other name: middle & inner ear disease
Overview
Otitis media and interna (OMI) refer to infections that affect the middle and inner ear. In some cases, this infection leads to the formation of abscess (localized pocket of pus) and inflammation that can damage nearby structures. When this abscess involves the inner ear, they can severely disrupt the animal’s sense of balance and coordination.
Cause
Otitis media and interna are most commonly caused by a bacterial infection that spreads from the outer ear into the deeper parts of the ear. Normally, the eardrum acts as a barrier that keeps bacteria and yeast from moving deeper into the ear. However, if the eardrum ruptures, it can allow these organisms to enter the middle and inner ear, potentially leading to more serious infections. It is important to note that inner ear infections can sometimes occur even without an outer ear infection.
The most common predisposing factors for inner ear disease in animals are allergies and polyps. Allergies can cause ongoing inflammation that throws off the natural balance of healthy microbes on the skin inside the ear. Inflammatory polyps or masses, particularly common in cats, can obstruct normal ear drainage, creating a favorable environment for an infection.
Clinical Signs
Otitis media and interna often affect the vestibular system, leading to problems with balance and coordination. Common clinical signs include:
- Head tilt
- Falling over, rolling, wobbliness
- Abnormal eye movements or position
- Vomiting or nausea due to motion sickness
Additionally, OMI can impair the ability to blink or move the facial muscles on the affected side, which may result in a reddened or inflamed eye.
Diagnosis
MRI is the diagnostic tool of choice for confirming a diagnosis of otitis media and interna, as well as for ruling out other potential causes of vestibular dysfunction. While examination of the outer ear can provide a diagnosis of outer ear infection or a ruptured eardrum, it often does not offer enough information to confirm inner ear involvement or assess the severity of the infection. In severe cases, the infection can spread deeper into the brain, which requires aggressive and prompt treatment. This is why MRI is imperative.
Treatment
Treatment for OMI typically involves one of two main approaches, depending on the pet’s clinical signs and MRI findings.
For stable cases with mild to moderate infection and neurological dysfunction, long-term broad-spectrum antibiotics are usually prescribed while we monitor for improvement in neurological symptoms. Antibiotics are often prescribed for weeks to months.
In more severe or cases unresponsive to broad-spectrum antibiotics, a procedure called a myringotomy may be recommended. A myringotomy involves creating a small opening in the eardrum to flush out the middle and inner ear and collect a sample for culture. This helps ensure the chosen antibiotic is effective against the specific infection. Myringotomies are often performed by veterinary dermatologists.
Supportive care is also important and may include medications to reduce nausea or dizziness, along with helping your pet stay comfortable and stable while they regain their balance.
Successfully treating middle and inner ear infections requires identifying and addressing any underlying cause, such as allergies. This is essential not only for effective treatment but also for preventing recurrence of the problem.
It is important to understand that even when the infection has been successfully treated, some signs such as a head tilt, slight incoordination or facial weakness may remain. While these changes can be disappointing at first, they are typically cosmetic and do not affect your pet’s overall well-being. Because some deficits may persist, repeating an MRI after the antibiotic course is completed may be recommended to ensure the infection has fully resolved.
Prognosis
The prognosis for OMI in both dogs and cats can vary, but with prompt and appropriate treatment, most pets have an excellent chance of recovery.
In case where infection spreads into the brain, the prognosis becomes more guarded and may require aggressive treatment and intensive care.