Mesenteric adenitis
From Medical-Wiki
Mesenteric adenitis (MA) is an entity best known as an excuse for the removal of normal appendixes. However, it is a real entity, demonstrable through biopsy as well as histology. It is a process that involves lymph nodes, often in the right lower quadrant—thus its confusion with appendicitis.
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Etiology
Most frequently, MA is associated with viral pathogens. However, Yersinia enterocolitica, Helicobacter jejuni, Campylobacter jejuni, and Shigella species have also been implicated. In children, there is an association with upper respiratory tract streptococcal infections.
A series of studies from 2000 to 2007 revealed that MA was the most frequent diagnosis made as an alternative to appendicitis (8% to 12%). A European study found that 3% to 9% of patients who underwent appendectomy were infected with Yersinia enterocolitica. [1]
The role of Yersinia enterocolitica in MA has been demonstrated in a number of studies. While it certainly does not account for all cases, its significance must be paramount in evaluations of abdominal pain, particularly that located in the RLQ. [2]
Clinical presentation
Patients with MA present with a wide spectrum of clinical courses—sometimes precipitous, sometimes insidious. Abdominal pain may be diffuse or located exclusively in the RLQ. Patients may also have fever, diarrhea, malaise, anorexia, nausea and vomiting, and possibly symptoms of an upper respiratory tract infection. [3]
Diagnosis
Physical findings
Physical findings vary considerably and include fever (38-38.5°C), flushed appearance, RLQ tenderness, voluntary guarding rather than abdominal rigidity, rectal tenderness, rhinorrhea, hyperemic pharynx, toxic appearance, and associated peripheral lymphadenopathy (usually cervical) in 20% of cases.
Laboratory findings
Lab studies should include a CBC count (leucocytosis with WBCs exceeding 10,000/L occurs in at least 50% of cases), electrolytes (normal unless there is dehydration), serology (positive in cases like Y enterocolitica), urinalysis, stool cultures (when diarrhea is present), and blood cultures, when appropriate. [4]
Radiological findings
At one time, it was felt that that helical CT scans would make the diagnosis of MA a relatively easy proposition—particularly in children where there is often a paucity of intra-abdominal fat. That has not proven to be the case. [5]
While ultrasound and CT scans are just tools and not gold standards for assessing RLQ pain, they may still elucidate a variety of abdominal pathology. [6]
Treatment
Treatment of MA should be conservative unless abdominal complaints make it apparent that whatever the cause, a patient is demonstrating clinical signs of a “surgical abdomen,” i.e. signs of peritonitis, toxicity, migration of pain, or sudden deterioration. While no one technical tool has become a magic bullet, laparoscopic surgery has greatly reduced the potential morbidity of surgical intervention.
