Confirmed 2,4-dichlorophenoxyacetic acid toxicosis in a dog.

Area of Science:

• Veterinary Neurology
• Toxicology

Background:

• Acquired myotonia in dogs can present with episodic extensor rigidity and stiff gait.
• Differential diagnoses for myotonia include various toxicological and neurological conditions.

Observation:

• A 2-year-old male Weimaraner exhibited symptoms of myotonia, including muscle dimpling upon percussion and characteristic electromyographic findings.
• Serum and urine analysis confirmed the presence of 2,4-dichlorophenoxyacetic acid (2,4-D) residues.

Findings:

• The case represents the first reported instance of clinical 2,4-D toxicosis manifesting as acquired myotonia in a canine patient.
• Intravenous fluid therapy over 36 hours resulted in dramatic resolution of clinical signs.

Implications:

• 2,4-D toxicosis should be considered in the differential diagnosis for dogs presenting with acquired myotonia, even in the absence of systemic signs.
• Canine patients with myotonia solely due to 2,4-D exposure can achieve favorable clinical outcomes with appropriate management.