Page 66 - Journal of Special Operations Medicine - Summer 2014

Treatment of Sea Urchin Injuries

David R. King, MD; Andreas Larentzakis, MD

ABSTRACT
Sea urchin injuries can be sustained in a variety of envi- The second mechanism of injury is via envenomation.
ronments in which U.S. Forces are operating, and famil- Approximately 80 species of sea urchin are known to
iarity with this uncommon injury can be useful. Injuries be toxic to humans. The solid spines may be coated
by sea urchin spines can occur during military activities with thermolabile toxin, and the hollow spines may
close to rocky salt aquatic ecosystems via three mecha- contain thermolabile toxin within their lumen or be at-
nisms. The author describes these mechanisms and dis- tached to a poison gland at the base of the spine. Tox-
cusses the diagnosis, management, and treatment of sea ins include steroids, serotonin, glycosides, hemolysin,
urchin injuries. proteases, cholinergic agents, neurotoxins, histamine,
and bradykinin-like substances. 1,4–9 The exact cellular/
Keywords: sea urchin, spines, laser, ablation pathophysiological response to any individual toxin, or
combination of toxins, remains largely unknown.

The third mechanism of injury is the foreign body re-
Introduction
action to fragments of spines that have been fractured
Sea urchin injuries can be sustained in a variety of envi- and retained in the wound. 10,11 Sea urchin spines are
ronments in which U.S. Forces are operating, and famil- mainly composed of calcium carbonate, and most of
iarity with this uncommon injury can be useful. There them are very fragile, resulting to a high possibility of
are more than 6000 species of the phylum Echinoder- usually nonvisible remnants after a removal attempt.
mata (echinodermata is a Greek word for “spiny skin”) The skin commonly heals over, the spines are entrapped,
and about 950 species of the class Echinoidea, which are and a chronic delayed-type hypersensitivity reaction sets
the marine echinoderms known as sea urchins. The in. 11,12 Inflammation, fibrosis, and scar formation maybe
1,2
sea urchin is a nonaggressive bottom-dweller that moves impressive. Neuropathic pain may develop.
very slowly but nonetheless may pose a risk to those
3
operating in coastal environments around the world.
Their tiny bodies are commonly surrounded by spines Diagnosis
(some are extremely sharp), which may be solid or hol- Signs and symptoms associated with sea urchin spine
low. Spines have been known to penetrate all body injuries should be described as (1) having a mechanical
4
parts, including the hands and feet, and may even pene- origin, (2) being toxin related, or (3) being late foreign
trate Neoprene wetsuits and the sole of a shoe or boot. body related. The patient’s history and the characteristic
2,4
The sea urchin is commonly encountered in coastal ar- small penetrating wounds made by the black spine frag-
eas around the world, and injuries from the sea urchin ments make the diagnosis easy. The majority of cases
5
spines can occur during military activities close to rocky present with only local signs and symptoms of mechani-
salt aquatic ecosystems via three mechanisms. cal origin that include sharp, localized pain exacerbated
by pressure application, along with slight or no local
erythema, edema, and rubor. 3,4,6,7
Mechanisms of Injury
The first mechanism of injury is the primary puncture In case of toxin envenomation, the signs and symptoms
wound. The spines can puncture any tissue with which of local inflammation (dolor, calor, rubor, swelling) are
they come in contact. The spines are fragile, though, much more intense in the early phase. Also, regional
and can fracture from the body of the sea urchin and and/or systematic symptoms may occur, manifested as
remain impaled into the wound. The puncture is pain- intense burning, synovitis, arthritis, radiating pain, par-
ful and usually felt immediately. 3,4,6 Purple or black dye esthesia, numbness, light-headedness, muscular weak-
contained in the spine may color the skin around the ness, hypotension, dyspnea, aphonia. 2,10 Even death can
wound and be evident deep into the puncture site. 7 occur, although this is not documented in the medical

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