Locked jaw syndrome in dogs and cats: 37 cases (1998-2005).

A consecutive series of cases of dogs and cats with locked jaw syndrome (inability to open or close the mouth) are reported in this study. Dogs were significantly overrepresented (84.0%) and adult dogs were more frequently affected (81.0%). Temporomandibular joint ankylosis due to fracture was the most common cause (54.0%) of locked jaw syndrome. Additional potential causes of locked jaw syndrome are masticatory muscle myositis, neoplasia, trigeminal nerve paralysis and central neurological lesions, temporomandibular joint luxation and dysplasia, osteoarthritis, retrobulbar abscess, tetanus, and severe ear disease. Treatment of locked jaw is directed towards the primary cause. It is important to treat the tonic spasm in order to minimize periarticular fibrosis. Surgical intervention is recommended for temporomandibular joint ankylosis. Masticatory muscle myositis treatment is initiated by gradually opening the mouth, with medical treatment based on immunosuppressive therapy. Fracture and masticatory muscle myositis are associated with a relatively good prognosis in regard to short-term outcome as compared to animals with central neurologic lesions or osteosarcoma which have a poor prognosis.

Topical effect of various agents on gelatinase activity in the tear film of normal dogs.

OBJECTIVE: To evaluate the topical effect of various agents, currently used in the treatment of melting ulcers, on gelatinase activity present in the tear film of normal dogs. ANIMAL STUDIED: Eight normal adult beagles. PROCEDURES: Each animal received the following agents: cyclosporine A 1%, N-acetylcysteine 10%, ciprofloxacin 0.3%, ethylenediaminetetraacetic acid (EDTA) 1%, doxycycline 0.001%, polysulfated glycosaminoglycans (PSGAG) 5%, autoserum, and artificial tears during a 48-h period following a Latin square design. Tear samples were collected with micro-capillary pipettes following a corneal surface irrigation of each eye with sterile saline on four different occasions. Basal and total gelatinase activities were evaluated by optical density after processing in a commercial gelatinase activity assay. From the optical density ratio, a semi-quantitative measure of gelatinase activity was obtained. Basal and total activities were measured in all samples. RESULTS: The lowest total gelatinase activity, representing a percent decline in the enzyme activity although not significant, was observed 1 h after the last treatment in seven out of the eight ophthalmic agents; EDTA (68%), ciprofloxacin (76%), cyclosporine A (68%), doxycycline (47%), artificial tears (26%), PSGAG (25%), and N-acetylcysteine (20%). However, only the reduction observed with EDTA 6 h after the last treatment was significantly lower compared to the reduction observed with the artificial tears. CONCLUSION: This study indicated that only EDTA was able to significantly reduce the gelatinase activity in a persistent manner in the tear film of normal canine eyes. Further studies will be required to evaluate the effect of EDTA under ulcerative conditions and to more accurately ascertain the potential in vivo effect of the other agents.