Emergency Medicine · Trauma and Wound Care
The facts most likely to be tested
Primary intention closure is indicated for clean, non-contaminated wounds with low risk of infection that can be approximated within 6 to 18 hours.
Delayed primary closure (tertiary intention) is the preferred management for heavily contaminated, high-risk, or infected wounds to allow for granulation before surgical approximation.
Tetanus prophylaxis is required for all wounds that are not clean or minor if the patient has an uncertain or incomplete vaccination history, regardless of the time since the last dose.
Facial lacerations have a high vascular supply and can be safely closed up to 24 hours after injury, whereas wounds on the trunk or extremities should generally be closed within 6 to 12 hours.
Prophylactic antibiotics are indicated for high-risk wounds, including those involving human or animal bites, deep puncture wounds, or wounds with significant devitalized tissue.
Irrigation with high-pressure saline is the most effective method for reducing bacterial load and preventing surgical site infection in traumatic wounds.
Lidocaine with epinephrine is contraindicated for use in distal appendages (fingers, toes, nose, penis, ears) due to the risk of vasoconstriction-induced tissue ischemia and necrosis.
Vignette unlocked
A 24-year-old male presents to the emergency department after sustaining a 4 cm laceration to his left forearm from a rusty piece of metal 14 hours ago. The wound is heavily contaminated with debris and shows signs of devitalized tissue at the edges. The patient has not received a tetanus booster in over 15 years. Physical examination reveals no neurovascular deficits.
What is the most appropriate management for this wound?
Debridement and delayed primary closure
This vignette tests the principle of delayed primary closure for contaminated wounds; because the wound is high-risk and exceeds the window for primary intention, it must be cleaned and left open to prevent abscess formation.
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Etiology / Epidemiology
Traumatic skin disruption requiring primary intention closure. Immunocompromised status and diabetes are primary risk factors for infection.
Clinical Manifestations
Assess for neurovascular compromise and tendon involvement. Active pulsatile bleeding indicates arterial injury.
Diagnosis
Clinical diagnosis via thorough physical exam. Radiographs are mandatory if foreign body or fracture is suspected.
Treatment
Irrigation with normal saline and primary closure within 6-18 hours. Do not use epinephrine on end-artery structures.
Prognosis
Monitor for cellulitis or abscess. Tetanus prophylaxis is required if status is unknown or >5 years for dirty wounds.
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Epidemiology & Etiology
Lacerations result from mechanical trauma, shear, or crush forces. Diabetes mellitus, peripheral vascular disease, and advanced age significantly impair healing and increase infection risk. High-risk wounds include those from animal bites or contaminated environments.
Pertinent Anatomy
The Langer lines dictate tension patterns; incisions parallel to these lines result in superior cosmetic outcomes. Always evaluate the neurovascular bundle distal to the wound to rule out nerve transection or ischemia. In hand injuries, assess for tendon retraction by checking active range of motion.
Pathophysiology
Wound healing progresses through hemostasis, inflammation, proliferation, and remodeling. Infection occurs when bacterial load exceeds 10^5 organisms per gram of tissue. Crush injuries and puncture wounds have higher infection rates due to tissue devitalization and deep inoculation.
Clinical Manifestations
Evaluate for neurovascular deficit, tendon laceration, and foreign body. Red flags include paresthesia, loss of distal pulse, or inability to move digits. A fish-mouth appearance of the wound edges suggests deep tissue involvement.
Diagnosis
Diagnosis is clinical, but plain film radiography is the gold standard for detecting radiopaque foreign bodies like glass or metal. If a deep puncture is present, ultrasound may be used to identify non-radiopaque objects. Always document distal neurovascular status before and after anesthesia.
Treatment
Irrigate with high-pressure normal saline. Use lidocaine with epinephrine for hemostasis, but do not use epinephrine on fingers, toes, nose, or penis due to risk of ischemic necrosis. Close with sutures or skin staples; avoid primary closure for high-risk bite wounds or wounds >18 hours old.
Prognosis
Infection is the most common complication, presenting as erythema, purulence, or fever. Tetanus status must be updated if the patient has not received a booster within 5 years for contaminated wounds or 10 years for clean wounds.
Differential Diagnosis
Tendon laceration: loss of active movement distal to injury
Nerve transection: sensory deficit or motor weakness
Foreign body: persistent pain or palpable mass
Arterial injury: pulsatile bleeding or distal pallor
Infected wound: spreading cellulitis or systemic toxicity