Mandibular Osteomyelitis
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Description
Lumpy jaw is a chronic infectious condition which affects cattle. It is caused by the anaerobic filamentous bacteria Actinomyces bovis Actinomyces is a normal commensal of the oral cavity, upper respiratory tract and digestive tract of cattle, it gains entry to underlying soft tissues when the mucosa is damaged by trauma or eruption of teeth. It causes an inflammatory reaction, the connective tissue proliferates and is followed by infiltration of leukocytes which results in the formation of a walled off granuloma. The granuloma invades the bones of the head, in particular the mandible, and continues to grow in size. Lesions are charcterised by gross swelling, abscesses and draining fistulae overlying granulation of the madible and maxila. In some cases the oesophagus and oesophageal groove may become involoved but the lymph nodes are not affected.
Signalment
The condition affects cattle 2-5 yrs old, those that are exposed to sharp objects whilst feeding and when the teeth are erupting. It is found worldwide but is most prevelent in Western and mid-western states of the USA.
Diagnosis
The condition is easily diagnosed on clinical signs and can be confirmed by crushing and staining the yellow granules expressed with the pus from skin leisions to reveal gram-positive filamentous rods.
Clinical signs
- Facial distortment
- Granuloma formation overlying the mandible and maxila
- Fistulae draining small amounts of thick pus with yellow granules
- Difficulties with mastication
- Loose teeth
- Dyspnoea
Pathology
Osteomyelitis of the bones of the head with surrounding granulomatous tissue and fistulae draining pus containing small yellow granules.
Treatment
Treatment is difficult due to the nature of the lesions and poor antibiotic penetration to the site of infection. In less severe cases where infection of the bones is not advanced treatment with penicillin or tetracyclines is recommended. Previously it has been sugested that systemic treatment with potassium iodide is successful but this is no longer recommended due to food safety concerns.
Prognosis
Treatment is rarely successful in advanced cases and recurrence of leisions is common; slaughter is advised.
References
- Andrews, A.H, Blowey, R.W, Boyd, H and Eddy, R.G. (2004) Bovine Medicine (Second edition), Blackwell Publishing
- Merck & Co (2008) The Merck Veterinary Manual (Eighth Edition) Merial
| Also known as: | Lumpy jaw |