Changes

Also known as: '''''Lion jaw'''''

Also known as: '''''Lion jaw'''''

==Introduction==

==Introduction==

Craniomandibular osteopathy is a '''non-neoplastic, non-inflammatory proliferative disease of the bones of the head'''.  

Craniomandibular osteopathy is a '''non-neoplastic, proliferative disease of the bones of the head'''.  

Primary bones affected include the mandibular rami, occipital and parietal bones, tympanic bullae and the zygomatic portion of the temporal bone.

Primary bones affected include the mandibular rami, occipital and parietal bones, tympanic bullae and the zygomatic portion of the temporal bone.

'''Symmetrical''' involvement is common.

'''Symmetrical''' involvement is common.

The condition is believed to be hereditary, and it is an autosomal recessive trait in '''West Highland White Terriers''' and possibly in '''Scottish Terriers'''. It has been reported in other breeds such as the '''Labrador, Great Dane  and Doberman'''.

The condition is believed to be hereditary, and it is an autosomal recessive trait in '''West Highland White Terriers''' and possibly in '''Scottish Terriers'''. It has been reported in other breeds such as the '''Labrador, Great Dane  and Doberman'''.

The condition usually occurs in growing puppies between the age of '''4 and 8 months'''.

The condition usually occurs in growing puppies between the age of '''4 and 8 months'''.

==Clinical Signs==

==Clinical Signs==

The owner may report that the dog has '''difficulty in prehension, mastication and swallowing of food''', and that it has pain around the mouth area.

 

Puppies present with swollen mandibles, inappetance and reluctance to open, and pain on opening the mouth. The owner may report that the dog has '''difficulty in prehension, mastication and swallowing of food''', and that it has pain around the mouth area.

Temporal and masseter '''muscle atrophy''' are common.

Temporal and masseter '''muscle atrophy''' are common.

There may be '''palpable irregular thickenings''' of the mandibular rami or the temporomandibular joint.

There may be '''palpable irregular thickenings''' of the mandibular rami or the temporomandibular joint caused by periosteal proliferation of the body of the mandible, sometimes incorporating the tympanic bullae or temporomandibular joint.  

The dog will be unable to fully open its jaw, even under anaesthesia.

The dog will be unable to fully open its jaw, even under anaesthesia. There may be bilateral exophthalmos and pyrexia, up to 40°C. Less commonly, there may be swelling and lameness in one or several limbs.

 

There may be bilateral exophthalmos.

 

'''Pyrexia''', up to 40°c, can occur.

 

Less commonly, there may be swelling and lameness in one or several '''limbs'''.

==Diagnosis==

==Diagnosis==

'''CT''' may help evaluate the osseous involvement of the temporomandibular joint.

'''CT''' may help evaluate the osseous involvement of the temporomandibular joint.

'''Bone biopsy''' may reveal: osteogenesis and resorption of periosteum, endosteum and trabeculae of the mandible, variable infiltration of lymphocytes, [[Neutrophils|neutrophils]] and plasma cells, mosaic appearance

'''Bone biopsy''' may reveal osteogenesis and resorption of periosteum, endosteum and trabeculae of the mandible, variable infiltration of [[lymphocytes]], [[Neutrophils|neutrophils]] and [[Plasma Cells|plasma cells]], mosaic appearance.

'''Bone culture''' may help to rule out osteomyelitis if the diagnosis is uncertain.

'''Bone culture''' may help to rule out [[osteomyelitis]] if the diagnosis is uncertain.

==Treatment==

==Treatment==

The condition follows an intermittent progressive course but is '''self-limiting''', and treatment is only '''palliative'''.

Craniomandibular osteopathy follows an intermittent progressive course but is '''self-limiting''' and treatment is only '''palliative'''. The condition usually regresses at about a year of age, corresponding with the completion of jaw growth and ossification.  

Analgesics and anti-inflammatories form the mainstay of therapy, and may include NSAIDs such as carprofen.

Analgesics and anti-inflammatories form the mainstay of therapy, and may include [[NSAIDs]] such as carprofen.

'''High-calorie, protein-rich food''' should be provided to help maintain adequate nutrition, and feeding tube placement may be considered in severe cases.

'''High-calorie, protein-rich food''' should be provided to help maintain adequate nutrition, and feeding tube placement may be considered in severe cases.

Lobprise, H. (2007) '''Blackwell's Five Minute Veterinary Consult: Small animal dentistry''' ''Wiley-Blackwell''

Lobprise, H. (2007) '''Blackwell's Five Minute Veterinary Consult: Small animal dentistry''' ''Wiley-Blackwell''

[[Category:Bones - Hyperplastic Pathology]]

[[Category:Bones - Hyperplastic Pathology]]