Tympanic Membrane Rupture and Middle Ear Infection in Cats
What are the tympanic membrane and middle ear?
The tympanic membrane (eardrum) is a thin membrane that separates the outer ear canal from the middle and inner ear. The middle ear contains the three tiniest bones in the body, the malleus, incus, and stapes, commonly referred to as the hammer, anvil, and stirrup. The eustachian tubes are also located in the middle ear.
What causes a ruptured eardrum?
A ruptured eardrum can be the result of trauma, infection, exposure to toxins, sudden severe changes in atmospheric pressure, very loud noises, and foreign objects.
What is a middle ear infection?
If the eardrum is perforated or tears, bacteria and fungi from the outer ear canal may enter the sensitive middle ear resulting in a middle ear infection (otitis media). A middle ear infection can also result from a polyp or mass (benign or malignant tumor) in the middle ear.
What are the clinical signs of a ruptured eardrum or middle ear infection?
Signs that your cat may have a ruptured eardrum or middle ear infection can include discharge from the ear (often thick and pus-like or bloody), sudden hearing loss, red and inflamed ear canal, pain when touching the ear, a head tilt, stumbling, and nystagmus (eyes darting back-and-forth). Facial nerve paralysis causing drooping of one side of the face and mouth and the inability to blink or a completely closed eyelid may occur in some cases. Middle ear infections are often accompanied by inner ear infections and disruptions of balance and equilibrium.
How are a ruptured eardrum and middle ear infection diagnosed?
A thorough ear examination by your veterinarian, sometimes requiring sedation or anesthesia, is necessary to diagnose a ruptured eardrum. Many cats will require warm saline flushes. A classic test is to look for tiny air bubbles that form deep in the ear canal when the cat breathes. Another common test is to infuse a special dye, fluorescein, into the ear canal. If it escapes and exits through the nose, the eardrum is ruptured.
"A thorough ear examination by your veterinarian, sometimes requiring sedation or anesthesia, is necessary to diagnose a ruptured eardrum."
A myringotomy is usually performed in cases of middle ear infections. A myringotomy involves obtaining a sterile sample of the fluid within the middle ear for culture and analysis. A myringotomy is performed under sedation or anesthesia and is usually part of the thorough ear examination. Your veterinarian will advise whether this diagnostic test is necessary for your cat.
Skull radiographs (X-rays) are often helpful in determining the severity of a middle ear infection. CT and MRI scans are also recommended in some cases and may provide certain diagnostic advantages.
How are these conditions treated?
A thorough ear flushing, usually under sedation or anesthesia, is required in most cases. Your veterinarian will use appropriate medications and sometimes water-based flushing solutions (most often TrizEDTA®). Topical antibiotics (such as Baytril® Otic) may be prescribed based on your cat’s specific condition. Oral antibiotics such as amoxicillin/clavulanate (Clavamox®), enrofloxacin (Baytril®), cefpodoxime (Simplicef®, Vantin®), or marbofloxacin (Zeniquin®) and/or antifungal medications such as fluconazole (Diflucan®) or itraconazole (Itrafungol®, Sporanox®) are used in many cases. In addition, systemic corticosteroids, typically prednisone (Deltasone®, Meticorten®), may be beneficial in cats that have severe inflammation and pain.
"Surgery is sometimes needed and is typically reserved for patients thought to have severe, irreversible changes of the outer ear occurring at the same time as a middle ear infection."
Surgery is sometimes needed and is typically reserved for patients thought to have severe, irreversible changes of the outer ear occurring at the same time as a middle ear infection. If surgery is recommended for your cat, your veterinarian will discuss the reasons why, the risks involved, and the expected outcomes with you.
What is the prognosis?
Many cats recover without significant complications. Most ruptured eardrums heal without surgery within three to five weeks. Middle ear infections may require oral antibiotics or antifungal medications for four to six weeks. Most cats will require frequent recheck examinations and follow-up care to ensure the infection is resolving and the eardrum is healing properly. You must follow your veterinarian’s instructions to prevent serious complications or prolonged healing.
In severe cases with nerve damage, there may be permanent changes in the face, lips, and eyes or hearing loss. Your veterinarian will provide you with a more accurate prognosis based on your cat’s specific condition.
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