Introduction

• Cause: toxin produced byClostridium tetani Clostridium tetani.
• Signs: generalized or localized muscle spasms.
• Diagnosis: clinical signs and history.
• Treatment: supportive.
• Prognosis: good provided animal is supported through critical period.

Pathogenesis

Etiology

• Toxin produced byClostridium tetani.

Pathophysiology

• Bacteria enters body → toxin production → enters motor nerves → extensor rigidity of all muscles.
• Dogs are relatively resistant to effects of toxin (as compared to man and horses).

• Clostridium tetanienters body usually via penetrating wound.
• Three different toxins produced:
  • Tetanospasmin: enters motor nerves and travels in a retrograde fashion to spinal cord along nerve axons.
  • Reduced inhibiton of motor nerve function → muscle extensor rigidity.
  • Hemolysin: promotes anaerobic conditions for multiplication ofClostridium tetaniby causing local tissue necrosis.
  • Nonspasmogen: has poorly defined role.

Timecourse

• Signs within 1 week of bacterial infection of wound.
• Occasionally signs delayed up to 3 weeks.
• Recovery usually over weeks to months.

Diagnosis

Treatment

Prevention

Outcomes