Septic arthritis and osteomyelitis

Case contributed by Dr Christopher Chen


Type 2 diabetic with erythema, swelling and pain in the left first metatarsophalangeal joint.

Patient Data

Age: 80
Gender: Male

Left foot


No cortical erosion or aggressive periosteal reaction. No subcutaneous gas. increased soft tissue swelling surrounding the first metatarsophalangeal joint. 

Tc-99m HDP bone scan

Nuclear medicine

On the dynamic flow images, there is hyperemia involving the medial aspect of the left foot from the distal phalange of the hallux to the mid foot. This persists on the blood pool images. Intense focal osteoblastic activity localized to the left first metatarsophalangeal joint, phalanges and metatarsal of the hallux. Less intense radiotracer accumulation in the left mid foot and medial left calf reflect hyperemia from increased tracer delivery to the left hallux.

These findings are consistent with septic arthritis of the left first metatarsal phalangeal joint and osteomyelitis of the 1st metatarsal and phalanges. 

The patient had a diabetic foot ulcer on the medial aspect of the first metatarsophalangeal joint that could be probed down to bone.

Wound swabs grew scanty growth of skin flora.

The patient recieved 6 weeks of IV tazocin. His CRP decreased from 120 to 64 and white cell count decreased from 12.4 x 109 to 8.5 x 109


Case Discussion

A radiograph often will not demonstrate any changes apart from soft tissue thickening in cases of osteomyelitis and septic arthritis. Changes may only be seen 10-14 days after onset in adults.

A bone scan is a very sensitive study for osteomyelitis. The typical appearance is increased activity in the same location on all 3 phases (dynamic flow, blood pool and delayed). Other differentials would include inflammatory arthopathies, acute fracture and osteitis deformans from Paget disease. Uptake on the bone may persist for many months to years even if the infection has been adequately treated. 

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