Tetanus in Dogs
| Also known as: | Lockjaw |
Description
Tetanus is a rare disease in dogs. The disease pathophysiology is similar to that seen in the horse; the causal agent the neurotoxin of the gram-positive bacterium Clostridiu tetani. Infection occurs due to contamination of a wound by C. tetani and replication of the bacteria in the wound's anerobic environment. Tetanospasmin (neurotoxin) produced by the bacteria is transported to distant sites via the circulation and intraaxonally along peripheral nerves. This causes inhibition of the release of GABA and glycine from interneurons in the spinal cord and brain, resulting in tetanic spasm of striated muscle. Because of their high natural resistance to tetanospasmin, affected dogs may have a longer incubation period than that described in the horse. Dogs may often develop a localised tetanus rather than the generalised tetanus seen in other species.
Signalment
Diagnosis
Clinical Signs
- Rigidity of the neck, trunk and limb muscles
- Hypersensitivity to external stimuli
The localised form of tetanus seen in dogs may cause differing clinical signs to those seen in other species. Unlike the generalised spastic paralysis seen in horses, dogs may present with an obvious wound and stiffness or rigidity in a single limb. The rigidity may spread to the contralateral limb and then begin to advance cranially.
- Cases may vary from mild signs of a short, stilted gait, to complete recumbency with spastic paralysis. Progression of the disease may lead to involvement of the pharyngeal and laryngeal muscles leading to aspiration pneumonia. Recumbency may be followed by paralysis of the respiratory muscles, leading to death due to hypoxia or respiratory arrest.
Treatment
The approach to treatment in the dog is the same as that described for the horse. Noise and external stimuli should be kept to a minimum. The dog should be kept in a quiet, darkened kennel positioned away from other dogs.
Prognosis
Prevention
References
- Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial