Description

Disclaimer: Content is for educational exam preparation only and does not constitute medical advice. Medicine changes quickly; always verify with current, local guidelines before applying to patient care.

I. WOUNDS

Wound Infection Risk Based on Location

(Highest risk to Lowest risk):

1. Legs and thighs.
2. Arms.
3. Feet.
4. Chest and back.
5. Face.
6. Scalp (lowest risk due to high vascularization).

Indications for Antibiotics (CC FAM)

Antibiotics are indicated for the following types of wounds:

• Contaminated or Crush injuries.
• Cartilage injuries (e.g., nose or ears).
• Fractures (open fractures).
• Animal bites (cat, dog, human, ferret, pig, camel, bear, big cats, monkeys, etc.).
• Missiles (penetrating injury to the foot like a nail, or a gunshot wound).
• Delayed wound closure.
• Through and through oral injuries.

Local Anesthetic Maximum Dosing

The following are the maximum doses of local anesthetics:

• Lidocaine with epinephrine (EPI): 7 mg/kg.
• Lidocaine without EPI: 4 mg/kg.
• Bupivacaine with EPI: 3.5 mg/kg.
• Bupivacaine without EPI: 2.5 mg/kg.

Local Anesthetic Toxicity Symptoms

Toxicity can manifest in several systems:

• Early: Headache, tinnitus, metallic taste, perioral numbness, irritability.
• CNS Complications: Seizure, coma.
• CVS Complications: Ectopy, arrhythmias, decreased contractility, and arrest.
• Other: Methemoglobinemia.

Tissue Adhesives (Pros and Cons)

Tissue adhesives are beneficial but have limitations:

• Pros: Quick, cheap, comfortable, do not require removal, possess some antimicrobial properties, eliminate risk of needlestick injuries, and offer similar cosmesis to sutures.
• Cons: Can only be used for small wounds (less than 4 cm), cannot be used for wounds with high tension, incompatible with creams, cannot be submerged (will dissolve), and carry a higher risk of dehiscence due to lower tensile strength.

Suture Material and Dissolution

Suture materials can be biologic (higher reactivity, lower tensile strength, better knot security) or synthetic (lower reactivity, higher tensile strength, lower knot security).

• Common Biologic Examples: Cat gut, rapid gut, collagen, silk, linen, cotton.
• Rapid gut: 50% dissolved in 1 week.
• Regular gut: 50% dissolved within 4 weeks.
• Common Synthetic Examples: Dacron, nylon, proline, Vicryl, steel.
• Vicryl rapid: 50% dissolved in 1 week.
• Vicryl: 50% dissolved in 3 weeks.
• Non-dissolving: Nylon, proline, and steel.

Suture Removal Timelines

General timelines for suture removal:

• Face: 5 days.
• Most sutures: within 7 days.
• Limbs and joints: around 14 days.

Tetanus Prophylaxis

Prophylaxis includes immunization and immunoglobulin:

• Tetanus Immunization (TaP): Required if it has been 10 years since the last booster.
• Tetanus Immunoglobulin (TIG): Give 250 international units for an adult with any wound if they have an incomplete primary series (as per Rosens, CDC differs).

II. FOREIGN BODIES

Foreign Body Removal

Rectal Foreign Bodies:

• Digital removal.
• Removal with an anoscope and ring forceps.
• Use of a Foley catheter to break suction.
• Surgery.
• Non-standard technique: Filling hollow objects with plaster and a rope (Rosens has this listed, but please don't do this)

Body Packers vs. Body Stuffers:

• Body Packers: Swallow large amounts of well-packaged drugs.
• Treatment: Whole bowel irrigation. They must be monitored until they have three packet-free poops and a negative CT. If systemic toxicity occurs, immediate surgery is needed as the dose is likely lethal.
• Body Stuffers: Rapidly insert drugs (oral, vaginal, rectal); usually smaller amounts but poorer packaging. Higher likelihood of toxicity, but less significant than body packers if toxicity occurs.

ENT Foreign Bodies:

• Direct removal with forceps, blunt right angle hook, balloon catheter, or irrigation.
• Irrigation in the ear is contraindicated if the material is biologic (like a bean) or if there is a tympanic membrane (TM) perforation, in which case PO and topical antibiotics are required.
• If the object is an insect (bug), kill it chemically using 10% lidocaine spray, 2% lidocaine gel, alcohol, or mineral oil.

Airway Foreign Bodies:

• Infants: Five back blows followed by chest thrusts.
• Older than infants (awake):  AHA recommends allowing them to cough if moving air. If not, then for Peds and adults to have 5 back blows and 5 abdominal thrusts, alternating.
• Unresponsive/CPR: CPR at 30 to 2 with mouth checks every time before breaths. Use a laryngoscope or NP scope and attempt removal with Magill forceps if visible.
• If unable to intubate, push the tube into the right main stem, remove it (may extract the foreign body), and then reintubate.

Esophageal Foreign Bodies:

• Three Most Likely Locations for Lodgement:
1. Cricopharyngeal muscle (at the clavicle on X-ray).
2. Mid-esophagus (at the aortic arch or carina).
3. Distally (at the GE junction).
• Coin Appearance: If in the esophagus, a coin will appear flat on an AP X-ray (if in the trachea, it appears on its long edge).

Endoscopy Indications (Immediate Removal):

• Sharp object.
• Object longer than 5 cm or wider than 2 cm.
• Button batteries (due to risk of pressure necrosis, corrosion, and electrical current damage).
• Multiple magnets.

Non-Invasive Removal Techniques:

• Glucagon (1 mg IV) (though not supported by literature).
• Coca-Cola (for fizziness and potential dissolving properties).
• Balloon catheter with fluoroscopy removal.

III. BITES AND STINGS

Mammalian Bites

Dog Bites:

• Primary Concern: Capnocytophaga canimorsus (30% mortality, higher in alcoholics, asplenic, and immunosuppressed people).
• Other Pathogens: Staph aureus, Pasteurella, Corynebacterium, Moraxella, Fusobacterium.
• Suturing: Can suture closed, except for hands and feet.
• Antibiotics: Only needed for hands, feet, and high-risk wounds.

Cat Bites:

• Primary Concern: Pasteurella multocida.
• Mortality: 30% mortality rate if P. multocida reaches the blood (higher in patients with liver disease, COPD, and malignancy).
• Suturing: Only suture the face.
• Antibiotics: Give antibiotics for all wounds that break the dermis.

General Animal Bite Antibiotics:

• PO: Amoxicillin-clavulanate (Amoxyclav).
• Alternatives PO: Ciprofloxacin or Clindamycin and Septra.
• IV (Admission): Ertapenem, Ampicillin-sulbactam, or Clindamycin and Ciprofloxacin.

Rodent Bites: Do not require prophylactic antibiotics, and wounds can be closed.

Monkey Bites:

• Require Amoxyclav and tetanus update.
• Require prophylaxis for Monkey B virus (Herpes B virus), which has an 80% mortality rate in humans.
• Prophylaxis Dosing: Valacyclovir for 14 days (generally required for every bite).

Human Bites:

• Primary Bacterial Concern: Eikenella corrodens.
• Viral Concerns: Give Post-Exposure Prophylaxis (PEP) for Hepatitis B virus and HIV if the biter is infected, or based on risk calculations and discussion.

Reptile and Spider Bites

Venomous Snake Families:

• Elapidae (Coral snake, Cobra): Carry a neurotoxin that blocks choline receptors.
• Treatment: Always need antivenom (3 to 5 vials).
• Viperidae (Pit vipers, Rattlesnakes): Carry a hemotoxic toxin.

Pit Viper Envenomation Grading Scale (0 to 4):

• Grade 0: No envenomation.
• Grade 1: local edema only
• Grade 2 (Systemic Symptoms Begin): Systemic symptoms are present and swelling is spreading.
• Grade 3: Vital sign changes (e.g., hypotension) and changes in DIC labs.
• Grade 4: Neuro symptoms (e.g., fasciculations).

Pit Viper Treatment (CROFAB):

• CROFAB (ovine derived antivenom) is given for all Grade 2 or more envenomations (aka systemic symptoms).
• Initial Dosing (Quick Guide): Grade of severity times 3 (number of vials).
• Maintenance Dosing (Quick Guide): Grade itself (number of vials).
• CROFAB is the first-line treatment for compartment syndrome secondary to a pit viper bite.
• Adverse Event: Serum sickness (Type III hypersensitivity) occurs in 15% of cases one week post-exposure.

Black Widow Spider (Lactrodectism):

• Toxin Type: Neurotoxic (causes increase in acetylcholine).
• Specific Symptoms: Hypertension, rigid abdomen, priapism.
• Management: Observe for at least 6 hours, give Diazepam for spasms.
• Antivenom (Lyovac): Given to pediatrics, elderly, pregnant patients, or those with severe symptoms (seizure, respiratory failure, uncontrolled hypertension/pain).

Brown Recluse Spider (Loxosceles reclusa):

• Toxin Type: Hemolytic, vasoconstrictive, necrotic toxin.
• Classic Sign: Red, white, and blue bite mark (inflammation, spasm, necrosis).
• Treatment: Supportive care; hyperbaric oxygen may benefit later wound healing. Antivenom is only available in Brazil.

Bark Scorpion (Centuroides sculpturatus):

• Toxin Type: Neurotoxin (opens sodium channels).
• Treatment: Ice, tetanus update, antivenom (available), Atropine (for hypersalivation/bradycardia), Nitroprusside (for hypertension).

Marine Stings

• Box Jellyfish: Can cause cardiac arrest.
• Treatment: Hot water submersion to inactivate the toxin. Also vinegar, ethanol, IV Verapamil, and antivenom (available).

IV. THERMAL BURNS

Burn Classification and Mortality

• Zones of Burn Injury (3): Central necrosis (irreversible), intermediate reversible stasis (target for resuscitation), and outer zone of inflammation.
• Mortality: Calculated via the Baux Score (TBSA + Age = Mortality). The LD50 is about 60 to 70% TBSA.

Burn Degrees/Classes:

• Superficial (First Degree): Red, blanches, heals in about 1 week.
• Superficial Partial (Second Degree): Red with blisters.
• Deep Partial (Second Degree): Red or white, may not blanch, wet appearance.
• Full Thickness (Third Degree): Leathery, charred, white, or yellow; does not blanch.
• Deep Full Thickness (Fourth Degree): Into muscle, tendon, or bone.
• Fifth Degree: Requires amputation.
• Note: Burns from superficial partial thickness and worse are counted within the TBSA calculation. Anything white or full thickness generally requires grafting.

Total Body Surface Area (TBSA) Estimation

• Palm Rule: A patient's palm (to fingertips) is 1% TBSA.
• Rule of Nines (Adults):
• Head and Neck: 9%.
• Anterior Thorax: 18%.
• Posterior Thorax: 18%.
• Each Arm: 9%.
• Each Leg: 18%.
• Groin: 1%.
• Rule of Nines (Pediatrics):
• Head: 18%.
• Each Leg: 14%.
• Otherwise same as adult

Burn Resuscitation Formulas and Goals

Most formulas estimate the total fluid required over 24 hours. Half of the total volume is given in the first 8 hours, and the remainder is given over the next 16 hours.

• Goal Urine Output: Adults: > 0.5 cc/kg/hr; Peds: 1 cc/kg/hr; Infants: 2 cc/kg/hr.
• Parkland: 4 cc/kg per TBSA.
• Modified Parkland: 3 cc/kg per TBSA.
• Brooke: 2 cc/kg per TBSA (0.5 cc of this volume is colloid infusion).
• Modified Brooke: 2 cc/kg per TBSA (Ringers Lactate only).
• Evans: 1 cc/kg per TBSA (Ringer's) + 1 cc/kg per TBSA (colloid) + 2 L of D5 water maintenance.
• Galveston (Peds): 5 L/m² TBSA + 2 L/m² TBSA (maintenance).
• Rule of 10 (Hourly Rate): TBSA times 10 cc/hour. If the patient is over 80 kg, add 100 cc/hour per 10 kg over the 80 kg threshold.

Burn Center Referral (10/3 CRISPLET Mnemonic)

A patient should be referred to a burn center if they meet any of these criteria:

• 10% TBSA.
• Third-degree burns, any.
• Chemical burns.
• Rascals (pediatrics).
• Inhalational injuries.
• Social factors.
• Past medical history/co-morbidities.
• Location (hands, face, feet, or groin).
• Electrical burns.
• Trauma associated.

Escharotomy Indications

Escharotomies are required when circumferential burns compromise circulation or ventilation:

• Chest: Difficulty with ventilation or high airway pressures.
• Neck: Airway compromise or neck vessel distension.
• Extremity: Decreased Doppler, or pulses showing 90% of the other side or an overall decreased pulse.

V. CHEMICAL EXPOSURES

Decontamination

Decontamination should occur on scene with Hazmat.

• General: All clothing must be removed.
• Dry Chemicals (e.g., dry lime, elemental metals, phenol, lye): Must be brushed off first.
• Wet Chemicals: Must be sprayed down with water for 10 or 15 minutes.

Mechanism of Injury

• Acid: Causes coagulation necrosis, forming an eschar that limits penetration.
• Bases: Cause liquefaction necrosis and saponification, which increases penetration and causes deeper damage.

Ocular Burns (Dua Classification)

The classification is based on limbal and conjunctival involvement. The primary treatment is copious irrigation of at least 2 L until the pH is 7.4. Any grade 2 or above requires an Emergency Department ophthalmology consult. Grading is based on a clock face.

• Grade 1: No limbal and no conjunctival involvement seen afterwards.
• Grade 2: Less than 3 hours limbal involvement and less than 30% conjunctival involvement.
• Grade 3: 3 to 6 hours limbal involvement and 30 to 50% conjunctival involvement.
• Grade 4: 6 to 9 hours limbal involvement and 50 to 75% conjunctival involvement.
• Grade 5: 9 to 12 hours limbal involvement and 75 to 100% conjunctival involvement.
• Grade 6: Complete (12 hours) limbal involvement and 100% conjunctival involvement.

Methemoglobinemia (MetHb)

MetHb occurs when Fe2+ is oxidized to the Fe3+ (ferric) state, rendering hemoglobin unable to carry oxygen.

• MetHb Symptoms by Percentage:
• 10%: Cyanosis with hypoxia.
• 20%: Headache, anxiety, increased respiratory rate and pulse.
• 50%: Confused, lethargic, acidotic.
• 70%: Coma, seizure, dysrhythmia, and death.
• Treatment:
• Methylene blue: 1 to 2 mg/kg of the 1% product.
• If G6PD deficiency is present (Methylene blue is contraindicated): Use Vitamin C or exchange transfusion.

Hydrofluoric (HF) Acid

HF acid is highly toxic because free fluoride binds calcium and magnesium, blocks ATPase, and blocks the Krebs cycle.

• Treatment Protocol:
1. Copious irrigation with water for 15 minutes.
2. Remove blisters (which may contain HF acid).
3. Topical: Calcium gluconate 3.5 g in KY jelly.
4. Subcutaneous: Injections of 10% calcium gluconate.
5. Intra-arterial: 10 mL of 10% calcium gluconate over 4 hours.
6. IV infusions to replete calcium and magnesium.

Phosphorus and Formic Acid

• Phosphorus (White, Elemental, Red): Found in munitions.
• Treatment: Water submersion of the burn and supportive care.
• Formic Acid: Causes metabolic acidosis.
• Treatment: Wound lavage, Bicarb for acidosis, folate, dialysis/exchange transfusion.

Chemical Warfare Agents

There are four types of agents:

1. Nerve Agents (e.g., Sarin, VX): Block acetylcholine esterases.
   • Symptoms (Cholinergic Toxidrome): Salivation, defecation, urination, lacrimation, bronchorrhea, bradycardia, and bronchoconstriction.
   • Treatment Dosing:
   • Atropine (until drying of airway secretions).
   • 2-PAM: 30 mg/kg initially, then 10 mg/kg/hour maintenance.
   • Benzodiazepines (for seizures).
2. Vesicants (e.g., Mustard Agents): Cause blisters; Mustard agents have a fishy/garlic odor and no immediate pain.
3. Choking Agents (e.g., Phosgene, Chlorine): Cause pulmonary edema.
4. Cellular Asphyxiants (e.g., Hydrogen cyanide).