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.


METHODS
Case report.


METHODS
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.


CONCLUSIONS
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.
Nanai
Beatrix
B
Animal Emergency and Critical Care Center of Brevard, Melbourne, FL 32935, USA. bnanai@yahoo.com
Phillips
Lesley
L
Christiansen
Jeffrey
J
Shelton
G Diane
GD
D000768:Anesthesia, General / Q000009:adverse effects / Q000662:veterinary; D018681:Anesthetics, General / Q000009:adverse effects*; D000818:Animals; D004283:Dog Diseases / Q000139:chemically induced*; D004285:Dogs; D008297:Male; D008410:Masticatory Muscles / Q000473:pathology*; D009220:Myositis / Q000662:veterinary*; D014059:Tongue / Q000473:pathology; D014313:Trismus / Q000150:complications / Q000662:veterinary*
D018681:Anesthetics, General