Your horse's sinus is part of his respiratory system. While equine sinusitis is relatively common, immediate action is necessary to keep the infectious condition from getting worse. It's important to know what symptoms to watch for so you'll know when your horse is suffering from sinusitis.
Equine Sinus Anatomy
Your horse's sinus system begins above his eyes, at the center of his forehead, and continues down his facial crest to halfway between his eyes and the tip of his nose. The equine sinus consists of numerous air cavities, including the frontal sinus, conchofrontal sinus, dorsal nasal meatus, dorsal nasal concha, middle nasal meatus, ventral nasal concha, palatine sinus and ventral nasal meatus. These air chambers, tucked between the bones of your horse's head, are aligned with a protective mucosal membrane. A horse's nasal sinus cavities lead to the esophagus and trachea, ultimately delivering air to the respiratory system and, by extension, the bloodstream.
Sinusitis Definition and Causes
An equine sinus infection typically effects each of the sinus cavities on one side of a horse's head. Sinus infections are common in horses, and there are two principal causes. In primary sinusitis, the bacterial infection breaches the lining of the sinus cavities and amasses bacterial pus, mucus and phlegm. Secondary sinusitis stems from a diseased and infectious cheek tooth. The roots of your horse's back teeth are adjacent to the sinus cavities, and an abscess infection of these teeth can spread to his sinuses. The symptoms of primary and secondary equine sinusitis are similar, with secondary symptoms appearing more severe, and are accompanied by an atrociously odorous breath. Aside from these more common causes, ahorse's sinus infection may also be caused by a nasal cyst or tumor, an ethmoid hematoma, a fungal granuloma or a facial bone fracture.
Symptoms of Equine Sinusitis
Report any unusual symptoms your horse displays to his veterinarian immediately. Nasal discharge in horses is usually due to an infection in the respiratory system. Nasal discharge that does not diminish with the administration of antibiotics, or that comes from a single nostril, indicates that the infection stems from the sinus pockets and is typically diagnosed as sinusitis. Other possible symptoms of equine sinusitis include facial swelling, reoccurring upper respiratory tract infections, head shaking, loss of facial hair and heavy breathing.
Diagnosis and Treatment
Your veterinarian may use a variety of diagnostic techniques to diagnose your horse's sinus infection. Reoccurring sinus problems may be the initial indicator; a physical exam would be in order. Diagnostic equipment your vet might use include endoscopy, sinoscopy, radiography, computer tomography or nuclear medicine. Your veterinarian might start with antibiotics to reduce the severity of the symptoms and follow with sinusitis surgery. If sinusitis is caught early, a horse's surgical procedure is less complicated -- it's a surgical debridement, where the sinus is opened surgically and flushed repeatedly with a disinfectant solution to cure the infection. In secondary sinusitis cases, an abscessed or damaged tooth requires removal. If the secondary cause is a cyst or tumor, the vet will order a biopsy and the growth may be removed via surgery.