An unusual cause of an 'acute abdomen'

Human infection with Fusobacterium necrophorum (Necrobacillosis), with a focus on Lemierre's syndrome

Human infection with Fusobacterium necrophorum usually involves F. necrophorum subsp. funduliforme rather than F. necrophorum subsp. necrophorum, which is a common pathogen in animals. Lemierre's syndrome, or postanginal sepsis, is the most common life-threatening manifestation. Tonsillitis is followed by septic thrombophlebitis of the internal jugular vein and then a septicemia with septic emboli in lungs and other sites. Recent evidence suggests that F. necrophorum can be limited to the throat and cause persistent or recurrent tonsillitis. F. necrophorum is unique among non-spore-forming anaerobes, first for its virulence and association with Lemierre's syndrome as a monomicrobial infection and second because it seems probable that it is an exogenously acquired infection. The source of infection is unclear; suggestions include acquisition from animals or human-to-human transmission. Approximately 10% of published cases are associated with infectious mononucleosis, which may facilitate invasion. Recent work suggests that underlying thrombophilia may predispose to internal jugular vein thrombophlebitis. Lemierre's syndrome was relatively common in the preantibiotic era but seemed to virtually disappear with widespread use of antibiotics for upper respiratory tract infection. In the last 15 years there has been a rise in incidence, possibly related to restriction in antibiotic use for sore throat.

Lemierre's Syndrome

Lemierre's syndrome is characterized by an oropharyngeal infection followed by internal jugular vein septic thrombophlebitis and metastatic emboli, most often to the lungs and joints. The syndrome is most commonly associated with the anaerobic gram-negative rod Fusobacterium necrophorum. Diagnosis is established with evidence of metastatic infection and internal jugular vein thrombophlebitis. CT is considered the diagnostic procedure of choice. Treatment should include an extended course of a beta-lactamase-resistant antibiotic and surgical drainage of any purulent fluid collection. Anticoagulation remains controversial, and ligation of the internal jugular vein is reserved for patients with persistent sepsis and recurrent emboli. With appropriate therapy, mortality is 4% to 12%; but mortality is increased when therapy is delayed.