Unable to open and close the mouth freely is called locked jaw syndrome, and diseases that affect the activity of mandibular joint or the function of masticatory muscles will cause locked jaw syndrome.
Second, several factors that control the opening and closing of oral cavity
1. The flexibility of the mandibular joint, that is, whether the mandibular joint can move freely, take the door as an example: the hinge of the fixed door and whether there is a cover in front of the door determine the range of movement of the door. Similarly, the rigidity of mandibular joint itself is called true rigidity, and the influence of surrounding bones such as zygomatic arch or condyle is called pseudo rigidity.
2. Whether the masticatory muscles function normally is just like whether the person who opens the door has the strength. It involves two aspects, on the one hand, whether the masticatory muscles have enough strength to open their mouths, and on the other hand, whether the nerves that control the masticatory muscles function normally.
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Thirdly, the anatomy of mandibular joint.
Combining these two factors, the main causes of mandibular atresia syndrome in dogs and cats are as follows:
1. The mandibular joint is stiff, that is, it can't move normally. It is mainly caused by fractures, which can be divided into intra-articular fractures and extra-articular fractures, including cornual process, condylar process and zygomatic arch fractures. Common in large dogs, large dogs have a larger relative range of activities and a greater chance of injury.
2. Mandibular joint dislocation, which is more likely to happen in cats, because cats have a large mandibular joint angle.
3. Congenital dysplasia of mandibular joint is rare, and some species such as Boston terrier may appear.
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4. Trigeminal nerve function is impaired, such as trigeminal paralysis, oral opening and closing disorder caused by trigeminal paralysis, and facial nerve function loss such as eyelid reaction loss can occur at the same time.
5. Masticatory myositis is usually autoimmune. There are 1 and 2M muscle fibers in the masseter and masticatory muscles. When masticatory myositis occurs, the immune system attacks 2M fibers, resulting in muscle atrophy. The detection of 2M antibody is the basis of diagnosis.
6. Mandibular joint tumors, including osteochondroma and osteosarcoma.
7. Retrobulbar tumor or abscess.
8. Mandibular joint infection or severe ear canal disease, pain caused by mandibular joint opening and closing disorder.
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Fourth, the clinical symptoms of dog-cat locked jaw syndrome
1. saliva
2. Have an appetite, but chew and eat
3. Obviously resist when touching your mouth.
4. Don't open or close your mouth
lose weight
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5. Diagnosis of dog-cat locking jaw syndrome.
1. Routine blood examination, routine blood examination and biochemical examination
2. imaging examination, CT diagnosis of mandibular joint has absolute advantages compared with x-ray,
The head structure is complex, the X-ray results overlap obviously, and many small fractures are difficult to judge.
3. Magnetic vibration examination, for cases of oral opening and closing disorders caused by trigeminal paralysis, it is necessary to check whether there are abnormalities in the brain, mainly the brain stem.
The detection of 4.2M antibody is the basis of diagnosing autoimmune masticatory myositis, but few laboratories can do it. Clinically, the exclusion method is mostly used for masticatory myositis. After the cause of mandibular ankylosis was ruled out, immunosuppressive agents were given for therapeutic diagnosis.
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Sixth, the treatment of dog-cat jaw lock syndrome.
1. surgery: for many cases of mandibular ankylosis, surgical treatment is recommended in order to restore the joint angle and restore the joint to a flexible state. Surgical schemes include partial zygomatic arch resection, condylar resection and even partial maxilla resection.
2. For the case of jaw atresia caused by ankylosis, if surgical intervention is not done, conservative treatment should be taken to relieve pain, prevent secondary infection by antibiotics, gradually rebuild and increase the opening and closing of the mouth.
3. The treatment of masticatory myositis needs the participation of hormones or immunosuppressants.
4. It is difficult to open and close due to tumor, retrobulbar abscess or severe ear disease. The primary problem was solved, the pain was relieved, and the clinical symptoms of some cases could be greatly improved.
5. Support therapy: No matter what causes the jaw lock syndrome, we should ensure the food intake at the initial stage of treatment, and we can feed liquid food, or bury a neck feeding tube or even a stomach tube.
Seven. Prognosis of Lockjaw comics's syndrome in dogs and cats
The prognosis of masticatory myositis and mandibular ankylosis is relatively good, and 80% can be controlled by surgery or drugs for a long time. The prognosis of trigeminal paralysis and mandibular joint tumor caused by neuropathy is very poor.
Tips: Click on "Causes of Bad Breath of Cats and Dogs" to learn more about oral problems of cats and dogs.