Inpatient Management of Diabetic Foot Disorders
Inpatient Management of Diabetic Foot Disorders
More than half of DFUs are clinically infected at the time of presentation. Recognizing the presence of infection in a DFU is crucial because infection is often the immediate precipitating event for a lower extremity amputation. Infection is diagnosed clinically by the presence of at least two signs or symptoms of inflammation or purulent secretions. Diabetic foot infections (DFI) should be classified according to their severity, using one of the similar validated systems devised by the Infectious Diseases Society of America (IDSA) or the International Working Group on the Diabetic Foot (Table 3).
Hospitalization is rarely required for mild infections and for only some of the patients with a moderate infection (defined as those with >2 cm surrounding erythema or infection that penetrates deeper than the subcutaneous tissue). Hospitalization is appropriate when a moderate infection is accompanied by limb ischemia or not responding to outpatient treatment. Patients with severe (grade 4) infections (those accompanied by fever, leukocytosis, or severe metabolic perturbations) should be hospitalized. The most recent guidelines of the IDSA define severe infection as the presence of local infection associated with signs of systemic inflammatory response syndrome. (Table 3) Although patients with diabetes can present with systemic signs of infection (fever, nausea, vomiting, anorexia, malaise, loss of glycemic control, etc.), they may not mount a robust systemic response. Correction of an abnormal white blood cell count or hyperglycemia should be tracked during hospitalization to help monitor the response to treatment. In most studies hyperglycemia is associated with poor wound healing and it is likely that its correction would increase the likelihood of a favorable outcome. Plain film radiographs of the foot and ankle should be obtained to assess for bone destruction, deformity, foreign body, or soft tissue emphysema. The presence of soft tissue gas on radiographs, abscess or extensive gangrene should alert the team that prompt surgical intervention is required (Figs. 2 and .
(Enlarge Image)
Figure 2.
Photograph of patient with a severe, limb-threatening necrotizing diabetic foot infection.
(Enlarge Image)
Figure 3.
Plain film radiograph demonstrating subcutaneous gas on the dorsum of the foot.
A team approach to management is optimal in patients with DFI in order to increase the likelihood of limb salvage. The initial evaluation should identify and correct any glycemic, fluid, and electrolyte or metabolic disorders, consulting with specialists as necessary. Patients with a DFI require a thorough examination of the foot, basic blood tests such as complete blood count, serum chemistries, and inflammatory markers (erythrocyte sedimentation rate and/or C-reactive protein). When deep soft tissue or bone infection is suspected, additional imaging (magnetic resonance in preference to nuclear medicine studies) may be helpful. Those with suspected limb ischemia should undergo further noninvasive vascular evaluation, although urgent treatment of deep infection takes immediate precedence. Surgical consultation should be sought for patients with infections that are deep, extensive, or accompanied by osteomyelitis or limb ischemia. The presence of crepitus (or subcutaneous gas on radiographs), bullae, ecchymosis, or skin necrosis suggest a necrotizing soft tissue infection, which represents a surgical emergency (Figs. 2 and 3).
Infected wounds should be cultured, preferably by obtaining tissue samples during any surgical procedure or by tissue biopsy or wound base curettage. Bone cultures are optimal for detecting the pathogen in osteomyelitis, but blood cultures are only necessary for those with a severe infection as defined by the IDSA/International Working Group on the Diabetic Foot (PEDIS) classifications scheme (Table 3). Appropriate deep culture technique is important because the results direct antibiotic therapy, enabling clinicians to alter their initial broad-spectrum empiric regimen to more narrow-spectrum antibiotic coverage. Initial therapy must usually be parenteral and empiric, based on the likeliest pathogens and their probable antibiotic susceptibility patterns. A broad-spectrum antibiotic regimen is recommended for severe infections, covering staphylococci, streptococci and commonly reported gram-negative pathogens. Where the likelihood is more than minimal of infection with methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, extended-spectrum β-lactamase–producing gram-negatives, or obligately anaerobic bacteria, antibiotics effective against these organisms should be considered. No one agent or regimen has shown superiority in treating DFIs, but those with demonstrated efficacy include β-lactams (penicillins and cephalosporins), glycopeptides (e.g., vancomycin), carbapenems, linezolid, clindamycin, and fluoroquinolones. The ability to appropriately initiate and then modify antibiotic therapy, based on culture results and clinical response is important. Proper antibiotic management of lower extremity infections reduces complications and length of stay. Infectious diseases specialists should be consulted when cultures yield multiple or antibiotic-resistant organisms, the patient has substantial renal impairment, or the infection does not respond to appropriate medical or surgical therapy in a timely manner.
Discharge planning should be initiated when the signs and symptoms of infection are clearly responding to treatment (resolution of the local and systemic signs of infection and improvement in white blood cell count). Most patients can be transitioned from parenteral to oral antibiotic therapy to complete a course of therapy as outpatients. Patients or caregivers may need training on how to apply dressings and offloading devices, and therapy for glycemic control will often need adjustment. It is important to arrange for timely outpatient follow-up with the appropriate provider(s) prior to hospital discharge. Even when managed at specialized centers, about half of patients hospitalized for DFI undergo a lower extremity amputation within a year. Glycemic control often requires a plan different from the prehospitalization regimen. Smoking cessation should be strongly recommended to the patient.
Medical Management of Infection
More than half of DFUs are clinically infected at the time of presentation. Recognizing the presence of infection in a DFU is crucial because infection is often the immediate precipitating event for a lower extremity amputation. Infection is diagnosed clinically by the presence of at least two signs or symptoms of inflammation or purulent secretions. Diabetic foot infections (DFI) should be classified according to their severity, using one of the similar validated systems devised by the Infectious Diseases Society of America (IDSA) or the International Working Group on the Diabetic Foot (Table 3).
Hospitalization is rarely required for mild infections and for only some of the patients with a moderate infection (defined as those with >2 cm surrounding erythema or infection that penetrates deeper than the subcutaneous tissue). Hospitalization is appropriate when a moderate infection is accompanied by limb ischemia or not responding to outpatient treatment. Patients with severe (grade 4) infections (those accompanied by fever, leukocytosis, or severe metabolic perturbations) should be hospitalized. The most recent guidelines of the IDSA define severe infection as the presence of local infection associated with signs of systemic inflammatory response syndrome. (Table 3) Although patients with diabetes can present with systemic signs of infection (fever, nausea, vomiting, anorexia, malaise, loss of glycemic control, etc.), they may not mount a robust systemic response. Correction of an abnormal white blood cell count or hyperglycemia should be tracked during hospitalization to help monitor the response to treatment. In most studies hyperglycemia is associated with poor wound healing and it is likely that its correction would increase the likelihood of a favorable outcome. Plain film radiographs of the foot and ankle should be obtained to assess for bone destruction, deformity, foreign body, or soft tissue emphysema. The presence of soft tissue gas on radiographs, abscess or extensive gangrene should alert the team that prompt surgical intervention is required (Figs. 2 and .
(Enlarge Image)
Figure 2.
Photograph of patient with a severe, limb-threatening necrotizing diabetic foot infection.
(Enlarge Image)
Figure 3.
Plain film radiograph demonstrating subcutaneous gas on the dorsum of the foot.
A team approach to management is optimal in patients with DFI in order to increase the likelihood of limb salvage. The initial evaluation should identify and correct any glycemic, fluid, and electrolyte or metabolic disorders, consulting with specialists as necessary. Patients with a DFI require a thorough examination of the foot, basic blood tests such as complete blood count, serum chemistries, and inflammatory markers (erythrocyte sedimentation rate and/or C-reactive protein). When deep soft tissue or bone infection is suspected, additional imaging (magnetic resonance in preference to nuclear medicine studies) may be helpful. Those with suspected limb ischemia should undergo further noninvasive vascular evaluation, although urgent treatment of deep infection takes immediate precedence. Surgical consultation should be sought for patients with infections that are deep, extensive, or accompanied by osteomyelitis or limb ischemia. The presence of crepitus (or subcutaneous gas on radiographs), bullae, ecchymosis, or skin necrosis suggest a necrotizing soft tissue infection, which represents a surgical emergency (Figs. 2 and 3).
Infected wounds should be cultured, preferably by obtaining tissue samples during any surgical procedure or by tissue biopsy or wound base curettage. Bone cultures are optimal for detecting the pathogen in osteomyelitis, but blood cultures are only necessary for those with a severe infection as defined by the IDSA/International Working Group on the Diabetic Foot (PEDIS) classifications scheme (Table 3). Appropriate deep culture technique is important because the results direct antibiotic therapy, enabling clinicians to alter their initial broad-spectrum empiric regimen to more narrow-spectrum antibiotic coverage. Initial therapy must usually be parenteral and empiric, based on the likeliest pathogens and their probable antibiotic susceptibility patterns. A broad-spectrum antibiotic regimen is recommended for severe infections, covering staphylococci, streptococci and commonly reported gram-negative pathogens. Where the likelihood is more than minimal of infection with methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, extended-spectrum β-lactamase–producing gram-negatives, or obligately anaerobic bacteria, antibiotics effective against these organisms should be considered. No one agent or regimen has shown superiority in treating DFIs, but those with demonstrated efficacy include β-lactams (penicillins and cephalosporins), glycopeptides (e.g., vancomycin), carbapenems, linezolid, clindamycin, and fluoroquinolones. The ability to appropriately initiate and then modify antibiotic therapy, based on culture results and clinical response is important. Proper antibiotic management of lower extremity infections reduces complications and length of stay. Infectious diseases specialists should be consulted when cultures yield multiple or antibiotic-resistant organisms, the patient has substantial renal impairment, or the infection does not respond to appropriate medical or surgical therapy in a timely manner.
Discharge planning should be initiated when the signs and symptoms of infection are clearly responding to treatment (resolution of the local and systemic signs of infection and improvement in white blood cell count). Most patients can be transitioned from parenteral to oral antibiotic therapy to complete a course of therapy as outpatients. Patients or caregivers may need training on how to apply dressings and offloading devices, and therapy for glycemic control will often need adjustment. It is important to arrange for timely outpatient follow-up with the appropriate provider(s) prior to hospital discharge. Even when managed at specialized centers, about half of patients hospitalized for DFI undergo a lower extremity amputation within a year. Glycemic control often requires a plan different from the prehospitalization regimen. Smoking cessation should be strongly recommended to the patient.
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