You are called out to…… an unvaccinated horse which is moving slowly and stiffly and having difficulty chewing. The owner had treated the horse for a leg wound 5 days previously, at which time it had been otherwise normal.

Differential Diagnosis•Tetanus

•Septic arthritis•Botulism•Lameness: Laminitis, arthritis, trauma, soft tissue injury, tendon/ligament injury, rhabdomyalysis

•Difficulty chewing: Dental disease, trauma (broken tooth/jaw fracture), tooth abscess.

•Pleuropneumonia

History Questions•When did the wound happen?•Where is the wound?•Was it lame on that leg initially?•When did you notice stiffness?•Has there been any swelling of the leg•When did the difficulty eating begin?•What have you been feeding the horse•Are they dropping food?•Have you given any medication to this horse for condition?

Physical Examination•Observe horse in environment & demeanour•Vital parameters•Examination of wound•Examination of stiff leg- palpation of leg,

joints & digital pulses•Examination of gait•Examination of head

▫Ocular exam – Tenatus causing protrusion of 3rd eyelid.

▫Dental examination• Tail head, facial expression, hyperalgesia, sweating, flared nostrils

Confirm Diagnosis

•Tetanus▫History, clinical signs▫Gram stain from wound

•Septic Arthritis▫Swelling of joint▫Pain on palpation▫Aseptic arthrocentesis

•Botulism▫History of feeding

•Rhabdomyalisis – ▫CK on biochemistry (massively elevated)

•Laminitis ▫other clinical signs and radiographs

•Dental disease/trauma/abscess▫dental examination

•Pleuropneumonia ▫auscultate thorax, pyrexia, chest tap

Treatment of tetanus•Tetanus anti-serum

▫100,000-250,000 IU IV (Knottenbelt)

▫300,000 IU - slow IV (Merck)

•Tetanus toxoid▫1ml deep IM

•Penicillin•Sedation? •Clean & debride wound and bandage•Fluids

▫NG tube or IV catherisation•Food & water offered from a height•Deep bedded stable

Further Prevention

•Tetanus vaccination▫Dose 1: Day 1▫Dose 2: 4-6weeks later▫Booster 6 monthly▫Clean wounds thoroughly ASAP

▫Mares vaccinated 4-6 weeks before parturition Foals given anti-toxin at birth

▫Start vaccination after 4-5 months of age after maternal antibodies waned.