CLINICALLY SPEAKING

Deep Soft-Tissue Necrosis of the Foot and Ankle Causedby Catfish Envenomation

A Case Report

Bryan J. Roth, DPM*Stephen M. Geller, DPM*

Catfish envenomations represent a relatively rare cause of complications in podiatricmedicine. We report a case of an unusual event eliciting a severe soft-tissue necrosis ina 21-year-old man and his complicated wound-healing process. This case reviews thepotential complications of catfish envenomations. (J Am Podiatr Med Assoc 100(6): 493-496, 2010)

Worldwide, there are more than 3,000 different

species of catfish, many of which are venomous to

humans.1 Catfish have axillary venom glands and

one dorsal and two pectoral fin barbels to inflict

envenomation.2 The fins are composed of sharp

retrorse teeth that can lacerate the skin, enhancing

exposure and absorption of the venom.3, 4 Soft-

tissue infections secondary to catfish envenomation

are relatively uncommon pathologic conditions

presenting to the daily podiatric medical office.

A review of the current literature uncovered only

seven articles that detail catfish injuries to the

foot.3, 5-10 Many of the previous articles described

the cases as unusual foreign bodies or wounds with

minor complications. Zeman5 presented a patient

who kicked a catfish and required removal of the

embedded catfish spine but healed without compli-

cation. Arlen and Vartian7 described a patient with a

unicameral bone cyst of the first metatarsal that was

presumed to stem from a catfish spine puncture

more than 25 years earlier. Banks8 reported on a

patient with a plantar foot puncture wound after

stepping on the dorsal spine of a catfish. An incision

and drainage was performed, with cultures return-

ing significant for Edwardsiella tarda.

Most long-term complications associated with

catfish envenomation involve infection. The severity

of the infection varies with the species of the

catfish. Clinical symptoms of the envenomation

process are typically associated with pain, erythe-

ma, edema, paleness, paresthesia, muscle fascicu-

lations, and tissue necrosis.2-6, 11-17 Another presen-

tation of catfish wounds is an advancing ring of

erythema.16 Reported complications in the literature

include puncture wounds and lacerations compli-

cated by soft-tissue infections, tenosynovitis of the

hands, bursitis, septic arthritis, osteomyelitis, bony

cysts, and necrotizing fasciitis.2-8, 11-18

Owing to the large diversity of the species, there

is no definitive treatment regimen for catfish stings.

However, many advocate local wound care param-

eters, including irrigation and debridement, serial

dressing changes, and topical and systemic antibi-

otics. An interesting concept includes the addition

of soaking the affected area in the warmest water

one can tolerate. The idea addresses the heat-labile

attitude of the catfish venom.8 Warm water soaks

(458C for 45 min) help with immediate pain relief

better than do narcotics and local anesthesia.4, 19

Radiographic evaluation is warranted, but caution

should be taken because not all catfish spines are

radiopaque. Clinical evaluation for abscess or

retained foreign body indicates a need for wound

exploration. A quickly spreading cellulitis or tissue

necrosis may require fasciotomy or amputation.

Empirical antibiotic coverage is difficult consid-

ering the wide array of causative organisms.

Edwardsiella tarda, Citrobacter freundii, Morga-

nella morganii, Pseudomonas aeruginosa, Entero-

bacter cloacae, Aeromonas hydrophila, Vibrio vul-

nificus, Streptococcus, Staphylococcus aureus, and

epidermis have all been identified.9 At a minimum,

*Department of Podiatric Medicine and Surgery, Maricopa

Medical Center, Phoenix, AZ.Corresponding author: Stephen M. Geller, DPM, Depart-

ment of Podiatric Medicine and Surgery, Maricopa Medical

Center, 2601 E Roosevelt Ave, Phoenix, AZ 85008. (E-mail:

desertfootdoc@hotmail.com)

Journal of the American Podiatric Medical Association � Vol 100 � No 6 � November/December 2010 493

the administration of antibiotics should cover gram-

negative organisms. In the literature, ciprofloxacin

and other fluoroquinolones are popular choices for

coverage of gram-negative organisms.11 The two

concerning organisms are the Vibrio species for

saltwater and the Aeromonas species for freshwa-

ter. The recommended regimen for coverage of most

Vibrio species includes a combination of doxycy-

cline and ceftazidime, and coverage of most Aero-

monas species includes fluoroquinolones.20 As with

any open wound, the patient should be given tetanus

prophylaxis when indicated.

Case Report

A 21-year-old Hispanic man sustained a puncture

wound from a catfish while working at a local

farmer’s market. The puncture wound was sus-

tained to the medial aspect of the right foot after

dropping a catfish while stocking shelves. After

piercing through his leather boots, the pectoral fin

penetrated the skin overlying the medial aspect of

the navicular. He presented to the emergency

department 4 days later secondary to constitutional

symptoms and intense pain in his right foot and

ankle.

On initial presentation, a small puncture wound

was noted on the medial aspect of the right midfoot

(Fig. 1). The puncture site was closed, with no sign

of associated wound infection. However, there was

intense erythema noted along the proximal dorsum

of the right foot and the anterior aspect of the right

ankle. There was no evidence of a foreign body, eg,

a catfish barb, on clinical or radiographic examina-

tion.

The patient was taken to the operating room for

incision and drainage of his right foot. A small

foreign body was removed from the puncture site

that was later identified as a catfish spine. Intraop-

erative findings revealed severe tissue necrosis of

the superficial and deep fascia along the course of

the anterior tibial tendon. The surrounding soft

tissues and the anterior tibial tendon sheath were

found to be necrotic (Fig. 2). Excision of all necrotic

tissue was completed. After thorough irrigation of

the wound, soft-tissue cultures were obtained and

sent to the pathology laboratory. Intraoperative

soft-tissue cultures later returned positive for

coagulase-negative Staphylococcus. There was no

associated growth of anaerobic or fungal species. A

negative-pressure wound dressing (GranuFoam and

V.A.C.; KCI, San Antonio, Texas) was then applied.

Three days later, wound debridement was per-

formed in the operating room. At this time, a sterile

collagen bioimplant (OrthADAPT; Synovis Orthope-

dic and Woundcare Inc, Irvine, California) was used

to cover the exposed tendon, and the V.A.C. was

reapplied after partially closing the wound. After

several weeks of wound care and a prolonged

Figure 1. Initial presentation of the right foot andankle. Notice the hyperpigmented nodule on themedial aspect of the foot. A catfish spine was lateridentified from this site.

Figure 2. Initial intraoperative view depicting theextensive soft-tissue necrosis of the right foot andankle along the course of the anterior tibial tendon.

494 November/December 2010 � Vol 100 � No 6 � Journal of the American Podiatric Medical Association

healing course intensified by patient noncompli-ance, the patient returned to the operating room fordelayed primary closure. Once again, the patientwalked on the affected extremity, and the woundreturned. Nonetheless, after a complicated postop-erative course intensified by patient noncompliance,the wound healed (Fig. 3). The patient wasdischarged from the clinic and has returned tonormal activities.

Discussion

Catfish (class: Osteichthyes; subclass: Siluroidea)vary widely in shape and size.11 Currently, 3,000species have been identified, with many more yet tobe verified. Although they live in both freshwaterand marine environments, the ability to causeenvenomation is species dependent. Most injuriesoccur to the extremities of freshwater and marinefishermen who improperly handle the catfish.12 Thestinging apparatus is composed of the dorsal andpectoral fins connected to the venom glands. Whenthe fish is disturbed, the fins extend from theirbodies, increasing the chance for puncture andenvenomation. Not only does the catfish possessvenom from the glands, but it also contains toxins inits epidermal cells that are secreted with excita-tion.5 Secretion of toxins from skin cells is knownas crinotoxicity, and if exposed to open skin it cancause similar complications as the venom.12

Halstead was one of the first to report on toxicepidermal secretions of fish unrelated to the venomapparatus and popularized the term ichthyocrino-

toxins.13 Thus, unlike venoms, epidermal secretionsare not injected into other organisms. Compositioncatfish crinotoxins have been found to be identical

and typically are composed of at least one hemo-

lysin, two lethal factors, and two edema-forming

factors.14 Much of the available research coincides

with the hypothesis that venoms evolved from

catfish toxins.13 The mechanisms of action of the

neurotoxic and hemotoxic effects of catfish toxin

have yet to be completely described in the

literature.15

We described a patient with a complicated wound

stemming from a catfish spine puncture. There is no

doubt that his delay in presentation hindered

treatment and resulted in the need for prolonged

and aggressive care. Moreover, if the patient had

been compliant with postoperative management, he

may have healed quicker. However, this was a

significant injury to his lower extremity.

The difference between this case and those

previously reported is that the present patient

required multiple surgical interventions and a

prolonged postoperative course. The only organism

obtained from the intraoperative cultures was

coagulase-negative Staphylococcus. It is likely that

the Staphylococcus was not the primary cause of

the tissue necrosis, and we believe that the tissue

necrosis was due solely to the spread of the toxins

associated with the envenomation process, which is

known to be potentially necrotic to the skin and

soft-tissue structures.

Conclusions

In summary, catfish envenomations can progress

through a wide array of complications varying from

a simple wound to necrotizing fasciitis, to a

gangrenous limb, and, ultimately, to death. This

article should be a reminder to all physicians that if

these wounds are left untreated, there is a high

associated morbidity rate that can lead to devastat-

ing outcomes. This patient’s delayed presentation to

the hospital eventually lead to his severe tissue

necrosis and prolonged healing. Treatment was

successful, and the patient returned to his normal

activities.

Financial Disclosure: None reported.

Conflict of Interest: None reported.

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