Constipation and fecal impactionMANAGEMENT

GASTROINTESTINAL PRESENTATIONS · 12 SECTIONS

⚲

580 items

☷ Legend

01Approach to the Critical Patient/attcp32

Dangerous causes to exclude before calling it simple constipation

›Most emergency department constipation is benign, but a small subset carries high mortality and must be excluded first

›Stercoral colitis and stercoral perforation from a rectosigmoid fecaloma

›Abdominal pain out of proportion, focal tenderness, peritonism, fever or leukocytosis in a patient with a heavy stool burden

›Stercoral perforation mortality historically 32 to 57 percent; most often older women, antimesenteric rectosigmoid wall

›Free air or extraluminal contrast on CT mandates immediate surgical consultation

›Large bowel obstruction from an obstructing colorectal cancer or stricture, including closed-loop obstruction

›Obstipation with no stool and no flatus, progressive distension, colicky then constant pain, feculent vomiting

›A competent ileocecal valve creates a closed loop with rapid cecal distension and ischemia risk

›Sigmoid volvulus and cecal volvulus

›Sudden distension, a single dilated loop, the coffee-bean sign; suspect ischemia if pain is constant and severe or lactate is above 2 mmol/l

›Acute colonic pseudo-obstruction (Ogilvie syndrome) with massive cecal dilation

›Cecal diameter at or above 12 cm, or dilation persisting beyond 3 to 6 days, predicts spontaneous perforation

›The threshold is lower with a rapidly increasing diameter or focal cecal tenderness; the 12 cm figure is not validated in children

›Autonomic dysreflexia triggered by fecal impaction in a spinal cord lesion at or above T6

›Paroxysmal severe hypertension with bradycardia, pounding headache, flushing and sweating above the lesion

›Untreated it can cause intracranial hemorrhage, seizure, retinal detachment or death

›Cauda equina syndrome presenting as new constipation with urinary retention

›Saddle anesthesia, reduced anal tone, bilateral sciatica and lower-limb weakness need emergent MRI, not a laxative

›Bowel ischemia or colonic perforation from any cause, presenting with sepsis and peritonitis

›Clozapine-induced or other drug-induced gastrointestinal hypomotility progressing to ileus, obstruction, ischemia and death

Immediate stabilization and resuscitation priorities

›Airway, breathing and circulation with attention to sepsis from colonic perforation or ischemia

›Two large-bore intravenous cannulae, continuous cardiac and SpO2 monitoring, early lactate and venous blood gas

›Balanced crystalloid 250 to 500 ml boluses titrated to perfusion, targeting a mean arterial pressure of at least 65 mmHg

›Target 80 to 85 mmHg if chronic hypertension; the usual pressure is lower in tetraplegia, so titrate to the patient's own baseline

›Broad-spectrum antibiotics within 1 hour if perforation, stercoral colitis, ischemia or septic shock is suspected

›Bowel rest and decompression for obstruction, pseudo-obstruction or peritonitis

02History/hx33

Bowel and symptom history

›Stool frequency of fewer than 3 complete spontaneous bowel movements per week

›Change from the patient's own baseline pattern is more informative than an absolute count

›Exclusively breastfed infants may pass stool every 7 to 10 days normally; chronic opioid users have a different baseline

›Stool form on the Bristol Stool Form Scale, with type 1 or 2 (hard lumps) supporting constipation

›Straining, sensation of incomplete evacuation, sensation of anorectal blockage

›Digital maneuvers to extract stool or support the perineum or posterior vaginal wall

›Overflow liquid stool leaking around a hard mass, often mistaken for diarrhea

›New fecal incontinence in an older or bedbound patient is impaction until proven otherwise

›Obstipation with complete absence of stool and flatus, suggesting mechanical obstruction

›Colicky pain with vomiting points to obstruction; feculent vomiting points to a distal or long-standing obstruction

›Duration, time course, and prior similar episodes with the treatments that did or did not work

›Abrupt onset with severe distension suggests volvulus or acute colonic pseudo-obstruction

›Associated abdominal pain characterized as colicky, constant, or peritoneal

›Urinary retention, low back pain, saddle numbness or leg weakness suggesting cauda equina

›Fever, rigors, or feeling systemically unwell suggesting stercoral colitis or perforation

Red flags, comorbidity, and medication history

›Colorectal malignancy concern with new-onset constipation after age 50, narrowed stool caliber, iron-deficiency anemia, weight loss or a family history of colorectal cancer

›Gastrointestinal bleeding with hematochezia, melena, or blood on the stool or paper

›Nocturnal symptoms waking the patient, unexplained fever, or drenching night sweats

›Secondary metabolic cause concern with polyuria and thirst (hypercalcemia), cold intolerance and fatigue (hypothyroidism), or muscle weakness (hypokalemia)

›Neurologic disease including spinal cord injury, multiple sclerosis, Parkinson disease, prior stroke, diabetic autonomic neuropathy, or spina bifida

›Prior abdominal or pelvic surgery, prior obstruction, hernia, radiation, or known diverticular or Crohn stricture

›Constipating medications

›Opioids, including tramadol and codeine-containing analgesics

›Anticholinergics, tricyclic antidepressants, sedating antihistamines, oxybutynin, antipsychotics (clozapine especially), antiparkinsonian anticholinergics

›Non-dihydropyridine calcium channel blockers, particularly verapamil

›Oral iron, calcium and aluminum antacids, sucralfate, cholestyramine

03Physical Exam/exam38

General, vital signs, and abdominal examination

›Temperature above 38.0 C with abdominal pain, concerning for stercoral colitis or perforation

›Tachycardia and hypotension suggesting sepsis, dehydration or third-spacing from obstruction

›Hypertension with bradycardia and headache in a spinal cord injury patient, indicating autonomic dysreflexia

›Respiratory rate interpreted against age norms

›Infant under 1 year: 30 to 53 breaths per minute

›Child 1 to 5 years: 22 to 37 breaths per minute

›Child 6 to 12 years: 18 to 25 breaths per minute

›Adult: 12 to 20 breaths per minute

›Abdominal distension with tympany to percussion

›Left lower quadrant fullness with a palpable stool-filled sigmoid, indenting on pressure

›High-pitched or tinkling bowel sounds in mechanical obstruction; silent abdomen in ileus or peritonitis

›Guarding, rigidity, rebound or percussion tenderness, indicating peritonitis

›If abdominal rigidity with fever, treat as stercoral perforation and obtain immediate surgical review

›Palpable abdominal mass, hepatomegaly or lymphadenopathy suggesting malignancy

›Surgical scars and a careful check of all hernia orifices for an incarcerated hernia

›Dehydration with dry mucous membranes, reduced skin turgor and delayed capillary refill

Digital rectal and perianal examination

›Hard stool filling the rectal vault, confirming distal fecal impaction

›Empty, collapsed rectum despite a heavy stool burden, suggesting a proximal impaction or obstruction

›A tight empty rectum with an explosive gush of stool on finger withdrawal suggests Hirschsprung disease

›Palpable rectal or pelvic mass, or a hard shelf, concerning for malignancy

›Reduced or absent resting and squeeze anal tone, part of the cauda equina assessment

›Anterior displacement of the anus, an anteriorly placed anus, or an absent anal wink in a child

›Perianal inspection findings

›Anal fissure, usually posterior midline, with a sentinel skin tag

›Thrombosed external hemorrhoid or prolapsing internal hemorrhoids

›Perianal abscess, fistula opening, or perianal Crohn disease

04Differential Diagnosis/ddx32

Life- and bowel-threatening causes

›Mechanical bowel obstruction

›Large bowel obstruction from obstructing colorectal cancer, diverticular stricture or extrinsic compression

›Small bowel obstruction from adhesions or an incarcerated hernia presenting with reduced stool and flatus

›Sigmoid volvulus, most common in elderly, institutionalized, neurologically impaired or high-fiber-diet populations

›Cecal volvulus, in younger patients with a congenitally mobile cecum

›Acute colonic pseudo-obstruction (Ogilvie syndrome), after surgery, sepsis, trauma or electrolyte derangement

›Stercoral colitis progressing to stercoral ulceration and perforation with feculent peritonitis

›Colonic or rectal perforation from any cause, including iatrogenic during disimpaction or enema

›Colonic ischemia, which can both cause and result from a low-flow state and colonic distension

›Autonomic dysreflexia from fecal impaction in a spinal cord lesion at or above T6

›Cauda equina syndrome or acute spinal cord compression from tumor, abscess or disc

›Hypercalcemia from malignancy or primary hyperparathyroidism, presenting with constipation and dehydration

›Severe hypokalemia or hypomagnesemia causing adynamic ileus

›Clozapine-associated gastrointestinal hypomotility

›Necrotizing enterocolitis or Hirschsprung-associated enterocolitis in a neonate with distension and no stool

›Infant botulism, in which constipation is often the first sign before descending weakness

Common and contributory causes

›Primary functional constipation

›Normal-transit constipation, the most common overall

›Slow-transit constipation with impaired colonic propulsion

›Defecatory disorder or dyssynergic defecation with paradoxical pelvic floor contraction

›Fecal impaction with overflow fecal incontinence

›Opioid-induced constipation and other medication-induced constipation

›Irritable bowel syndrome with constipation

›Painful anorectal conditions driving stool withholding, especially anal fissure and thrombosed hemorrhoid

›Hypothyroidism and poorly controlled diabetes with enteric autonomic neuropathy

›Pregnancy-related constipation and postpartum constipation

05Laboratory Tests/lt24

Blood tests

›Complete blood count for anemia of malignancy or chronic bleeding and for leukocytosis of stercoral colitis, ischemia or perforation

›Serum electrolytes for hypokalemia and hyponatremia contributing to ileus

›Corrected or ionized calcium for hypercalcemia as a cause of constipation

›A normal total calcium with a low albumin can hide hypercalcemia, so use the corrected or ionized value

›Magnesium for hypomagnesemia as a cause and for hypermagnesemia after magnesium-containing laxatives in renal impairment

›Phosphate at baseline and after any sodium phosphate preparation, watching for a rising phosphate with a falling calcium

›Urea and creatinine for dehydration, acute kidney injury, and to guide avoidance of magnesium and phosphate agents

›Glucose and, when chronic, glycated hemoglobin for diabetic enteropathy; point-of-care glucose in any lethargic or poorly feeding patient

›Thyroid-stimulating hormone for hypothyroidism when constipation is chronic, recognizing that acute illness can produce a sick-euthyroid pattern

›Venous lactate for bowel ischemia, perforation and sepsis, remembering a normal early lactate does not exclude localized stercoral ischemia

›C-reactive protein as a nonspecific marker of inflammation or infection

›Lipase if epigastric pain could represent pancreatitis

›Coagulation profile and anti-Xa or equivalent in anticoagulated patients before disimpaction, endoscopy or surgery

›Group and screen when surgery or transfusion is anticipated

›Blood cultures before antibiotics in the febrile or septic patient

›Beta-hCG in every patient of childbearing potential, before imaging and before prescribing laxatives in pregnancy

Microbiology, urine, and point-of-care tests

›Stool test for occult blood, and stool culture with Clostridioides difficile toxin testing when overflow diarrhea could be infectious

›Place the patient in contact precautions until C difficile is excluded when infectious diarrhea is plausible

›Urinalysis for retention with overflow, urinary tract infection, and hypercalciuria

›Post-void residual bladder volume by catheter or bladder scan when a rectal fecaloma may be obstructing the outlet

›Capillary blood glucose at the bedside for any lethargic adult, poorly feeding infant, or suspected infant botulism

›Blood lead level in a child with pica, developmental delay or unexplained constipation with abdominal pain

›12-lead ECG for hypercalcemia (short QT interval), hypokalemia and hypomagnesemia (U waves, QT prolongation), and before neostigmine or ondansetron when electrolytes are deranged

›Venous blood gas for a rapid acid-base and potassium assessment in the distended or vomiting patient

06Diagnostic Tests/dt52

Scoring Systems

›Bristol Stool Form Scale to categorize stool consistency and track response

›Types 1 and 2 indicate slow transit; types 6 and 7 with a palpable mass indicate overflow around an impaction

›Rome IV criteria for functional constipation used to frame the diagnosis once alarm features are excluded

›Features include straining, lumpy or hard stools, sensation of incomplete evacuation, sensation of anorectal obstruction, manual maneuvers, and fewer than 3 spontaneous bowel movements per week

›Loose stools are rarely present without laxatives and criteria for irritable bowel syndrome are not met

›Rome IV criteria for functional defecation disorders, requiring abnormal manometry, balloon expulsion or imaging of evacuation, guide referral for biofeedback

›Complete spontaneous bowel movement frequency as the standard endpoint for judging pharmacologic response

›Radiographic fecal loading scores such as the Barr, Leech and Blethyn scales, used inconsistently and not required to diagnose impaction clinically

›Cecal diameter of 12 cm on plain film or CT as a marker of perforation risk in acute colonic pseudo-obstruction rather than a validated cutoff

›No emergency department constipation severity score changes acute management

Plain Radiography

›Supine and upright abdominal radiographs as a rapid first study when obstruction, volvulus or perforation is considered

›Colonic and rectal fecal loading, colonic and small bowel dilation, and air-fluid levels

›Free air under the diaphragm on an upright chest film or a lateral decubitus film indicating perforation

›Volvulus signs on plain film

›Sigmoid volvulus: a massively dilated inverted-U loop, the coffee-bean sign, apex pointing to the right upper quadrant

›Cecal volvulus: a dilated comma-shaped cecum in the left upper quadrant with a distal collapsed colon

›Acute colonic pseudo-obstruction: dilation of the colon extending to the rectum with no mechanical transition point, with serial films to trend cecal diameter

›A normal plain film does not exclude stercoral colitis, early ischemia or a partial obstruction, so proceed to CT if suspicion persists

›Plain film is a reasonable first study in a child to confirm a fecal mass and reduce the need for repeated rectal examination

›CT of the abdomen and pelvis with intravenous contrast as the primary test when a dangerous cause is suspected

›Determines the presence, level and cause of obstruction and identifies a closed loop

›Identifies free air, extraluminal fluid, abscess and mesenteric changes of ischemia

›Stercoral colitis findings

›Focal colonic wall thickening with an impacted fecaloma, mucosal enhancement defect, and pericolonic fat stranding

›Extraluminal air or fluid, a wall defect, or contrast extravasation indicates stercoral perforation

›Volvulus findings including the whirl sign of twisted mesentery, the bird-beak transition, and a closed loop

›Acute colonic pseudo-obstruction shows colonic dilation to the rectum with a gradual transition and no obstructing lesion

›Colorectal mass, pericolic lymph nodes and liver deposits when malignancy is the cause

›Water-soluble oral or rectal contrast when distinguishing mechanical obstruction from pseudo-obstruction is difficult

›Low-dose non-contrast CT when iodinated contrast is contraindicated, still reliably showing free air, volvulus and stool burden

›In pregnancy, reserve CT for a suspected life-threatening diagnosis that ultrasound and MRI cannot resolve, and do not withhold it when it is needed

MRI

›Emergent MRI of the spine when cauda equina syndrome or cord compression is suspected on the basis of retention, saddle anesthesia or reduced anal tone

›MRI of the lumbosacral spine as the initial study

›Extend to the whole spine if a compressive lesion above the conus is possible

›MR defecography as an outpatient test for dyssynergic defecation, rectocele, enterocele or rectal intussusception

›Pelvic MRI for local staging of a known rectal cancer, arranged after the acute presentation rather than in the emergency department

›MRI without gadolinium as the preferred cross-sectional study in pregnancy when ultrasound is inconclusive

Ultrasound

›Point-of-care ultrasound has a limited role and cannot exclude perforation or ischemia

›Bladder volume measurement for urinary retention caused by a large rectal fecaloma

›Transabdominal measurement of rectal diameter in children to support a diagnosis of megarectum and fecal retention

›Dilated fluid-filled small bowel loops with to-and-fro peristalsis supporting small bowel obstruction

›Free intraperitoneal fluid as a nonspecific sign that raises concern in the unwell patient

›Assessment of the gallbladder, kidneys and aorta to identify mimics of lower abdominal pain

›First-line cross-sectional modality in pregnancy and in young patients to limit ionizing radiation

Endoscopy, contrast studies, and physiologic testing

›Lower endoscopy, both diagnostic and therapeutic

›Flexible sigmoidoscopy or rigid proctoscopy for sigmoid volvulus, with rectal tube placement after detorsion when there is no ischemia or perforation

›Colonoscopic decompression for acute colonic pseudo-obstruction when neostigmine is contraindicated or has failed

›Colonoscopy to exclude malignancy after the acute episode and for any patient with alarm features or who is due for screening

›Water-soluble contrast enema to demonstrate the bird-beak of sigmoid volvulus and to differentiate mechanical obstruction from pseudo-obstruction

›Anorectal manometry with the balloon expulsion test as outpatient studies for suspected dyssynergic defecation

›Colonic transit study with radiopaque markers or a wireless motility capsule as an outpatient study for suspected slow-transit constipation

›Rectal suction biopsy for definitive diagnosis of Hirschsprung disease, arranged through pediatric surgery

07Disposition/dispo18

Discharge and observation

›Discharge home when constipation is uncomplicated, red flags are absent, stool or effective relief has been achieved, oral intake is tolerated, and follow-up is arranged

›Provide a written bowel regimen with specific doses and clear return precautions

›Confirm the patient or caregiver can obtain and administer the laxatives prescribed

›A short emergency department observation period for the patient who needs repeated enemas or manual disimpaction and is improving

›Reassess the abdomen and vital signs after disimpaction for pain, bleeding, distension or a vagal response

›Arrange early primary care follow-up within 1 to 2 weeks and gastroenterology or colorectal referral for refractory symptoms, suspected dyssynergia, or alarm features

›Refer for outpatient colonoscopy when the patient is over 45 to 50 with new constipation, or has anemia, bleeding, weight loss, or a family history of colorectal cancer

Admission, ICU, consultation, and transfer criteria

›Admit for large bowel obstruction, volvulus, acute colonic pseudo-obstruction, stercoral colitis, perforation, ischemia, or significant electrolyte derangement

›Admit also for intractable symptoms despite emergency department treatment, inability to self-care, or a newly suspected malignancy needing inpatient workup

›Intensive care admission for perforation with peritonitis or septic shock, hemodynamic instability, or autonomic dysreflexia with end-organ effects

›Surgical consultation for peritonitis, free air, closed-loop or complete obstruction, volvulus, ischemia, or cecal diameter at or above 12 cm

›Gastroenterology consultation for endoscopic detorsion of sigmoid volvulus and for colonoscopic decompression of pseudo-obstruction

›Transfer criteria

›No 24-hour CT, general surgery, or endoscopic decompression available on site

›Suspected volvulus, obstruction, perforation or ischemia without surgical coverage

›A child with suspected Hirschsprung disease, anorectal malformation, necrotizing enterocolitis, Hirschsprung-associated enterocolitis or infant botulism without pediatric surgery and pediatric intensive care

›Need for intensive care not available locally, or autonomic dysreflexia refractory to bedside measures

›Begin resuscitation, nasogastric decompression, analgesia and antibiotics before transfer and do not delay for imaging that will not change the need to transfer

08Treatment/t182

Resuscitation of the obstructed, perforated, or septic patient

›Treat suspected stercoral perforation, colonic perforation or ischemic colitis as intra-abdominal sepsis

›Two large-bore intravenous lines, balanced crystalloid in 250 to 500 ml aliquots to a mean arterial pressure of at least 65 mmHg

›Aim 80 to 85 mmHg with chronic hypertension; accept the patient's lower usual pressure in tetraplegia

›Nil by mouth, nasogastric tube to free drainage, urinary catheter for hourly urine output

›Serial abdominal examinations and repeat lactate

›Empiric antibiotics for feculent peritonitis or stercoral perforation, covering enteric gram-negative bacilli and anaerobes

›Piperacillin-tazobactam 4.5 g IV every 6 to 8 hours

›Reduce the frequency in renal impairment per creatinine clearance

›Continue until source control and clinical resolution

›Alternative: ceftriaxone 2 g IV every 24 hours plus metronidazole 500 mg IV every 8 hours

›Penicillin allergy: ciprofloxacin 400 mg IV every 12 hours plus metronidazole 500 mg IV every 8 hours, or aztreonam 2 g IV every 8 hours plus metronidazole

›Healthcare-associated or critically ill: meropenem 1 g IV every 8 hours

›Add vancomycin dosed to a trough of 15 to 20 mg/l if resistant gram-positive cover is indicated

›Norepinephrine for fluid-refractory hypotension

›Start 0.05 mcg/kg/min IV through a central or reliable large peripheral line

›Titrate every 5 minutes in 0.02 to 0.05 mcg/kg/min steps to a mean arterial pressure of at least 65 mmHg

›Reassess intravascular volume before escalating; excessive alpha agonism can worsen borderline colonic perfusion

›Add vasopressin 0.03 units/min IV as a fixed-rate adjunct if high norepinephrine doses are needed

›Correct coagulopathy and transfuse to a hemoglobin of 70 g/l, or higher with active bleeding or cardiac disease

›Urgent operative source control, typically a Hartmann procedure or segmental resection for stercoral perforation

›Withhold all laxatives, enemas, prokinetics and oral contrast bowel preparation once perforation or complete obstruction is confirmed

Rectal disimpaction and evacuant measures

›Manual disimpaction of a distal fecal impaction that will not pass with softeners

›Analgesia beforehand, and procedural sedation when the impaction is large or the patient cannot tolerate the procedure

›Lidocaine 2 percent gel to the anal canal 3 to 5 minutes before examination

›Mandatory in a spinal cord lesion at or above T6 to prevent autonomic dysreflexia

›Left lateral position, gentle fragmentation and piecemeal removal of hard stool

›Stop for significant bleeding, severe pain, or a vagal response with bradycardia or hypotension

›Softening and evacuant agents used in sequence

›Glycerin suppository 2 to 3 g PR to stimulate a distal reflex

›Bisacodyl 10 mg PR suppository

›Sodium phosphate enema 118 ml PR once

›Contraindicated in renal impairment, suspected obstruction or perforation, Hirschsprung disease, and in children under 2 years

›Risk of hyperphosphatemia, hypocalcemia, hypernatremia and acute phosphate nephropathy, with deaths reported in the elderly

›Check phosphate and calcium afterward in older or at-risk patients

›Tap water enema 500 to 1000 ml PR, the safest high-volume option

›Mineral oil retention enema 60 to 150 ml PR to soften a firm bolus before manual removal

›Avoid oral mineral oil in patients with dysphagia or who are bedbound because of aspiration and exogenous lipoid pneumonia

›Milk and molasses enema, roughly equal parts to a total of about 300 ml PR, as an alternative softening enema

›Avoid soapsuds enemas because of chemical proctocolitis and mucosal injury

›Therapy-is-not-working pathway for impaction

›If oral polyethylene glycol plus enemas over 24 to 48 hours do not clear the impaction, proceed to manual disimpaction

›If manual disimpaction fails, arrange examination under anesthesia or endoscopic fragmentation

›Re-image with CT to reassess for proximal obstruction, megacolon, volvulus or stercoral colitis

›Reconsider an unrecognized mechanical cause and obtain surgical review

Osmotic, stimulant, and softening laxatives

›Polyethylene glycol 3350, an osmotic agent that is minimally absorbed, first-line for most patients

›17 g dissolved in 240 ml of water or juice PO once daily

›Titrate by 17 g every 2 to 3 days to one soft formed stool daily

›Onset 1 to 3 days; safe for sustained daily use

›Usual chronic ceiling around 34 g/day; higher volumes are reserved for supervised cleanout

›Withhold if obstruction or perforation is suspected

›Lactulose, a nonabsorbed osmotic disaccharide

›15 to 30 ml PO once or twice daily

›Titrate to effect; maximum 60 ml/day

›Expect bloating and flatus; onset 1 to 2 days

›Preferred over polyethylene glycol only when polyethylene glycol is unavailable or not tolerated

›Sorbitol 70 percent 30 to 150 ml PO as a lower-cost osmotic alternative to lactulose

›Magnesium hydroxide 30 to 60 ml PO once daily, or magnesium citrate 150 to 300 ml PO once

›Avoid if estimated glomerular filtration rate is below 30 ml/min because of hypermagnesemia

›Monitor magnesium in older patients and any renal impairment

›Senna, a stimulant laxative

›8.6 to 17.2 mg PO at bedtime

›Titrate upward every few days if needed

›Maximum 34.4 mg PO twice daily

›Onset 6 to 12 hours; long-term use is effective and not associated with structural colonic damage

›Bisacodyl, a stimulant laxative

›5 to 15 mg PO once daily, or 10 mg PR suppository for a faster distal effect

›Oral onset 6 to 12 hours; rectal onset 15 to 60 minutes

›Abdominal cramping is common; avoid in suspected obstruction

›Docusate sodium 100 mg PO twice daily as a stool softener, acknowledging minimal evidence of benefit over placebo

›Bulk-forming psyllium 3.4 to 7 g PO up to three times daily, each dose with at least 240 ml of water

›Do not use in acute impaction, obstruction, or a defecatory disorder, where it worsens symptoms

Bowel cleanout for severe impaction

›High-volume polyethylene glycol electrolyte solution for a heavy proximal stool burden after obstruction and perforation are excluded

›Polyethylene glycol electrolyte solution 236 g in 2 litres of water, or a standard 4 litre preparation, PO or by nasogastric tube

›Give 240 ml every 10 to 15 minutes until the rectal effluent is clear

›Hold for vomiting, rising distension or abdominal pain and re-image

›Aspiration risk with impaired consciousness or a poor gag; protect the airway or defer

›Alternatively continue polyethylene glycol 3350 17 g in 240 ml every 15 minutes for several doses

›Combine oral cleanout with daily enemas until disimpaction is complete

›After disimpaction, start scheduled maintenance polyethylene glycol 3350 17 g PO daily plus a stimulant to prevent early re-impaction

›Check and replace potassium, magnesium and phosphate during and after a large-volume cleanout, and obtain an ECG if any are low before giving ondansetron

Opioid-induced and refractory constipation pharmacotherapy

›Start a prophylactic stimulant plus osmotic regimen whenever an opioid is initiated, because fiber alone fails for opioid-induced constipation

›Methylnaltrexone, a peripherally acting mu-opioid receptor antagonist, for opioid-induced constipation refractory to standard laxatives

›8 mg SC for body weight 38 to under 62 kg; 12 mg SC for 62 to 114 kg; otherwise 0.15 mg/kg SC

›No more than one dose per 24 hours

›Reduce dose in severe renal impairment

›Contraindicated in known or suspected mechanical gastrointestinal obstruction because of perforation risk

›Stop if severe or persistent abdominal pain or if perforation is suspected

›Naloxegol 25 mg PO once daily in the morning on an empty stomach

›Reduce to 12.5 mg once daily if creatinine clearance is below 60 ml/min

›Avoid with strong CYP3A4 inhibitors and in suspected obstruction

›Naldemedine 0.2 mg PO once daily as an alternative peripherally acting antagonist, contraindicated in suspected obstruction

›Lubiprostone, a chloride channel activator

›24 mcg PO twice daily with food for chronic idiopathic constipation

›8 mcg PO twice daily for irritable bowel syndrome with constipation in women

›Nausea is common and reduced by taking with food

›Contraindicated in mechanical gastrointestinal obstruction

›Linaclotide, a guanylate cyclase-C agonist

›145 mcg PO once daily on an empty stomach for chronic idiopathic constipation, with a 72 mcg option

›Diarrhea is the main adverse effect

›Contraindicated in pediatric patients under 2 years and in mechanical obstruction

›Plecanatide 3 mg PO once daily as an alternative guanylate cyclase-C agonist

›Prucalopride, a selective 5-HT4 agonist prokinetic

›2 mg PO once daily

›1 mg PO once daily if estimated glomerular filtration rate is below 30 ml/min

›Headache and transient diarrhea are common; review cardiovascular history before starting

›Reassess at follow-up: escalate to these agents only after confirming adherence to osmotic and stimulant laxatives, and refer dyssynergic defecation for biofeedback rather than adding more laxatives

Acute colonic pseudo-obstruction and colonic volvulus

›Acute colonic pseudo-obstruction, initial supportive management for 24 to 48 hours

›Exclude mechanical obstruction with CT or a water-soluble contrast enema first

›Nil by mouth, nasogastric tube, and a rectal tube

›Correct potassium, magnesium, calcium and phosphate; stop opioids and anticholinergics; treat sepsis; mobilize and reposition

›Serial abdominal films to trend cecal diameter

›Neostigmine for refractory acute colonic pseudo-obstruction after mechanical obstruction and ischemia are excluded

›2 mg IV over 3 to 5 minutes

›Indicated for cecal diameter at or above 12 cm or no improvement after 24 to 48 hours of supportive care

›Continuous cardiac monitoring, atropine 1 mg drawn up at the bedside, patient supine near a bedpan

›Keep the patient recumbent and monitored for at least 30 minutes; blood pressure and heart rate every 3 to 5 minutes

›May repeat once after 3 to 4 hours for a partial response

›Contraindicated in mechanical obstruction, suspected ischemia or perforation, heart rate below 60 per minute, systolic blood pressure below 90 mmHg, active bronchospasm, and recent myocardial infarction

›Colonoscopic decompression when neostigmine is contraindicated or fails, with placement of a decompression tube

›Surgery, cecostomy or resection, for perforation, ischemia, or failure of pharmacologic and endoscopic decompression

›Sigmoid volvulus without ischemia or perforation

›Endoscopic detorsion by flexible sigmoidoscopy with rectal tube placement, successful in roughly 70 to 90 percent

›Recurrence is high, so plan semi-elective sigmoid resection during the same admission

›Peritonitis, ischemia or perforation means immediate laparotomy without an endoscopic attempt

›Cecal volvulus

›Operative management, usually right hemicolectomy, or cecopexy in selected patients

›Endoscopic reduction is rarely successful and is not recommended

Autonomic dysreflexia from fecal impaction

›Recognize autonomic dysreflexia in a spinal cord lesion at or above T6 with a sudden systolic pressure 20 to 40 mmHg above the patient's baseline, headache, and flushing or sweating above the lesion

›Immediate non-drug measures

›Sit the patient fully upright and lower the legs to induce orthostatic pooling

›Loosen tight clothing, abdominal binders and leg straps

›Check the bladder first: relieve a blocked or kinked catheter, or catheterize with lidocaine gel lubricant

›Then address the bowel: apply lidocaine 2 percent gel to the anal canal and wait 3 to 5 minutes before gentle disimpaction

›Pharmacologic blood pressure control if systolic pressure remains at or above 150 mmHg in an adult while the trigger is being found

›Nifedipine 10 mg immediate-release capsule, bite and swallow, not sublingual

›May repeat once after 20 to 30 minutes

›It is a dihydropyridine arterial vasodilator, appropriate here because the goal is rapid afterload reduction, not rate control

›Glyceryl trinitrate 0.4 mg SL or 2.5 cm of 2 percent topical paste

›Absolutely contraindicated if a phosphodiesterase-5 inhibitor was taken in the preceding 24 to 48 hours

›Captopril 25 mg SL or PO as an alternative rapid-onset agent

›Second-line: labetalol or hydralazine IV titrated to effect with close monitoring

›Recheck blood pressure every 2 to 5 minutes until it is stable, and continue monitoring for at least 2 hours because recurrence is common until the stimulus is fully removed

›Pediatric thresholds are lower and age-based; treat a sustained rise of 15 to 20 mmHg above the child's baseline

Analgesia, antiemetics, deprescribing, and iatrogenic-harm review

›Acetaminophen 1 g PO or IV every 6 hours, maximum 4 g in 24 hours

›Maximum 3 g in 24 hours in frail elderly, body weight under 50 kg, hepatic impairment or chronic alcohol use

›Minimize opioids; if severe pain is unavoidable, morphine 0.05 to 0.1 mg/kg IV titrated, recognizing opioids worsen the underlying problem and can mask perforation

›Co-prescribe a stimulant plus osmotic laxative with any opioid

›Ketorolac 15 to 30 mg IV every 6 hours for up to 5 days for colicky pain

›Avoid in renal impairment, gastrointestinal bleeding risk, and in the elderly

›Hyoscine butylbromide 20 mg IV or IM for colic is discouraged because its anticholinergic action slows the gut and can precipitate ileus

›Ondansetron 4 mg IV or orally dissolving every 8 hours for nausea

›Check QT interval and correct potassium and magnesium first when they are low

›Metoclopramide 10 mg IV every 8 hours as a prokinetic antiemetic, contraindicated in mechanical obstruction and perforation

›Iatrogenic-harm review for routine emergency interventions this patient may receive

›Intubation and post-intubation sedation: opioid-based sedation plus immobility promotes ileus and colonic pseudo-obstruction; avoid succinylcholine in chronic spinal cord injury from about 72 hours to 12 months because of hyperkalemia

›Procedural sedation for disimpaction: prefer propofol or ketamine; avoid adding opioids and anticholinergic premedication that further slow transit

›Fluid loading: correct dehydration and prerenal injury but avoid overload in heart failure and chronic kidney disease; fluids alone do not treat an established impaction

›Oxygen: no specific hazard and no therapeutic role here

›Vasopressors: norepinephrine is first-line for septic perforation, but restore volume first and avoid excessive alpha agonism that can worsen marginal colonic perfusion

›Mechanical circulatory support including intra-aortic balloon pump: not indicated for this condition; if used for concurrent cardiogenic shock, expect reduced splanchnic flow and a higher risk of pseudo-obstruction

›Anticoagulation: many of these patients are anticoagulated; a stercoral ulcer, hemorrhoids, fissure or occult cancer can bleed, so check coagulation and hold or reverse for bleeding or perforation, while continuing venous thromboembolism prophylaxis in the admitted immobile patient unless actively bleeding

›Fibrinolysis: no role in this condition; if given for concurrent stroke or myocardial infarction, a stercoral ulcer or colorectal cancer is a bleeding source, so examine the rectum and weigh the risk

›Analgesia: opioids are the dominant iatrogenic driver of constipation; prefer acetaminophen, use opioid-sparing strategies, and always pair opioids with a bowel regimen

›Deprescribe or substitute constipating drugs

›Switch verapamil to an agent without a constipating effect where clinically appropriate

›Reduce anticholinergic burden, change oral iron to alternate-day or intravenous dosing, and review antihistamines and tricyclics

›Correct reversible contributors: potassium to above 4.0 mmol/l, magnesium into the normal range, calcium toward normal, and start levothyroxine for confirmed hypothyroidism

›Lab-interpretation and monitoring traps

›Overflow diarrhea around an impaction misread as gastroenteritis leads to harmful loperamide; do a rectal examination or plain film first

›Leukocytosis with a left shift and abdominal pain in an impacted patient is stercoral colitis until proven otherwise

›A normal lactate does not exclude localized stercoral ischemia or early perforation

›Aggressive cleanout and phosphate agents can drop potassium, magnesium and calcium, prolonging the QT interval; obtain an ECG before giving ondansetron or neostigmine when electrolytes are deranged

Non-pharmacologic and supportive measures

›Fluid intake of 1.5 to 2 litres per day

›Restrict in heart failure, chronic kidney disease with a fluid limit, hyponatremia, and dialysis dependence

›Gradual increase in dietary fiber toward 25 to 30 g per day over 1 to 2 weeks to limit bloating

›Do not increase fiber in acute impaction, obstruction, stricture, or a defecatory disorder

›Early and regular mobilization, particularly after surgery and in the elderly

›Structured toileting: attempt defecation 5 to 10 minutes after meals to use the gastrocolic response, with feet on a footstool to approximate squatting, and avoid straining and prolonged sitting

›Treat a painful anal fissure that drives withholding with sitz baths, topical anesthetic, and topical nifedipine 0.3 percent or diltiazem 2 percent applied to the anal margin, plus stool softening

›Relieve urinary retention that coexists with a large rectal fecaloma

›Refer dyssynergic defecation for pelvic floor physical therapy with biofeedback, which is first-line and outperforms laxatives for that phenotype

›Establish a scheduled bowel program with digital stimulation and a suppository for neurogenic bowel in spinal cord injury and spina bifida

09Special Populations/sp59

Pregnancy

›Constipation affects up to 40 percent of pregnancies from progesterone-mediated slowing of transit, iron supplementation, mechanical pressure and reduced activity

›First-line non-drug measures with fiber, fluid and activity, then a bulk-forming agent such as psyllium 3.4 g PO up to three times daily

›Osmotic laxatives are preferred pharmacotherapy

›Polyethylene glycol 3350 17 g in 240 ml of water PO once daily, minimally absorbed

›Lactulose 15 to 30 ml PO once or twice daily, maximum 60 ml/day

›Stimulant laxatives senna 8.6 to 17.2 mg PO at bedtime or bisacodyl 5 to 15 mg PO once daily are acceptable for short-term use when osmotics fail

›Agents to avoid

›Mineral oil, which impairs maternal fat-soluble vitamin absorption and is linked to neonatal coagulopathy

›Castor oil, which can provoke uterine contractions

›High-dose magnesium and routine sodium phosphate preparations because of electrolyte disturbance

›Look for a secondary cause such as hypothyroidism, hypercalcemia, or hypokalemia from hyperemesis gravidarum

›Do not anchor on constipation: appendicitis with a displaced appendix, ovarian torsion, and bowel obstruction still occur, so examine and image as needed

›Imaging preference is ultrasound first, then MRI without gadolinium; use CT without hesitation for a suspected life-threatening diagnosis it alone can resolve

›Postpartum constipation is aggravated by perineal trauma, opioids and hemorrhoids; polyethylene glycol and a stool softener are standard

Geriatric

›Constipation is highly prevalent and multifactorial in older adults

›Symptoms in up to half of long-term care residents, with laxative use in roughly three-quarters of that group

›Contributors include immobility, low fiber and fluid intake, polypharmacy, and comorbidity such as Parkinson disease, diabetes, hypothyroidism and prior stroke

›Fecal impaction with overflow incontinence is frequently misdiagnosed as diarrhea; perform a rectal examination or plain film before any antidiarrheal

›The risk of stercoral colitis and stercoral perforation is higher; keep a low threshold for CT with abdominal pain, tenderness or leukocytosis

›Sodium phosphate preparations, oral or enema, should be avoided or used with great caution because of acute phosphate nephropathy, hyperphosphatemia, hypocalcemia and reported deaths

›Magnesium-containing laxatives risk hypermagnesemia when the estimated glomerular filtration rate is below 30 ml/min; avoid them and monitor magnesium

›Acetaminophen maximum is 3 g in 24 hours; NSAIDs carry renal, gastrointestinal bleeding and cardiac risk

›Acute colonic pseudo-obstruction is more common after hip fracture, major surgery, sepsis and electrolyte derangement

›New-onset constipation with iron-deficiency anemia, weight loss or rectal bleeding after age 50 mandates colonoscopy to exclude malignancy

›Screen for hypercalcemia and hypothyroidism, and review every medication for a constipating effect with active deprescribing

Pediatrics

›About 95 percent of childhood constipation is functional, peaking at toilet training, school entry, and after a painful hard stool triggers withholding

›Rome IV supports functional constipation with two or more of: two or fewer defecations per week, at least one episode of fecal incontinence per week, stool-withholding posture, painful or hard stools, a large fecal mass in the rectum, and large-diameter stools

›Red flags for organic disease

›Onset before 1 month of age or delayed passage of meconium beyond 48 hours, suggesting Hirschsprung disease or cystic fibrosis

›Ribbon stools, failure to thrive, bilious vomiting, severe distension, or a tight empty rectum with an explosive stool on withdrawal of the finger

›Absent anal wink or cremasteric reflex, a sacral dimple, hair tuft or deviated gluteal cleft, or an abnormally positioned anus

›Consider Hirschsprung disease, anorectal malformation, tethered cord, hypothyroidism, celiac disease, cow milk protein intolerance, hypercalcemia, lead toxicity, cystic fibrosis with distal intestinal obstruction syndrome, and infant botulism

›Disimpaction with polyethylene glycol 3350 1 to 1.5 g/kg/day PO for 3 to 6 days, maximum 100 g/day

›Verify against current pediatric guideline before use

›Maintenance with polyethylene glycol 3350 0.4 to 0.8 g/kg/day PO titrated to one soft stool daily, continued for at least 2 months and weaned slowly

›Verify against current pediatric guideline before use

›Alternatives: lactulose 1 to 2 g/kg/day PO divided twice daily, or milk of magnesia 1 to 3 ml/kg/day PO in children over 1 year with normal renal function

›Infants under 1 year: dietary measures, lactulose 1 ml/kg/day, and a glycerin suppository for acute relief; avoid stimulant laxatives and phosphate or soap enemas

›Rectal options in children 2 years and older: glycerin or bisacodyl 5 mg suppository, a saline or mineral oil enema, or a weight-appropriate sodium phosphate enema only with normal renal function

›Isotonic crystalloid 10 to 20 ml/kg IV for the dehydrated or vomiting child, and dextrose 10 percent 2 to 5 ml/kg IV for documented hypoglycemia

›Verify against current pediatric guideline before use

›Behavioral program: scheduled toilet sits after meals, a reward system, foot support, education and demystification, and a 2 to 4 week trial of cow milk protein elimination in refractory cases

›Avoid routine digital disimpaction; if it is required, perform it under sedation

›Suspected Hirschsprung disease: contrast enema for a transition zone, anorectal manometry for an absent rectoanal inhibitory reflex, and rectal suction biopsy for diagnosis, with surgical referral

›Hirschsprung-associated enterocolitis with fever, explosive foul diarrhea, distension and sepsis is a surgical emergency needing decompression and antibiotics

›In a neonate use ampicillin plus gentamicin plus metronidazole, because ampicillin monotherapy is inadequate at this age

›Ampicillin 50 mg/kg IV every 8 hours in the first week of life and every 6 hours thereafter

›Gentamicin 4 to 5 mg/kg IV every 24 to 36 hours in the neonate, with level monitoring

›Metronidazole 7.5 mg/kg IV every 8 to 12 hours by postnatal age, or enteral 30 mg/kg/day divided for luminal disease

›Verify against current pediatric guideline before use

Neurologic Disease and Spinal Cord Injury

›Neurogenic bowel in spinal cord injury, multiple sclerosis, Parkinson disease and spina bifida needs a scheduled program rather than as-needed laxatives

›Consistent timing, a stimulant suppository or digital rectal stimulation, and maintenance polyethylene glycol titrated to one soft stool daily

›Fecal impaction is a leading trigger of autonomic dysreflexia in lesions at or above T6; pretreat the anal canal with lidocaine 2 percent gel before any rectal manipulation

›Parkinson disease constipation can precede motor symptoms by years

›Avoid anticholinergics, use polyethylene glycol first-line, and recognize that constipation can impair levodopa absorption and contribute to an akinetic crisis

›Clozapine and other antipsychotics can cause gastrointestinal hypomotility that progresses to ileus, obstruction, ischemia and death

›Use prophylactic laxatives, image early for abdominal symptoms, and do not dismiss the presentation as simple constipation

›Diabetic autonomic neuropathy, systemic sclerosis with intestinal pseudo-obstruction and bacterial overgrowth, amyloidosis, and chagasic megacolon are myopathic or neuropathic causes to recognize

›Systemic sclerosis renal and cardiac disease alters drug tolerance; use osmotic agents and avoid dehydration

10Background/b38

Epidemiology

›Chronic constipation is common in adults

›Pooled worldwide prevalence roughly 14 percent, with North American estimates of 12 to 19 percent

›About twice as common in women, and more common with older age, lower socioeconomic status, physical inactivity and low fiber intake

›Up to 30 to 40 percent of community-dwelling older adults report symptoms, rising to about half of long-term care residents, with laxative use near three-quarters in that setting

›Constipation drives hundreds of thousands of United States emergency department visits per year and billions of dollars in direct costs

›Pediatric prevalence pools around 9 to 12 percent, accounts for roughly 3 to 5 percent of pediatric primary care visits and up to a quarter of pediatric gastroenterology referrals, and is about 95 percent functional

›Opioid-induced constipation affects 40 to 80 percent of patients on chronic opioids

›Sigmoid volvulus accounts for about 2 to 5 percent of large bowel obstruction in Western countries and up to 20 to 50 percent in the endemic volvulus belt; cecal volvulus accounts for roughly 10 to 40 percent of colonic volvulus and affects younger patients

›Stercoral perforation is uncommon but increasingly recognized on CT, with mortality of 32 to 57 percent, while stercoral colitis without perforation carries a mortality of roughly 15 to 40 percent

›Acute colonic pseudo-obstruction has a spontaneous perforation risk of about 3 to 15 percent and a mortality of 15 percent with early treatment, rising to 30 to 45 percent with ischemia or perforation

Pathophysiology

›Normal colonic transit is 20 to 72 hours, and defecation requires adequate stool volume and softness, colonic propulsion, intact rectal sensation, coordinated pelvic floor relaxation and voluntary effort

›Primary constipation subtypes

›Normal-transit constipation, the most common, with perceived difficulty despite normal transit

›Slow-transit constipation from reduced high-amplitude propagating contractions and fewer interstitial cells of Cajal

›Defecatory disorder or dyssynergia from paradoxical anal sphincter contraction, failure of puborectalis relaxation, or inadequate propulsive force

›Secondary constipation arises from mechanical, neurologic, metabolic, myopathic and drug causes

›Opioids act on mu receptors in the myenteric plexus to reduce propulsion, raise sphincter tone and increase water absorption

›Hypercalcemia, hypokalemia, hypomagnesemia, hypothyroidism, diabetes and pregnancy slow motility metabolically

›Fecal impaction develops when prolonged stasis allows continued colonic water reabsorption, producing a progressively harder mass that distends the rectum, blunts the call to stool, lowers sphincter tone, and permits liquid stool to leak around it as overflow incontinence

›A large rectal fecaloma can compress the bladder neck and cause urinary retention

›Stercoral colitis results from sustained pressure of a fecaloma on the colonic wall causing ischemic pressure necrosis, mucosal ulceration and then transmural necrosis and perforation, with the antimesenteric rectosigmoid most vulnerable because of watershed perfusion and a narrow lumen

›Volvulus occurs when a redundant sigmoid on a narrow mesenteric pedicle, or a congenitally mobile cecum, twists to create a closed loop with venous congestion followed by arterial compromise and gangrene

›Acute colonic pseudo-obstruction reflects an autonomic imbalance, with increased sympathetic or decreased sacral parasympathetic tone in the setting of surgery, sepsis, trauma, metabolic derangement or medication, causing massive dilation without a mechanical block; by the Laplace relationship the cecum has the highest wall tension and perforates first

›Autonomic dysreflexia occurs when a noxious stimulus below a cord lesion at or above T6, most often bladder or bowel distension, produces an unmodulated sympathetic surge with severe hypertension and reflex bradycardia, risking intracranial hemorrhage, seizure and death

Therapeutic Considerations

›Fiber helps normal- and slow-transit constipation but worsens bloating and is ineffective or harmful in defecatory disorders and dangerous in acute impaction or obstruction

11Patient Discharge Instructions/pdi32

Discharge readiness and clinician checklist

›Confirm before discharge

›The patient has passed stool or has a clear, workable home regimen

›The abdomen is soft and non-tender, and vital signs are normal

›Red flags for obstruction, perforation, cauda equina and malignancy have been excluded

›Actions to complete

›Provide written instructions with specific drug names, doses and timing

›Reconcile medications and stop or substitute constipating agents where possible

›Arrange primary care follow-up within 1 to 2 weeks and a colonoscopy referral when age or alarm features indicate one

›Give explicit return precautions and confirm the patient understands them

copy discharge instructions

›Take polyethylene glycol (PEG 3350) 17 grams, which is one capful or one packet, dissolved in 240 millilitres of water once a day; it is safe to take every day and may take 1 to 3 days to work

›If you have not had a bowel movement in 2 to 3 days, add senna 2 tablets (17.2 milligrams) at bedtime or bisacodyl 10 milligrams, or use a glycerin suppository

›Drink about 1.5 to 2 litres of fluid each day unless your doctor has told you to limit fluids

›Aim for 25 to 30 grams of fibre a day from food, and increase it slowly over 1 to 2 weeks so you do not get bloated

›Do not add extra fibre or bulk laxatives if you were told you have a blockage or a very hard stool that has not cleared

›Be active every day and walk after meals

›Sit on the toilet for 5 to 10 minutes about 30 minutes after breakfast, put your feet on a low stool, and do not strain

›Do not use enemas or rectal suppositories for more than a few days without medical advice, and do not use mineral oil by mouth if you have any trouble swallowing

›Ask your doctor about any medicine that constipates you, including opioid pain pills, iron, calcium, verapamil and antihistamines

›If you were given a set number of days of laxative clean-out, finish the whole course

›Go to an emergency department or call emergency services now if you have any of the following

›No bowel movement and no gas for more than 24 hours together with a swollen, hard or very painful belly

›Severe or worsening abdominal pain, or a rigid board-like abdomen

›Repeated vomiting, or vomit that looks or smells like stool

›A fever above 38.0 degrees Celsius with abdominal pain

›Blood in the stool, black tarry stools, or vomiting blood

›Being unable to pass urine, or new numbness between the legs, or new weakness in the legs

12References/r40

Society guidelines

›American College of Gastroenterology chronic constipation guideline

›American College of Gastroenterology Clinical Guideline: Management of Chronic Idiopathic Constipation, 2021

›Recommends polyethylene glycol and, as options, stimulant laxatives, prucalopride, lubiprostone, linaclotide and plecanatide, and peripherally acting mu-opioid antagonists for opioid-induced constipation

›American Gastroenterological Association position statement and guideline on constipation

›American Gastroenterological Association Medical Position Statement on Constipation, 2013

›American Gastroenterological Association and American College of Gastroenterology joint clinical practice guideline on pharmacological management of chronic idiopathic constipation, 2023

›American Society of Colon and Rectal Surgeons clinical practice guidelines

›Clinical Practice Guideline for the Evaluation and Management of Constipation, 2016

›Clinical Practice Guidelines for the Management of Colonic Volvulus and Acute Colonic Pseudo-Obstruction, 2021

›World Gastroenterology Organisation Global Guidelines: Constipation

›World Gastroenterology Organisation, updated 2010

›Provides a resource-stratified approach to evaluation and laxative selection

›Consortium for Spinal Cord Medicine clinical practice guidelines

›Acute Management of Autonomic Dysreflexia, Paralyzed Veterans of America, 2001

›Neurogenic Bowel Management in Adults with Spinal Cord Injury

Landmark trials and key reviews

›Neostigmine for acute colonic pseudo-obstruction

›Ponec RJ, Saunders MD, Kimmey MB. Neostigmine for the treatment of acute colonic pseudo-obstruction. New England Journal of Medicine, 1999

›Randomized trial showing rapid colonic decompression after 2 mg intravenous neostigmine versus placebo

›Methylnaltrexone for opioid-induced constipation

›Thomas J, Karver S, Cooney GA, et al. Methylnaltrexone for opioid-induced constipation in advanced illness. New England Journal of Medicine, 2008

›Subcutaneous methylnaltrexone induced laxation without reversing analgesia

›Prucalopride for severe chronic constipation

›Camilleri M, Kerstens R, Rykx A, Vandeplassche L. A placebo-controlled trial of prucalopride for severe chronic constipation. New England Journal of Medicine, 2008

›Mechanisms and management reviews of chronic constipation

›Bharucha AE, Lacy BE. Mechanisms, evaluation, and management of chronic constipation. Gastroenterology, 2020

›Wald A. Constipation: advances in diagnosis and treatment. Journal of the American Medical Association review series

Evidence & Review

Reviewed by SymptomDx Medical Team · Last reviewed September 13, 2026

SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.