Fecal Impaction

- Metabolic disease - Hypothyroidism - Hyperparathyroidism - Diabetes mellitus

- Anatomic abnormalities - Anorectal stenosis - Neoplasm - Megarectum - Painful rectal conditions inhibiting voluntary defecation (anal fissure, hemorrhoids, fistulas)

- Psychological comorbidities - Depression - Anxiety - Anorexia nervosa

- 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

- 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.

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 dietInadequate fiber, water, and caloric intake all contribute to impaction.
Medication side effect (6,7)Stimulant laxativesOpiate analgesicsAnticholinergicsDiureticsCalcium channel blockersAluminum (sucralfate, antacids)IronNSAIDs
Neurogenic disordersHirschsprung diseaseChagas diseaseAutonomic neuropathyMultiple sclerosisSpinal cord injury (13%) (8)Cauda equinaParkinson diseaseAlzheimer disease (9)
Metabolic diseaseHypothyroidismHyperparathyroidismDiabetes mellitus
Electrolyte disturbancesHypokalemiaHypercalcemiaHypermagnesemia
Anatomic abnormalitiesAnorectal stenosisNeoplasmMegarectumPainful rectal conditions inhibiting voluntary defecation (anal fissure, hemorrhoids, fistulas)
Psychological comorbiditiesDepressionAnxietyAnorexia 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 signsTachycardiaTachypneaLow-grade fever
GeneralAgitatedConfusedPoor hydration status
AbdominalDistentionPalpable, tubular mass in lower quadrant
RectalCopious stool in rectal vault. If impaction is in sigmoid colon, rectal exam will be nondiagnostic.Hard stoolAnal fissuresHemorrhoidsLoss 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 CBCVarious electrolyte abnormalities: hyponatremia; hypokalemia; hypercalcemia; hypermagnesemiaElevated TSHStool 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 defecationMineral oil enema or warm water enema to aid passage of stool
Osmotic laxatives, such as polyethylene glycol solutions and magnesium citrate, may soften stool.
PrecautionsOsmotic 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.

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.