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Diabetic foot infection with suspected osteomyelitis — MSRA MCQ

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HardAnkle and FootDiabetic foot infection with suspected osteomyelitisMSRA

A 59-year-old man with type 2 diabetes, peripheral sensory neuropathy and CKD G3b attends general practice with a plantar ulcer beneath the right first metatarsal head. It has been present for 5 weeks despite offloading footwear. Over the last 2 days, he has developed increasing surrounding erythema and malodorous discharge. He is afebrile and feels well. Examination shows a 1.8 cm ulcer with purulent discharge and a depth of 9 mm; bone is contacted with a sterile probe. Pedal pulses are palpable and capillary refill is normal. CRP is 7 mg/L and white cell count is normal. A same-day foot radiograph shows no bony destruction or gas. What is the most appropriate management today?

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Correct answer: A — Refer immediately to acute services and inform the multidisciplinary foot care service; obtain an appropriate deep tissue or bone sample before, or as close as possible to, starting antibiotics

This is a limb-threatening diabetic foot problem because there is clinical concern about a deep soft-tissue or bone infection: the ulcer is deep, purulent and probe-to-bone is positive. Immediate referral to acute services is therefore required, with notification of the multidisciplinary foot care service. Antibiotics should be started as soon as possible, but microbiological sampling should be obtained before, or as close as possible to, treatment. A deep tissue or bone sample from the base of a debrided wound is preferred; a superficial swab is not the recommended specimen. Normal CRP, white cell count and plain radiography do not exclude diabetic foot osteomyelitis. MRI is appropriate if osteomyelitis remains unconfirmed after initial radiography, but arranging this as an outpatient investigation would inappropriately delay escalation where deep infection is suspected. Referral within 1 working day is appropriate for other active diabetic foot problems, but not for suspected deep infection. Vascular assessment is important where ischaemia is suspected, but this patient has palpable pulses and normal capillary refill; it must not distract from the immediate infection pathway.

Reference: NICE NG19: Diabetic foot problems: prevention and management — Recommendations (2015; antimicrobial prescribing recommendations updated 2019) — https://www.nice.org.uk/guidance/ng19/chapter/Recommendations NICE NG19: Diabetic foot problems: prevention and management — Diabetic foot infection investigation and treatment (2015; antimicrobial prescribing recommendations updated 2019) — https://www.nice.org.uk/guidance/ng19/chapter/Recommendations NICE NG19: Diabetic foot problems: prevention and management — Osteomyelitis investigation (2015; antimicrobial prescribing recommendations updated 2019) — https://www.nice.org.uk/guidance/ng19/chapter/Recommendations