What is your diagnosis? Displaced avulsion fracture of the basisphenoid-basioccipital bone.

This research article documents the medical history, evaluation, treatment and complications experienced by a 9-year-old Arabian stallion after suffering from an acute head trauma and a displaced avulsion fracture of the basisphenoid-basioccipital bone.

Research Context and Initial Diagnosis

• The study details the case of a horse, adrenalized in a halter class, which reared up and fell, hitting the left side of its head. Symptoms of severe bilateral epistaxis (nosebleeds from both nostrils) set in once the horse was standing.
• Upon admission, despite the evident severe bilateral epistaxis, the heart rate, respiratory rate, and rectal temperature were deemed normal. An initial neurologic examination did not detect any abnormalities.
• Subsequent radiographs led to the diagnosis of a displaced avulsion fracture of the basisphenoid-basioccipital bone.

Treatment and Aftercare

• Initial treatments for the skull fracture included administration of Trimethoprim-sulfadoxine, dexamethasone, and confinement to a stall.
• The horse experienced a partial seizure, which was addressed with treatment including diazepam, phenobarbital, and DMSO.
• A brief period of ataxia developed 6 days later but resolved without treatment.
• Follow-up skull radiography revealed ventral rotation of the fragment and gradual reabsorption of fluid within the guttural pouches.
• The patient also experienced three mild episodes of colic within the first three weeks, and these responded positively to medical treatment.

Complications and Further Treatments

• The horse was readmitted to the hospital three days after discharge for surgical treatment of severe impaction colic.
• Post-surgery complications included continued episodes of colic, dysphagia, and acute dyspnea.
• A subsequent endoscopy showed severe pharyngeal swelling and bilateral arytenoid paresis.
• Persistent endoscopies revealed a mucosa-covered mass protruding from the guttural pouches, which corresponded with the displaced fragment of the basisphenoid bone. This was confirmed by skull radiography.