Introduction
Background
Mesenteric adenitis is a self-limited inflammatory process that affects the mesenteric lymph nodes in the right lower quadrant. Its clinical presentation mimics that of acute appendicitis.1 Cross-sectional imaging is routinely applied in the examination of patients and may help avoid unnecessary surgery in cases of mesenteric adenitis. Previously, the diagnosis was most frequently made when laparotomy performed to assess presumed appendicitis yielded negative findings.2,3,4,5,6,7,8
Supine abdominal radiograph shows a mild localized ileus and suggests nodular thickening of the terminal ileum.
Abdominal CT scan shows a cluster of enlarged nodes in the right lower quadrant.
Frequency
United States
In 2 series involving patients with clinical symptoms suggestive of acute appendicitis, mesenteric adenitis was the most frequent alternative diagnosis; it was present in 8-12% of patients. In Europe and North America, the proportion of patients with Yersinia enterocolitica infection who undergo appendectomy is 3.0-9.0%.1,2,3,6,9,10,11
International
As an etiologic agent of mesenteric adenitis, Y enterocolitica is less common in developing nations than in other nations. In Europe and North America, the proportion of patients with Y enterocolitica infection who undergo appendectomy is 3.0-9.0%. In 2 small studies of children who underwent appendectomy in Bangladesh, Yersinia organisms were not found.
Mortality/Morbidity
Most cases are self-limited, although disease lasting longer than 2 weeks is common. With Yersinia ileocolitis, small-bowel disease may be severe, and gangrene and death have been reported. Children who undergo laparotomy for presumed appendicitis are at risk for surgical complications.
On the other hand, children and adolescents who experience mesenteric adenitis appear to be at significantly reduced risk of developing ulcerative colitis in adulthood; reduced risk has also been seen with appendicitis in this population.2
Race
No racial predilection is reported.
Sex
Two large published series provide no information about the sex ratio. The clinical differential diagnosis in patients with right lower quadrant pain is broader in girls, especially in adolescents in whom gynecologic pathology must be considered.
Age
Mesenteric adenitis can occur in adults, but it is most common in children and adolescents younger than 15 years. Associated enteric disease most often occurs in those younger than 5 years.12
Presentation
Anatomy
Mesenteric lymph nodes are present near mesenteric vessels and between bowel loops. They normally appear flattened, ovoid, or disc-shaped, and they have a characteristic fatty central hilum and a solid peripheral cortex (see Image 1).
Sonogram of normal mesenteric lymph nodes shows that they are ovoid, with a prominent fatty hilum and a short-axis diameter less than 5 mm.
Vessels enter and exit the node at the hilum and branch within the node in a fashion similar to that of the kidney. Normal mesenteric lymph nodes vary in size, but in general, the short-axis diameter is 4 mm or less.
Pathophysiology
Mesenteric adenitis is most frequently caused by viral pathogens, but other infectious agents have been implicated, including Yersinia enterocolitica, Helicobacter jejuni, Campylobacter jejuni, and Salmonella or Shigella species.9,10,13 An association with streptococcal infections of the upper respiratory tract, particularly the pharynx, has been reported. In younger children and infants, concurrent ileocolitis may be present; this finding suggests that the lymph node involvement may occur in reaction to a primary enteric pathogen.
Clinical presentation
Mesenteric adenitis is a self-limited condition characterized by fever, abdominal pain, nausea, and, occasionally, diarrhea. Pain and tenderness are often centered in the right lower quadrant, but they may be more diffuse than in appendicitis. The site of tenderness may shift when the patient's position changes, whereas the location of the tenderness tends to be fixed with appendicitis. Leukocytosis is common.
The diagnosis of mesenteric adenitis is one of exclusion; confirmation is based on a benign clinical course, and management is conservative.
Preferred Examination
Ultrasonography of the right lower quadrant with graded compression has been the mainstay of diagnosis in children.14 The American College of Radiology (ACR) recommends this procedure as the most appropriate for patients under the age of 14 years with fever, leukocytosis, and possible appendicitis but an atypical presentation.15 The ACR notes that abdominal CT with intravenous contrast may be useful in children with negative ultrasound studies and recommends this technique as the most appropriate for adolescents and adults with this presentation. CT is especially useful for evaluation of possible appendicitis in men and in patients in whom visualization of the appendix may be compromised by their body habitus. Although the findings are frequently nonspecific, abdominal radiographs occasionally reveal findings and permit alternative diagnoses (eg, appendicoliths).
Limitations of Techniques
The normal appendix is sonographically occult in a significant subset of patients. When lymph node enlargement is detected on sonographic examination in these patients, excluding appendicitis as a cause of reactive adenopathy is difficult.3,11
In some centers, CT is performed for the evaluation of appendicitis without intravenous and/or oral contrast enhancement. This approach reduces the sensitivity of CT for bowel wall thickening and mesenteric adenopathy, especially in small children with a paucity of intraperitoneal fat.
With any imaging modality, the finding of lymph node enlargement as an isolated finding is nonspecific; it can be observed in association with several inflammatory processes. Occasionally, nodes exceeding the normal size threshold are observed in children who have no demonstrable disease.16
Differential Diagnoses
Appendicitis
Crohn Disease
Sprue
Other Problems to Be Considered
Infectious gastroenteritis
Lymphoma
More on Mesenteric Adenitis |
 Overview: Mesenteric Adenitis |
| Imaging: Mesenteric Adenitis |
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References
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Frisch M, Pedersen BV, Andersson RE. Appendicitis, mesenteric lymphadenitis, and subsequent risk of ulcerative colitis: cohort studies in Sweden and Denmark. BMJ. Mar 9 2009;338:b716. [Medline]. [Full Text].
Schulte B, Beyer D, Kaiser C, et al. Ultrasonography in suspected acute appendicitis in childhood-report of 1285 cases. Eur J Ultrasound. Dec 1998;8(3):177-82. [Medline].
Borgia G, Ciampi R, Nappa S, et al. Tuberculous mesenteric lymphadenitis clinically presenting as abdominal mass: CT and sonographic findings. J Clin Ultrasound. Sep 1985;13(7):491-3. [Medline].
Puylaert JB. Mesenteric adenitis and acute terminal ileitis: US evaluation using graded compression. Radiology. Dec 1986;161(3):691-5. [Medline].
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Zganjer M, Roic G, Cizmic A, Pajic A. Infectious ileocecitis--appendicitis mimicking syndrome. Bratisl Lek Listy. 2005;106(6-7):201-2. [Medline].
Zippi M, Colaiacomo MC, Marcheggiano A, et al. Mesenteric adenitis caused by Yersinia pseudotubercolosis in a patient subsequently diagnosed with Crohn's disease of the terminal ileum. World J Gastroenterol. Jun 28 2006;12(24):3933-5. [Medline].
Black RE, Slome S. Yersinia enterocolitica. Infect Dis Clin North Am. Sep 1988;2(3):625-41. [Medline].
Hervas JA, Alberti P, Bregante JI, et al. Chronic intussusception associated with Yersinia enterocolitica mesenteric adenitis. J Pediatr Surg. Dec 1992;27(12):1591-2. [Medline].
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Garcia-Corbeira P, Ramos JM, Aguado JM, Soriano F. Six cases in which mesenteric lymphadenitis due to non-typhi Salmonella caused an appendicitis-like syndrome. Clin Infect Dis. Jul 1995;21(1):231-2. [Medline].
Hayden CK Jr. Ultrasonography of the acute pediatric abdomen. Radiol Clin North Am. Jul 1996;34(4):791-806. [Medline].
American College of Radiology. ACR Appropriateness Criteria® right lower quadrant pain. National Guideline Clearinghouse. Available at http://www.guideline.gov/summary/summary.aspx?doc_id=8593&nbr=004780. Accessed May 26, 2009.
Simanovsky N, Hiller N. Importance of sonographic detection of enlarged abdominal lymph nodes in children. J Ultrasound Med. May 2007;26(5):581-4. [Medline].
Rao PM, Rhea JT, Novelline RA. CT diagnosis of mesenteric adenitis. Radiology. Jan 1997;202(1):145-9. [Medline]. [Full Text].
Wiersma F, Toorenvliet BR, Ruige M, Holscher HC. Increased echogenicity of renal cortex: a transient feature in acutely ill children. AJR Am J Roentgenol. Jan 2008;190(1):240-3. [Medline]. [Full Text].
Lee MW, Kim YJ, Jeon HJ, Park SW, Jung SI, Yi JG. Sonography of acute right lower quadrant pain: importance of increased intraabdominal fat echo. AJR Am J Roentgenol. Jan 2009;192(1):174-9. [Medline].
Simonovsky V. Ultrasound in the differential diagnosis of appendicitis. Clin Radiol. Nov 1995;50(11):768-73. [Medline].
Al-Kawas FH, Murgo A, Foshag L, Shiels W. Lymphadenopathy in celiac disease: not always a sign of lymphoma. Am J Gastroenterol. Mar 1988;83(3):301-3. [Medline].
Achong DM, Oates E, Harris B. Mesenteric lymphadenitis depicted by indium 111-labeled white blood cell imaging. J Pediatr Surg. Dec 1993;28(12):1550-2. [Medline].
Ikeda Y, Ikeda Y, Nakai T, Sano K, Ueda W, Aoki T, et al. A case of mesenteric lymphadenitis with long-acting symptom, showing marked response to corticosteroid. Nippon Shokakibyo Gakkai Zasshi. Sep 2007;104(9):1371-6. [Medline].
Further Reading
Related eMedicine topics
Mesenteric Lymphadenitis
Yersinia Enterocolitica
Yersinia Enterocolitica Infection
Campylobacter Infections
Keywords
mesenteric adenitis, mesenteric lymphadenitis, acute ileitis, appendicitis, lymphoma
