Medial pterygoid myositis in a Thoroughbred gelding

Abstract

SummaryThis case report describes the investigation and treatment of an adult horse with purulent, malodorous exudate originating from a large intermandibular mass. Microbial culture of fluid aspirated from a draining tract yielded Peptostreptococcus and Prevotella species which are usually considered to originate from the oral cavity. Computed tomography (CT) was used to aid in the diagnosis and to allow careful presurgical planning, and the horse underwent successful debridement of the abscess cavity under general anaesthesia. Post‐operatively, the horse developed trismus (reduced opening of the jaws) but repeat CT identified that the surgery site was healing appropriately. It was recommended to continue feeding the horse hay to act as physiotherapy and the masticatory action of the horse subsequently returned to normal.

The facultative human oral pathogen Prevotella histicola in equine cheek tooth apical/ periapical infection: a case report

“…Cross-species distribution seems not unlikely, since e.g. P. melaninogenica and P. oralis were isolated both from human and equine patients [ 23 , 32 , 33 ]. On a genus-level, Prevotella ssp.…”

“…Nevertheless, resistances are increasing here too, but susceptibility of Prevotella ssp. to metronidazole is still up to 100 % [ 32 , 43 – 47 ]. Thus, we decided to use metronidazole.…”

“…In a case of medial pterygoid myositis caused by Prevotella ssp. in a horse, metronidazole was discontinued five days after surgery but infection reemerged within one month post-surgery [ 32 ]. This might indicate that in horses, metronidazole should be administered at least longer than 5 days and that anaerobes likely recolonize affected areas when treated improperly.…”

“…Anaerobe antibiotic treatment is predominantly based on empirical value, thus literature evidence on Prevotella ssp . susceptibility was considered [ 32 , 43 – 48 ], and antibiotic treatment changed to metronidazole (20 mg*kg −1 p.o. TID; Metrobactin; CP-Pharma, Burgdorf, Germany) for 12 days.…”

“…(2010) [ 31 ]. Just recently, P. melaninogenica and P. oralis have been isolated from an aspirate of a purulent medial pterygoid muscle myositis, presumably of oral origin, in a horse [ 32 ]. Santoshi and Leshem (2014) isolated P. melaninogenica from a horse bite wound in a human patient [ 33 ].…”