What are Diseases Affecting the Ear Balance Systems?
The vestibular system is a major component of the sensory system that links the inner ear, the medulla of the brain, and the vestibular nerve. This sensory system is responsible for the positioning of different parts of the body, the smooth movements of the limbs and trunk, and balance. When this system is not functioning properly it leads to ataxia, vertigo and in some cases permanent hearing loss. If you suspect your pet is suffering from this disease contact your veterinarian immediately.
The most common disease that affects the inner ear balance system in rabbits is bacterial infection of the inner and middle ear. Other causes include trauma, toxicity, immune disease, neoplasia or idiopathic vestibular disease.
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Symptoms of Diseases Affecting the Ear Balance Systems in Rabbits
This disease usually has rapid onset of symptoms. These may include:
- Loss of balance/ataxia
- Nasal and eye discharge
- Rolling eyes
- Inability to lift head or head tilting
- Signs of ear infection such as pain, fever, ear discharge and anorexia
The most common type of inner ear balance disease in rabbits is infection. Pasteurella multocida, staphylococcus aureus and streptococcus are common causes of infection in rabbits, leading to abscess, lactation infections and middle and inner ear infections. In order to isolate these as causative bacteria your veterinarian may take a sample of exudate for laboratory testing. Other possible bacterial causes are Escherichia coli, Enterococcus, Proteus and Pseudomonas sp.
Other pathogens that may be found in laboratory testing are yeast infection caused by an overgrowth of Candida sp. or Pityrosporum sp and fungal infection by Cryptococcus (this is rare in rabbits but has also been known to affect the respiratory system).
Causes of Diseases Affecting the Ear Balance Systems in Rabbits
There are known factors that increase the risk of developing diseases of the inner ear balance system. These include:
- Poor hygiene or cramped living conditions
- Certain breeds such as lop eared rabbits
- Idiopathic cause (unknown)
- Degenerative diseases
- Cancer or other lesions on the pinna
- Immune suppression due to other disease or age
Diagnosis of Diseases Affecting the Ear Balance Systems in Rabbits
Your veterinarian will perform a full clinical exam on your rabbit, taking into account the history of symptoms and possible incidents that may have caused this condition such as ear cleaning or a fall. The differential diagnosis will involve taking into account the numerous possible causes for this condition and finding which one fits the symptoms and history best.
Your veterinarian will likely use an otoscope to examine your rabbit’s ears, this will allow her to visualise the eardrum and determine if it has ruptured, as well as check for pus, foreign bodies or crusting that would indicate parasitic infestation. In order to perform this examination sedation will be necessary. During this time, radiographs may also be taken. This will allow your veterinarian to check for foreign objects that may have gotten lodged in the ear, tumors or lesions. Middle ear infections are often visible in radiographs, characterized by a grayish mass.
Your veterinarian will take a blood sample to perform a complete blood profile, including a chemical blood profile, a complete blood count, and a urinalysis. If possible your veterinarian will also take a sample of the discharge from the ear. This will help determine if infection is the underlying cause, and if so, whether it is bacterial, yeast or parasitic. This sample will also be sent off for a culture and sensitivity test.
Treatment of Diseases Affecting the Ear Balance Systems in Rabbits
Your rabbit may need to stay in the clinic for monitoring and treatment depending on the cause of their imbalance and the severity of their symptoms.
If trauma was the cause of the inner ear balance upset, your rabbit will be given anti-inflammatory drugs to bring down swelling.
If an infection is suspected antibiotics may be given. Your veterinarian will likely use the results from the culture and sensitivity test to determine the most effective antibiotic treatment for your pet. The course of antibiotics will last 4 to 6 weeks or 2 weeks after full recovery. Your veterinarian will monitor your pet’s recovery and if there is no improvement of symptoms after 2 weeks they may change the antibiotic medication.
If your veterinarian suspects the cause is an adverse reaction to medications that your rabbit has been receiving, your rabbit will need to stop these drugs until your veterinarian can find a substitute.
If a fracture or tumor is suspected, a CTG may be performed and surgical removal or repair may be necessary.
If your pet is suffering from a parasitic infection, your veterinarian may recommend a course of subcutaneous ivermectin injections. These injections will be repeated 3 times over a 6 week period.
For pain relief non-steroidal anti-inflammatory drugs (NSAIDs) may be given to your pet. As these are metabolized by the liver and kidneys, your veterinarian will assess the results of the blood tests to ensure sufficient renal function.
If your rabbit is not eating, your veterinary caregiver may feel that force-feeding is needed. A member of the team may use a syringe to feed your rabbit a puree; there are commercially available rabbit foods ideal for compromised patients, or foods such as canned pumpkin can be used.
Recovery of Diseases Affecting the Ear Balance Systems in Rabbits
The earlier your rabbit receives treatment, the better the prognosis. In cases where the cause of imbalance was ear mite infestation or infection, the prognosis is fair.
If the middle ear or nerves were damaged, deafness or head-tilt is irreversible.
For your pet’s comfort provide warm, soft bedding. Due to the ataxia and imbalance that is often caused by ear disorder ensure your rabbit is not placed on hard or uneven flooring. For pet’s whose inner ear balance disorder was caused by ear mites it is vital that the environment is treated with a parasitical spray and all in-contact rabbits are also treated.
Offer a selection of different foods such as fresh romaine lettuce, kale, spinach, and grass hay. Encourage fluid intake by offering moistened leaves or flavored water. If your rabbit refuses these foods, you will need to contact your veterinarian and syringe feeding or fluid therapy may be needed, until he can eat again on his own. As rabbits deteriorate quickly in cases of anorexia, if your pet is refusing food, force-feeding or readmission for fluid therapy may be necessary.