Evaluation of acute abdomen

Acute abdomen refers to the rapid onset of severe symptoms of abdominal pathology. It may indicate a potentially life-threatening condition that requires urgent surgical intervention. Acute abdominal pain is a common reason for emergency department attendance.[1]Hooker EA, Mallow PJ, Oglesby MM. Characteristics and trends of emergency department visits in the United States (2010-2014). J Emerg Med. 2019 Mar;56(3):344-51. http://www.ncbi.nlm.nih.gov/pubmed/30704822?tool=bestpractice.com

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]Silen W. Cope's early diagnosis of the acute abdomen. 22nd ed. New York, NY: Oxford University Press; 2010. Data from the UK suggest that access to an experienced surgeon reduces unnecessary admissions.[3]Association of Surgeons of Great Britain and Ireland. Commissioning guide: emergency general surgery (acute abdominal pain). Apr 2014 [internet publication]. https://www.rcseng.ac.uk/library-and-publications/rcs-publications/docs/emergency-general-guide

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, patients who are immunocompromised, and women in the last trimester of pregnancy.

Diagnostic workup

An acute abdomen is diagnosed by a combination of history, physical exam, laboratory results and imaging.

Diagnostic laparoscopy can be considered in selected patients.[4]Stefanidis D, Richardson WS, Chang L, et al. The role of diagnostic laparoscopy for acute abdominal conditions: an evidence-based review. Surg Endosc. 2009 Jan;23(1):16-23. http://www.ncbi.nlm.nih.gov/pubmed/18814014?tool=bestpractice.com [5]Maggio AQ, Reece-Smith AM, Tang TY, et al. Early laparoscopy versus active observation in acute abdominal pain: systematic review and meta-analysis. Int J Surg. 2008 Oct;6(5):400-3. http://www.journal-surgery.net/article/S1743-9191(08)00086-1/fulltext http://www.ncbi.nlm.nih.gov/pubmed/18760983?tool=bestpractice.com [6]Society of American Gastrointestinal and Endoscopic Surgeons. Guidelines for diagnostic laparoscopy. Apr 2010 [internet publication]. https://www.sages.org/publications/guidelines/guidelines-for-diagnostic-laparoscopy

Analgesia

Give patients adequate analgesia.[3]Association of Surgeons of Great Britain and Ireland. Commissioning guide: emergency general surgery (acute abdominal pain). Apr 2014 [internet publication]. https://www.rcseng.ac.uk/library-and-publications/rcs-publications/docs/emergency-general-guide 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]Manterola C, Vial M, Moraga J, et al. Analgesia in patients with acute abdominal pain. Cochrane Database Syst Rev. 2011 Jan 19;(1):CD005660. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD005660.pub3/full http://www.ncbi.nlm.nih.gov/pubmed/21249672?tool=bestpractice.com [ ] In people with acute abdominal pain with an undiagnosed cause, how does the use of opioid analgesia affect the clinical evaluation process?/cca.html?targetUrl=http://cochraneclinicalanswers.com/doi/10.1002/cca.536/fullMostre-me a resposta

Special groups

Abdominal pain in older people, patients who are immunocompromised, and pregnant women often presents atypically, which can lead to delayed diagnosis of life-threatening abdominal pathology.[8]Chen EH, Mills AM. Abdominal pain in special populations. Emerg Med Clin North Am. 2011 May;29(2):449-58. http://www.ncbi.nlm.nih.gov/pubmed/21515187?tool=bestpractice.com

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]Ragsdale L, Southerland L. Acute abdominal pain in the older adult. Emerg Med Clin North Am. 2011 May;29(2):429-48. http://www.ncbi.nlm.nih.gov/pubmed/21515186?tool=bestpractice.com

• 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]Ragsdale L, Southerland L. Acute abdominal pain in the older adult. Emerg Med Clin North Am. 2011 May;29(2):429-48. http://www.ncbi.nlm.nih.gov/pubmed/21515186?tool=bestpractice.com

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 make it difficult to localize pain and can blunt peritoneal signs.[10]Kilpatrick CC, Monga M. Approach to the acute abdomen in pregnancy. Obstet Gynecol Clin North Am. 2007 Sep;34(3):389-402. http://www.ncbi.nlm.nih.gov/pubmed/17921006?tool=bestpractice.com

• Pregnant women may have 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.

• See also Assessment of abdominal pain in pregnancy (urgent considerations).

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]McKean J, Ronan-Bentle S. Abdominal pain in the immunocompromised patient-human immunodeficiency virus, transplant, cancer. Emerg Med Clin North Am. 2016 May;34(2):377-86. http://www.ncbi.nlm.nih.gov/pubmed/27133250?tool=bestpractice.com

• 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]Spencer SP, Power N. The acute abdomen in the immune compromised host. Cancer Imaging. 2008 Apr 22;8:93-101. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2365454 http://www.ncbi.nlm.nih.gov/pubmed/18442955?tool=bestpractice.com

• A lower threshold for admission to hospital and cross-sectional imaging is required in immunocompromised patients.[11]McKean J, Ronan-Bentle S. Abdominal pain in the immunocompromised patient-human immunodeficiency virus, transplant, cancer. Emerg Med Clin North Am. 2016 May;34(2):377-86. http://www.ncbi.nlm.nih.gov/pubmed/27133250?tool=bestpractice.com