What is the diagnosis and management for an elderly male with diabetes presenting with swelling of the right lower extremity, leukocytosis (elevated white blood cell count), and elevated liver enzymes (alanine transaminase)?

Diagnosis: Diabetic Foot Infection (Moderate to Severe)

This elderly diabetic male with unilateral lower extremity swelling, leukocytosis with left shift, and mildly elevated transaminases most likely has a moderate-to-severe diabetic foot infection requiring urgent evaluation for deep tissue involvement, possible osteomyelitis, and immediate initiation of broad-spectrum antibiotics. 1

Immediate Clinical Assessment Required

Examine the foot systematically for signs of infection and limb-threatening complications:

• Look for purulent drainage or at least 2 cardinal signs of inflammation (erythema, warmth, swelling, pain/tenderness) to confirm infection clinically 1

• Probe any open wound to bone - a positive probe-to-bone test in this high-risk patient is largely diagnostic of osteomyelitis 1

• Assess for critical red flags indicating necrotizing infection:

  • Crepitus or tissue gas (suggests necrotizing fasciitis or gas gangrene) 2
  • Extensive ecchymoses, petechiae, or hemorrhagic bullae 2
  • Pain out of proportion to findings 2
  • Rapid progression or extensive necrosis 2
  • Foul odor suggesting anaerobic involvement 1

• Evaluate vascular status immediately - check pedal pulses, capillary refill, and obtain ankle-brachial index (ABI), as peripheral arterial disease is present in up to 40% of diabetic foot infections and critically affects outcomes 1, 3

Severity Classification

Categorize infection severity to guide management venue and urgency: 1

• Mild infection: Local inflammation only, <2 cm cellulitis, no systemic signs
• Moderate infection: >2 cm cellulitis OR deeper structures involved OR systemic inflammatory response
• Severe infection: Systemic toxicity (fever, tachycardia, hypotension) OR metabolic instability OR limb-threatening

This patient's leukocytosis (12,000 with elevated segmenters) suggests at minimum a moderate infection, possibly severe depending on clinical findings. 1

Immediate Diagnostic Workup

Obtain cultures BEFORE starting antibiotics:

• Collect deep tissue specimens via curettage, biopsy, or aspiration - NOT superficial swabs, as these yield inaccurate results 1
• Obtain blood cultures if systemically ill or severe infection 1

Imaging studies:

• Plain radiographs immediately to detect gas in tissues, foreign bodies, and bone involvement 1
• MRI is the preferred advanced imaging if osteomyelitis suspected or deep abscess needs definition - more sensitive and specific than nuclear scans 1
• Consider urgent CT scan if necrotizing infection suspected to assess extent of deep tissue involvement 2

Laboratory tests:

• Markedly elevated ESR is suggestive of osteomyelitis in suspected cases 1
• The mildly elevated SGOT (2x normal) likely reflects underlying diabetic hepatic steatosis rather than the infection itself, as ALT elevation is common in type 2 diabetes and associated with insulin resistance 4, 5

Empirical Antibiotic Management

Initiate broad-spectrum IV antibiotics immediately for moderate-to-severe infection: 1

For moderate-to-severe infections, cover:

• MRSA (given prevalence in diabetic foot infections) 1
• Gram-negative rods including Enterobacteriaceae (common in chronic wounds) 1
• Anaerobes if extensive necrosis, gangrene, or foul odor present 1

Typical pathogens in diabetic foot infections:

• Staphylococcus aureus (most common, ~50% of cases) 1
• Coagulase-negative staphylococci and streptococci 1
• Enterobacteriaceae in chronic/previously treated wounds 1
• Anaerobes with ischemia or gangrene 1

Duration of therapy: 1

• 1-2 weeks for mild-moderate soft tissue infections
• 6 weeks if osteomyelitis present without bone resection
• <1 week if all infected bone surgically removed

Surgical Consultation

Obtain urgent surgical evaluation if: 1, 6

• Deep abscess present
• Extensive bone/joint involvement
• Crepitus or gas in tissues
• Substantial necrosis or gangrene
• Necrotizing fasciitis suspected
• Failed medical management

Vascular surgery consultation if arterial insufficiency detected, as revascularization may be necessary for healing 1, 6

Essential Wound Care

Provide aggressive local wound management: 1, 6

• Debride all necrotic tissue and callus
• Off-load pressure completely - this is crucial and often overlooked
• Appropriate wound dressing (specific type less important than other measures) 1

Critical Pitfalls to Avoid

• Do NOT rely on swab cultures - they are inaccurate and yield contaminants 1
• Do NOT delay antibiotics for culture results in moderate-severe infections 1
• Do NOT miss Charcot neuroarthropathy - if foot is warm/swollen but skin intact with temperature asymmetry >2°C, consider active Charcot rather than infection 7
• Do NOT underestimate vascular disease - inadequate perfusion dooms medical therapy to failure 1
• Do NOT continue antibiotics indefinitely - treat until infection resolves, not until wound heals 1

Disposition

Hospitalize this patient given moderate-to-severe infection with systemic inflammatory response (leukocytosis), need for IV antibiotics, surgical evaluation, and close monitoring 1