Commentary

A diabetic foot infection progresses to amputation


 

The story

KL was a 56-year-old man with multiple comorbidities, including obesity, coronary artery disease, hypertension, insulin-dependent diabetes, chronic kidney disease, and dyslipidemia. He presented to Hospital A with fever and chills, along with an open wound on the bottom of his left foot. Laboratory studies revealed a WBC 14,000 cells/mL and a serum creatinine of 3.1 mg/dL. KL was admitted by Dr. Hospitalist for cellulitis and an infected diabetic foot ulcer.

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Diabetic foot infections are associated with substantial morbidity and mortality.

KL was started on intravenous vancomycin and piperacillin/tazobactam and blood cultures were drawn. A bone scan was negative for osteomyelitis. Blood cultures did not grow any bacteria, but a wound culture from his foot ulcer grew Klebsiella. Dr. Hospitalist consulted inpatient podiatry for wound debridement, but KL apparently refused in favor of being seen by his own podiatrist as an outpatient. By hospital day 2, KL was afebrile, eating well, and he was discharged on oral ciprofloxacin later that same day.

Two days after discharge, KL followed up with his primary care physician (PCP). KL was again febrile and his foot ulcer looked worse. The PCP recommended hospitalization with intravenous antibiotics, but KL was reluctant to return to the hospital. The PCP arranged for midline placement and KL was referred to a local wound clinic for intravenous vancomycin to begin the next day. KL remained on the oral ciprofloxacin.

Over the next 3 days, KL received daily intravenous vancomycin at the wound clinic. However, the foot ulcer continued to drain purulent material with associated cellulitis and advancing erythema across the forefoot. The wound nurse contacted the PCP who had sent KL to the emergency department of Hospital B. Laboratory studies revealed a WBC 18,300 cells/mL and a serum creatinine of 2.2 mg/dL. KL was informed that he needed wound debridement and was offered the same podiatrist that he refused at Hospital A. Once again, KL deferred in favor of his own podiatrist who apparently was on vacation. Blood and wound cultures were obtained and KL received a dose of intravenous amoxicillin/sulbactam in the ED, but because of his refusal to receive wound debridement and care at Hospital A or B, he was sent home that same afternoon.

KL left Hospital B and drove 2 hours to the ED of Hospital C. He was immediately admitted and intravenous vancomycin and piperacillin/tazobactam were begun. Plain films of the foot were consistent with osteomyelitis. An MRI of the foot demonstrated cellulitis, myositis, and a forefoot abscess. Within 24 hours of admission, KL developed chest pain and was subsequently ruled-in for a non–ST-elevation MI. KL ended up getting a left heart catheterization, and this delayed surgical debridement of his infected foot. Ultimately, KL did have debridement of his foot, but the infection had an advanced to the point that a below-the-knee amputation was required. Surgical pathology cultures were positive for methicillin-resistant Staphylococcus aureus (MRSA).

Complaint

KL was now facing life without his left leg, and he was angry and felt that the medical system had let him down. A complaint was quickly filed and alleged multiple breaches in the standard of care against multiple providers. The complaint included Dr. Hospitalist and asserted that he failed to obtain an MRI of the left foot from the very start, stopped intravenous vancomycin inappropriately, and failed to obtain infectious disease and orthopedic surgery consults.

The complaint further asserted that the PCP and the ED providers at Hospital B were negligent for not readmitting KL and obtaining infectious disease and orthopedic surgery consults. If the providers in this case had continued intravenous vancomycin throughout his case and otherwise obtained appropriate specialty care, KL’s leg would have been saved.

Scientific principles

Diabetic foot infections are associated with substantial morbidity and mortality. Important risk factors for development of diabetic foot infections include neuropathy, peripheral vascular disease, and poor glycemic control. Most diabetic foot infections are polymicrobial, but MRSA is a common pathogen. Although severe diabetic foot infections warrant hospitalization for urgent surgical consultation, antimicrobial administration, and medical stabilization, most mild infections and many moderate infections can be managed in the outpatient setting with close follow-up.

The possibility of osteomyelitis should be considered in diabetic patients with foot wounds associated with signs of infection in the deeper soft tissues and in patients with chronic ulcers. Many patients with confirmed osteomyelitis of the foot benefit from surgical resection.

Complaint rebuttal and discussion

Although Dr. Hospitalist had a negative bone scan result, he should have considered MRSA as a pathogen for KL despite a wound culture growing Klebsiella only. Most experts agreed, however, that it would be pure speculation as to what an MRI would have shown so early in KL’s course and ultimately, Dr. Hospitalist was defensible because KL did have appropriate follow-up just 48 hours after discharge. In fact, more than 21 days from original presentation to his amputation, KL only had 3 days off of intravenous vancomycin.

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