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This is a clinician-written, evidence-based summary aligned to the USMLE Step 2 CK Content Outline. It is intended for medical students preparing for USMLE Step 2 CK. Management reflects current ACC/AHA, USPSTF, and APA guidelines. Always cross-reference with UpToDate, institutional protocols, and clinical judgment.
The Bottom Line
- Wound healing phases: hemostasis, inflammation, proliferation/granulation, remodeling
- Major causes of poor healing: ischemia, infection, diabetes, edema, malnutrition, smoking, steroids, pressure/shear, foreign body
- Pressure injuries occur over bony prominences: sacrum, heels, hips, ischia, elbows, occiput
- Management requires pressure offloading/repositioning, moisture control, nutrition, debridement of devitalized tissue, and treatment of infection only when clinically present
- Stage 1 has nonblanchable erythema; Stage 2 partial-thickness; Stage 3 full-thickness fat; Stage 4 exposed bone/tendon/muscle; unstageable is obscured by slough/eschar
Overview
Normal wound healing proceeds through hemostasis, inflammation, proliferation with granulation tissue and re-epithelialization, and remodeling with collagen maturation. Chronic wounds stall because of persistent inflammation, bacterial burden, ischemia, edema, pressure, or systemic impairment. Pressure injuries are localized damage to skin and underlying soft tissue, usually over a bony prominence or related to a medical device, caused by pressure, shear, or both. Step 2 CK emphasizes staging, prevention, and the principle that pressure relief is the treatment foundation.
Epidemiology
Pressure injuries are common in hospitalized, nursing home, spinal cord injury, critically ill, immobile, malnourished, incontinent, and older patients. Risk increases with impaired sensation, diabetes, peripheral arterial disease, edema, poor perfusion, vasopressors, moisture, friction/shear, and low albumin or inadequate protein intake. Chronic wounds also include venous leg ulcers, arterial ulcers, diabetic foot ulcers, and nonhealing surgical wounds, each requiring etiology-specific management.
Clinical Features
Symptoms
Pain may be present, but patients with neuropathy or spinal cord injury may not feel pressure injury
Drainage, odor, increasing pain, warmth, spreading erythema, fever, or systemic symptoms suggest infection
Nonhealing despite appropriate care suggests ischemia, osteomyelitis, malignancy, or ongoing pressure
Claudication/rest pain suggests arterial insufficiency; heavy exudate/edema suggests venous disease
Signs
Stage 1 pressure injury: intact skin with nonblanchable erythema or color change
Stage 2: partial-thickness skin loss with exposed dermis or serum-filled blister; no slough
Stage 3: full-thickness skin loss with visible adipose tissue; no exposed bone/tendon/muscle
Stage 4: exposed or directly palpable fascia, muscle, tendon, ligament, cartilage, or bone
Unstageable: full-thickness tissue loss obscured by slough/eschar; deep tissue injury: persistent nonblanchable deep red/maroon/purple discoloration
Investigations
First-line
Risk and wound assessmentLocation, size, depth, undermining/tunneling, exudate, odor, necrosis, surrounding skin, pain, pressure source, mobility, continence, nutrition
Pressure injury stagingStage by deepest visible tissue type. Do not reverse-stage healing ulcers; document healing stage instead
Vascular assessmentPalpate pulses; ABI or toe pressures if lower-extremity wound, diabetes, PAD signs, or before compression therapy
Second-line
LabsCBC, CMP, HbA1c, ESR/CRP if infection/osteomyelitis concern; albumin/prealbumin may reflect risk but are inflammation-sensitive
CultureDo not culture clean colonized wounds routinely. Obtain deep tissue/bone culture after debridement when clinical infection suspected
Probe-to-bone and imagingProbe-to-bone, plain X-ray, ESR/CRP; MRI is best imaging for osteomyelitis if diagnosis uncertain
Specialist
BiopsyChronic nonhealing ulcer with rolled/everted edges, exuberant granulation, bleeding, or atypical features to rule out SCC/Marjolin ulcer or inflammatory ulcers
Surgical/wound care consultationFor Stage 3/4, extensive necrosis, suspected osteomyelitis, ischemia, deep infection, or flap closure consideration
1
Prevention
- Risk assessment on admission and when clinical status changes
- Repositioning schedule individualized to support surface, tissue tolerance, and goals of care
- Pressure-redistributing mattress/cushions; heel offloading; minimize head-of-bed elevation when possible to reduce shear
- Moisture/incontinence management, barrier products, gentle cleansing
- Optimize nutrition: adequate calories, protein, hydration, vitamins/minerals when deficient
2
Local wound care
- Relieve pressure/offload the wound; no dressing will heal an ulcer under ongoing pressure
- Cleanse with normal saline or appropriate wound cleanser; avoid cytotoxic routine antiseptics in clean healing wounds
- Choose moisture-balancing dressings based on exudate: foam, hydrocolloid, alginate, hydrofiber, hydrogel, transparent film, or gauze when appropriate
- Debride devitalized tissue unless contraindicated by stable dry heel eschar or severe ischemia awaiting vascular evaluation
- Manage pain before dressing changes and debridement
3
Infection management
- Colonization is expected; systemic antibiotics are not indicated without clinical infection
- Treat cellulitis, sepsis, osteomyelitis, or deep soft-tissue infection with systemic antibiotics guided by cultures when possible
- Urgent surgical evaluation for crepitus, necrosis, rapidly spreading infection, systemic toxicity, or suspected necrotizing infection
4
Advanced and etiology-specific care
- Negative pressure wound therapy may help selected Stage 3/4 or surgical wounds after adequate debridement and infection control
- Vascular referral/revascularization for arterial insufficiency; compression for venous ulcers only after adequate arterial assessment
- Diabetic foot ulcers require offloading, glycemic control, vascular assessment, infection management, and footwear/podiatry care
- Flap closure for selected clean, well-vascularized Stage 3/4 ulcers when nutrition, pressure control, and comorbidities are optimized
Complications
- Cellulitis and sepsis: Spreading erythema, warmth, fever, systemic instability
- Osteomyelitis: Especially Stage 4 ulcers over sacrum/ischium/heel or diabetic foot wounds
- Necrotizing soft tissue infection: Pain out of proportion, crepitus, shock, necrosis
- Marjolin ulcer: SCC arising in chronic wound or burn scar
- Amputation: Severe diabetic/ischemic infected wounds
- Recurrence: Common if pressure, nutrition, mobility, or moisture drivers persist
USMLE Step 2 CK Exam Tips
- 1Best treatment for pressure ulcer is pressure relief/offloading; dressings alone are never enough
- 2Stage 1 = nonblanchable erythema with intact skin
- 3Stage 2 = partial-thickness dermis; Stage 3 = fat visible; Stage 4 = bone/tendon/muscle exposed
- 4Unstageable means slough/eschar blocks depth assessment
- 5Do not give antibiotics for colonized chronic ulcer without clinical infection
- 6MRI is best test for suspected osteomyelitis under chronic ulcer; bone biopsy/culture is definitive
- 7Stable dry heel eschar may be left intact if no infection and poor perfusion
- 8Chronic ulcer that becomes heaped/rolled/bleeding = biopsy for Marjolin SCC
practicetest your knowledge on wound healing & pressure ulcersApply what you've learnt with USMLE Step 2 CK-style questions from the iatroX Q-Bank — dermatology and beyond.
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