Evaluation of acute abdomen
Summary
The term acute abdomen refers to the rapid onset of severe symptoms of abdominal pathology. Acute abdomen may indicate a potentially life-threatening condition that requires urgent surgical intervention. Acute abdominal pain is a common reason for emergency department attendance.[1]
Clinical features
Immediate assessment should focus on distinguishing patients with true acute abdomen that requires urgent surgical intervention from patients who can initially be managed conservatively.[2] Data from the UK suggest that access to an experienced surgeon reduces unnecessary admissions.[3]
A patient with acute surgical pathology may deteriorate rapidly; patients with severe, unremitting symptoms warrant thorough investigation and close monitoring.
Pain may:
be located in any quadrant of the abdomen
be intermittent, sharp or dull, achy, or piercing
radiate from a focal site
be accompanied by nausea and vomiting.
Acute abdomen can occur without pain in older people, children, and the immunocompromised, and in the last trimester of pregnancy.
Diagnostic workup
An acute abdomen is diagnosed by a combination of history, physical exam, imaging, and laboratory results.
Diagnostic laparoscopy can be considered in selected patients.[4][5][6]
Analgesia
One meta-analysis of randomized controlled trials that included adult patients with acute abdominal pain found that opioid analgesia does not increase the risk of diagnosis error or treatment decision error, and improves patient comfort.[7]
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Special groups
Abdominal pain in older people, the immunocompromised, and pregnant women often presents atypically, which can lead to delayed diagnosis of life-threatening abdominal pathology.[8]
Older people
Comorbid conditions or medications used to treat them may affect an older patient's ability to mount a characteristic physiologic response.
Older patients are at higher risk for more severe disease due to decreased immune function.[9]
Central and peripheral nervous systems are affected by aging. Conditions such as dementia can restrict an older person's ability to communicate problems, and decreased peripheral nervous system function can alter perception of pain and temperature, making diagnosis and management more difficult.
One study of patients with perforated ulcers found that only 21% of older patients presented with peritonitis.[9]
Pregnant women
The physical and physiologic changes associated with pregnancy may present a challenge to diagnosis and treatment.
The enlargement of the uterus, which displaces and compresses intra-abdominal organs, and the laxity of the abdominal wall makes it difficult to localize pain and can blunt peritoneal signs.[10]
Pregnant women may have a mild physiologic leukocytosis, so this finding is nonspecific in pregnant women presenting with an acute abdomen.
If there is a high index of suspicion for intra-abdominal pathology, further studies are warranted and may include additional laboratory testing, radiographic testing, or in some cases serial physical exams.
Immunocompromised patients
Immunocompromised patients mount an altered inflammatory response, and may display atypical symptoms and signs of acute abdominal pathology. Abdominal pain is usually nonspecific, and physical exam is often inconclusive.[11]
Immunocompromised patients are susceptible to opportunistic infections, e.g., cytomegalovirus colitis in patients with AIDS.
An acute abdomen may occur as a result of immunosuppressive therapy. Typhlitis (neutropenic enterocolitis) is a complication of chemotherapy that typically presents with fever, neutropenia, and right iliac fossa pain 10 to 14 days after initiation of chemotherapy.[12]
A lower threshold for admission to hospital and cross-sectional imaging is required in immunocompromised patients.[11]
Differentials
Common
- Adhesions
- Incarcerated/strangulated hernia
- Cholecystitis
- Perforated gastric ulcer
- Appendicitis
- Ectopic pregnancy
- Pelvic inflammatory disease
- Acute pancreatitis
- Acute diverticulitis
- Ulcerative colitis
- Crohn disease
- Cholelithiasis
- Gastrointestinal malignancy
- Mallory-Weiss tear
- Diabetic ketoacidosis
- Opioid withdrawal
- Hepatitis
- Gastroenteritis
- Infectious colitis
- Sickle cell crisis
- Endometriosis
- Testicular torsion
- Kidney stones
- Pyelonephritis
Uncommon
- Volvulus
- Intussusception
- Perforated duodenal ulcer
- Ruptured ovarian cyst
- Ovarian torsion
- Abdominal aortic dissection
- Ruptured aortic aneurysm
- Acute mesenteric ischemia (AMI) and infarction
- Myocardial infarction
- Meckel diverticulitis
- Hepatic abscess
- Psoas abscess
- Tuberculosis
- Esophageal perforation (Boerhaave syndrome)
- Fitz-Hugh Curtis syndrome
- Ischemic colitis
- Ruptured splenic artery aneurysm
- Budd-Chiari syndrome
- Splenic infarct
- Abdominal wall hematoma
- Uremia
- Addisonian crisis
- Hypercalcemia
- Acute intermittent porphyria (AIP)
- Hereditary Mediterranean fever
- Typhlitis (neutropenic enterocolitis)
- Radiation enteritis
- Heavy metal poisoning
- Spider bite
Contributors
Authors
Charles A. Leath III, MD, MSPH, FACS
Professor, Ellen Gregg Shook Culverhouse Chair in Gynecologic Oncology
Division of Gynecologic Oncology
The University of Alabama
Birmingham
AL
Disclosures
CAL has served on advisory boards for Celsion and Mateon Therapeutics. CAL has received grants from the National Institutes of Health and has performed contracted research for the following: AbbVie, Agenus, AstraZeneca, Celsion, Immunogen, Merck, Novartis, Roche/Genentech, Syros, and Tesaro. He has served as a consultant and/or on scientific advisory boards for AbbVie, Clovis Oncology, Eisai, Syros, and Unleash Immuno Oncolytics.
Neil T. Phippen, MD
Assistant professor
Gynaecological oncology
Brooke Army Medical Center
San Antonio
TX
Disclosures
NTP declares that he has no competing interests.
Acknowledgements
Dr Charles A. Leath III and Dr Neil T. Phippen would like to gratefully acknowledge Dr William J. Lowery, Dr Aaron W. Campbell and Dr Jin H. Ra, previous contributors to this topic.
Disclosures
WJL has participated in a speakers' bureau for AstraZeneca to discuss Lynparza for ovarian cancer. AWC and JHR declare that they have no competing interests.
Peer reviewers
William Winter, MD
Staff
Gynecologic Oncologist
Northwest Cancer Specialists
Rose Quarter Cancer Center
Portland
OR
Disclosures
WW declares that he has no competing interests.
Michaela West, MD, PhD
Professor and Vice Chair
UCSF Department of Surgery
Chief of Surgery
San Francisco General Hospital
San Francisco
CA
Disclosures
None declared.
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