Mesenteric adenitis

Definition
- nonspecific self-limiting inflammation of the mesenteric lymph nodes
- cluster of >3 lymph nodes, each measuring 5 mm or greater
- in the right lower quadrant mesentery.
This process may be acute or chronic, depending on the causative agent
clinical presentation that is often difficult to differentiate from acute appendicitis, particularly in children.

Pathophysiology

Microbial agents are thought to gain access to the lymph nodes via the intestinal lymphatics.
Organisms subsequently multiply and, depending on the virulence of the invading pathogen, elicit varying degrees of inflammation and, occasionally, suppuration.
Grossly, the lymph nodes are enlarged and often soft.
The adjourning mesentery may be edematous, with or without exudates. If a contiguous primary source of infection (eg, the appendix) is present, evidence of inflammation is often apparent.

Etiology

Primary etiology occurs when the lymphadenopathy is the result of an unidentifiable inflammatory process.
Secondary mesenteric adenitis occurs secondary to an intra-abdominal inflammatory process with a known source or etiology
beta-hemolytic streptococcus
Numerous organisms have been cultured from mesenteric lymph nodes and blood, such as
- Yersinia pseudotuberculosis
- Yersinia enterocolitica.
- Staphylococcus species
- Escherichia coli
- Streptococcus viridans
- Yersinia species (responsible for most cases currently)
- Mycobacterium tuberculosis
- Giardia lamblia
- non–Salmonella typhoid
- Viruses, such as coxsackieviruses (A and B), rubeola virus, and adenovirus, Epstein-Barr virus (EBV), acute human immunodeficiency virus (HIV) infection, and catscratch disease (CSD)

Epidemiology

The true incidence of this disease is not known, because it can be easily missed or mistaken for other diagnoses.
The condition is generally thought to be common.
Up to 20% of patients undergoing appendectomy have been found to have nonspecific mesenteric adenitis.
Mesenteric lymphadenitis can occur in adults but is more common in children and adolescents younger than 15 years, and this condition during childhood or adolescence is linked to a significantly reduced risk of ulcerative colitis in adulthood.

Prognosis

The prognosis is good. Typically, complete recovery can be expected without specific treatment. Death is rare

Morbidity/mortality

Mesenteric lymphadenitis generally is a benign disease, but patients with sepsis may have a fatal outcome

Complications

Volume depletion and electrolyte imbalance in patients with severe diarrhea, nausea, and vomiting
Abscess formation
Peritonitis (rare)
Sepsis

Clinical features

Mesenteric adenitis commonly follows recent gastroenteritis or upper respiratory infection. /
Abdominal pain – Often right lower quadrant (RLQ) but may be more diffuse
Fever
Diarrhea
Malaise
Anorexia
Concomitant or antecedent upper respiratory tract infection
Nausea and vomiting (which generally precedes abdominal pain, as compared to the sequence in appendicitis)
History of ingestion of raw pork may be obtained in areas with endemic Yersinia (eg, Belgium).

Physical Examination