Mesenteric adenitis

Question 1

Define mesenteric adenitis.

Answer 1

Mesenteric lymph node inflammation associated with systemic illness and abdominal symptoms.

Question 2

Explain the aetiology of mesenteric adenitis.

Answer 2

Most common differential diagnosis for acute appendicitis, URTI’s and tonsillitis. Acute or chronic problem that causes inflammation and enlargement of mesenteric lymph nodes. Intra-abdominal or retroperitoneal lymph nodes most commonly involved.

Macroscopic: LNs are enlarged and often soft. Oedema of the adjacent mesentery.

Microscopic: Non-specific hyperplasia, necrotic changes may be present with suppurative mesenteric adenitis.

Question 3

What are causative agents of mesenteric adenitis?

Answer 3

Viruses (upper respiratory tract viruses most common cause)

Bacterial URTI/gastrointestinal:

• Group A beta-haemolytic streptococcus
• Yersinia enterocolitica
• Helicobacter jejuni
• Campylobacter jejuni
• Salmonella or Shigella species

Question 4

Summarise the epidemiology of mesenteric adenitis.

Answer 4

Children of all ages affected.

Question 5

What are the signs and symptoms of mesenteric adenitis?

Answer 5

Often diagnosis of exclusion. Most common finding a ta negative appendicectomy. URTI or gastrointestinal infection; symptoms of coryza, pharyngitis or gastroenteritis may still be present (mainly diarrhoea). Gastrointestinal; vague abdominal pain may vary intermittently.

General: May be identical to acute appendicitis. Cervical lymphadenopathy. Signs of URTI/tonsillitis or high pyrexia (>38.5) with vague abdominal signs.

Specific: Peritoneal irritation may be present (guarding and percussion tenderness).

Question 6

What are appropriate investigations for mesenteric adenitis?

Answer 6

Bloods: High WCC, U&Es (may be dehydrated), high CRP. May not aid the differentiation between appendicitis.

USS of RIF: May confirm the diagnosis with the visualisation of an inflamed appendix (non-compressible tubular structure in the RIF)/presence of free intraperitoneal pus/ enlarged lymph nodes. With mesenteric adenitis the nodes are in clusters of >5 and >1 cm in diameter. Operator dependent.

CT scan: Rarely performed in UK (radiation dose high) but has excellent positive predictor value for mesenteric adenitis and high negative predictive value for appendicitis.

Question 7

What is the management for mesenteric adenitis?

Answer 7

Continued observation and re-examination.

Have to differentiate to acute appendicitis, which requires surgery, while mesenteric adenitis is a self-limiting condition.

Question 8

What are complications associated with mesenteric adenitis?

Answer 8

None

Question 9

What is the prognosis of mesenteric adenitis?

Answer 9

Benign, self-limiting disease