- Regular exercise and ambulation (11)[B]
- Establish regular toilet time leveraging gastrocolic reflex to promote defecation after meals (11)[C].
- Psyllium (12)[B]
- Periodic enemas, if indicated
- Periodic polyethylene glycol powder (MiraLAX) (12)[A]
- Lactulose (12)[A]
DIAGNOSIS
HISTORY
- Abdominal pain and bloating
- Constipation
- Rectal discomfort
- Fecal incontinence, paradoxical (overflow) diarrhea
- Nausea, vomiting, anorexia
- General malaise
- Agitation and confusion in elderly
- Urinary frequency
- Urinary incontinence
- Straining to move bowels
PHYSICAL EXAM
May be unremarkable
- Vital signs
- Tachycardia
- Tachypnea
- Low-grade fever
- General
- Agitated
- Confused
- Poor hydration status
- Abdominal
- Distention
- Palpable, tubular mass in lower quadrant
- Rectal
- Copious stool in rectal vault. If impaction is in sigmoid colon, rectal exam will be nondiagnostic.
- Hard stool
- Anal fissures
- Hemorrhoids
- Loss of sphincter tone
DIFFERENTIAL DIAGNOSIS
- Colitis
- Diverticulitis
- Appendicitis
- Colorectal cancer
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
- Laboratory tests are often unremarkable. If obtained, the following are possible:
- Leukocytosis on CBC
- Various electrolyte abnormalities: hyponatremia; hypokalemia; hypercalcemia; hypermagnesemia
- Elevated TSH
- Stool may be positive for occult blood.
- Plain abdominal radiography may reveal stool or signs of obstruction, including dilated loops of colon or small bowel, and air fluid levels.
- CT scan may show localized fecal material of impressive diameter (13).
Geriatric Considerations
Identify underlying cause. Thyroid and electrolyte disturbances are particularly common in elderly patients presenting with impaction.
Follow-Up Tests & Special Considerations
Pediatrics
- Celiac antibodies (antigliadin and antiendomysial)
- Lead levels
Diagnostic Procedures/Other
Sigmoidoscopy may be used to clarify the nature of a rectosigmoid mass after disimpaction.
TREATMENT
GENERAL MEASURES
- Treatment centers on removal of the impaction and prevention of future recurrence
- Manual disimpaction and extraction of fecal mass is often required.
- For stool located higher in the rectum, a rigid proctoscope may be used to disimpact stool or to pass enema solution to soften stool (7).
- Exclude contraindications (perforation or massive hemorrhage) prior to disimpaction (14).
- In the elderly, digital disimpaction may cause syncope or arrhythmias due to vagal stimulation (15).
- Gastrografin can be used for both identifying the extent of impaction and aid in stool removal (15).
- Oral laxatives are contraindicated in the presence of air fluid levels on imaging, as they can lead to pressure/ischemic necrosis of colon wall (7).
MEDICATION
First Line
- Enemas to soften stool and stimulate defecation
- Mineral oil enema or warm water enema to aid passage of stool
- Osmotic laxatives, such as polyethylene glycol solutions and magnesium citrate, may soften stool.
- Precautions
- Osmotic laxatives are contraindicated with bowel obstruction (7).
- Use magnesium citrate with caution in patients with renal insufficiency.
- Lactulose may result in colonic distension due to bacterial fermentation.
- Avoid soap, hot water, and hydrogen peroxide enemas as they may result in rectal mucosal irritation.
SURGERY/OTHER PROCEDURES
- Neostigmine can be combined with glycopyrrolate for patients with spinal cord injury (8) and severe impaction. This must be done in ICU setting.
- Surgery with intestinal perforation
- After disimpaction, colonoscopy or barium enema can evaluate for anatomic abnormalities if necessary (16).
COMPLEMENTARY & ALTERNATIVE MEDICINE
Biofeedback improves constipation (reducing incidence of impaction) in patients with dyssynergic defecation.
INPATIENT CONSIDERATIONS
Admission Criteria/Initial Stabilization
- Disimpaction is usually performed as an outpatient.
- Hospitalization is necessary if outpatient management has failed.
- Signs and symptoms of obstruction, intestinal perforation, or peritonitis
- Hemodynamic instability or poor hydration status
ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
Maintain ≥3 bowel movements/week.
DIET
High fiber (30 g/day) with adequate hydration (minimum 2 L/day). Fermentable (soluble) fiber sources: psyllium seed husk, oat bran, barley, soybeans, chia, broccoli, almonds, avocados, plums, berries, pears, apples
PATIENT EDUCATION
- Increased activity
- Comprehensive bowel program, including use of osmotic laxatives, bulking agents, behavioral changes, dietary changes
- Effective education is crucial to meaningfully change chronic bowel behavior patterns.
- Regular toileting using gastrocolic reflex
- Attempt defecation when urge for bowel movement is sensed.
- Maintain good hydration.
PROGNOSIS
- Reimpaction is likely if bowel hygiene regimen is not followed.
- Prognosis is poor if intestinal perforation or peritonitis.
- Mortality with impaction and obstruction is highest in the very young and the very old (up to 16%).
COMPLICATIONS
- Intestinal obstruction; urinary tract obstruction
- Recurrent UTIs
- Spontaneous perforation of colon; sepsis is possible with perforation.
- Incarcerated hernia
- Megacolon, rectal prolapse, rectovaginal fistula
- Dystocia in pregnancy
- Peritonitis (17)
- Colonic volvulus (17)
REFERENCES
11 Read NW, Abouzekry L, Read MG, et al. Anorectal function in elderly patients with fecal impaction. Gastroenterology. 1985;89(5):959-966.22 Maurer CA, Renzulli P, Mazzucchelli L, et al. Use of accurate diagnostic criteria may increase incidence of stercoral perforation of the colon. Dis Colon Rectum. 2000;43(7):991-998.33 Higgins PD, Johanson JF. Epidemiology of constipation in North America: a systematic review. Am J Gastroenterol. 2004;99(4):750-759.44 Constipation Guideline Committee of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. Evaluation and treatment of constipation in infants and children: recommendations of the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition. J Pediatr Gastroenterol Nutr. 2006;43(3):e1-e13.55 McCrea GL, Miaskowski C, Stotts NA, et al. Pathophysiology of constipation in the older adult. World J Gastroenterol. 2008;14(17):2631-2638.66 Leung L, Riutta T, Kotecha J, et al. Chronic constipation: an evidence-based review. J Am Board Fam Med. 2011;24(4):436-451.77 Araghizadeh F. Fecal impaction. Clin Colon Rectal Surg. 2005;18(2):116-119.88 Ebert E. Gastrointestinal involvement in spinal cord injury: a clinical perspective. J Gastrointestin Liver Dis. 2012;21(1):75-82.99 Obokhare I. Fecal impaction: a cause for concern? Clin Colon Rectal Surg. 2012;25(1):53-58.1010 Fargo MV, Latimer KM. Evaluation and management of common anorectal conditions. Am Fam Physician. 2012;85(6):624-630.1111 Hsieh C. Treatment of constipation in older adults. Am Fam Physician. 2005;72(11):2277-2284.1212 Brandt LJ, Prather CM, Quigley EM, et al. Systematic review on the management of chronic constipation in North America. Am J Gastroenterol. 2005;100(Suppl 1):S5-S22.1313 Kumar P, Pearce O, Higginson A. Imaging manifestations of faecal impaction and stercoral perforation. Clin Radiol. 2011;66(1):83-88. doi:10.1016/j.crad.2010.08.002.1414 Wald A. Management and prevention of fecal impaction. Curr Gastroenterol Rep. 2008;10(5):499-501.1515 Hussain ZH, Whitehead DA, Lacy BE. Fecal impaction. Curr Gastroenterol Rep. 2014;16(9):404.1616 Rao SS, Seaton K, Miller M, et al. Randomized controlled trial of biofeedback, sham feedback, and standard therapy for dyssynergic defecation. Clin Gastroenterol Hepatol. 2007;5(3):331-338.1717 Halawi HM, Maasri KA, Mourad FH, et al. Faecal impaction: in-hospital complications and their predictors in a retrospective study on 130 patients. Colorectal Dis. 2012;14(2):231-236.
ADDITIONAL READING
Enck RE. An overview of constipation and newer therapies. Am J Hosp Palliat Care. 2009;26(3):157-158.
SEE ALSO
Constipation; Diarrhea, Chronic; Encopresis
CODES
ICD10
- K56.41 Fecal impaction
- K59.00 Constipation, unspecified
- R15.9 Full incontinence of feces
ICD9
- 560.32 Fecal impaction
- 564.00 Constipation, unspecified
- 787.60 Full incontinence of feces
SNOMED
- Fecal impaction (disorder)
- Constipation (disorder)
- Encopresis (disorder)
CLINICAL PEARLS
- Constipation and fecal impaction are common in elderly and hospitalized patients.
- Opioids are a common cause of constipation and subsequent impaction. Use a bowel hygiene regimen for patients on chronic opioid therapy.
- Increased fiber intake (>30 g/day), adequate hydration (≥2 L water/day), exercise, osmotic laxatives, and bulking agents can help prevent recurrent fecal impaction.