The Clinical Value of Cranial CT Venography for Predicting Fusobacterium necrophorum as the Causative Agent in Children with Complicated Acute Mastoiditis.

BACKGROUND AND PURPOSE: Fusobacterium necrophorum ( F necrophorum ) is an anaerobic bacteria that causes invasive head and neck infections in children. Several studies have demonstrated an increasing prevalence of F necrophorum as the causative agent in acute mastoiditis in children, with associated high rates of intracranial complications such as epidural abscess and sinus venous thrombosis, to name a few. F necrophorum requires a treatment protocol that differs from the empiric treatment that is tailored to more common pathogens (eg, group A streptococci, Streptococcus pneumonia), and hence expediting the diagnosis is important. For evaluating complicated acute mastoiditis in children, cranial CT venography remains the imaging study of choice in most medical centers due to its availability in emergency situations. Based on our clinical experience, our hypothesis is that children with F necrophorum -associated complicated acute mastoiditis can be differentiated from those with other etiologies using CT venography.

MATERIALS AND METHODS: CT venography studies of 76 children hospitalized and treated for complicated acute mastoiditis were retrospectively reviewed. Retrieved imaging data included intracranial complications (epidural abscess, sinus venous thrombosis), cranial bone-related complications, and extracranial complications (subperiosteal abscess, temporomandibular joint abscess, and soft-tissue inflammation). The cohort was divided into children with F necrophorum -related disease (study group) and those with non- F necrophorum -related disease (control group).

RESULTS: Thirty-seven children (49%) comprised the study group, and 39 children in whom the causative agents were other bacteria comprised the control group. There were significantly higher rates of complications in the study group: sinus venous thrombosis ( P < .001), perisigmoid epidural abscess ( P  = .036), and extramastoid osteomyelitis ( P  < .001). Thrombosis in venous sites beyond the sigmoid sinus and jugular foramen (a pattern consistent with an otogenic variant of Lemierre syndrome) and emphysematous osteomyelitis were found only among children in the F necrophorum -related study group (32% and 22% accordingly).

CONCLUSIONS: In children with complicated acute mastoiditis, CT venography findings of emphysematous osteomyelitis and/or thrombosis in venous sites beyond the sigmoid sinus and jugular foramen (a pattern consistent with the otogenic variant of Lemierre syndrome) should lead the radiologist to suggest F necrophorum -related mastoiditis.