Shark bite

Background

Great white shark (#1 most fatal unprovoked attacks).

Tiger shark (#2 most fatal unprovoked attacks).

Bull shark (#3 most fatal unprovoked attacks).

• White shark (Carcharodon carcharias), tiger shark (Galeocerdo curvier) appear to be disposed to human attacks than other species
• Approximately 70-100 shark attacks worldwide per year and 5-15 deaths

Clinical Features

Healed thigh many years after a shark attack.

• Direct traumatic effects depend on size and species of shark
• Typically, attack appendages of victims
  • In 70% on surface swimmers, only the lower limb is involved
  • Upper limb may be injured when the victim attempts to fight off the attack
• Massive tissue injury
  • Substantial tissue loss from stripping mechanism and extremity amputation are common
• Hemorrhagic shock
• Extremely high incidence of contamination with atypical microorganisms leading to soft tissue infections and necrosis
  • Most common organisms include Vibrio spp.
  • Other potential organisms include Pseudomonas, Staph, Citrobacter, Micrococcus
• Death is usually due to lack of prehospital resuscitation, hemorrhagic shock, or drowning

Differential Diagnosis

Marine toxins, envenomations, and bites

• Toxins
  • Ciguatera
  • Scombroid
  • Tetrodotoxin (e.g. pufferfish)
  • Shellfish poisoning
    • Amnesic shellfish poisoning
    • Diarrheal shellfish poisoning
    • Neurotoxic shellfish poisoning
    • Paralytic shellfish poisoning
• Stingers
  • Stingray injury
• Venomous fish
  • Cone shell
  • Lionfish
  • Sea urchins
  • Crown-of-Thorns Starfish
  • Stonefish
  • Other: Catfish, zebrafish, scorpion fish
• Nematocysts
  • Coral reef
  • Fire coral
  • Jellyfish (Cnidaria)
    • Box jellyfish
      • Irukandji syndrome
    • Sea wasp
  • Portuguese man-of-war
  • Sea anemones
  • Seabather's eruption
• Phylum porifera (sponges)
• Bites
  • Alligator and crocodile attacks
  • Octopus bite
  • Shark bite
• Infections
  • Vibrio species in saltwater
  • Aeromonas species in freshwater

Evaluation

• Plain radiographs of all injured areas to identify fractures, periosteal stripping, retained foreign bodies (e.g. teeth)
• Wound cultures

Management

• Abrasions and small puncture wounds can be treated with thorough irrigation and topical antibiotics
• Devitalized tissue should undergo debridement and copious irrigation
  • Most injuries require debridement and repair in OR
• Prophylactic antibiotics indicated for all shark bites, even when minor
  • Coverage against Vibrio (doxycycline), Staph, Strep species
  • Patients with abdominal injuries should be covered against enteric and anaerobic organisms

See also

• Marine toxins and envenomations