Diabetic Foot Infections

Transcription

1 PL Detail-Document # This PL Detail-Document gives subscribers additional insight related to the Recommendations published in PHARMACIST S LETTER / PRESCRIBER S LETTER May 2016 Diabetic Foot Infections Foot ulcers and infections are a major complication in patients with diabetes. 1 These infections are the leading cause of diabetes-related hospitalizations and lower extremity amputations. 2 At least one-quarter of diabetic foot ulcers do not heal properly, and about 25% lead to some form of amputation. 3 If left untreated, diabetic foot infections can also lead to osteomyelitis and gangrene. 4,5 Prevention and treatment of diabetic foot ulcers and infections requires an interdisciplinary approach. 4 The table below provides information and approaches to important clinical questions (e.g., preventions, signs and symptoms, treatment) regarding diabetic foot infections. Abbreviations: A1C = hemoglobin A1C; ABI = ankle-brachial index; DM = diabetes mellitus; DFO = diabetic foot osteomyelitis; DFU = diabetic foot ulcer; DPN = diabetic peripheral neuropathy; MRI = magnetic resonance imaging; MRSA = methicillin-resistant Staphylococcus aureus; PAD = peripheral artery disease; TMP/SMX = trimethoprim/sulfamethoxazole; WBC = white blood cells What are risk factors for diabetic foot infections? What are key factors to preventing diabetic foot infections? Peripheral neuropathy 1,5,8 Foot deformity 1 Peripheral artery disease 1,5,8 Previous foot ulceration 1,4,9 Previous amputation 1,4,9 Visual impairment caused by diabetic retinopathy 8 Advanced age 8 Living alone 8 Renal impairment 5,8 Provide patient education regarding foot care, with periodic reinforcement. 3 Ensure patients receive an annual diabetic foot exam (see details below). 3 Recommend off-loading (i.e., removing pressure) and therapeutic footwear, as appropriate (see details below). 3 How should diabetic foot exams be completed? Recommend all patients with diabetes receive an annual foot exam by a trained provider. 3,10 Increased frequency of DM foot exams should be based on patient risk: 3 o Recommend yearly exams for patients without additional risks. o Recommend an exam every six months for patients with DPN.

2 (PL Detail-Document #320509: Page 2 of 8) Diabetic foot exams, continued How are diabetic foot infections diagnosed? o Recommend an exam every three months for patients with DPN with deformity or PAD. o Recommend monthly exams, minimum of quarterly, for patients with previous amputation or ulcer. Comprehensive diabetic foot exams include: 3 o Assessment for DPN: recommend Semmes-Weinstein monofilament test over tuning fork test or neurothesiometer. o Assessment for pedal pulses o Assessment for deformity and/or calluses, including between toes o Nail assessment Recommend ABI or measurement of toe pressure, to assess blood flow to the feet, beginning at age 50, or as needed based on symptoms. 3 o Toe pressure may be more useful in predicting wound healing and risk of ulceration. 11 Typical signs and symptoms of infection include erythema, warmth, swelling, and pain or tenderness, or purulent drainage. 4 Other symptoms can include nonpurulent secretions, friable or discolored granulation tissues, or a foul odor. 4 Recommend diagnosing infection based on clinical findings over cultures, due to colonization of most DFUs. 4 Infections are diagnosed with at least 2 of the following: local swelling, erythema around the wound, local pain or tenderness, local warmth, purulent discharge. 4,5,9 o Mild infections only involve the skin or subcutaneous tissue, with erythema extending <2 cm from the wound margin, and do not present with systemic signs or symptoms. 4,5,9 o Moderate infections have erythema extending >2 cm from the wound margin, involve bone, joint, tendon, or muscle, without systemic symptoms. 4,5,9 o Severe infections are any foot infection with >2 of the following: temp >38 C or <36 C, heart rate >90 beats per minute, respiratory rate >20 breaths per minute or PaCO2 <32 mmhg, WBC >12,000 per mcl or <4,000 per mcl, or >10% bands. 4,5,9 Recommend an x-ray in moderate and severe DFIs, to assess for bone involvement, soft tissue gas, and foreign bodies. 3 o Recommend an MRI when soft tissue or bone involvement is suspected, based on x-ray. 3 Cultures o Recommend against culturing all uninfected DFU and most mild DFI. 4 o Suggest culturing wounds requiring debridement, prior to initiating empiric antibiotic therapy. 4 o If cultures are obtained: Recommend properly cleaning and debriding the wound PRIOR to collecting culture

3 (PL Detail-Document #320509: Page 3 of 8) Diagnosis, continued specimens. 3 Recommend scraping wound with scalpel or dermal curette to obtain culture sample. 3 Avoid obtaining culture by swabbing the wound or wound drainage. 3 Review culture and sensitivities to guide antibiotic selection and adjustments. 4 How should diabetic foot infections be treated? Recommend against antibiotic use in DFU without infection. 3,4 Oral therapy is appropriate for mild infections. 4 For mild infections, recommend empiric cephalexin, dicloxacillin (cloxacillin in Canada), or clindamycin, to cover gram-positive organisms (e.g., Staphylococcus and Streptococcus). 4 o For patients who have been treated with antibiotics in the last month, recommend amoxicillin/clavulanate or TMP/SMX, to ensure gram-negative coverage (e.g., E. coli, Klebsiella pneumonia, Proteus). 4,5 o For patients with a recent hospitalization or at risk for MRSA, recommend doxycycline or TMP/SMX. 4 For moderate infections, ensure empiric coverage for gram-positive, gram-negative, and possibly anaerobes. 4 o Oral antibiotic therapy is appropriate for most moderate infections (e.g., levofloxacin [plus metronidazole if significant concern for anaerobes]). 4 o Intravenous antibiotics can be used at the discretion of the provider, based on patient presentation. 4 For most patients recommend an extended-spectrum penicillin, a higher generation cephalosporin, or a quinolone (e.g., ampicillin-sulbactam [U.S. only], ceftriaxone + IV metronidazole, moxifloxacin). 4,22 Consider imipenem-cilastatin, ertapenem, or tigecycline for an even broader spectrum of coverage. 4,22 Recommend an antipseudomonal penicillin or fluoroquinolone, if Pseudomonas is suspected (e.g., piperacillin-tazobactam, levofloxacin). 4,22 Consider adding vancomycin, linezolid, or daptomycin if MRSA is suspected. 4,22 o Conversion to oral antibiotics can occur once infection begins to improve on intravenous therapy. 4 Utilize cultures and sensitivities to select most appropriate oral agent, if available. 4 Most often, when converting from intravenous to oral therapy, selection of oral agent will be empiric. Recommend converting to a broad spectrum oral agent, providing gram-positive and gram-negative coverage, (e.g., fluoroquinolones, amoxicillin/clavulanate, TMP/SMX). 4 For severe infections, recommend empiric broad-spectrum intravenous therapy (see antibiotic choices above). 4 o Recommend surgical intervention for infections involving abscess, gas, or necrotizing fasciitis. 3

4 (PL Detail-Document #320509: Page 4 of 8) Treating diabetic foot infections, continued When and how should anaerobic coverage be used? When and how should Pseudomonas coverage be used? Duration of therapy should be based on severity of infection, presence or absence of bone involvement, and clinical response to antibiotic therapy. 4 o Most mild infections can be treated with one to two weeks of antibiotics. 4 o Most moderate infections can be treated with two to three weeks of antibiotics. 4 o Severe infections, especially those involving bone (see below for more about osteomyelitis), will likely require longer therapy. 4 o Recommend re-evaluation in one week, with measurements, to assess for improvement or need to change therapy. 3 o Antibiotics can be discontinued when signs and symptoms of infection have resolved. It is not necessary to continue therapy until the wound is completely healed. 4 Antibiotic therapy is often insufficient unless combined with appropriate wound care (see details below). Anaerobic coverage is not usually necessary, 2 especially when diabetic foot ulcers are properly debrided. 4 Cultures from diabetic foot osteomyelitis rarely grow anaerobes. 4 Consider anaerobic coverage for chronic, previously treated, or severe infections, especially if there is foul odor or necrosis. 4 Pseudomonas is not a frequent pathogen in most mild to moderate diabetic foot infections. 4 o Consider Pseudomonas coverage for severe, and some moderate, DFI in areas with high local Pseudomonas prevalence (e.g., >30%), in warmer climates, or in patients with frequent water exposure (e.g., hydrotherapy). 4,6 If Pseudomonas is suspected, consider using an intravenous antipseudomonal agent (e.g., ciprofloxacin, piperacillin-tazobactam, ticarcillin/clavulanate, imipenem/cilastatin, meropenem). 4 When and how should MRSA coverage be used? It s not necessary to routinely cover for MRSA with empiric therapy. Consider empiric MRSA coverage: o For patients with a history of MRSA infections. 4 o When local prevalence of MRSA is high. 4 o In clinically severe infections. 4 Consider the following antibiotics to cover MRSA: o Mild infections: TMP/SMX and doxycycline. 4 o Moderate to severe infections: linezolid, daptomycin, and vancomycin. 4

5 (PL Detail-Document #320509: Page 5 of 8) What are the concerns with osteomyelitis? Which other interventions have been used to prevent initial or recurrent infections? When and what type of offloading should be recommended? Consider osteomyelitis in chronic, deep, or large ulcers, especially if located over a bony prominence. 4 o If osteomyelitis is suspected based on x-ray, recommend a probe-to-bone test, and confirm with an MRI, if needed. 4 o After an initial course of one to four weeks of IV antibiotics, recommend converting to oral therapy for the remainder of treatment (typically >4 to 6 weeks). 18,19 o For more information on oral therapy for osteomyelitis, see PL Chart, Oral Antibiotics for Acute Osteomyelitis in Adults. Consider home-monitoring of foot skin temperature (e.g., TempTouch), with appropriate actions taken when abnormal temperatures are recorded. 1 o Recommend contacting the prescriber if temperature differences >4 F (>2.2 C) between right and left foot are observed. 17 Surgical procedures to lengthen the Achilles tendon, resect metatarsal head, and metatarsophalangeal joint arthroplasty have been shown to reduce recurrent ulcers in select patients with non-healing ulcers. 1 Recommend against prophylactic arterial revascularization. 3 o Consider arterial revascularization for indications such as claudication, pain at rest, and tissue loss. 3,12 If wound is not improving and size is not reduced by 50% after four weeks, consider adjunctive options: 3 o Negative pressure (e.g., wound vacuum) therapy for chronic wounds not responding to standard or advanced dressings after four to eight weeks of therapy. 3 Negative pressure therapy has been shown to be safe and effective, compared to moist wound therapy. 3 o A topical platelet derived growth factor (e.g., becaplermin) for wounds not responding to good ulcer care after four weeks. 3 Becaplermin has shown improved ulcer healing compared to ulcer care alone. 15 o Hyperbaric oxygen therapy in patients with adequate tissue perfusion for wounds not responding to four to six weeks of therapy, to reduce the risk of amputation. 3,16 o Limited data support the use of living cellular therapy (e.g., bilayered keratinocyte/fibroblast construct, fibroblast-seeded matrix) or extracellular matrix products (e.g., acellular human dermis, porcine small intestine) in the management of DFU. 3,7 Recommend against therapeutic footwear for average-risk patients. 3 Recommend custom footwear for higher-risk patients (e.g., significant DPN, deformities, previous amputation). 3 o Consider using foot shape and plantar pressure to ensure the most effective and proper fitting

6 (PL Detail-Document #320509: Page 6 of 8) Off-loading, continued therapeutic footwear. 1 For patients with non-plantar DFU, recommend surgical sandals or heal-relief shoes. 3 For patients with plantar DFU, recommend a total contact cast or fixed ankle walking boot. 3 o Removable cast walkers can be used for patients requiring frequent dressing changes. 3 Recommend therapeutic footwear after healing, to prevent recurrent or new lesions. 11,13,14 What type of wound care is recommended? What can patients do to prevent diabetic foot infections? Recommend general wound care measures using the TIME method: 21 o Tissue management: debride to remove necrotic tissue. o Infection or inflammation: prevent or treat infection, minimizes inflammation. o Moisture balance: avoid scabbing over as it delays healing. o Edge of wound: keep wound edges healthy to promote closure. Encourage patients to limit pressure on ulcerated areas, to reduce risk of worsening infection or increasing the size of the ulcer. 10 Honey has some antimicrobial and anti-inflammatory properties. 20 o Discourage use of food-grade honey for wound care, due to the presence of spores/contaminents. 20 o Though medical honey (Manuka or Medihoney) may provide some benefit in mild burns, there is little evidence to support its use in other types of wounds. 20 For more information on wound care, refer to our PL CE, Advanced Wound Care: Beyond First Aid for Common Chronic Wounds Recommend the following to patients to keep feet healthy: 10 Check feet every day. o Look for cuts, sores, blisters, and swelling. o If patients have trouble seeing their feet, have them use a mirror or have someone else check. Increase physical activity. Inquire about special footwear. Wash feet daily. Dry thoroughly, especially between toes. Keep skin soft and smooth by using lotion on top and bottom of feet. Avoid using lotion between toes. Keep toenails trimmed straight across. Use a file or emery board to smooth edges. Don t go barefoot. o Ensure shoes are comfortable, have a smooth lining, and fit well. o Do not wear shoes without socks. Consider white socks over colored ones to more easily identify bleeding or drainage. Check inside shoes for foreign objects before inserting foot. Protect feet from extreme temperatures.

7 (PL Detail-Document #320509: Page 7 of 8) Preventing diabetic foot infections, continued o Test bath water before putting feet in. o Avoid using hot water bottles, heating pad, or electric blankets. Increase blood flow to feet. o Prop feet up when seated. Minimize time spent with crossed legs. o Wiggle toes and move ankles up and down for five minutes a few times each day. o Avoid smoking, as this decreases circulation. Users of this PL Detail-Document are cautioned to use their own professional judgment and consult any other necessary or appropriate sources prior to making clinical judgments based on the content of this document. Our editors have researched the information with input from experts, government agencies, and national organizations. Information and internet links in this article were current as of the date of publication.

8 (PL Detail-Document #320509: Page 8 of 8) Project Leader in preparation of this PL Detail- Document: Beth Bryant, PharmD, BCPS, Assistant Editor References 1. van Netten JJ, Price PE, Lavery IA, et al. Prevention of foot ulcers in the at-risk patient with diabetes: a systemic review. Diabetes Metab Res Rev 2016;32: Uckay I, Aragon-Sanchez J, Lew D, Lipsky BA. Diabetic foot infections: what have we learned in the last 30 years? Int J Infect Dis 2015;40: Hingorani A, LaMuraglia GM, Henke P, et al. The management of diabetic foot: a clinical practice guideline by the Society for Vascular Surgery in collaboration with the American Podiatric Medical Association and the Society for Vascular Medicine. J Vasc Surg 2016;63:3S-21S. 4. Lipsky BA, Berendt AR, Cornia PB, et al Infectious Disease Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections. Clin Infect Dis 2012;54: Lipsky BA, Aragon-Sanchez J, Diggle M, et al. IWGDF Guidance on the diagnosis and management of foot infections in persons with diabetes. (Accessed April 8, 2016). 6. Peters EJ, Lipsky BA, Aragon-Sanchez J, et al. Interventions in the management of infection in the foot in diabetes: a systematic review. Diabetes Metab Res Rev 2016;32: Game FL, Apelqvist J, Attinger C, et al. Effectiveness of interventions to enhance healing of chronic ulcers of the foot in diabetes: a systematic review. Diabetes Metab Res Rev 2016;32: Cheer K, Shearman C, Jude EB. Managing complications of the diabetic foot. BMJ 2009;339:b4905. doi: /bmj.b Lipsky BA, Peters EJ, Senneville E, et al. Expert opinion on the management of infections in the diabetic foot. Diabetes Metab Res Rev 2012;28: American Diabetes Association. Foot Care. diabetes/complications/foot-complications/foot- care.html?referrer= (Accessed April 9, 2016). 11. Frykberg RG, Zgonis T, Armstrong DG, et al. Diabetic foot disorders: a clinical practice guideline (2006 revision). J Foot Ankle Surg 2006;45:S Norgren L, Hiatt WR, Dormandy JA, et al. Intersociety consensus for the management of peripheral arterial disease (TASC II). J Vasc Surg 2007;45:S Bus SA. Priorities in offloading the diabetic foot. Diabetes Metab Res Rev 2012;28: Cavanagh PR, Bus SA. Off-loading the diabetic foot for ulcer prevention and healing. J Vasc Surg 2010;52:37S-43S. 15. Smiell JM, Wieman TJ, Steed DL, et al. Efficacy and safety of becaplermin (recombinant human plateletderived growth factor-bb) in patients with nonhealing, lower extremity diabetic ulcers: a combined analysis of four randomized studies. Wound Repair Regen 1999;7: Elraiyah T, Tsapas A, Prutsky G, et al. A systematic review and meta-analysis of adjunctive therapies in diabetic foot ulcers. J Vasc Surg 2016;63:46S-58S. 17. Lavery LA, Higgins KR, Lanctot DR, et al. Preventing diabetic foot ulcer recurrence in high-risk patients: use of temperature monitoring as a selfassessment tool. Diabetes Care 2007;30: Kim BN, Kim ES, Oh MD. Oral antibiotic treatment of staphylococcal bone and joint infections in adults. J Antimicrob Chemother 2014;69: Fraimow HS. Systemic antimicrobial therapy in osteomyelitis. Semin Plast Surg 2009;23: PL CE, Advanced wound care: beyond first aid for common chronic wounds. Pharmacist s Letter/Prescriber s Letter Course: Dowsett C, Newton H. Wound bed preparation: TIME in practice. pdf. (Accessed April 12, 2016). 22. Selva Olid A, Sola I, Barajas-Nava LA, et al. Systemic antibiotics for treating diabetic foot infections (review). Cochrane Database Syst Rev 2015;(9):CD Cite this document as follows: PL Detail-Document, Diabetic Foot Infections. Pharmacist s Letter/Prescriber s Letter. May Evidence and Recommendations You Can Trust 3120 West March Lane, Stockton, CA ~ TEL (209) ~ FAX (209) Copyright 2016 by Therapeutic Research Center Subscribers to the Letter can get PL Detail-Documents, like this one, on any topic covered in any issue by going to or