Emergency medicine
Acute Abdomen
Acute abdomen requires parallel resuscitation and diagnosis: identify patients with peritonitis, shock, obstruction, ischemia, or hemorrhage who need urgent surgical or procedural management, while using focused laboratory testing and imaging to distinguish operative disease from conditions appropriate for monitored conservative care.
First priority
Identify time-critical abdominal emergencies
Treat physiologic instability and diagnostic uncertainty concurrently.
Acute abdomen denotes rapidly developing severe symptoms from abdominal pathology that may represent life-threatening disease requiring urgent surgical intervention.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US The initial task is not to establish a complete differential diagnosis, but to recognize shock, peritonitis, hemorrhage, obstruction, ischemia, or evolving organ failure that requires immediate resuscitation and early surgical involvement.BMJ+1BMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice USScienceDirectAcute Abdomen - an overview
A surgical process may deteriorate quickly. Severe, persistent symptoms warrant close observation and thorough investigation even when early findings are nondiagnostic.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US Physical examination and clinical context remain central; imaging supplements rather than replaces a careful history and examination.ScienceDirectScienceDirectAcute Abdomen - an overview
Escalate immediately for hemodynamic instability, generalized peritoneal findings, progressive abdominal distention with obstructive features, or concern for intra-abdominal hemorrhage, perforation, bowel ischemia, or sepsis.BMJ+1BMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice USScienceDirectAcute Abdomen - an overview
Obtain early surgical consultation when an urgent surgical process is suspected; diagnostic laparoscopy may be considered in selected patients with unresolved acute abdominal pathology.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Use serial examinations when the diagnosis remains uncertain or symptoms evolve; this is particularly important when initial testing does not explain persistent severe pain.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
| Clinical priority | Action | Reason |
|---|---|---|
| Physiologic stabilization | Assess hemodynamics and monitor closely; prioritize resuscitation and urgent specialist evaluation when unstable.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US | Instability may reflect life-threatening abdominal pathology requiring urgent intervention.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US |
| Focused diagnostic assessment | Integrate history, examination, laboratory results, and imaging rather than relying on any single modality.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US | Acute abdomen is diagnosed from the combined clinical and diagnostic assessment.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US |
| Reassessment | Repeat examination and reassess trajectory when symptoms are severe or unresolved.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US | Surgical pathology can deteriorate rapidly and may not be fully evident initially.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US |
Diagnostic strategy
Use focused testing to answer the operative question
Order tests that identify a mechanism requiring immediate intervention.
The diagnostic workup should be directed by pain location, associated symptoms, physiologic status, examination findings, pregnancy potential, comorbidity, and the suspected mechanism. For example, pregnancy testing is important in patients with lower abdominal pain, and pancreatic enzyme testing is useful when acute pancreatitis is suspected.ScienceDirectScienceDirectAcute Abdomen - an overview Basic blood counts may identify neutrophilia or anemia; renal function and electrolytes affect resuscitation and operative planning.ScienceDirectScienceDirectAcute Abdomen - an overview
Imaging is integral to triage and can help separate patients requiring immediate surgery from those appropriate for conservative treatment or less urgent intervention.ScienceDirectScienceDirectAcute Abdomen - an overview Cross-sectional imaging should be used with a lower threshold in immunocompromised patients because symptoms and examination findings may be nonspecific or inconclusive.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Use laboratory studies to define physiologic derangement and test disease-specific hypotheses; do not use isolated laboratory abnormalities to exclude serious abdominal pathology.ScienceDirectScienceDirectAcute Abdomen - an overview
In patients with suspected acute pancreatitis, lipase remains elevated longer than amylase and is more specific for pancreatic pathology, although either enzyme can be elevated in nonpancreatic disease.ScienceDirectScienceDirectAcute Abdomen - an overview
For possible ectopic pregnancy, rapid urine hCG establishes pregnancy status; quantitative serum hCG and pelvic ultrasonography inform localization when ectopic pregnancy remains possible.ScienceDirectScienceDirectAcute Abdomen - an overview
Choose imaging by suspected pathology and patient factors. CT and ultrasonography are complementary diagnostic tools, but neither substitutes for clinical assessment.ScienceDirectScienceDirectAcute Abdomen - an overview
When CT changes management
For suspected acute left-sided diverticulitis with diagnostic uncertainty, abdominal and pelvic CT is the preferred modality because it confirms diverticulitis, identifies complications, and evaluates alternative causes of lower abdominal pain.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine In the index episode, CT is particularly useful because complicated disease occurs most often at initial presentation and imaging may inform future care planning.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
Red flags such as severe pain with high fever, rectal bleeding, obstructive features, peritonitis, or concern for malignancy should prompt evaluation in a setting with CT capability and surgical expertise.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
Oral and intravenous contrast are preferred when feasible for diverticulitis, although noncontrast CT has similar diagnostic utility in patients with poor renal function.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
Supportive care
Provide analgesia while evaluation proceeds
Pain treatment and diagnostic accuracy are not competing objectives.
Adequate analgesia should be provided during evaluation of undifferentiated acute abdominal pain. A meta-analysis of randomized trials found that opioid analgesia improved patient comfort without increasing diagnostic error or treatment-decision error in adults with acute abdominal pain.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Antiemetic therapy, fluid resuscitation, correction of major metabolic abnormalities, and organ-specific supportive care should be tailored to the suspected process and physiologic status. The supplied evidence supports the principle of adequate analgesia but does not provide a source-supported universal medication regimen or dosing scheme for undifferentiated acute abdomen.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Do not defer opioid analgesia solely to preserve examination findings.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Continue serial examinations after analgesia; evolving focal tenderness, guarding, distention, or hemodynamic deterioration should change disposition and consultation urgency.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Avoid treating symptom control as evidence that a dangerous diagnosis has been excluded; reassess persistent or recurrent pain in the context of the full clinical trajectory.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Diagnostic modifiers
Lower the threshold for escalation in high-risk populations
Atypical presentation is a major source of delayed diagnosis.
Older adults, pregnant patients, children, and immunocompromised patients may have atypical symptoms and signs of acute abdominal pathology.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US In older adults, comorbidity, medications, altered pain perception, and impaired inflammatory responses can obscure classic presentations; in one cited study of perforated ulcer, only 21% of older patients had peritonitis.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Pregnancy can alter symptom localization and blunt peritoneal signs through uterine enlargement and abdominal wall laxity. Mild physiologic leukocytosis also reduces the specificity of leukocytosis in pregnant patients with abdominal pain.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Immunocompromised patients may have nonspecific pain and inconclusive examination findings because of altered inflammatory responses. A lower threshold for hospital admission and cross-sectional imaging is recommended in this population.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
In pregnancy, pursue further laboratory testing, imaging, or serial examinations when clinical suspicion for intra-abdominal pathology remains high despite equivocal initial findings.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
In immunocompromised patients, include therapy-related and opportunistic etiologies; neutropenic enterocolitis may present with fever, neutropenia, and right iliac fossa pain 10 to 14 days after chemotherapy initiation.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
In pediatric patients, select imaging according to age and differential diagnosis; ultrasound is a radiation-free first-line modality for several common pediatric acute abdominal conditions.ScienceDirectScienceDirectPediatric Acute Abdomen: Bread-and-Butter Diagnoses
Clinical application
Match disposition to disease severity and reliability of follow-up
Outpatient management is appropriate only after dangerous pathology is reasonably excluded.
Selected patients with imaging-confirmed uncomplicated diverticulitis may be managed as outpatients when they are immunocompetent, have controlled comorbidities, tolerate oral intake, and have reliable support and follow-up.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine High fever, poor oral intake, rectal bleeding, palpable rectal mass, or focal peritonitis with guarding generally warrant admission.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
For selected uncomplicated diverticulitis, initial management without antibiotics is supported by randomized evidence, but antibiotics remain appropriate in higher-risk patients with comorbidity, immunosuppression, or systemic infection.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine This disease-specific example illustrates the broader acute abdomen principle: disposition depends on physiologic stability, complication risk, diagnostic confidence, capacity for follow-up, and the expected trajectory rather than diagnosis alone.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
Do not apply outpatient evidence from carefully selected uncomplicated diverticulitis cohorts to patients with peritoneal signs, systemic illness, inability to tolerate intake, immunocompromise, or unreliable follow-up.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
Complicated diverticulitis with perforation, obstruction, abscess, or fistula generally requires surgical or interventional radiology management.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
When acute diverticulitis is the first complicated episode, colonoscopy is recommended after recovery if recent colonoscopy is absent, to assess for underlying malignancy.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
Common questions
Should opioid analgesia be withheld until the diagnosis is established?
No. In adults with undifferentiated acute abdominal pain, randomized-trial evidence summarized in a meta-analysis found opioid analgesia improved comfort without increasing diagnostic or treatment-decision errors.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
What defines an acute abdomen requiring urgent surgical evaluation?
The key concern is rapidly evolving abdominal pathology with physiologic instability, peritoneal findings, obstruction, ischemia, hemorrhage, or another process likely to require urgent intervention. Severe, persistent symptoms require close monitoring and thorough investigation.BMJ+1BMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice USScienceDirectAcute Abdomen - an overview
When should imaging be escalated in immunocompromised patients?
Use a lower threshold for hospital admission and cross-sectional imaging because immunocompromised patients may have nonspecific symptoms and an inconclusive examination despite significant pathology.BMJBMJEvaluation of acute abdomen - Differential diagnosis of symptoms | BMJ Best Practice US
Can uncomplicated diverticulitis be managed without antibiotics?
Selected immunocompetent, clinically stable patients with uncomplicated disease can be managed initially without antibiotics; use antibiotics for higher-risk patients with comorbidity, immunosuppression, or systemic infection.ccjmccjmAcute left-sided colonic diverticulitis: A surgeon’s perspective on the ACP guidelines | Cleveland Clinic Journal of medicine
References
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- These highlights do not include all the information needed to use FIRAZYR<sup>®</sup> (icatibant) safely and effectively. See full prescribing information for FIRAZYR. <br/> <br/>FIRAZYR (icatibant) Injection, for subcutaneous use <br/>Initial U.S. Approval: 2011 — www.accessdata.fda.gov · www.accessdata.fda.gov
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