Diseases Affecting the Inner Ear Balance Systems in Rabbits

Head Tilt (Vestibular Disease) in Rabbits

The vestibular system is a major component of the sensory system, a complex system that includes the labyrinth of the inner ear, the medulla of the brain, and the vestibular nerve. Together, the system contributes to the correct positioning of different parts of the body, the smooth movements of the limbs and trunk, and proper balance. Therefore, dysfunction in the system can result in a false sense of movement, vertigo, wobbling eyes, heat tilt, and hearing loss.

In rabbits, vestibular disease is commonly due to ear infection and brain abscesses. Lop-eared rabbits may be more likely to be affected by ear infection, while dwarf breeds and older rabbits with poor immunity may be more predisposed to signs due to bacterial infection.

Symptoms and Types

Initially, the symptoms of vestibular disease are severe and sudden, including rolling eyes, loss of balance, tremors, head tilting, or an inability to lift the head. Other typicaly signs include:

• Nasal and eye discharge
• Signs of ear infection — pain, fever, and ear discharge

Causes

• Inflammatory — infections, bacterial, viral, parasitic or fungal
• Idiopathic — unknown origin
• Traumatic — fracture, aggressive ear flushing (cleaning related)
• Neoplastic — tumors of the bone
• Toxic — lead poisoning
• Degenerative diseases
• Suppressed immune system
• Nutritional — lack of vitamin A (rare)

Diagnosis

Your veterinarian will perform a thorough physical exam on your rabbit, taking into account the background history of symptoms and possible incidents that might have led to this condition. There are several possible causes for this condition such as tumors, infection, or injury, and a differential diagnosis can be the best method for diagnosis. This process is guided by deeper inspection of the apparent outward symptoms, ruling out each of the more common causes until the correct disorder is settled upon and can be treated appropriately.

Often, head tilt is a symptom of an ear infection or injury, so your veterinarian will conduct a detailed examination of the ear, with an ear swab analysis of the contents or discharge in the ear canal. A complete blood profile will be conducted, including a chemical blood profile, a complete blood count, and a urinalysis. These tests may indicate if your rabbit is suffering from an infection, and if so, what kind. Visual diagnostics are also a necessary part of making a diagnosis. X-rays of the ear and skull will be used to look for the presence of lesions, internal injury, or the presence of tumors, and computed tomography (CT) and magnetic resonance imaging (MRI) can be used to for a more detailed visualization of the internal ear so that the exact location of any lesions or growths can be found.

Treatment

Based on the severity of the symptoms, your veterinarian will determine whether inpatient treatment is necessary. In case of trauma, anti-inflammatory drugs may be given to bring down swelling. Antibiotics are used to treat or prevent an infection, and intravenous fluids may be given to replace or maintain body fluids. If the cause is thought to be related to an adverse reaction to medications that your rabbit has been receiving previous to this condition, your doctor will recommend that you stop giving these drugs to your rabbit until a substitute can be found. Meanwhile, if the cause is related to a fracture or tumor of the inner ear, a resolution may be difficult to achieve, either by repair or removal, considering the constraints of the location.

Living and Management

You will need to protect your rabbit from stairs and slippery surfaces based on the extent of loss of balance, and provide a warm, quiet environment for your rabbit to recover in. Encourage return to safe activity as soon as safely possible, as activity may enhance recovery of vestibular functioning. If the rabbit is not too tired, encourage exercise (hopping) for at least 10-15 minutes every 6-8 hours.

It is important that your rabbit continue to eat during and following treatment. Encourage oral fluid intake by offering fresh water, wetting leafy vegetables, or flavoring water with vegetable juice, and offer a large selection of fresh, moistened greens such as cilantro, romaine lettuce, parsley, carrot tops, dandelion greens, spinach, collard greens, and good-quality grass hay. If your rabbit refuses these foods, you will need to syringe feed a gruel mixture until it can eat again on its own. Also, offer your rabbit its usual pelleted diet, but do not feed your rabbit high-carbohydrate, high-fat nutritional supplements unless your veterinarian has specifically advised it.