Large bowel obstructionMANAGEMENT

GASTROINTESTINAL PRESENTATIONS · 12 SECTIONS

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405 items

☷ Legend

01Approach to the Critical Patient/attcp36

Triage priorities

›Immediate threat screen

›Shock physiology

›SBP < 90 mmHg

›Lactate ≥ 2 mmol/l

›Peritonitis

›Rebound tenderness

›Involuntary guarding

›Bowel ischemia risk

›Severe continuous pain

›Rising lactate trend

›Perforation risk

›Free air concern

›Sepsis physiology

Monitoring and access

›Monitoring setup

›Cardiac monitor

›Pulse oximetry

›Frequent BP cycling

›Strict input and output

›Foley catheter if shock or high risk AKI

Resuscitation targets

›Hemodynamic and metabolic targets

›MAP ≥ 65 mmHg

›Urine output ≥ 0.5 ml/kg/hour

›Lactate downtrend within 2-4 hours if elevated

›Potassium 3.5-5.0 mmol/l

›Magnesium ≥ 0.7 mmol/l

Immediate actions

›Early stabilization bundle

›NPO status

›Two large bore IV lines

›Crystalloid bolus if hypovolemia

›Nasogastric tube if vomiting or significant distention

›Broad-spectrum antibiotics if ischemia, perforation, or sepsis concern

›Early general surgery notification for suspected large bowel obstruction

Consultation and escalation

›Time-critical escalation

›If peritonitis, shock, or free air, immediate surgery and resuscitation bay

›If suspected malignant obstruction, GI and surgery discussion for stent vs operative management

›If suspected volvulus, urgent endoscopic decompression pathway plus surgery backup

02History/hx44

Symptom pattern

›Obstruction syndrome

›Abdominal distention

›Constipation

›Obstipation

›Last flatus time

›Pain pattern

›Crampy pain

›Progressive constant pain

›Nausea and vomiting

›Late vomiting pattern

›Feculent emesis

Timeline and severity

›Time course

›Onset time

›Progression speed

›Prior similar episodes

›Oral intake tolerance

Etiology risk factors

›Structural risk factors

›Colorectal cancer history

›Diverticular disease history

›Inflammatory bowel disease history

›Prior pelvic radiation

›Prior colorectal surgery

›Known hernias

›Volvulus risk factors

›Chronic constipation

›Neuropsychiatric disease

›Institutionalization

›Prior volvulus

Red flags

›Ischemia and perforation indicators

›Fever

›Rigors

›Syncope or near syncope

›Severe constant pain out of proportion

›Bloody stool or hematochezia

›Immunosuppression

Medications and exposures

›Medication contributors and confounders

›Opioids

›Anticholinergics

›Recent chemotherapy

›Anticoagulants and antiplatelets

Prior evaluations

›Baseline and recent data

›Prior colonoscopy findings

›Prior CT findings

›Known strictures or tumors

03Physical Exam/exam30

General and vitals

›Physiologic severity

›Temperature pattern

›Heart rate trend

›Blood pressure trend

›Respiratory rate trend

›Mental status change

Abdominal exam

›Abdominal findings

›Distention severity

›Tympany pattern

›Bowel sounds

›High-pitched early pattern

›Decreased late pattern

›Tenderness distribution

›Peritoneal signs

›Guarding

›Rebound tenderness

›Palpable mass

Hernia and perineum

›Mechanical cause screening

›Inguinal hernia exam

›Femoral hernia exam

›Surgical scars and stomas

Rectal exam

›Rectal and pelvic clues

›Stool burden

›Gross blood

›Mass

›Rectal tone

PITFALLS

›Common misses

›Normal bowel sounds do not exclude obstruction

›Minimal pain does not exclude ischemia in older adults

›Large bowel obstruction may present with limited vomiting early

04Differential Diagnosis/ddx37

Life-threatening mimics

›High-risk abdominal diagnoses

›Mesenteric ischemia (ICD-10 K55.9)

›Pain out of proportion

›Lactate elevation pattern

›Perforated viscus (ICD-10 K63.1)

›Free air concern

›Peritonitis

›Toxic megacolon (ICD-10 K59.31)

›Systemic toxicity

›Colitis history

Bowel motility disorders

›Functional obstruction

›Acute colonic pseudo-obstruction (Ogilvie syndrome) (ICD-10 K59.81)

›Severe distention without transition point

›Precipitating illness or surgery

›Paralytic ileus (ICD-10 K56.0)

›Diffuse small and large bowel dilation

›Medication or metabolic trigger

Mechanical obstruction categories

›Intestinal obstruction spectrum

›Small bowel obstruction (ICD-10 K56.60)

›Early vomiting prominence

›Less distal gas pattern

›Large bowel obstruction (ICD-10 K56.69)

›Marked distention

›Obstipation

›Colonic volvulus (ICD-10 K56.2)

›Sigmoid volvulus pattern

›Cecal volvulus pattern

Other common mimics

›Non-obstructive causes

›Severe constipation or fecal impaction (ICD-10 K59.00)

›Rectal vault stool

›No transition point on CT

›Acute appendicitis (ICD-10 K35.80)

›RLQ focal pain

›Leukocytosis pattern

›Acute diverticulitis (ICD-10 K57.32)

›LLQ focal tenderness

›Pericolic fat stranding

05Laboratory Tests/lt31

Core tests

›Baseline labs

›Complete blood count

›Leukocytosis for ischemia or perforation concern

›Hemoglobin trend for malignancy or bleeding concern

›Electrolytes and renal function

›Sodium and potassium derangements from dehydration

›Creatinine for contrast planning and AKI risk

›Liver panel

›Alternative diagnosis screen

›Baseline for operative planning

Perfusion and sepsis markers

›Ischemia and infection assessment

›Lactate

›Elevated lactate as ischemia or shock marker

›Normal lactate does not exclude early ischemia

›Venous blood gas

›Metabolic acidosis pattern

›pCO2 compensation pattern in mmHg

›Blood cultures if sepsis concern

›Two sets before antibiotics when feasible

›Do not delay antibiotics in shock

Coagulation and transfusion planning

›Bleeding and procedure readiness

›INR and aPTT

›Anticoagulant effect screen

›Baseline for emergent surgery

›Type and screen

›Operative readiness

›Hemodynamic instability pathway

PITFALLS

›Lab interpretation traps

›Mild leukocytosis common in dehydration

›Normal WBC does not exclude strangulation

›Rising lactate trend more concerning than isolated value

06Diagnostic Tests/dt38

Scoring Systems

›Risk stratification frameworks

›Sepsis screening (qSOFA or SIRS)

›Altered mentation

›SBP ≤ 100 mmHg

›RR ≥ 22/min

›Shock severity (lactate-guided resuscitation)

›Lactate ≥ 2 mmol/l as abnormal

›Lactate ≥ 4 mmol/l as high risk

›Peritonitis triggers for operative pathway

›Rebound tenderness

›Involuntary guarding

MRI

›MRI role

›Pregnancy or radiation avoidance scenarios

›Non-contrast MRI abdomen as alternative when stable

›Limited availability and longer acquisition time

›Contraindications and limitations

›Unstable patient

›Metallic implant constraints

›CT abdomen and pelvis utility

›CT with IV contrast as first-line in most suspected large bowel obstruction

›Transition point localization

›Etiology suggestion

›CT ischemia and perforation signs

›Pneumatosis intestinalis

›Portal venous gas

›Free intraperitoneal air

›Mesenteric edema or ascites

›Reduced bowel wall enhancement

›Closed-loop and competent ileocecal valve considerations

›Marked cecal dilation risk

›Increased perforation risk with progressive diameter

Ultrasound

›Bedside ultrasound adjunct

›FAST or free fluid assessment

›Free fluid in hypotension pathway

›Peritoneal fluid as severity marker

›Limited LBO performance

›Poor colonic gas windows

›Not a rule-out test

07Disposition/dispo20

Level of care

›Admission decisions

›Inpatient admission as default for suspected large bowel obstruction

›ICU criteria

›Vasopressor requirement

›Rising lactate despite fluids

›Respiratory failure

›Transfer criteria

›No on-site colorectal surgery capability

›Need for emergent endoscopy and no local access

Operative vs nonoperative pathway

›Operative indications

›Peritonitis

›Perforation evidence

›Ischemia evidence

›Complete obstruction with clinical decline

›Temporizing or bridging options

›Endoscopic decompression for sigmoid volvulus without peritonitis

›Colonic stent for malignant obstruction in selected settings

Discharge criteria

›Discharge rarity and constraints

›Large bowel obstruction generally not discharge-eligible from ED

›Discharge only if obstruction excluded and symptoms resolved with alternative diagnosis established

08Treatment/t83

Initial supportive care

›Supportive bundle

›NPO status

›Oral meds held unless essential

›Aspiration risk reduction

›IV fluids

›0.9% sodium chloride 500-1000 ml bolus

›Repeat bolus based on perfusion and urine output

›Electrolyte correction

›Potassium chloride IV 10 mmol/hour via peripheral line

›Magnesium sulfate IV 2 g over 1 hour if low

›Antiemetics

›Ondansetron IV 4 mg

›Repeat 4 mg every 6-8 hours as needed

Gastric and colonic decompression

›Decompression strategy

›Nasogastric tube

›Persistent vomiting

›Significant distention

›Rectal tube consideration

›Distal colonic decompression attempt in selected cases

›Avoid if suspected perforation

Analgesia protocols

›Pain control

›Fentanyl IV 25-50 micrograms

›Repeat every 5-10 minutes to effect

›Caution with hypotension and respiratory depression

›Hydromorphone IV 0.2-0.5 mg

›Repeat every 10-15 minutes to effect

›Lower starting dose in older adults

›Acetaminophen IV 1 g

›Maximum 4 g/day

›Lower maximum in liver disease

Antibiotics

›Broad-spectrum coverage indications

›Suspected ischemia

›Lactate elevation or CT ischemia signs

›Severe continuous pain pattern

›Suspected perforation

›Free air or peritonitis

›Sepsis physiology

›Preoperative prophylaxis pathway

›Timing within 60 minutes of incision when operative

›Redose if prolonged surgery per protocol

›Empiric regimens

›Piperacillin-tazobactam IV 4.5 g

›Repeat every 6-8 hours

›Renal dose adjustment

›Ceftriaxone IV 2 g

›Metronidazole IV 500 mg

›Metronidazole repeat every 8 hours

›Ertapenem IV 1 g

›Once daily dosing

›Option for beta-lactam allergy patterns based on local guidance

Definitive management by etiology

›Malignant obstruction

›Surgical management options

›Resection with primary anastomosis in selected stable patients

›Diverting stoma in unstable or high-risk anastomosis

›Endoscopic stent consideration

›Bridge to surgery in selected left-sided malignant obstruction

›Palliative intent for unresectable disease

›Diverticular stricture or inflammatory stricture

›Operative pathway

›Resection strategy planning

›Diversion consideration if contamination or instability

›Sigmoid volvulus

›Endoscopic detorsion if no peritonitis

›Flexible sigmoidoscopy decompression

›Rectal tube placement post-detorsion

›Surgery if failed endoscopic decompression or ischemia

›Resection and diversion options

›High recurrence risk without definitive surgery

›Cecal volvulus

›Surgical management as primary approach

›Right hemicolectomy consideration

›Cecopexy in selected cases

Thromboprophylaxis and supportive inpatient care

›VTE prophylaxis

›Enoxaparin SC 40 mg daily

›Dose adjustment in renal impairment

›Hold for active bleeding or urgent procedure per protocol

›Mechanical prophylaxis

›Intermittent pneumatic compression devices

›Early mobilization when feasible

Evidence and guideline signals

›Evidence-based positioning

›Class I recommendation based on consensus for urgent surgery in peritonitis or perforation physiology

›Class IIa recommendation based on guideline consensus for endoscopic decompression in uncomplicated sigmoid volvulus

›ACEP Level C style evidence framing for lactate and CT ischemia signs as escalation triggers

09Special Populations/sp30

Pregnancy

›Pregnancy considerations

›Maternal stabilization priority

›Shock correction to preserve uteroplacental perfusion

›Early obstetrics notification in viable gestations

›Imaging adjustments

›Ultrasound as adjunct only

›MRI as alternative when stable and available

›Medication safety

›Opioids for severe pain with monitoring

›Avoid NSAIDs in later pregnancy

Geriatric

›Older adult risk profile

›Malignancy prevalence higher

›Weight loss history

›Iron deficiency anemia pattern

›Atypical presentations

›Blunted fever response

›Minimal tenderness despite ischemia

›Medication sensitivity

›Lower opioid starting doses

›Higher delirium risk

Pediatrics

›Pediatric differences

›Large bowel obstruction uncommon

›Hirschsprung-associated obstruction pattern

›Congenital malformations

›Weight-based resuscitation

›Crystalloid 20 ml/kg bolus for shock

›Weight-based opioid and antiemetic dosing

›Early pediatric surgery involvement

›Lower threshold for transfer

›Radiation minimization strategy

10Background/b27

Epidemiology

›Frequency and causes

›Common etiologies

›Colorectal cancer as leading cause in adults

›Diverticular stricture as common benign cause

›Volvulus epidemiology

›Sigmoid volvulus association with chronic constipation

›Cecal volvulus in younger adults relative to sigmoid

Pathophysiology

›Mechanism and complications

›Proximal dilation and pressure

›Increased intraluminal pressure with ongoing gas and fluid accumulation

›Bacterial overgrowth and translocation risk

›Ileocecal valve competence effects

›Closed-loop physiology when competent

›Rapid cecal dilation and perforation risk

›Ischemia pathways

›Venous congestion preceding arterial compromise

›Transmural necrosis leading to perforation and sepsis

Therapeutic Considerations

›Management principles

›Early recognition of ischemia and perforation

›CT ischemia signs as high-risk markers

›Lactate trend as perfusion marker

›Source control emphasis

›Operative intervention for perforation or necrosis

›Antibiotics as adjunct, not definitive source control

›Bridge strategies in malignancy

›Stent vs urgent surgery based on stability and local expertise

›Oncologic staging planning when stabilized

11Patient Discharge Instructions/pdi20

Copy discharge instructions

›Discharge guidance when obstruction excluded or resolved alternative diagnosis

›Hydration plan

›Frequent oral fluids as tolerated

›Avoid alcohol and dehydration triggers

›Diet guidance

›Small frequent meals

›Avoid very large high-fiber boluses until fully improved

›Medications

›Use antiemetic as prescribed

›Avoid opioids if possible due to constipation risk

›Return to ED now triggers

›Worsening abdominal pain

›Persistent vomiting

›No stool or no flatus with increasing distention

›Fever or rigors

›Blood in stool

›Fainting or severe weakness

›Follow-up plan

›Primary care within 24-72 hours

›Urgent GI or surgery referral if cancer or stricture concern

12References/r9

Clinical guidelines and evidence sources

›Guideline sources

›American Society of Colon and Rectal Surgeons clinical practice guidelines for colon cancer and obstructing colon cancer

›European Society of Gastrointestinal Endoscopy guideline on colonic stenting for malignant large bowel obstruction

›World Society of Emergency Surgery guidance on management of colonic volvulus and large bowel obstruction pathways

›Surviving Sepsis Campaign guidelines for sepsis and septic shock resuscitation targets

Decision support and reviews

›Evidence summaries

›Review literature on CT findings predicting ischemia in bowel obstruction

›Systematic reviews comparing stent bridge-to-surgery vs emergency surgery outcomes in left-sided malignant obstruction

›Emergency general surgery texts on volvulus decompression and recurrence risk

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Reviewed by SymptomDx Medical Team · Last reviewed June 16, 2026

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