Trismus due to myotonia associated with hyperadrenocorticism in a dog.

We present the report of trismus due to hyperadrenocorticism-associated myotonia diagnosed by electromyography in a dog. An intact female Miniature Dachshund, 13 years and 9 months old, presented with stiff gait and trismus as well as polyuria and polydipsia. Abdominal ultrasonography showed enlarged adrenal glands. An adrenocorticotropic hormone stimulation test revealed an exaggerated response. Based on these findings, this case was diagnosed with hyperadrenocorticism. Electromyography revealed myotonic discharge in the temporalis muscle and limbs. Therefore, trismus was considered to be caused by hyperadrenocorticism-associated myotonia, and the case was treated with oral trilostane (1.3 mg/kg, once daily). During the 4-month follow-up period, despite the partial improvement in stiff gait, trismus did not recover. Long-term data on more cases are warranted to assess the prognosis and clinical characteristics of trismus due to hyperadrenocorticism-associated myotonia.

Nebulised adrenaline to manage a life-threatening complication in a pug with trismus.

A 13-month-old pug with severe trismus because of suspected masticatory muscle myositis underwent anaesthesia for magnetic resonance imaging. When regurgitation occurred, the tongue was pulled from the mouth to enable suctioning but could not be repositioned into the oral cavity as it was not possible to open the mouth. Swelling due to venous congestion and a bite wound were treated using nebulised adrenaline and resolved within 2 hours allowing retraction of the tongue. The use of nebulised adrenaline offers a non-invasive method of managing this potentially life-threatening complication.

Clinical experience with a lipid-free, ready-made parenteral nutrition solution in dogs: 70 cases (2006-2012).

OBJECTIVE: To review the clinical use of a lipid-free, ready-made amino acid and glucose parenteral nutrition (PN) solution in dogs. DESIGN: Retrospective study of dogs from 2006 to 2012 that received this form of PN. SETTING: University veterinary teaching hospital. ANIMALS: Seventy dogs presented to the hospital for treatment of various diseases in which PN was used as part of patient management. Dogs were administered PN at the discretion of the primary clinician. INTERVENTION: A lipid-free, ready-made solution containing amino acid (59 g/L) and dextrose (100 g/L) was administered intravenously as a constant rate infusion to provide nutritional support. MEASUREMENTS AND MAIN RESULTS: PN was provided for a median of 2.2 days (range 0.5-9.5 days) in the 70 dogs, totaling 168 days of PN. The PN provided a median of 5.5 g/100 kcal of protein (range 1-9.5 g/100 kcal) and a median of 2.2 mg/kg of bodyweight per minute (range 0.8-5.2 mg/kg/min) of glucose, which reflected a median of 57% of the resting energy requirement (range 9-100%). Metabolic complications developed in 43 of 67 dogs where these data were recorded, but the development of hyperkalemia was the only complication associated with a poor outcome (eg, death or euthanasia). Mechanical complications were seen in 28 dogs, and all but one of these occurred when PN was delivered through peripheral catheters. Septic complications were confirmed in 5 dogs. CONCLUSIONS: This form of PN is suitable for clinical use and can provide both protein and calories to ill dogs. It was, however, associated with a high rate of complications and requires careful patient monitoring.

Use of a laryngeal mask airway in a brachycephalic dog with masticatory myositis and trismus.

An 8-month old, male, neutered bulldog was presented for investigation of a 2-day history of trismus. Endotracheal intubation was impossible as the dog was only able to open his mouth approximately 2 cm. A laryngeal mask airway was blindly inserted after induction of general anesthesia to maintain the patient on inhalational anesthesia and improve respiration for computed tomography and muscle biopsy. The dog recovered from anesthesia uneventfully.

Oronasal fistula repair utilizing a temporalis muscle flap in a dog with severe trismus.

A 9 yr old spayed female cocker spaniel presented for evaluation of an invasive maxillary squamous cell carcinoma. Curative intent surgery and radiation therapy allowed for local control of the neoplasm; however, the development of a persistent oronasal fistula prevented a complete recovery. A temporalis myofascial rotation flap allowed for successful resolution of the maxillary defect. Implementation of the flap was relatively simple and was associated with few complications.

Life threatening complication associated with anesthesia in a dog with masticatory muscle myositis.

OBJECTIVE: To report a serious complication in a dog with masticatory muscle myositis (MMM) that occurred during general anesthesia for diagnostic testing. STUDY DESIGN: Case report. ANIMALS: A 2-year-old male Pug. METHODS: MMM was diagnosed in a Pug with a 2-week history of trismus by electrodiagnostics, histopathology, and 2M antibody test. During anesthesia tongue protrusion occurred and because of trismus, an inability to reposition the tongue resulted in venous congestion and severe swelling. Forceful physical attempts and subsequent removal of the rostral digastricus and masseter muscle attachments from the mandible did not increase jaw mobility. Mandibular symphysiotomy was necessary to resolve lingual venous congestion and to reposition the tongue into the oral cavity. RESULTS: Tongue swelling rapidly subsided after symphysiotomy allowing the tongue to be repositioned into the oral cavity. After treatment of MMM with corticosteroids, jaw range of motion improved and at 6 months was approximately 70% normal. CONCLUSIONS: Trismus could not be overcome by detachment of the masseter and digastricus muscle insertions from the mandible, and symphysiotomy was required to reposition the tongue in the oral cavity. CLINICAL RELEVANCE: In dogs with MMM, tongue position should be monitored during anesthesia to avoid inadvertent protrusion and swelling from venous congestion. Use of anesthetic monitoring equipment on the tongue, such as a pulse oximeter probe, should be avoided in these patients.

Atypical masticatory muscle myositis in three cavalier King Charles spaniel littermates.

This case report describes a novel manifestation of the immune-mediated disease, masticatory muscle myositis. Clinical signs, including difficulty in opening the mouth (trismus), were seen in three of four 12-week-old cavalier King Charles spaniel littermates. Diagnosis was established by 2M immunohistochemistry, supported by characteristic histopathological changes in affected temporal muscle. Treatment using corticosteroids at immune-modifying doses resulted in resolution of clinical signs in all the affected animals. Masticatory muscle myositis should be considered as a differential diagnosis in groups of young dogs with clinical signs of myositis localised to the head.

Masseter myodegeneration as a cause of trismus or dysphagia in adult horses.

The medical records of eight horses with histological evidence of myodegeneration of the masseter muscles were examined. While they were alive their most common clinical signs had included difficulty in eating or opening their mouths, weight loss, difficulty in moving, and noticeable atrophy of the masseter muscles. The serum activities of muscle enzymes were abnormally high in all of the horses. Whole blood and/or liver selenium and vitamin E concentrations were less than the reference ranges in some of the horses. The lesions varied with the stage of the disease and consisted of swelling and discoloration, or muscle atrophy and fibrosis. Histologically, the muscle changes ranged from acute to subacute degeneration, with regenerative changes accompanying ongoing degeneration, to chronic degeneration with fibrotic replacement of muscle tissue. There were changes in the masseter muscle of all the horses, but some had widespread lesions in skeletal muscle, and a few also had myocardial lesions.

Masticatory muscle myositis.

This report examines a case of masticatory muscle myositis in a dog. Inflammatory disorders can affect the muscles of mastication. Two types of inflammatory myopathies have been described. The histopathology and immunochemical features of this case suggest an immune mediated basis for this disorder. The diagnosis and treatment are described for this immune mediated inflammatory myositis.