History Part 3: Competing diagnoses that can mimic Mesenteric Adenitis. Some patients may have signs or symptoms of infection elsewhere such as pharyngitis or lymphadenopathy. The tenderness to palpation may be less localized than in appendicitis. There is a paucity of data on the illness caused by other pathogens. Diarrhea has been reported in over one-third and fever in over a half of confirmed cases of mesenteric adenitis caused by Y. The pain may start in the upper abdomen or periumbilical region but will localize in the RLQ. The typical patient is an adolescent or young adult with the acute onset of RLQ pain often with mild diarrhea. However, cases have been reported due to Mycobacterium tuberculosis, Staphlococcus aureus, beta hemolytic Streptococcus, Parvovirus B19, HIV, and rarely, Cryptococcus. Primary mesenteric adenitis has various causes with a large number of cases due to Yersina enterocolitica or Yersina pseudotuberculosis. If the diagnosis remains uncertain, then laparoscopic appendectomy sometimes with mesenteric lymph node biopsy may be needed for confirmation. Therefore, imaging is required to make a diagnosis. A recent study in the pediatric population suggests that it is not clinically possibly to accurately distinguish between mesenteric adenitis and acute appendicitis. Primary mesenteric adenitis classically presents with fever, RLQ abdominal pain, and leukocytosis mimicking acute appendicitis. Diagnostic Confirmation: Are you sure your patient has Mesenteric Adenitis? In these cases, operative or non-operative biopsies may be needed to make a diagnosis. Older patients, patients with multiple comorbidities, patients with worrisome symptoms such as weight loss or patients with a subacute course may have diseases that mimic mesenteric adenitis such as malignancy, Crohn’s disease or ruptured cecal diverticulitis. Observation in the hospital may be prudent and close outpatient follow-up will detect most misdiagnoses in a timely manner. If these patients have an acute onset, are relatively young and lack worrisome symptoms such as weight loss, then a presumptive diagnosis of mesenteric adenitis may be reasonable. Secondary mesenteric adenitis is defined as lymphadenitis associated with an underlying inflammatory process such as Crohn’s disease, systemic lupus erythematosous, and diverticulitis. In the era of imaging, approximately 2-16% of patients presenting with symptoms of acute appendicitis are found to have mesenteric adenitis. Classically, most cases were diagnosed after surgery for suspected appendicitis. The average age of patients presenting with mesenteric adenitis is approximately 25 years with an age range of 5-44 years. Primary mesenteric adenitis is usually a self-limited disease, caused by both viruses and bacteria. Primary mesenteric adenitis is defined as three or more RLQ lymph nodes measuring 5mm or larger with or without mild terminal ileal wall thickening of <5mm. Mesenteric adenitis can be classified as primary or secondary. Mesenteric adenitis, also known as mesenteric lymphadenitis, is caused by inflamed mesenteric lymph nodes and is the second most common cause of acute RLQ abdominal pain. Right lower quadrant (RLQ) pain is a common initial presenting complaint with acute appendicitis as the most frequent cause. All in all, I interpret what you wrote to me as good news.Mesenteric Adenitis I.

Had he left out the word 'reactive' and simply said 'small submandibular lymph nodes.', the report would still be the same. So that radiologist is saying that you have scattered bilateral (meaning both sides of your body) and that they look reactive in nature (not malignant). On CT scans, we seldom get excited about lymph nodes less than 1 cm. After a while, we get a sense of which lymph nodes are worrisome and which are not. That said, radiologists as well as clinicians see lymph nodes day in and day out.

The truth is that the only way for one to really know if a lymph node is reactive (enlarging as it's fighting off an infection) or malignant is to biopsy the lymph node. A 'reactive' lymph node is one which is enlarged because it is trying to fight off an infection. Health care professionals, including myself, use the word 'reactive' frequently. 'Small reactive submandibular lymph nodes and normal sized lymph nodes in bilateral jugolodigastric nodal stations remain stable since the prior exam.' Answer The conclusion on the MRI of the radiologist was this: 'There are scattered bilateral submadibular lymph nodes which range in dimension from 5 to 12 mm in the long axis and remain unchanged relative to the previous MRI (3 months ago).'

Shotty retroperitoneal lymph nodes