eMedicine Specialties > Radiology > Pediatrics
Mesenteric Adenitis
Updated: Aug 25, 2009
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
Radiography
Findings
Findings on supine and upright abdominal radiographs are often normal. Nonspecific findings include a regional ileus or evidence of bowel wall thickening in the right lower quadrant (see Image 2).
Supine abdominal radiograph shows a mild localized ileus and suggests nodular thickening of the terminal ileum.
Degree of Confidence
Plain radiographic findings can never indicate a specific diagnosis in mesenteric adenitis, but they can occasionally confirm an alternative diagnosis. Cross-sectional imaging may be indicated regardless of the plain radiographic findings.
Computed Tomography
Findings
Diagnostic features include enlarged mesenteric lymph nodes, with or without associated ileal or ileocecal wall thickening, in the setting of a normal appendix.4 Rao et al specified the criterion of 3 or more nodes with a short-axis diameter of at least 5 mm, clustered in the right lower quadrant (see Images 3-4).17 Lymph nodes are generally larger, more numerous, and more widely distributed in mesenteric adenitis than in appendicitis. Ileal thickening is diagnosed when the wall is thicker than 3 mm over at least 5 cm of the bowel despite bowel lumen opacification and distention (see Image 5).
Abdominal CT scan shows a cluster of enlarged nodes in the right lower quadrant.
Mesenteric thickening associated with right lower quadrant adenopathy.
A thickened ileum and cecum and a normal appendix are depicted adjacent to an enlarged lymph node in this patient with mesenteric adenitis and terminal ileocolitis.
Degree of Confidence
In the prospective study by Rao et al, none of the 18 patients with the aforementioned CT criteria had surgical or clinical evidence of appendicitis, whereas appendicitis was correctly diagnosed in 56.17 Further imaging is generally not indicated, although a definitive diagnosis might not be made in a case with equivocal findings until laparotomy performed for the evaluation of appendicitis reveals negative findings.
False Positives/Negatives
Nonopacified bowel may be mistaken for enlarged lymph nodes, especially in thin patients or small children. Bowel wall thickness is difficult to determine in this setting.
Ultrasonography
Typical sonographic appearance of a normal appendix.
Typical sonographic appearance of a lymph node.
Lymph node clustering in the right lower quadrant.
Distended appendix with an appendicolith in acute appendicitis.
Reactive lymph nodes in acute appendicitis.
Color sonogram demonstrates nodal hyperemia.
Spectral Doppler sonogram demonstrates nodal hyperemia.
Circumferential thickening of the ileal wall and associated nodal enlargement.
Findings
In patients with fever, abdominal tenderness, and a normal appendix, adenopathy that predominantly involves but is not limited to the right lower quadrant suggests the diagnosis (see Images 6-7). Usually, 5 or more nodes are present and are often clustered (see Image 8 ). Nodal tenderness in response to transducer pressure is typical. Nodes are more rounded and hypoechoic than normal. Abnormal nodes have a short-axis diameter of at least 5 mm, and the diameter can exceed 1 cm. The nodes are typically larger and more numerous with mesenteric adenitis than with appendicitis (see Images 9-10).16
The demonstration of hyperemia within the node and surrounding mesentery with Doppler imaging is variably reported (see Images 11-12). Other findings include intestinal hyperperistalsis, which is seldom observed in appendicitis; nodular or circumferential thickening of the bowel wall; mesenteric thickening; fluid-filled loops; cecal involvement; and free fluid (see Image 13).18 Occasionally, a fluid-filled appendix is seen, but the lumen is readily compressible.5
Increased echogenicity of intra-abdominal fat has been reported as a nonspecific marker for right lower quadrant inflammatory disease, seen in appendicitis, mesenteric adenitis, and other illnesses.19 Similarly, increased echogenicity of renal parenchyma has been noted in children with mesenteric adenitis, as well as appendicitis and other acute illness; it is a transient feature and does not necessarily indicate renal disease.18
Degree of Confidence
Although nodal size and number are generally greater in mesenteric adenitis than in appendicitis, overlap does occur. In Simonovsky's large series of 609 patients, 426 had appendicitis, and 81 had mesenteric adenitis.20 The inflamed appendix was missed in 2 of the latter cases. Puylaert stated that in adult patients with right lower quadrant pain in whom the sole findings are enlarged mesenteric lymph nodes, the risk of appendicitis is 64%.6 Therefore, the diagnosis of mesenteric adenitis is hazardous when the appendix is not visualized; correlative CT may be beneficial in this setting.
In mesenteric adenitis and lymphoma, the size, shape, distribution, and Doppler imaging characteristics of the lymph nodes overlap considerably, although the clinical context is useful in narrowing the differential diagnosis.21
False Positives/Negatives
Mesenteric lymph nodes that exceed the normal size threshold may be visualized in the absence of disease, although these are usually nontender.
Nuclear Imaging
Findings
Nuclear scintigraphy is seldom useful in this setting. A single case report describes abnormal white-cell localization in the nasopharynx, cervical lymph nodes, and right lower quadrant during imaging with indium-111–labeled white blood cells in a 4-year-old boy with fever, pharyngitis, and abdominal pain.22
Intervention
Mesenteric adenitis is usually a self-limited disease, and management is conservative. Radiologic intervention is generally not indicated. Rotavirus and other viral vectors are the presumed cause in most cases. Although cultures are seldom obtained, most cases resolve without antibiotic treatment. There is a single case report, in the Japanese literature, of a patient with mesenteric adenitis and persistent abdominal pain whose symptoms responded to treatment with systemic corticosteroids; this patient also had erythema nodosum, suggesting an autoimmune process.23
Medicolegal Pitfalls
- Medicolegal pitfalls are related to the possibility of misinterpreting the imaging findings in acute appendicitis as indicating mesenteric adenitis when reactive adenopathy is demonstrated but the appendix itself is not adequately seen. Fortunately, this is an uncommon scenario.
- Although a normal appendix may be visualized in only 20-50% of patients, an inflamed appendix is more readily apparent, especially in small children.
Special Concerns
- In the context of recent concerns about the radiation dose associated with pediatric CT, tailoring the examination protocol to the patient is prudent to minimize exposure during studies for benign and self-limited conditions such mesenteric adenitis.
- In this respect, sonography is favored as the initial diagnostic test.
Multimedia
Media file 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.
Media file 2: Supine abdominal radiograph shows a mild localized ileus and suggests nodular thickening of the terminal ileum.
Media file 3: Abdominal CT scan shows a cluster of enlarged nodes in the right lower quadrant.
Media file 4: Mesenteric thickening associated with right lower quadrant adenopathy.
Media file 5: A thickened ileum and cecum and a normal appendix are depicted adjacent to an enlarged lymph node in this patient with mesenteric adenitis and terminal ileocolitis.
Media file 6: Typical sonographic appearance of a normal appendix.
Media file 7: Typical sonographic appearance of a lymph node.
Media file 8: Lymph node clustering in the right lower quadrant.
Media file 9: Distended appendix with an appendicolith in acute appendicitis.
Media file 10: Reactive lymph nodes in acute appendicitis.
Media file 11: Color sonogram demonstrates nodal hyperemia.
Media file 12: Spectral Doppler sonogram demonstrates nodal hyperemia.
Media file 13: Circumferential thickening of the ileal wall and associated nodal enlargement.
References
Sung T, Callahan MJ, Taylor GA. Clinical and imaging mimickers of acute appendicitis in the pediatric population. AJR Am J Roentgenol. Jan 2006;186(1):67-74. [Medline]. [Full Text].
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].
Puylaert JB, van der Zant FM. Mesenteric lymphadenitis or appendicitis?. AJR Am J Roentgenol. Aug 1995;165(2):490. [Medline].
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].
Quillin SP, Siegel MJ. Appendicitis in children: color Doppler sonography. Radiology. Sep 1992;184(3):745-7. [Medline].
Blattner RJ. Acute mesenteric lymphadenitis. J Pediatr. Mar 1969;74(3):479-81. [Medline].
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].
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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].
Keywords
mesenteric adenitis, mesenteric lymphadenitis, acute ileitis, appendicitis, lymphoma
Contributor Information and Disclosures
Author
Brian Burke, MD, Assistant Professor, Department of Radiology, University of New York School of Medicine; Consulting Radiologist, Department of Radiology, North Shore University Hospital
Brian Burke, MD is a member of the following medical societies: American College of Radiology, American Institute of Ultrasound in Medicine, American Roentgen Ray Society, and Radiological Society of North America
Disclosure: Nothing to disclose.
Coauthor(s)
Micha Ziprkowski, MD, Associate Chief, Pediatric Radiology, Associate Professor of Clinical Radiology, Department of Radiology, North Shore University Hospital
Micha Ziprkowski, MD is a member of the following medical societies: American Academy of Pediatrics, American College of Radiology, American Institute of Ultrasound in Medicine, Association of University Radiologists, Radiological Society of North America, and Society for Pediatric Radiology
Disclosure: Nothing to disclose.
Medical Editor
Henrique M Lederman, MD, PhD, Consulting Staff, Department of Radiology, LeBonheur Children's Medical Center and St Jude Children's Research Hospital; Professor of Radiology and Pediatric Radiology, Chief, Division of Diagnostic Imaging in Pediatrics, Federal University of Sao Paulo, Brazil
Henrique M Lederman, MD, PhD is a member of the following medical societies: Society for Pediatric Radiology
Disclosure: Nothing to disclose.
Pharmacy Editor
Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.
Managing Editor
David A Stringer, BSc, MBBS, FRCR, FRCPC, Professor, National University of Singapore; Head, Diagnostic Imaging, KK Women's and Children's Hospital, Singapore
David A Stringer, BSc, MBBS, FRCR, FRCPC is a member of the following medical societies: British Columbia Medical Association, Canadian Association of Radiologists, European Society of Paediatric Radiology, Ontario Medical Association, Radiological Society of North America, Royal College of Physicians and Surgeons of Canada, Royal College of Radiologists, and Society for Pediatric Radiology
Disclosure: Sirius d'innovation None Board membership
CME Editor
Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.
Chief Editor
John Karani, MBBS, FRCR, Clinical Director of Radiology and Consultant Radiologist, Department of Radiology, King's College Hospital, London
John Karani, MBBS, FRCR is a member of the following medical societies: British Institute of Radiology, British Society of Interventional Radiology, Cardiovascular and Interventional Radiological Society of Europe, European Society of Gastrointestinal and Abdominal Radiology, European Society of Radiology, Radiological Society of North America, and Royal College of Radiologists
Disclosure: Nothing to disclose.