L-29 Skin Trauma: Abrasions, Punctures, and Lacerations

• Skin trauma involves disruption of the epidermis and underlying tissues.
• Acute traumatic injuries, such as abrasions, punctures, crushes, burns, gunshots, animal bites, or surgery, can cause skin trauma.
• Disease states like peripheral artery disease, diabetes, and chronic venous disease can alter wound healing.
• Small vessel arterial diseases lead to skin ulcers and poor healing due to vascular issues.

Four Basic Types of Wounds:

• Abrasions occur when skin scrapes against a rough surface.
• Puncture wounds are small holes from pointy objects and can damage internal organs if deep.
• Lacerations involve deep cuts or tearing of skin, potentially causing rapid, heavy bleeding if deep.
• Avulsions are partial or complete tearing away of skin and underlying tissue.

Skin Abrasion Details:

• Skin abrasions are superficial injuries to the skin, confined to the epidermis, with minimal bleeding.
• Three types of abrasions exist: linear, grazed/brushed, and pattern.
• Wound evaluation involves determining the injury mechanism, timing, and assessment for foreign bodies.
• Abrasions are susceptible to Clostridium tetani and Staphylococcus aureus infections due to the loss of the epidermis.

Puncture Wound Details:

• A puncture wound is a penetrating injury from a pointed object.
• Common in distal extremities, especially the plantar surface of the foot.
• Complications: mild soft tissue infections to osteomyelitis.
• Infection risk factors: puncture wound characteristics (location, depth), material causing the puncture, host comorbidities (like S. Aureus in diabetes), and retained foreign bodies.

Cut/Laceration Details:

• Lacerations are wounds produced by tearing soft body tissue, often irregular and jagged.
• Lacerations are contaminated with bacteria and debris.
• Split lacerations: caused by compression of the skin between the weapon and bone.
• Torn lacerations: caused by a projecting surface of an object being dragged over the skin.
• Stretch lacerations: caused by a heavy blunt impact on a fixed, localized area of skin causing the skin to overstretch.

Wound Assessment:

• Key considerations: cleanliness, time since injury, tetanus status, foreign bodies, extent of wound, neurovascular injury, and cosmetic significance.

Normal Wound Healing:

• Wound healing progresses through hemostasis, inflammation, proliferation, and remodeling phases.
• Hemostasis: platelet aggregation, fibrin plug formation, growth factor release.
• Inflammation: wound debridement and cell recruitment (macrophages, neutrophils, monocytes).
• Proliferation: keratinocyte activity, ECM synthesis, angiogenesis, re-epithelization.
• Remodeling: fibroblast conversion, wound closure and formation of scar tissue.
• Chronic wounds are characterized by continual inflammation, damaging the developing extracellular matrix.

Risk Factors for Impaired Wound Healing:

• Infection impairs multiple wound healing steps, with smoking being associated with surgical site infection and pulmonary complications.
• Aging, malnutrition, and immobilization all hinder wound healing, as well as vascular disease which diminishes the delivery of oxygen and nutrients to the tissues.
• Immunosuppressive therapy can blunt the inflammatory phase of wound healing.

Initial Care for All Types of Wounds:

• Well-vascularized wound base, free of devitalized tissue and infection, is key for proper healing.
• Includes debridement and irrigation.
• All wounds are colonized with microbes, but antibiotics should be reserved for clinically infected wounds.

Abrasions and Minor Puncture Wounds Treatment:

• Keep wound clean and dry, cover as needed.
• Heal well without intervention.

Lacerations and Extensive Puncture Wounds Repair:

• Wounds from clean, sharp objects can undergo primary closure within 12-18 hours of injury.
• Head and neck wounds can be closed within 24 hours.
• Secondary intention (by granulation) is for deep stab or puncture wounds, contaminated wounds, abscess cavities, and late presentations.
• Cellulitis is an absolute contraindication to wound closure.

Adjunctive Therapies and Medications:

• Hyperbaric Oxygen Therapy (HBOT): increases oxygen levels in the blood, treats chronic wounds.
• Growth Factors and Bioengineered Tissue: promotes tissue growth and treats chronic wounds or burns.
• Electrical Stimulation Therapy: stimulates wound healing, treats chronic wounds or pressure ulcers.
• Compression Therapy: reduces swelling and improves blood flow to treat venous leg ulcers.
• Topical Agents and Dressings: promotes wound healing and prevents infection.

Prophylactic Antibiotics:

• Not needed for healthy patients with uncomplicated traumatic skin lacerations.

Special Circumstances: Animal and Human Bites

• Dog bites: about 90% of animal bites.
• Most victims are children.
• Bites by stray dogs in resource-limited regions are common causes of rabies transmission.
• Cat bites: approximately 10% of animal bite wounds.
• Cat bites are responsible for most emergency department visits for seriously infected bite wounds.
• Other mammals: uncommon.

Treatment for Animal Bites:

• Important to consider rabies prophylaxis in addition to tetanus.
• Dogs and cats: treat with amoxicillin-clavulanate, mixed oral flora, pasteurella multocida, anaerobes.
• Human bites: treat with amoxicillin-clavulanate, human oral flora, streptococcal spp, eikenella corrodens, anaerobes.

Puncture Wound to the Sole of the Foot:

• Empirical antibiotics use is not recommended.
• Antibiotics are usually used in highly contaminated injuries, or in patients with diabetes or who are immunocompromised.
• Organisms: pseudomonas aeruginosa and staph aureus.
• Pseudomonas aeruginosa: commonly isolated from plantar punctures in those wearing tennis shoes.
• Antibiotics: cephalexin for s. aureus, fluoroquinolones for pseudomonas aeruginosa.