Progressive Ulnar Neuropathy Following a Presumed Catfish Sting.

Catfish are a highly diverse group of fish comprising more than 3500 species found in both freshwater and marine ecosystems. Upon handling, they can inflict a sting, with certain species capable of inducing significant pain and injury to the affected extremity. The prevalence of aquatic activities, such as fishing by line or manual capture ("noodling"), increases the likelihood of catfish stings, making prompt identification and treatment an important aspect of managing such encounters. A case of a presumed catfish spine injury during noodling in Tallahassee, Florida, is presented. The pectoral fin penetrated the volar aspect of the patient's right hand resulting in immediate pain and numbness. Over the course of 2 weeks, the patient developed distal ulnar neuropathy with conduction block at the wrist level. Surgical exploration revealed the ulnar nerve to be grossly intact, but the area surrounding the terminal division point of the ulnar nerve in the hand displayed infiltration by fibrous tissue that entrapped the nerve and its branches. Following surgical release of the ulnar nerve and its terminal branches from the fibrous tissue, complete resolution of distal ulnar neuropathy was achieved. In this patient's case, the absence of foreign bodies and the lack of visible nerve damage suggest that the injury to the patient's hand was largely attributable to toxin-mediated proinflammatory response and fibrosis.