Lockjaw in Dogs

A dog suffering from a locked jaw will be in obvious discomfort. Depending on the cause, there could be swelling and pain. In some cases, pets develop an atrophy of muscles and are unable to eat properly resulting in further complications. Many canines will not show signs of the various lockjaw conditions until there is evidence of a problem like visible pain, a shift in the bones, or paralysis to the jaw. Diagnosing the condition will place importance on the underlying cause for the lockjaw. The prognosis will depend on whether the lockjaw can be resolved; important factors are age, seriousness of the condition, and present health condition of your pet. There is no age, sex or breed predisposition though adult dogs seem to be affected more often.

A canine who has lockjaw has the inability to completely open or close his mouth. Illness, arthritis, tetanus and neurological disorders are just a few reasons why a dog may have this condition.

There are many signs associated with the condition of lockjaw which can be secondary in nature. If your pet has any of the signs below or seems to have jaw discomfort, consult the veterinarian without delay.

• Abnormal facial expression
• Paralysis of facial expression
• Swelling
• Pain
• Dehydration
• Salivation
• Inability or difficulty with opening the jaw
• Inability to close the jaw
• Masticatory muscle atrophy (may display as weakness when chewing or biting)
• Fever
• Loss of appetite
• Weight loss
• Jawbone shift (may only be evident upon veterinarian examination)

The condition of lockjaw can become debilitating in some instances. The inability to open or close the jaw can become progressive in nature, worsening in time. Some forms of the condition can have a regression of sorts, but relapse is very common.

• Temporomandibular joint ankylosis - immobility and consolidation of the joint cause this painful condition which can lead to total inability to open the mouth
• Temporomandibular joint luxation and dysplasia - abnormal separation in the joint
• Trigeminal nerve paralysis - results in the inability to close the mouth causing difficulty in eating and drinking
• Masticatory muscle myositis - swollen muscles create a difficulty in opening the jaw; this is an immune-mediated disorder
• Neoplasia
• Osteoarthritis
• Tetanus
• Systemic disorder like hypoadrenocorticism
• Severe ear disease
• Horner’s syndrome - this is a neurological disorder
• Retrobulbar abscess - this is a canine ocular disease
• Trauma to the mandibular bones
• Central neurological lesions

Your veterinarian will begin the diagnostic process with a physical examination. Although care will be taken, physical manipulation to the jaw could cause pain for your pet. Of course, force will not be used, but the analysis of movement may be needed to determine the extent and type of lockjaw. Your pet could also be experiencing pain with the oral mucosa, teeth, ears or tongue that you may not be aware of. Some animals may need sedation to allow for a thorough physical examination.  

Blood tests will be done and could show increased levels of muscle enzymes, the presence of autoantibodies which can change muscle fibers, or give an indication of tetanus. Underlying illnesses or malignant disease can also be evident after blood analysis. 

Further diagnostic tools can be radiographs, CT scan, and MRI of the skull and jaw. Electromyography is an additional test which is helpful in seeing how well the jaw and face muscles are performing normal functions. A biopsy can show the extent of fibrosis and muscle atrophy.

Whether the condition can be resolved depends on the cause; the range of success is quite variable.

As examples, surgical intervention, in the form of a resectioning of the bone, is the usual necessary treatment for temporomandibular ankylosis. Tetanus treatment is approached with antitoxins and antibiotics. Masticatory muscle myositis responds to immunosuppressive doses of corticosteroids to which the response is variable, but it must be noted that your pet may need lifelong therapy.

Treating an underlying illness like severe ear disease can hasten the recovery of the lockjaw. Medication for a systemic ailment, such as hypoadrenocorticism might aid in the recovery too, keeping in mind that a systemic disease will need continual medication and monitoring. If muscle atrophy is extensive (because of complications like fibrous muscle) the outlook can be guarded due to difficulties for your pet like eating and drinking. In addition, causes like a tumor or a severe trauma may have a less positive outcome.

In the case of mandibular muscle myositis , part of the treatment for your pet may have involved a procedure of gradually opening the mouth. With trigeminal nerve paralysis, the opposite is the case, and the therapy may be aimed at getting the mouth to close properly. In either case, nutrition and hydration are key needs that your canine companion will have difficulties with as he recovers or manages with this disorder. 

This being said, you will probably need to change your method of feeding him, whether this be temporary or permanent. A gruel type food could be needed, one that he can lap up and not need to chew.