View source for Diabetic foot ulcer

==Background==
*A diabetic foot ulcer (DFU) is a break in the skin of the foot in a person with [[diabetes]] that fails to heal promptly.
*DFUs occur in approximately 15–25% of diabetic patients over their lifetime and are the leading cause of non-traumatic lower extremity amputation.<ref name="IDSA">Lipsky BA, et al. 2012 Infectious Diseases Society of America clinical practice guideline for the diagnosis and treatment of diabetic foot infections. ''Clin Infect Dis''. 2012;54(12):e132-e173.</ref> The ED physician's role is to assess ulcer severity, identify infection and limb-threatening complications, initiate appropriate treatment, and determine disposition.
*Diabetic foot ulcers result from the convergence of three pathologic processes:
** Peripheral neuropathy (~60% of cases) — loss of protective sensation leads to repetitive unrecognized trauma
** Peripheral arterial disease (~15–20%) — impaired perfusion compromises healing and host defense
** Immunopathy — hyperglycemia impairs neutrophil function, increasing infection risk
*A foot ulcer that becomes infected ([[diabetic foot infection]]) is a limb-threatening emergency
* 1-year outcomes of patients presenting with an infected DFU: ~46% healed, ~15% dead, ~17% required amputation<ref name="IWGDF">IWGDF/IDSA. Guidelines on the diagnosis and treatment of foot infection in persons with diabetes. 2023.</ref>
*5-year mortality after major amputation exceeds 50%

==Clinical Features==
===Ulcer characteristics===
*Typically on pressure points: plantar metatarsal heads, tips of toes, heel, dorsal interphalangeal joints
*Neuropathic ulcers: Painless, well-circumscribed, surrounded by callus, located on plantar surface
*Ischemic ulcers: Painful, irregular borders, pale or necrotic base, located on tips of toes or lateral foot
*Neuroischemic (mixed): Features of both; most common in practice

===Signs of infection (IDSA/IWGDF classification)===
* Uninfected: Ulcer present without signs of infection
* Mild (local) infection: ≥2 of the following: erythema >0.5 cm but ≤2 cm around wound, local warmth, tenderness/pain, swelling, purulent discharge — confined to skin and superficial subcutaneous tissue
* Moderate infection: Local infection with erythema >2 cm, or involvement of structures deeper than skin/subcutaneous tissue (abscess, [[osteomyelitis]], [[septic arthritis]], tendon involvement) — without systemic inflammatory response
* Severe infection: Local infection with [[SIRS]] criteria (temperature >38°C or <36°C, HR >90, RR >20, WBC >12,000 or <4,000) — this is limb- and life-threatening<ref name="IDSA"/>

===Red flags in the ED===
*Crepitus or subcutaneous gas (consider [[necrotizing fasciitis]] or [[gas gangrene]])
*Exposed bone or ability to probe to bone (strongly suggests [[osteomyelitis]])
*Rapid spread of erythema despite antibiotics
*Purplish discoloration, hemorrhagic bullae, or skin necrosis ([[necrotizing soft tissue infections]])
*Sepsis, hemodynamic instability, or altered mental status

==Differential Diagnosis==
{{Foot infection}}


{{SSTI DDX}}

==Evaluation==
===Workup===
Assess the whole patient:
*Vital signs (identify [[sepsis]]/SIRS)
*Point-of-care glucose; [[basic metabolic panel]] (renal function, electrolytes, glucose, acidosis)
*CBC with differential
*[[Erythrocyte sedimentation rate|ESR]], CRP, procalcitonin (support but do not confirm infection diagnosis)
*Blood cultures if febrile, septic, or moderate-severe infection
*HbA1c if not recently available (indicates long-term glycemic control)

Assess the affected limb:
* Vascular assessment: Palpate dorsalis pedis and posterior tibial pulses. Assess capillary refill. Document any pulse deficits. Ankle-brachial index (ABI) if available (>0.9 normal; <0.4 suggests critical limb ischemia; note: ABI may be falsely elevated >1.3 in calcified vessels common in diabetes)
* Neurologic assessment: Test sensation with 10 g monofilament (or sharp end of a broken wooden cotton applicator if monofilament unavailable). Loss of sensation at ≥1 site indicates neuropathy<ref name="emDocs">Phelps JT, Doty CI. The diabetic foot infection: when and what types of antibiotics are warranted. ''emDocs''. January 2019.</ref>
* Lymphatic assessment: Ascending lymphangitis or lymphadenopathy suggests spreading infection

Assess the wound:
*Document location, size (length × width × depth), and wound bed characteristics (granulation vs. slough vs. necrotic tissue)
* Probe to bone test: Using a sterile blunt metal probe, gently probe the wound base. If you can feel bone, the positive predictive value for [[osteomyelitis]] is ~89% in high-risk ulcers<ref name="IDSA"/>
*Identify undermining, tunneling, sinus tracts, or fluctuance (deep space abscess)
*Note wound odor (foul odor suggests anaerobic involvement)

Cultures:
*'''Do not culture clinically uninfected ulcers''' — recovered organisms represent colonization, not infection<ref name="IDSA"/>
*For infected ulcers: Obtain tissue culture (curette or biopsy of wound base after debridement) rather than superficial wound swab when possible. Deep tissue cultures are more reliable than swabs
*If swab is the only option, cleanse wound first and sample the wound base (not surface exudate)

Imaging:
* Plain radiographs of the foot — obtain on all moderate/severe infections and any ulcer where osteomyelitis is suspected. Look for: soft tissue gas, foreign bodies, bony destruction, periosteal reaction, cortical disruption
* MRI — gold standard for osteomyelitis diagnosis if plain films are equivocal and clinical suspicion remains high
* Ultrasound — useful at bedside to identify fluid collections/abscesses in the plantar space

===Diagnosis===
====Wagner Classification====
{| class="wikitable"
|-
! Grade !! Description
|-
| '''0''' || Intact skin; pre-ulcerative lesion, deformity, or [[cellulitis]]
|-
| '''1''' || Superficial ulcer (partial or full-thickness)
|-
| '''2''' || Deep ulcer extending to tendon, ligament, joint capsule, or bone — without abscess or osteomyelitis
|-
| '''3''' || Deep ulcer with abscess, [[osteomyelitis]], or tendon involvement
|-
| '''4''' || Localized [[gangrene]] (forefoot or heel)
|-
| '''5''' || Extensive gangrene involving the entire foot
|}
*Wagner grades ≥3 generally require surgical consultation and likely admission<ref name="Wagner">Wagner FW. The dysvascular foot: a system for diagnosis and treatment. ''Foot Ankle''. 1981;2(2):64-122.</ref>

==Management==
===All diabetic foot ulcers===
* Glycemic control: Optimize glucose management; hyperglycemia impairs immune function and healing
* Offloading: The most important factor for healing neuropathic ulcers — instruct patient on strict non-weight-bearing or provide offloading shoe/boot. Referral for total contact casting as outpatient
* Wound care: Debridement of necrotic tissue and surrounding callus (can be performed in the ED for superficial ulcers). Moist wound dressing. Avoid soaking the foot

===Uninfected ulcers===
* No antibiotics — antibiotics do not improve healing of uninfected DFUs and promote resistance<ref name="IDSA"/>
*Wound care, offloading, glucose optimization
*Outpatient follow-up with wound care or podiatry within 1–2 weeks

===Mild infection===
*Oral antibiotics targeting Gram-positive cocci (most common pathogens: ''S. aureus'' and beta-hemolytic streptococci)<ref name="IDSA"/>
* Non-MRSA risk: Cephalexin 500 mg PO QID or amoxicillin-clavulanate 875/125 mg PO BID
* MRSA risk (prior MRSA, purulence, IVDU, recent hospitalization): TMP-SMX DS 1–2 tabs PO BID or doxycycline 100 mg PO BID (add cephalexin if need Strep coverage with TMP-SMX)
*Duration: 1–2 weeks; re-evaluate if not improving
*Outpatient management with close follow-up

===Moderate infection===
*IV antibiotics; consider admission
* Non-MRSA: Ampicillin-sulbactam 3 g IV q6h or piperacillin-tazobactam 3.375 g IV q6h or ertapenem 1 g IV daily
* MRSA risk: Add vancomycin 15–20 mg/kg IV
* Surgical consultation for abscess drainage, deep space infection, or suspected osteomyelitis requiring debridement
*If probe-to-bone positive or imaging suggests osteomyelitis, treat as osteomyelitis (prolonged antibiotics ± surgery; consult ID and surgery)

===Severe infection (limb- and life-threatening)===
* Resuscitate: IV fluids, correct hyperglycemia/DKA/electrolytes, vasopressors if needed
* Broad-spectrum IV antibiotics: Vancomycin + piperacillin-tazobactam (or meropenem if Pseudomonas/resistant organisms suspected)
* Emergent surgical consultation — urgent debridement, drainage, and assessment for [[necrotizing soft tissue infections]] or the need for amputation
*Blood cultures, lactate
*ICU admission if septic shock

===Vascular assessment and referral===
*If absent pulses, ABI <0.5, or signs of critical limb ischemia (rest pain, tissue loss, gangrene), obtain urgent vascular surgery consultation — revascularization may be needed before the ulcer can heal

==Disposition==
* Discharge with close outpatient follow-up (1–2 weeks): Uninfected ulcers; mild infections with reliable patient, adequate perfusion, and no systemic toxicity
* Admit for: Moderate-severe infection, sepsis/SIRS, limb-threatening ischemia, need for IV antibiotics, surgical intervention, inability to perform wound care at home, unreliable follow-up, failed outpatient management, concurrent DKA/metabolic derangement
* Surgical consultation before discharge if: Wagner ≥3, suspected osteomyelitis, deep space abscess, gangrene, crepitus, or [[necrotizing soft tissue infections]]
* All patients: Counsel on offloading, glucose control, daily foot self-inspection, appropriate footwear, and warning signs to return (worsening redness, streaking, fever, foul odor, new drainage)

==See Also==
*[[Diabetic foot infection]]
*[[Cellulitis]]
*[[Osteomyelitis]]
*[[Necrotizing fasciitis]]
*[[Charcot foot]]
*[[Peripheral artery disease]]
*[[Sepsis]]
*[[Diabetes]]

==External Links==
*[https://www.emdocs.net/diabetic-foot-infection-types-antibiotics-warranted/ emDocs: Diabetic Foot Infection — Antibiotics]
*[https://iwgdfguidelines.org/ IWGDF Guidelines]
*[https://www.idsociety.org/practice-guideline/diabetic-foot-infections/ IDSA Diabetic Foot Infection Guidelines]

==References==
{{reflist|2}}



[[Category:Orthopedics]][[Category:ID]]