Mesenteric Adenitis

Introduction 

Mesenteric adenitis, also known as mesenteric lymphadenitis, is inflammation of lymph nodes found in the mesentery. Typically, this condition presents in children or young adults (1).

Mesenteric adenitis can be primary or secondary in nature. Primary is thought to be lymphadenopathy without an obvious underlying inflammatory cause found. Secondary mesenteric adenitis is due to other underlying inflammatory conditions. This can be subdivided into acute or chronic (2): 

Acute: 

• Appendicitis 
• Other infections – yersiniosis, EBV

Chronic: 

• Inflammatory bowel disease
• Systemic lupus erythematosus
• Sarcoidosis 
• Malignancy 
• HIV infection
• Tuberculosis 

This article is going to focus on primary mesenteric adenitis.

By TeachMeSeries Ltd (2024)

Mesenteric adenitis can present similarly to many other abdominal pathologies including appendicitis and intussusception

Epidemiology

Due to the self-resolving nature of the condition, epidemiology of mesenteric adenitis is unknown. 

Pathophysiology

Mesenteric adenitis is lymphadenopathy found usually around the terminal ileum. The cause for this lymphadenopathy is usually not found in primary mesenteric adenitis (1) but it is thought to occur after a recent viral or bacterial infection. Some of the organisms implicated in causing mesenteric adenitis are as follows (3): 

• Coxsackieviruses 
• Adenovirus
• Rubeola virus 
• Yersenia species – Yersinia pseudotuberculosis and Yersinia enterocolitica (1)
• Streptococcus 
• Staphylococcus 
• E. coli 

These organisms are thought to be ingested orally, cause gastroenteritis, and travel into the mesenteric lymph nodes, which results in localised inflammatory changes (1,3)

Clinical features

The clinical presentation of mesenteric adenitis is very similar to other conditions, such as appendicitis. The severity of features can vary, which means that there may be several less severe cases that may not present to healthcare. 

Some of the symptoms can be as follows (1)

• Abdominal pain – commonly right iliac fossa and/or periumbilical pain
• Fever 
• Vomiting 
• Change in bowel habits

On examination, the patient will appear to be in severe pain but may present colic-like. The pain may follow a similar distribution to appendicitis (2). 

Differential diagnosis (1,2):

• Acute appendicitis – ultrasound abdomen helps confirm diagnosis, but if it was unable to visualise the appendix, then exploratory laparoscopy may be considered (4).
• Intussusception – typically a sausage shaped mass may be felt on palpation. The abdominal pain tends to come in episodes, can be associated with vomiting, and sometimes presents as obstruction. Examination is best done on a settled child, the mass can be identified on ultrasound abdomen (5). 
• Meckel’s diverticulum – this is similar to appendicitis therefore could be excluded with ultrasound abdomen. However, if the ultrasound is inconclusive, then exploratory laparoscopy may be considered. 
• Ovarian pathology – with the aid of ultrasound, pelvic pathology could be identified such as ovarian torsion, ectopic pregnancy, ovarian cysts, abscess. Sometimes this will be identified in exploratory laparoscopy. 
• Basal pneumonia – this could be identified on chest x-ray which may be considered as an additional investigation if abdominal cause for pain is thought to be unlikely. 
• Urinary tract infection (UTI) – urine can be dipped and sent for microscopy, along with culture if high suspicion of UTI. The patient may also complain of lower urinary tract symptoms such as burning sensation on passing urine, along with the history of abdominal pain. 
• Inflammatory bowel disease (IBD) – including Crohn’s and Ulcerative Colitis. The history with IBD will tend to be more long standing with other associated concerns such as weight loss, rectal bleeding, anaemia.
• Constipation – largely could be differentiated with thorough history however, if still ongoing worries, constipation will be identified on ultrasound abdomen or abdominal x-ray. 

Investigations (1,2)

Laboratory tests: 

• FBC, CRP – may be mildly raised, but can be normal as well
• Urinalysis – to rule out urine infection 

Imaging or invasive tests: 

• Ultrasound abdomen – gold standard as it can help differentiate between mesenteric adenitis and other differentials such as appendicitis or intussusception. 

Management 

Mesenteric adenitis is a self-limiting condition therefore treatment is supportive in nature. Patients are generally advised to be kept hydrated and use appropriate analgesia for abdominal pain – paracetamol, NSAIDs. (2)

Complications and prognosis 

There are no complications associated with mesenteric adenitis and generally the abdominal pain resolves within four weeks (1,3).

References

1. Otto M, Nagalli S. Mesenteric Adenitis. StatPearls [Internet]. 2022 [cited 2023 Mar 2]; Available from: http://www.ncbi.nlm.nih.gov/books/NBK560822/
2. Helbling R, Conficconi E, Wyttenbach M, Benetti C, Simonetti GD, Bianchetti MG, et al. Acute Nonspecific Mesenteric Lymphadenitis: More Than “No Need for Surgery”. BioMed Res Int. 2017;2017:9784565.
3. Team TP. Mesenteric adenitis – PulseNotes [Internet]. 2022. Available from: https://app.pulsenotes.com/specialities/paediatrics/notes/mesenteric-adenitis
4. Appendicitis NICE CKS Guidelines [Internet]. Available from: https://cks.nice.org.uk/topics/appendicitis/management/managing-suspected-appendicitis/ 
5. Intussusception RCH Clinical Guidelines [Internet]. 2019. Available from: https://www.rch.org.au/clinicalguide/guideline_index/Intussusception/