Background: Systemic infections due to F. necrophorum (anaerobic gram-negative bacillus), arising from the oropharynx, are referred to as Lemierre's syndrome, postanginal sepsis or necrobacillosis, but they can all be included under the term of “invasive F. Necrophorum disease” (IFND)1. Although it has been well documented for over a century, invasive Fusobacterium infection is rare (“forgotten”), but can result in significant morbidity and mortality 2,3.
Case report: A previously healthy 39 year old female presented to the emergency department, with a 3 day history of sore throat, diarrhoea, vomiting, rigors and headache. The patient required aggressive fluid resuscitation, broad-spectrum antibiotics, and vasopressor support for refractory hypotension secondary to sepsis. An initial bedside ultrasound of the abdomen identified a gallbladder collection as a possible source of sepsis, and a percutaneous cholecystostomy was performed. Subsequently CT thorax, abdomen and pelvis revealed consolidation in the posterior lung base, multiple splenic abscesses, free fluid within the abdomen and a thick-walled gallbladder. Whilst the underlying infection source remained unclear, the patient responded well to therapy but continued to complain of left-sided neck tenderness. Blood cultures returned positive for Fusobacterium Necrophorum. Antibiotic therapy was reviewed accordingly. Investigations undertaken to rule out left internal jugular thrombophlebitis/ vein thrombosis (as a source of septic emboli within the spleen) were negative. 
Discussion: Data supports a rising incidence of IFND thought to be due to restricted use of antibiotics for sore throat in the community 3. A high index of clinical suspicion should be kept for this “re-emerging” anaerobic gram-negative bacterium in the setting of postanginal septicaemia and metastatic infection.
References: 
1. Brazier JS. Anaerobe 2006;12:165-172
2. Hagelskjaer L et al. Eur. J. Clin. Microbiol. Infect. Dis. 1998;17:561-565. 
3. Riordan T. Clinical Microbiology Reviews 2007;20:622-659
Learning points: Although uncommon, Fusobacterium Necrophorum invasive disease may result in significant morbidity and mortality. Evidence of metastatic infection should prompt imaging of the internal jugular vein to rule out thrombophlebitis or thrombosis. Management includes antibiotics, with consideration of anticoagulants (confirmed thrombosis) and drainage of collections of pus (such as empyema or abscess).

A case of invasive Fusobacterium necrophorum infection: the &#8220;forgotten&#8221; disease

A case of invasive Fusobacterium necrophorum infection: the “forgotten” disease