Retrobulbar Abscess in Dogs

Like many other carnivores, canines have an incomplete orbit for their eyes. This allows for the carnivore to open its mouth wider, but also leaves the orbital socket unprotected by the bony floor that we have protecting ours. This leaves canines, and other such carnivores, more susceptible to trauma and infections to the eye. Infections and foreign objects in the eye cavity can cause eye bulging and damage to the ocular nerve. When the infection causes a pocket to form behind the eyeball itself, it is known as a retrobulbar abscess.

Retrobulbar abscess occurs when an infection or intrusion causes a pus filled cavity to form behind the eyeball. This disorder requires veterinary care to mend.

Although the retrobulbar abscess is actually located behind the eye, the pain seems to spring from the jaw, due to the proximity of the orbital cavity to the jaw. Signs include:

• Bulging eye
• Discharge from around the eye
• Fever
• Foul breath
• Lethargy
• Loss of appetite
• Pain on eating
• Redness around eye
• Reluctance or refusal to chew
• Squinting
• Swelling around eye
• Unilateral nasal discharge
• Yelping when mouth is opened

Types 

Abscesses are not the only thing that can invade the area behind the eyeball. There are a few diseases and disorders that can affect the area behind the eye. Although many of the symptoms are similar, they tend to vary on the amount of pain, pressure, and growth rate. Differentials include:

• Cysts
• Hemorrhage
• Mucocele
• Neoplasia
• Parasitic infection
• Tumor

There are also other disorders that have many of the same basic symptoms as a retrobulbar abscess, but with slightly different origins. These can include disorders such as: 

• Craniomandibular osteopathy
• Extraocular polymyositis
• Masticatory muscle myositis
• Physical trauma
• Various vascular anomalies

Adjacent Infections

Infections of the sinus cavities and in the gums can travel to the eye and cause abscesses. 

Foreign Object

Abscesses caused by foreign objects occur more frequently during dry months. This is usually caused by a splinter or other types of dry, pointed plant material. These fragments of wood or dried bits of plant material can get caught in the back teeth, then migrate to the orbital socket, where it lodges. Pus generally forms in the orbital socket, and bacterial and fungal infections can also develop.

Penetrating Trauma

Infections can also be introduced to the retrobulbar area through penetrating trauma through the roof of the mouth.

The symptoms that are present with a retrobulbar abscess in dogs will prompt a thorough eye exam to be completed. The cornea will be checked for ulceration and the pressure within the eye will also be measured. Pus that is found behind the eye will usually be evaluated for the presence of pathogens as well. Standard tests, such as a complete blood count, urinalysis, and biochemical profile, will usually be completed at this time to check for systemic infections and other concurrent disorders. 

The mouth area will be carefully examined and evaluated. Sometimes the pain in the mouth and jaw area necessitates sedation or anesthesia in order to complete this evaluation. Both x-ray and ultrasound technology are frequently used to better visualize the space behind the eye as well as the bones around the eye. These forms of imaging can help to discover not only abscesses but also to evaluate growths and to determine the health of the underlying bone structure.

The first step in treating a retrobulbar abscess is to drain the abscess from the orbital cavity. This is accomplished by a surgical procedure, in which an incision is made in the top of the mouth, behind the last molar. The surgeon will then allow the abscess to drain completely, ensuring that none of the infected material falls down into the throat.

Any foreign objects that do not flush out with the pus from the incision will also be removed at this time, and the wound is left open during healing to ensure no new infections are allowed to collect in the area. If an infection is found when the discharge is cultured, then medication will be given to counter it. Bacterial infection is more common and would be treated with antibiotics. The antibiotic therapy is frequently started intravenously at the clinic, then changed over to orally administered antibiotic therapy and is generally quite successful. Fungal infections are treated with antifungal medication and can take longer to resolve.

After oral surgery, as with the drainage of a retrobulbar abscess, most pets will be able to eat fairly effectively again within just 6-12 hours, but canned food or moistened kibble is advised to avoid pain for 10 to 14 days, and there is likely to be more salivation and mess than usual as your dog’s mouth is healing. If any antibiotic or antifungal medications were prescribed, it is essential to complete the full course in order to prevent a reoccurrence of the infection. With most antibiotics that can be around 2-3 weeks and courses of antifungal treatment can be even longer.