When to intubate in GCS?

GCS ≤ 8 requires intubation for airway protection. The patient cannot protect their own airway at this level of consciousness. Motor score is the most prognostically important component.

What is the best initial fluid for sepsis resuscitation?

Lactated Ringer's (LR) is the preferred resuscitation fluid. The SMART trial (2018) showed balanced crystalloids reduced death, new renal failure, and persistent renal dysfunction compared to normal saline.

When to start vasopressors in septic shock?

Start norepinephrine (first-line vasopressor) if MAP remains < 65 mmHg after initial 30 mL/kg crystalloid resuscitation, or earlier if patient is profoundly hypotensive. Do not delay pressors to complete full fluid resuscitation.

Why can serum uric acid be normal during acute gout?

During acute inflammation, IL-6 increases renal urate excretion and redistributes urate from plasma to tissues. Up to 40% of acute gout flares have normal serum uric acid. Joint aspiration with polarized microscopy is needed for definitive diagnosis.

How do you distinguish lupus flare from infection in SLE?

Key clues: CRP is low/normal in flare but elevated in infection. Complement (C3/C4) drops in flare but is normal/elevated in infection. Procalcitonin is elevated in bacterial infection but normal in flare. Anti-dsDNA rises in flare, stable in infection.

What is the difference between DKA and HHS?

DKA features acidosis (pH 600), hyperosmolality (> 320), and minimal ketosis -typically in Type 2 DM. DKA requires insulin drip; HHS requires aggressive fluid resuscitation first.

When to give tPA in acute ischemic stroke?

IV alteplase (tPA) can be given within 4.5 hours of last known well time in eligible patients. CT head must rule out hemorrhage first. For large vessel occlusion, mechanical thrombectomy can be performed up to 24 hours with favorable imaging.

What antibiotics for community-acquired pneumonia?

Inpatient non-ICU: ceftriaxone + azithromycin. ICU: ceftriaxone + azithromycin (add vancomycin if MRSA risk). Outpatient healthy: amoxicillin. Outpatient with comorbidities: augmentin + azithromycin or respiratory fluoroquinolone. Duration: 5 days if clinically stable for 48 hours.

How to interpret iron studies?

Iron deficiency: low ferritin (< 30), high TIBC, low iron, low transferrin saturation (< 20%). Anemia of chronic disease: normal/high ferritin (acute phase reactant), low TIBC, low iron. A ferritin of 50-100 in an inflamed patient may still represent iron deficiency.

What is the correction rate for hyponatremia?

Correct sodium no more than 8 mEq/L in 24 hours to avoid osmotic demyelination syndrome (ODS). For symptomatic severe hyponatremia with seizures, give 3% hypertonic saline 100-150 mL bolus over 10-20 minutes. If overcorrected, use D5W + DDAVP rescue protocol.

When to start antibiotics in meningitis?

Within 30-60 minutes. Do NOT delay antibiotics for LP or CT. Draw blood cultures, start empiric antibiotics (vancomycin + ceftriaxone ± ampicillin if > 50 or immunocompromised), then perform LP when possible. Dexamethasone should be given before or with the first antibiotic dose.

DOACs vs warfarin in antiphospholipid syndrome?

DOACs are contraindicated in APS. The TRAPS trial (2018) showed rivaroxaban was inferior to warfarin with more thrombotic events in triple-positive APS patients. Warfarin with INR target 2-3 is the standard for APS, indefinitely.

How to manage scleroderma renal crisis?

ACE inhibitors (captopril) are life-saving -start immediately and titrate aggressively. Do NOT hold for rising creatinine. Steroids > 15 mg prednisone per day precipitate scleroderma renal crisis. ARBs are NOT a substitute -evidence is only for ACEi.

What are the 4 pillars of heart failure treatment?

Guideline-directed medical therapy (GDMT) for HFrEF: (1) ARNI or ACEi/ARB, (2) beta-blocker (carvedilol, metoprolol succinate, or bisoprolol), (3) MRA (spironolactone or eplerenone), (4) SGLT2 inhibitor (dapagliflozin or empagliflozin). All four should be initiated and titrated to target doses.

Diabetic Foot Infection -RoundsRx

🔍 Overview

Epidemiology

15–25% of diabetics develop a foot ulcer in their lifetime; ~50% of those ulcers become infected
Diabetic foot infections (DFI) are the leading cause of non-traumatic lower-extremity amputation
Annual incidence: ~6% in patients with neuropathy; 5-year mortality after major amputation approaches 50%
Most infections are polymicrobial -gram-positives (Staph, Strep) dominate mild cases; gram-negatives and anaerobes join in moderate-severe

Pathophysiology

Neuropathy → deformity → ulceration → infection. Peripheral neuropathy (sensory, motor, autonomic) removes protective sensation. Motor neuropathy causes intrinsic muscle wasting and foot deformity (claw toes, prominent metatarsal heads). Autonomic neuropathy reduces sweating → dry, cracked skin. Combined with peripheral arterial disease (PAD), the result is tissue breakdown with impaired healing and immune response. Hyperglycemia further impairs neutrophil function and wound healing.

The Triad of Diabetic Foot Failure: Neuropathy (can't feel injury) + PAD (can't heal injury) + Hyperglycemia (can't fight infection). All three must be addressed for treatment success.

IDSA/IWGDF Classification

IDSA Grade	Severity	Clinical Features	Setting
1	Uninfected	Wound without purulence or signs of inflammation	Wound care only, offloading
2	Mild	Erythema < 2 cm from wound edge, superficial (skin/subcutaneous only), no systemic signs	Outpatient oral antibiotics
3	Moderate	Erythema > 2 cm, deep tissue involvement (abscess, fascia, muscle, bone, joint), no SIRS	Inpatient IV antibiotics ± surgery
4	Severe	Any foot infection with SIRS/sepsis, limb-threatening ischemia, or necrotizing features	ICU, emergent surgery, broad-spectrum IV

IDSA DFI Guidelines, 2012 -classification drives antibiotic selection, setting of care, and need for surgical intervention.

Wagner Classification

Grade	Description
0	Intact skin, bony deformity (at-risk foot)
1	Superficial ulcer
2	Deep ulcer to tendon, capsule, or bone (no abscess/osteo)
3	Deep ulcer with abscess, osteomyelitis, or joint sepsis
4	Localized gangrene (forefoot or heel)
5	Extensive gangrene (entire foot)

Limb-Threatening vs Non-Limb-Threatening

Limb-threatening features (any one = urgent): deep space abscess, extensive cellulitis (> 2 cm), crepitus/gas gangrene, necrotizing fasciitis, critical limb ischemia (ABI < 0.4), wet gangrene, SIRS/sepsis. These require emergent surgical evaluation and broad-spectrum IV antibiotics.

Non-limb-threatening: Superficial infection, erythema < 2 cm, no deep tissue involvement, intact vasculature, no systemic signs → outpatient management with close follow-up

When to Suspect Osteomyelitis

Probe-to-bone test positive -sterile blunt probe contacts bone through ulcer → positive LR ~6 for osteomyelitis (PPV ~89% in high-prevalence population)
Ulcer > 2 cm in diameter or > 3 mm deep
ESR > 70 mm/hr (specificity ~90% for osteomyelitis in DFI setting)
Visible bone or palpable bone at wound base
"Sausage toe" (diffuse swelling of a single digit)
Non-healing ulcer despite 6 weeks of appropriate wound care and offloading

Rule of thumb: If you can see or feel bone, assume osteomyelitis until proven otherwise. A positive probe-to-bone test in a high-risk patient has a PPV approaching 89% -order MRI to confirm.

Microbiology

Mild / acute: Gram-positive cocci dominate -S. aureus (including MRSA), Streptococcus spp.
Moderate-severe / chronic: Polymicrobial -add gram-negatives (E. coli, Proteus, Klebsiella) and anaerobes (Bacteroides, Peptostreptococcus)
MRSA risk factors: Prior MRSA, recent hospitalization, hemodialysis, prior antibiotics, nasal colonization
Pseudomonas risk: Water exposure, failed prior therapy, warm/tropical climate

🧪 Workup

Bedside Assessment

Probe-to-bone test -do on EVERY diabetic foot wound. Insert sterile blunt metal probe into wound. If you touch hard, gritty surface → positive (PPV ~89%). Simple, bedside, takes 10 seconds.
Measure erythema -mark borders with skin marker, measure from wound edge. < 2 cm = mild, > 2 cm = moderate.
Assess depth -superficial (skin/subcut only) vs deep (fascia, muscle, tendon, bone, joint)
Pedal pulses -dorsalis pedis and posterior tibial. Absent/diminished → order ABI
Monofilament test -10g monofilament to assess neuropathy at plantar sites

Laboratory Workup

Routine (all patients)

CBC -leukocytosis (may be absent in immunocompromised diabetics)
BMP -renal function (impacts antibiotic dosing), glucose
CRP -sensitive but nonspecific; useful for trending treatment response
ESR -> 70 mm/hr has ~90% specificity for osteomyelitis in DFI
HbA1c -chronic glycemic control (target < 7% for wound healing)
Wound culture -deep tissue biopsy or curettage >>> surface swab. Surface swabs grow colonizers, not pathogens. Obtain AFTER debridement of necrotic tissue.

If moderate-severe or systemic signs

Blood cultures × 2 -draw before starting antibiotics. Positive in ~15% of moderate-severe DFI.
Procalcitonin -helps distinguish systemic infection from localized; useful for monitoring treatment response
Lactate -if concern for sepsis
Coags -if surgical intervention planned

NEVER base antibiotic therapy on surface swab cultures. Every chronic wound is colonized -swabs grow colonizers (often multidrug-resistant), leading to inappropriately broad antibiotics. Always obtain deep tissue culture during debridement or curettage of the ulcer base.

Imaging

Modality	When to Order	Key Findings	Limitations
X-ray (plain film)	First-line, all patients	Soft tissue gas, foreign body, cortical erosion, periosteal reaction	Osteomyelitis changes take 10-14 days to appear; sensitivity only ~55%
MRI	Gold standard for osteomyelitis	Bone marrow edema, rim enhancement, soft tissue extent	Sensitivity ~90%, specificity ~80%. Charcot arthropathy can mimic osteo.
WBC-labeled scan	When MRI contraindicated	Focal uptake in bone = osteomyelitis	Lower resolution; paired with sulfur colloid scan for specificity

Vascular Assessment

ABI (ankle-brachial index) -first-line. ABI < 0.9 = PAD. ABI < 0.5 = critical limb ischemia. Caution: ABI may be falsely elevated (> 1.3) in diabetics due to medial artery calcification.
TBI (toe-brachial index) -more reliable in diabetics (toe arteries less prone to calcification). TBI < 0.7 = PAD, TBI < 0.4 = unlikely to heal without revascularization.
Arterial duplex ultrasound -anatomic localization of stenosis/occlusion if revascularization considered
CTA/MRA -pre-surgical planning for revascularization

No wound will heal without adequate blood supply. If ABI < 0.5 or TBI < 0.4, consult vascular surgery for revascularization BEFORE expecting wound healing from antibiotics and wound care alone.

Consults

Podiatry -wound care, debridement, offloading strategies, custom orthotics
Vascular surgery -if ABI/TBI abnormal or absent pedal pulses → revascularization evaluation
Orthopedics/Plastics -if deep tissue debridement needed, bone resection for osteomyelitis, or soft tissue reconstruction
Infectious disease -moderate-severe infections, osteomyelitis, MRSA/MDR organisms, treatment failures
Endocrinology -if HbA1c > 9% or uncontrolled glycemia

🚨 Management

Management by Severity

Mild (IDSA Grade 2) -Outpatient

Oral antibiotics targeting gram-positives (Staph, Strep)
Amoxicillin-Clavulanate (Augmentin) 875/125 mg PO BID -covers MSSA, Strep, anaerobes
If MRSA risk: TMP-SMX (Bactrim) DS BID + Cephalexin (Keflex) 500 mg QID (TMP-SMX alone has gaps in Strep coverage)
Wound care: sharp debridement of necrotic tissue, moist wound environment
Offloading: non-weight-bearing or therapeutic footwear
Follow-up in 48-72 hours to assess response. If worsening or no improvement → escalate to inpatient.
Duration: 1-2 weeks

Moderate (IDSA Grade 3) -Inpatient

Hospitalize for IV antibiotics, surgical evaluation, vascular assessment
Ampicillin-Sulbactam (Unasyn) 3g IV q6h -covers gram-positives, gram-negatives, anaerobes
OR Piperacillin-Tazobactam (Zosyn) 3.375g IV q6h if Pseudomonas risk (water exposure, failed prior therapy)
Add Vancomycin (Vancocin) if MRSA risk factors present
Surgical evaluation: debridement, I&D of abscesses, bone biopsy if osteomyelitis suspected
Vascular assessment: ABI/TBI → vascular surgery consult if abnormal
IV-to-oral step-down when clinically improving, adequate source control, and susceptibilities known OVIVA, 2019
Duration: 2-3 weeks (soft tissue only); 6 weeks if osteomyelitis

Severe (IDSA Grade 4) -Emergent

Urgent surgical debridement -do not delay for imaging
Broad-spectrum IV: Vancomycin (Vancocin) + Piperacillin-Tazobactam (Zosyn) 4.5g IV q6h
OR Vancomycin (Vancocin) + Meropenem (Merrem) 1g IV q8h if MDR risk
ICU admission if septic (hemodynamic instability, organ dysfunction)
Blood cultures, lactate, aggressive fluid resuscitation
Amputation may be limb- or life-saving in extensive gangrene or necrotizing infection
Duration: 2-4 weeks (adjust based on surgical margins and response)

Osteomyelitis Management

Medical (antibiotics alone): 6 weeks total duration. Consider if no surgical indication (stable bone, no abscess, no dead bone).
Surgical resection + antibiotics: If bone is resected with clean margins, duration can be shortened to 2-4 weeks post-resection IDSA DFI Guidelines, 2012
Bone biopsy -gold standard for diagnosis AND culture-guided therapy. Surface swab does NOT correlate with bone pathogens.
IV-to-oral switch -acceptable once clinically stable with identified organism and susceptibility-guided oral agent with good bone penetration (fluoroquinolones, TMP-SMX, linezolid, doxycycline) OVIVA, 2019

OVIVA Trial (2019): Oral antibiotics were non-inferior to IV for bone and joint infections at 1 year (treatment failure 14.6% oral vs 14.1% IV). This supports early IV-to-oral switch when an appropriate oral agent is available.

Wound Care Principles

Debridement -sharp debridement of all necrotic, callous, and nonviable tissue. Repeat as needed.
Offloading -total contact cast (TCC) is gold standard for plantar ulcers. Alternatives: removable cast walkers, therapeutic shoes. Non-weight-bearing if possible.
Moist wound healing -appropriate dressings (foam, alginate, hydrogel) to maintain moisture without maceration
Glycemic control -target glucose < 180 mg/dL during acute infection. Long-term HbA1c < 7% for optimal healing.
Nutrition -correct protein-calorie malnutrition. Consider wound healing supplements (zinc, vitamin C). Note: albumin/prealbumin reflect inflammation, not nutritional status (ASPEN, 2021).

Vascular Intervention

Revascularization if ABI < 0.5 or TBI < 0.4 -wound will not heal without adequate perfusion
Options: angioplasty/stenting (endovascular) or bypass grafting (surgical)
Timing: revascularize early -do not wait for antibiotic course to fail before addressing ischemia
Multidisciplinary approach: vascular surgery + ID + podiatry = best outcomes

💊 Medications

Empiric Antibiotic Selection

Severity	Empiric Regimen	Organisms Covered	Duration	Key Notes
Mild	Amoxicillin-Clavulanate (Augmentin) 875/125 PO BID	MSSA, Strep, anaerobes	1–2 weeks	First-line for most mild DFI without MRSA risk
Mild + MRSA risk	TMP-SMX (Bactrim) DS BID + Cephalexin (Keflex) 500 mg QID	MRSA, MSSA, Strep	1–2 weeks	TMP-SMX alone has Strep gap -add cephalexin
Moderate	Ampicillin-Sulbactam (Unasyn) 3g IV q6h	Gram-pos, gram-neg, anaerobes	2–3 weeks	Workhorse for moderate DFI. Add vanco if MRSA risk.
Moderate (Pseudomonas risk)	Piperacillin-Tazobactam (Zosyn) 3.375g IV q6h ± Vancomycin (Vancocin)	Broad including Pseudomonas, MRSA	2–3 weeks	Water exposure, failed prior therapy, tropical climate
Severe	Vancomycin (Vancocin) + Piperacillin-Tazobactam (Zosyn) 4.5g IV q6h	MRSA, Pseudomonas, GNR, anaerobes	2–4 weeks	Escalate to meropenem if MDR risk
Severe (MDR risk)	Vancomycin (Vancocin) + Meropenem (Merrem) 1g IV q8h	MRSA, ESBL, Pseudomonas, anaerobes	2–4 weeks	Reserve for MDR, prior broad abx exposure, nosocomial
Osteomyelitis	Guided by bone culture	Culture-directed	6 weeks (or 2–4 wks post-resection)	IV-to-oral switch acceptable OVIVA, 2019

MRSA-Specific Agents

Drug	Dose	Route	Key Notes
Vancomycin (Vancocin)	15–20 mg/kg IV q8–12h (target AUC/MIC 400-600)	IV	First-line IV MRSA agent. Monitor troughs or AUC. Nephrotoxic.
Daptomycin (Cubicin)	6–8 mg/kg IV daily	IV	Alternative to vancomycin. Check weekly CPK. Inactivated by surfactant -do not use for pneumonia.
Linezolid (Zyvox)	600 mg PO/IV q12h	PO/IV	100% oral bioavailability. Good bone penetration. Limit to 2 weeks if possible (serotonin syndrome, myelosuppression, lactic acidosis with prolonged use).
TMP-SMX (Bactrim)	DS 1-2 tabs PO BID	PO	Good MRSA coverage. Add cephalexin for Strep gap. Good bone penetration.
Doxycycline	100 mg PO BID	PO	Alternative oral MRSA option. Good soft tissue penetration.

OPAT-Friendly Options

Ertapenem (Invanz) 1g IV daily -once-daily, covers gram-pos + gram-neg + anaerobes. NO Pseudomonas coverage. Excellent for moderate DFI OPAT. SIDESTEP, 2005
Daptomycin (Cubicin) 6 mg/kg IV daily -once-daily MRSA option for OPAT
Ceftriaxone (Rocephin) 2g IV daily + Metronidazole (Flagyl) 500 mg PO TID -alternative once-daily IV backbone

SIDESTEP Trial (2005): Ertapenem was non-inferior to piperacillin-tazobactam for diabetic foot infections, with the advantage of once-daily dosing -making it ideal for outpatient parenteral therapy (OPAT).

Duration Summary

Infection Type	Duration	Notes
Mild soft tissue	1–2 weeks	Outpatient oral. Reassess at 48–72h.
Moderate soft tissue	2–3 weeks	IV → oral step-down when improving
Severe soft tissue	2–4 weeks	Based on response, source control adequacy
Osteomyelitis (no surgery)	6 weeks	Culture-guided. IV-to-oral switch acceptable.
Osteomyelitis (post-resection, clean margins)	2–4 weeks	Shortened if bone resected with no residual infected bone
Post-amputation (clean margins)	2–5 days	Prophylactic only if margins clear. Longer if margins positive.

📋 On Rounds

Pimp Questions

Why should you get deep tissue cultures instead of surface swabs in diabetic foot infections?

Surface swabs grow colonizing organisms (every chronic wound is colonized), NOT the true pathogens causing deep infection. Deep tissue cultures from debridement or curettage provide accurate pathogen ID and sensitivities. Surface swabs lead to inappropriately broad antibiotics and treatment failures. Never base antibiotic selection on surface swab cultures.

What is the significance of ESR > 70 in a diabetic foot wound?

ESR > 70 mm/hr has ~90% specificity for osteomyelitis in the DFI setting. Combined with a positive probe-to-bone test, the probability of osteo approaches 95%. While not diagnostic alone, it significantly raises pre-test probability and supports MRI imaging. ESR is also useful for monitoring treatment response during antibiotic therapy.

A patient has a diabetic foot ulcer with a positive probe-to-bone test but normal X-ray. What do you do next?

Order an MRI -gold standard for osteomyelitis (sensitivity ~90%). Plain film changes take 10-14 days to appear and have sensitivity of only ~55%. A positive probe-to-bone test (LR ~6) already raises probability significantly. MRI shows bone marrow edema and rim enhancement before cortical destruction is visible on X-ray. Do not wait for X-ray changes to treat osteomyelitis.

When can you switch from IV to oral antibiotics for diabetic foot osteomyelitis?

The OVIVA trial (2019) showed oral antibiotics are non-inferior to IV for bone/joint infections. Switch when: (1) clinically improving, (2) adequate source control (debridement done), (3) organism identified with susceptibilities, (4) a highly bioavailable oral agent with good bone penetration is available (fluoroquinolones, TMP-SMX, linezolid). No need for 6 weeks of IV.

Why is vascular assessment critical before starting wound care in a diabetic foot?

No wound heals without adequate blood supply. If ABI < 0.5 or TBI < 0.4, the foot has critical limb ischemia -antibiotics and wound care alone will fail. Revascularization must be pursued before expecting healing. Note: ABI may be falsely elevated (> 1.3) in diabetics due to medial artery calcification -TBI is more reliable. The triad for DFI success = antibiotics + surgery + vascular perfusion.

What is the role of total contact casting in diabetic foot ulcers?

Total contact cast (TCC) is the gold standard for offloading plantar ulcers. It redistributes pressure across the entire foot, reducing focal pressure at the ulcer site by 60-80%. TCC achieves healing rates of ~90% within 12 weeks vs ~30% with standard footwear. Compliance is built in -the patient cannot remove it. Contraindications: active deep infection, significant PAD, excessive drainage.

Clinical Examples

📋 Case 1, Moderate DFI with Osteomyelitis

Patient: 62M with T2DM (A1c 9.8%), presents with left foot ulcer between 4th and 5th toes, purulent drainage, erythema extending 3 cm from wound edge, no fever, WBC 11.2.

Bedside assessment:

Probe-to-bone test: sterile probe contacts hard, gritty surface → POSITIVE (PPV ~89%).
Erythema 3 cm → moderate infection (IDSA grade 3).
Pedal pulses: dorsalis pedis faint, posterior tibial absent → order ABI.

Workup: ESR 82 (> 70 → high specificity for osteo). X-ray: cortical erosion 5th metatarsal head. MRI: bone marrow edema with rim enhancement → confirms osteomyelitis. ABI 0.6 → significant PAD.

Management:

Admit. Ampicillin-Sulbactam (Unasyn) 3g IV q6h + Vancomycin (Vancocin) (MRSA risk)
Surgical consult: debridement + deep bone biopsy for culture (NOT surface swab)
Vascular surgery consult: ABI 0.6 → may need revascularization for wound healing
6 weeks antibiotics for osteomyelitis, guided by bone culture. IV-to-oral switch acceptable OVIVA, 2019
Glucose control: target < 180 during acute infection

Teaching point: The triad for DFI success = antibiotics + surgical debridement + vascular assessment. Missing any one → treatment failure.

📋 Case 2, Severe DFI with Sepsis

Patient: 71F with T2DM, CKD3, presents with foul-smelling left foot wound, crepitus on palpation, T 39.4°C, HR 118, BP 88/52, WBC 24k, lactate 4.1.

Key findings: Wet gangrene of 1st and 2nd toes with gas on palpation. Absent pedal pulses bilaterally. SIRS/sepsis criteria met → IDSA grade 4 (severe).

Management:

Fluid resuscitation: 30 mL/kg LR. Blood cultures × 2.
Vancomycin (Vancocin) + Meropenem (Merrem) 1g IV q8h (broad coverage including MRSA, Pseudomonas, anaerobes)
Emergent surgical consult: debridement vs partial amputation. Do NOT delay surgery for imaging.
X-ray confirms gas in soft tissue → surgical emergency.
Vascular assessment post-stabilization: CTA to evaluate for revascularization potential.

Teaching point: Gas gangrene / necrotizing infection in a diabetic foot is a surgical emergency. Antibiotics are adjunctive -the scalpel is the definitive treatment. Amputation may be life-saving.

📋 Case 3, Mild DFI Managed Outpatient

Patient: 55M with well-controlled T2DM (A1c 6.9%), presents with plantar ulcer under 2nd metatarsal head, mild surrounding erythema (1.5 cm from wound edge), no purulence, no systemic signs. Pedal pulses 2+ bilaterally.

Assessment: IDSA grade 2 (mild). Probe-to-bone negative. ABI 1.0 (normal vasculature). X-ray: no bony changes.

Management:

Amoxicillin-Clavulanate (Augmentin) 875/125 PO BID × 2 weeks
Sharp debridement of wound edges, moist dressing changes daily
Offloading: removable cast walker, strictly non-weight-bearing to affected foot
Follow-up in 48-72 hours: mark erythema borders to track progression
Diabetes education: daily foot checks, proper footwear, glucose control

Teaching point: Not every DFI needs hospitalization. Mild infections with intact vasculature, no deep tissue involvement, and no systemic signs can be safely managed outpatient with close follow-up. The key is reliable follow-up at 48-72h to confirm response.

Sample Presentation

One-Liner

"Mr. Garcia is a 62-year-old with uncontrolled T2DM who presented with a left foot ulcer with 3 cm surrounding erythema, positive probe-to-bone test, and MRI-confirmed osteomyelitis of the 5th metatarsal, consistent with moderate diabetic foot infection with osteomyelitis."

Key Points to Cover on Rounds

IDSA severity: moderate (grade 3) with osteomyelitis. Antibiotics: Unasyn day 3, bone biopsy culture growing MSSA -narrowing to nafcillin, planning IV-to-oral switch to TMP-SMX per OVIVA data. Wound: post-debridement, granulation tissue forming, no residual necrosis. Vascular: ABI 0.6, vascular surgery recommends angioplasty for SFA stenosis -scheduled for tomorrow. Glucose: on insulin drip, target < 180, transitioning to basal-bolus today. ESR trending 82 → 64. Plan: 6-week antibiotic course from bone biopsy date, oral step-down after revascularization, podiatry for TCC when wound ready.

Daily Rounds Checklist

Wound assessment → Erythema improving or expanding? Mark borders daily. Any new drainage, crepitus, or necrosis?
Cultures finalized? → Narrow antibiotics when sensitivities return. What day of antibiotics are we on?
Osteomyelitis addressed? → Bone biopsy done? MRI obtained? Surgical plan for resection vs medical management?
Vascular status → ABI/TBI ordered? Vascular surgery consult? Revascularization plan?
Glucose control → Target < 180 mg/dL. On insulin drip vs basal-bolus? HbA1c obtained?
Offloading in place? → Non-weight-bearing? TCC or removable cast walker ordered?
Inflammatory markers → ESR/CRP trending down? If plateauing, reassess source control and antibiotic adequacy.
Nutrition → Adequate protein intake for wound healing? Note: albumin/prealbumin reflect inflammation, NOT nutritional status (ASPEN, 2021). Assess nutrition by intake history, weight trend, and physical exam.
IV-to-oral switch? → Clinically improving + adequate source control + oral agent with good bone penetration available? OVIVA, 2019
Discharge planning → OPAT if continued IV needed? Podiatry follow-up? Wound care plan? Diabetes education?

Monitoring Parameters

Parameter	Frequency	Target / Action
Wound assessment	Daily	Mark erythema borders, measure wound size, assess drainage
Temperature	q4–8h	Defervescence expected within 48–72h of appropriate therapy
WBC / CRP	q48–72h	Trending down = responding. Plateau = reassess source control.
ESR	Weekly (osteo)	Slow decline expected. Useful for monitoring 6-week course.
Blood glucose	AC/HS or q6h	< 180 mg/dL. Hyperglycemia impairs wound healing + neutrophil function.
Vancomycin level	Before 4th dose or per protocol	AUC/MIC 400–600. Troughs 15–20 mcg/mL (traditional). Monitor renal function.
Renal function (BMP)	q48–72h on nephrotoxic abx	Vancomycin, aminoglycosides, contrast dye → monitor Cr closely.

⚡ Summary

One-Screen Summary

Classification

IDSA 1-4: uninfected → mild (erythema < 2 cm) → moderate (> 2 cm, deep) → severe (SIRS/sepsis). Classification drives management.

Probe-to-Bone

PPV ~89% for osteomyelitis. Do on every DFI. Positive LR ~6. If positive → order MRI. Simple, bedside, 10 seconds.

Mild (Outpatient)

Augmentin PO or TMP-SMX + cephalexin (if MRSA risk). 1-2 weeks. Follow-up 48-72h.

Moderate-Severe

Unasyn or Zosyn IV ± vancomycin. Severe: vanco + Zosyn/meropenem. Surgical eval for debridement.

Osteomyelitis

MRI gold standard. ESR > 70 specific. Bone biopsy for culture. 6 wks abx (2-4 wks if resected). IV-to-oral OK (OVIVA).

Vascular

ABI/TBI assessment. ABI < 0.5 or TBI < 0.4 = revascularize. Ischemic foot won't heal regardless of antibiotics.

Cultures

Deep tissue only. NEVER surface swabs -grow colonizers, not pathogens. Bone biopsy for osteo.

Triad for Success

Antibiotics + surgical debridement + vascular perfusion. Missing any one = treatment failure.

📄 One Pager

Infectious Disease · One Pager

Diabetic Foot Infection

Neuropathy + ischemia + hyperglycemia = ulcer + infection. Classify by IDSA severity. Probe every wound for bone. Triad: antibiotics + surgery + vascular perfusion.

🧪 Workup

Probe-to-bone on every wound (PPV ~89%)
Deep tissue culture (NOT surface swab)
X-ray first, MRI for osteo (sens ~90%)
ESR > 70 = high specificity for osteo
ABI/TBI for vascular assessment
CBC, BMP, CRP, HbA1c

📊 IDSA Classification

Mild (2): Erythema < 2 cm, superficial
Moderate (3): Erythema > 2 cm, deep, no SIRS
Severe (4): SIRS/sepsis, limb-threatening
Limb-threatening: gas, crepitus, wet gangrene
Osteomyelitis: probe-to-bone +, ESR > 70

🚨 Management by Severity

1

Mild: Augmentin PO or TMP-SMX + cephalexin. Outpatient. 1-2 wks.

2

Moderate: Unasyn IV ± vanco. Zosyn if Pseudomonas risk. Surgery eval. 2-3 wks.

3

Severe: Vanco + Zosyn/meropenem. Emergent debridement. ICU if septic.

4

Osteo: Bone biopsy + 6 wks abx. Post-resection: 2-4 wks. IV→PO OK (OVIVA).

5

Vascular: ABI < 0.5 / TBI < 0.4 → revascularize before expecting healing.

6

Wound: Debride, offload (TCC), moist dressing, glucose < 180.

💊 Key Drugs

Augmentin875/125 PO BID

Unasyn3g IV q6h

Zosyn3.375-4.5g IV q6h

Vancomycin15-20 mg/kg IV q8-12h

Ertapenem1g IV daily (OPAT)

Meropenem1g IV q8h (severe)

📊 Duration

Mild: 1-2 weeks
Moderate: 2-3 weeks
Severe: 2-4 weeks
Osteo (medical): 6 weeks
Osteo (post-resection): 2-4 wks

⚠️ Pitfalls

Surface swab cultures (colonizers!)
Ignoring vascular assessment
Falsely elevated ABI (calcification)
Delaying surgery for imaging
No offloading plan

🏥 Consults

Podiatry: wound care, offloading
Vascular surgery: if PAD / ischemia
Ortho/Plastics: debridement, resection
ID: moderate-severe, osteo, MDR

🎓 Key Trials

OVIVA 2019: Oral non-inferior to IV for bone/joint infections
SIDESTEP 2005: Ertapenem non-inferior to pip-tazo for DFI
IDSA 2012: DFI classification and management guidelines