A case of emphysematous osteomyelitis of the midfoot: imaging findings and review of the literature

Abstract

Emphysematous osteomyelitis is a rare but potentially fatal condition that must be considered whenever intraosseous gas is identified on imaging. The organisms implicated in most cases of emphysematous osteomyelitis are anaerobes or members of the Enterobacteriaceae family. Significant comorbidities, such as malignancy and diabetes mellitus, frequently predispose to this condition, and high mortality rates have been reported. The radiologist must be aware of the implications of identifying intraosseous gas in order to facilitate early diagnosis and expedite management. We report a unique case of a 58-year-old male with diabetes mellitus who presented with emphysematous osteomyelitis of the midfoot and necrotising fasciitis of the ipsilateral distal lower limb. Specimen cultures in this case revealed a pure growth of Group G Streptococcus.

Figure 1

Right foot radiographs reveal extensive soft tissue gas in the dorsum of the foot ((a), short arrow) and anterior to the distal tibia ((a), long arrow). Anteroposterior view demonstrates discrete radiolucencies in the metatarsals remnants ((b), arrow) and midtarsal bones. Previous transmetatarsal amputation is noted.

Figure 2

Computed tomography demonstrates gas within the midtarsal bones (long arrow, (a) and (b)) and head of talus and gas in the soft tissues surrounding the midfoot (short arrow, (a) and (b)).

Figure 3

Computed tomography demonstrates soft tissue abscess formations anterior to the distal tibia with fluid (short arrow) and air-fluid levels (long arrow). Gas locules in the midfoot bones and extensive subcutaneous gas involving predominantly the dorsum of the foot (dashed arrow) and anterior aspect of the ankle are evident.