Mesenteric lymphadenitis refers to inflammation of the mesenteric lymph nodes. This process may be acute or chronic, depending on the causative agent. It causes a clinical presentation that is often difficult to differentiate from acute appendicitis.
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.
Microscopically, the lymph nodes show nonspecific hyperplasia and, in suppurative infection, necrosis with numerous pus cells.
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.
Frequency is similar to that of the United States. Yersinia enterocolitica infection has a geographic variation. This infection is most common in the temperate countries of Europe, North America, and Australia; it has been particularly noted in Eastern Europe.
Mesenteric lymphadenitis generally is a benign disease, but patients with sepsis may have a fatal outcome.
The condition affects males and females equally. Yersinia infection is more common in boys than in girls.
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.
Frisch et al reviewed Swedish and Danish cohort studies involving 709,353 patients who had undergone appendicectomy and were followed up for subsequent ulcerative colitis to determine the role of appendicitis and mesenteric lymphadenitis in the risk of ulcerative colitis following appendicectomy. The investigators also studied the impact of appendicectomy in 224,483 patients with a family history (parents or siblings) of inflammatory bowel disease and found that regardless of familial predisposition to inflammatory bowel disease, appendicitis and mesenteric lymphadenitis during childhood or adolescence is linked to a significantly reduced risk of ulcerative colitis in adulthood.
Onset and progression may be insidious or sometimes dramatic. Clinical features of associated organ involvement, such as enterocolitis or ileitis in Yersinia infection, may be present. Clinical presentations include the following:
No set of physical findings is pathognomonic of mesenteric lymphadenitis.
Contrast computed tomography (CT) demonstrates enlarged mesenteric lymph nodes, with or without associated ileal or ileocecal wall thickening, and a normal appearing appendix. In mesenteric adenitis, lymph nodes tend to be larger, greater in number, and more widely distributed than in appendicitis. Rao et al specified the criterion of 3 or more nodes with a short-axis diameter of at least 5 clustered in the right lower quadrant. CT scanning is also important to exclude other differential diagnoses, especially acute appendicitis.
Abdominal ultrasonographic scanning with Doppler scanning is a useful adjunct for excluding other differential diagnoses.[1, 3] For instance, ultrasonographic demonstration of mural thickening of the terminal ileum plus mesenteric thickening is indicative of regional enteritis. Focal abdominal tenderness in response to transducer pressure is common. Ultrasonography is often the preferred initial diagnostic procedure, especially in children with uncomplicated abdominal pain.
A study by Ja Lim et al supported the use of ultrasonography in the diagnosis of mesenteric lymphadenitis. The retrospective study involved 100 children with clinically suspected intussusception, with abdominal ultrasonography instead demonstrating the presence of mesenteric lymphadenitis in 13 of these patients. Other conditions identified in the study included ileocolitis, terminal ileitis, choledochal cyst, accessory spleen torsion, small bowel ileus, midgut volvulus with bowel ischemia, and hydronephrosis, as well as intussusception (in 37 patients).
The objective of medical management is to quickly identify patients who require surgical intervention (ie, for appendicitis) and to refer appropriately. Empiric, broad-spectrum antibiotics may be used in moderately to severely ill patients and should cover Yersinia strains, commonly causative in mesenteric adenitis. General supportive care includes hydration and pain medication after excluding acute surgical abdomen. Patients with mild, uncomplicated presentations do not require antibiotics, and supportive care generally suffices.
Make early contact with a general surgeon while evaluating the patient to exclude etiologies that require urgent surgery.
No particular diet is recommended. Temporary withholding of oral intake may be necessary while nausea and vomiting resolve and initially until a definitive diagnosis is confirmed.
No restriction of activity is required.
Antibiotics are often started empirically in moderately to severely ill patients, using broad-spectrum antibiotics intended to cover the commonly associated pathogens. Antibiotic treatment should then be adjusted based on the sensitivity of the isolated pathogen. Treatment duration is variable based on the cause and severity of illness. For uncomplicated cases, antibiotic treatment is not necessary.
Clinical Context: Imidazole ring-based antibiotic active against various anaerobic bacteria and protozoa. Exerts a bactericidal effect by inhibiting protein synthesis. Used in combination with other antimicrobial agents (except for Clostridium difficile enterocolitis).
Clinical Context: Lincosamide used for treatment of serious skin and soft tissue staphylococcal infections. Also effective against aerobic and anaerobic streptococci (except enterococci). Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, thus causing cessation of RNA-dependent protein synthesis.
Clinical Context: Bactericidal activity against susceptible organisms. Alternative to amoxicillin when unable to take medication orally.
Clinical Context: Interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria.
Clinical Context: Fluoroquinolone with activity against pseudomonads, streptococci, MRSA, Staphylococcus epidermidis, and most gram-negative organisms but no activity against anaerobes. Inhibits bacterial DNA synthesis and, consequently, growth. Trovafloxacin (Trovan) overcomes many of these limitations. Continue treatment for at least 2 d (7-14 d typical) after signs and symptoms have disappeared.
Clinical Context: For treatment of multiple organism infections in which other agents do not have wide-spectrum coverage or are contraindicated because of potential for toxicity.
Clinical Context: Second-generation cephalosporin indicated for gram-positive cocci and gram-negative rod infections. Infections caused by cephalosporin- or penicillin-resistant gram-negative bacteria may respond to cefoxitin.
Clinical Context: Inhibits biosynthesis of cell wall mucopeptide and is effective during stage of active growth. Antipseudomonal penicillin plus beta-lactamase inhibitor that provides coverage against most gram-positive bacteria, most gram-negative bacteria, and most anaerobes.
Clinical Context: Drug combination of beta-lactamase inhibitor with ampicillin. Covers skin, enteric flora, and anaerobes. Not ideal for nosocomial pathogens.
When indicated, empiric antimicrobial therapy must be comprehensive and should cover the likely pathogens in the context of the clinical setting. Given the predominance of Y enterocolitica, initial antibiotic selection from trimethoprim-sulfamethoxazole (TMP-SMX), third-generation cephalosporins, fluoroquinolones, aminoglycosides, and doxycycline should be considered. These agents provide broad coverage for enteric pathogens.