01Approach to the Critical Patient/attcp56

Immediate priorities

›Peritonitis and perforation recognition

›Peritoneal signs mandate emergent surgery, NOT endoscopic detorsion

›Guarding, rigidity, rebound tenderness

›Involuntary peritoneal response

›Hemodynamic instability triggers immediate resuscitation

›SBP < 90 mmHg

›MAP < 65 mmHg

›Bowel gangrene mortality exceeds 50%

›Fever with leukocytosis and elevated lactate

›Pneumatosis intestinalis on CT

›Pneumoperitoneum on imaging requires emergent surgical consultation

›Upright CXR or CT confirmation

›Do not proceed with endoscopy

Resuscitation targets

›Hemodynamic resuscitation

›IV access with large bore peripheral lines

›Two large bore IVs minimum

›Central access if peripheral inadequate

›Aggressive IV fluid resuscitation

›Isotonic crystalloid bolus 1-2 L initial

›Reassess lactate clearance and urine output

›Electrolyte correction

›Hypokalemia from vomiting

›Metabolic acidosis if ischemic

›Vasopressors if fluid refractory hypotension

›Norepinephrine 0.01-0.5 mcg/kg/min titrated to MAP >= 65 mmHg

›ICU level care required

02History/hx70

Classic presentation

›Cardinal triad

›Constipation and obstipation

›No bowel movement and no flatus

›Duration hours to days

›Progressive abdominal distension

›Asymmetric tympanic distension

›Onset may be insidious

›Abdominal pain

›Variable severity

›Colicky or constant

Alarm features

›Symptoms suggesting complicated volvulus

›Fever

›Bowel ischemia or necrosis concern

›Sepsis

›Bloody stool

›Mucosal ischemia

›Late finding

›Symptom duration > 24 hours

›Associated with higher incidence of intestinal necrosis

›Urgency escalated

›Nausea and vomiting

›May be late finding

›Dehydration risk

Prior episodes and history

›Recurrence context

›Prior episodes of similar symptoms with spontaneous resolution

03Physical Exam/exam64

Vital signs

›Hemodynamic status

›Blood pressure

›Hypotension suggests ischemia, perforation, or dehydration

›SBP < 90 mmHg as critical threshold

›Heart rate

›Tachycardia from ischemia, dehydration, or sepsis

›Persistent tachycardia after fluids requires reassessment

›Temperature

›Fever suggests ischemia, necrosis, or peritonitis

›Hypothermia as severe sepsis marker

›Respiratory rate

›Tachypnea from sepsis or pain

›Metabolic acidosis from ischemia

Abdominal exam

›Distension and tympany

›Markedly distended abdomen

›Hallmark of sigmoid volvulus

›Asymmetric distension possible

›Tympanic to percussion

›Dilated gas-filled loop

›Hyper-resonant throughout

›Bowel sounds

›High-pitched early (obstruction)

›Absent late (ileus, ischemia, peritonitis)

Peritoneal exam

›Peritoneal signs

›Guarding

04Differential Diagnosis/ddx45

Life-threatening diagnoses

›Immediate surgical emergencies

›Perforated viscus

›ICD-10 K63.1

›Pneumoperitoneum on imaging

›Bowel ischemia with gangrene

›ICD-10 K55.0

›Elevated lactate, fever, peritonitis

›Strangulated hernia

›ICD-10 K46.0

›External mass on exam

Common causes of large bowel obstruction

›Mechanical obstruction mimics

›Obstructing colorectal cancer

›ICD-10 C18.7

›Most common cause of large bowel obstruction overall

›CT differentiates from volvulus

›Cecal volvulus

›ICD-10 K56.2

›Younger patients, female predominance

›Different management: surgery preferred over endoscopy

›Diverticular stricture

›Chronic history and diverticulosis on CT

›Narrowing without torsion

›Fecal impaction

›Rectal vault full on digital exam

›CT and rectal exam differentiate

05Laboratory Tests/lt44

Ischemia and infection markers

›Complete blood count

›Leukocytosis suggests ischemia, necrosis, or peritonitis

›Elevated neutrophil ratio correlates with intestinal necrosis

›Leukopenia as severe sepsis marker

›Hemoglobin baseline

›Pre-operative assessment

›Transfusion threshold planning

Metabolic panel

›Electrolytes and renal function

›Hypokalemia from vomiting

›Correct before surgery when possible

›QT prolongation risk if severe

›Metabolic alkalosis from vomiting

›Common in prolonged obstruction

›Chloride responsive

›Metabolic acidosis

›Bowel ischemia marker

›Anion gap elevation

›Creatinine and BUN

›AKI from dehydration and third spacing

›Antibiotic dosing adjustment

Perfusion and sepsis labs

›Lactate

›Elevated lactate associated with bowel ischemia and need for emergency surgery

›Target clearance > 10% per 2 hours

›Lactate >= 2 mmol/l as threshold for concern

›Repeat measurement to assess trajectory

06Diagnostic Tests/dt67

Scoring Systems

›Clinical risk stratification

›No validated disease-specific scoring system for sigmoid volvulus

›Clinical gestalt guides uncomplicated vs complicated classification

›Peritoneal signs, vitals, lactate, and CT findings drive decision

›ASA physical status classification for surgical risk

›ASA III-IV associated with higher perioperative mortality

›Guides Hartmann vs primary anastomosis decision

›APACHE II in post-surgical ICU patients

›Severity of illness stratification

›Mortality prediction in critical cases

›Symptom duration as risk stratification

›Duration > 24 hours associated with higher intestinal necrosis incidence

›Urgency of endoscopy or surgery escalated

MRI

›MRI in sigmoid volvulus

›Limited acute utility

›Availability constraints

›Motion artifact from bowel gas and distension

›Not standard of care in acute presentation

›CT is gold standard

›MRI reserved for specific complex cases

›Potential problem-solving role

›Suspected malignancy underlying obstruction

›Radiation-sparing in young patients if stable

›Contraindications in acute setting

›Hemodynamically unstable patient

›Non-MRI-compatible implants

07Disposition/dispo46

Admission indications

›Universal admission requirement

›All patients with sigmoid volvulus require admission

›No role for ED discharge

›Even successfully detorsed patients require colectomy planning

›ICU admission criteria

›Hemodynamic instability

›Sepsis or septic shock

›Post-emergent surgery

›Significant multiorgan comorbidities

Surgical consultation triggers

›Emergent surgical consultation

›Peritonitis or perforation

›Immediate operative planning

›No role for endoscopy

›Failed endoscopic detorsion

›Inability to traverse torsion

›Incomplete decompression

›Evidence of bowel ischemia on CT or endoscopy

›Pneumatosis intestinalis

›Loss of mucosal viability on endoscopy

›Hemodynamic instability

›Shock not responding to resuscitation

›Surgical damage control planning

›Recurrent volvulus during index admission

›Colectomy indication strengthened

Level of care

›Floor vs ICU determination

08Treatment/t96

Initial stabilization

›Immediate resuscitation measures

›IV access and fluid resuscitation

›Isotonic crystalloid 1-2 L bolus

›Titrate to urine output >= 0.5 mL/kg/hr

›Reassess after initial bolus

›NPO status

›No oral intake for procedural or surgical readiness

›NG tube if significant vomiting or proximal dilation

›Electrolyte correction

›Potassium repletion for hypokalemia

›Magnesium correction

›Phosphate correction if nutritionally depleted

›Foley catheter for urine output monitoring

›Strict fluid balance

›AKI assessment

Antibiotics

›Antibiotic indications

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

›Initiate within 1 hour of recognition

›Class I recommendation for peritonitis

›Not routinely required for uncomplicated volvulus without ischemia signs

›Clinical and imaging assessment guides decision

›Surgical team input

›Pre-operative antibiotics when surgery planned

›Colorectal surgery prophylaxis

›Cefazolin 2 g IV plus metronidazole 500 mg IV

›Administer within 60 minutes of incision

Antibiotic regimens for peritonitis or sepsis

›Empiric broad-spectrum coverage

›Piperacillin-tazobactam IV

›4.5 g IV every 6 hours

›Extended infusion 4.5 g over 4 hours every 8 hours per local protocol

›Renal dose adjustment required

›Meropenem IV for high-resistance risk or severity

›1 g IV every 8 hours

›500 mg IV every 8 hours for renal impairment

›Add vancomycin if MRSA risk factors

›15-20 mg/kg IV every 8-12 hours

›AUC-guided monitoring preferred

Endoscopic detorsion

›Flexible sigmoidoscopy

›First-line therapy for uncomplicated sigmoid volvulus

›Successful in 60-95% of cases

›ASCRS strong recommendation

›Prerequisites for safe endoscopy

›No peritoneal signs

›Hemodynamically stable

›No CT evidence of ischemia or perforation

›Procedure considerations

›Minimal air insufflation to reduce perforation risk

›Identify point of torsion

›Advance scope past twist carefully

›After successful detorsion

›Place rectal decompression tube

›Decompression tube reduces immediate recurrence

›Keep in place 24-48 hours

›Endoscopic failure triggers

›Inability to pass torsion point

›Dark or necrotic mucosa on endoscopy

›Immediate surgical escalation required

Surgical management

›Operative approach selection

›Emergent sigmoid resection for complicated volvulus

›Peritonitis, perforation, failed detorsion, ischemia

›Resect non-viable bowel

›Hartmann procedure

›End colostomy and closure of rectal stump

›Preferred in high-risk patients

›Sepsis, acidosis, coagulopathy, high ASA class

›Mortality 5-7%

›Primary anastomosis

›Considered in stable lower-risk patients

›Anastomotic leak rate approximately 4.7%

›Mortality approximately 3.4%

›Elective sigmoid colectomy during index admission

›Strongly recommended by ASCRS after successful detorsion

›Prevents recurrence

›Lower mortality than emergency surgery

Endoscopic fixation for high-risk patients

›Endoscopic options for non-operative candidates

›Endoscopic sigmoidopexy or colopexy

›Fixation of sigmoid to abdominal wall under endoscopic guidance

›Considered when operative intervention contraindicated

›Randomized controlled trial support for high-risk surgical elderly

›Percutaneous endoscopic colostomy

›Alternative fixation technique

›Reserved for highest surgical risk patients

›Patient selection

›High ASA class

›Significant cardiopulmonary comorbidity

›Surgeon and endoscopist shared decision

Bowel regimen and recurrence prevention

›Long-term bowel management

›High-fiber diet and adequate hydration

›Reduce chronic constipation

›Increase dietary fiber to 25-35 g per day

›Osmotic laxatives

›Polyethylene glycol 17 g orally daily

›Lactulose 15-30 mL orally twice daily as alternative

›Minimize constipating medications

›Review and reduce opioids when possible

›Switch anticholinergics to alternatives if feasible

09Special Populations/sp57

Pregnancy

›Sigmoid volvulus in pregnancy

›Rare but reported in third trimester

›Enlarged uterus displaces sigmoid colon

›Anatomic predisposition from uterine pressure

›Fetal and maternal mortality risk high without prompt treatment

›Bowel ischemia threatens maternal perfusion and fetal oxygenation

›Multidisciplinary management required

›Imaging approach

›CT indicated when diagnosis uncertain and condition critical

›Radiation risk vs maternal benefit favors CT in life-threatening scenario

›MRI if available and patient stable

›Management

›Endoscopic detorsion if uncomplicated

›Surgical resection for complicated presentation

›Obstetric involvement mandatory

›Antibiotic selection

›Beta-lactams generally preferred

›Avoid fluoroquinolones and tetracyclines

›Metronidazole acceptable in second and third trimester

Geriatric

›Elderly patient considerations

›Predominant affected population

›6th to 8th decade in Western countries

›Age > 70 years major risk factor

›Atypical presentation common

›Cognitive impairment masks pain reporting

›Fever may be absent despite ischemia

10Background/b68

Epidemiology

›Incidence and distribution

›60-75% of all colonic volvulus cases

›Most common type of colonic volvulus in Western countries

›Second most common cause of intestinal obstruction globally

›10-15% of large bowel obstructions in the US

›First most common cause of LBO is colorectal cancer

›Sigmoid volvulus second

›Geographic variation

›Higher incidence in the volvulus belt: Africa, Middle East, South Asia

›High-altitude residence and high-fiber diet implicated

›Younger patients affected in endemic regions

›US demographics

›Predominantly elderly men in 6th to 8th decade

›Male to female ratio approximately 2:1

›African American race associated with higher incidence

›Mortality

›Exceeds 50% when bowel gangrene develops

›Emergency surgery for recurrence carries mortality 13-62%

›Elective colectomy mortality 3.3-32%

Pathophysiology

›Anatomic basis

›Torsion of redundant sigmoid colon around its mesenteric axis

›Long redundant sigmoid loop predisposes

›Narrow mesenteric attachment creates fulcrum

›Closed-loop large bowel obstruction

›Both proximal and distal limbs obstructed at torsion point

›Rapid intraluminal pressure rise

11Patient Discharge Instructions/pdi54

copy discharge instructions

›Sigmoid volvulus home care after detorsion

›Take all prescribed medications as directed

›Laxatives and fiber supplements as instructed

›Do not skip doses

›Diet progression

›Start with clear fluids and advance slowly

›High-fiber diet once tolerated

›Avoid constipating foods

›Hydration

›Drink at least 6-8 glasses of water per day

›Adequate fluid intake supports bowel function

›Bowel regimen after discharge

›High-fiber diet

›Fruits, vegetables, whole grains

›Target 25-35 g fiber per day

›Osmotic laxative as prescribed

›Polyethylene glycol powder mixed in water daily

›Do not use stimulant laxatives without physician guidance

›Regular physical activity as tolerated

›Ambulation and mobility support bowel motility

›Discuss activity restrictions after surgery

›Warning signs to return to ER immediately

›Abdominal pain returning or worsening

›Any severe abdominal pain

›Return promptly without delay

›Abdomen becoming distended or bloated again

›Progressive enlargement

12References/r34

Guidelines and key sources

›Society guidelines

›ASCRS Clinical Practice Guidelines for Colonic Volvulus and Acute Colonic Pseudo-Obstruction

›Alavi K, Poylin V, Davids JS et al. Diseases of the Colon and Rectum. 2021

›DOI 10.1097/DCR.0000000000002159

›Strongly recommends colectomy during index admission after detorsion

›ASGE Guideline on Role of Endoscopy in Management of Acute Colonic Pseudo-Obstruction and Colonic Volvulus

›Naveed M, Jamil LH, Fujii-Lau LL et al. Gastrointestinal Endoscopy. 2020

›DOI 10.1016/j.gie.2019.09.007

›American College of Surgeons Gastrointestinal Surgical Emergencies Textbook

›Ashley EA, Amabile A, Andolfi C et al. ACS 2021

Key studies

›Outcomes and prognostic studies

›Girgin T, Erozkan K, Basci F et al. Optimizing Management of Sigmoid Volvulus: Predictors of Surgical Intervention and Early Recurrence. European Journal of Radiology. 2026

›CRP and lactate as predictors of need for emergency surgery

›PMID 42167002

›Fo Y, Kang X, Tang Y, Zhao L. Analysis of Clinical Diagnosis and Treatment of Intestinal Volvulus. BMC Gastroenterology. 2023

›Symptom duration and necrosis risk

›PMID 36977994

›Tantinam T, Buakhrun S, Chandrachamnong P et al. Two Decades of Endoscopic Detorsion in Sigmoid Volvulus: Prognostic Factors for Failure. Surgical Endoscopy. 2025

›PMID 40659948

›Choi S, Hyun HK, Park J et al. Clinical Factors Associated With Endoscopic Decompression Failure and Recurrent Sigmoid Volvulus. Journal of Gastroenterology and Hepatology. 2026

›PMID 41793213

›Negm S, Farag A, Shafiq A, Moursi A, Abdelghani AA. Endoscopic Management of Acute Sigmoid Volvulus in High Risk Surgical Elderly Patients: A Randomized Controlled Trial. Langenbeck's Archives of Surgery. 2023

›PMID 37635200

›Lai SH, Vogel JD. Diagnosis and Management of Colonic Volvulus. Diseases of the Colon and Rectum. 2021

›PMID 33496483

Evidence & Review

Evidence & Review