Necrobacillosis.

Necrobacillosis is a severe septicaemic illness caused by the gram negative anaerobe, Fusobacterium necrophorum, that typically occurs in previously healthy young adults following a mild sore throat. Radiological changes in the chest are prominent and include rapidly developing empyema, pneumonic consolidation, cavitation and pneumatocele formation. Metastatic abscesses in other sites are also seen. The clinical setting and time course are in marked contrast to the presentation of most anaerobic pleuro-pulmonary infections. Two cases are described, in one of which the outcome was fatal. Both displayed marked chest disease as an early manifestation of their illness. As the condition is relatively uncommon, radiological diagnosis demands a high index of suspicion in order to facilitate early treatment.