14: Diseases of the Ear

SECTION 14 Diseases of the Ear



Section Editor: Lynette K. Cole, DVM, MS, DACVD



Aural Hematoma

Deafness

Otitis Externa

Otitis Interna

Otitis Media


Aural Hematoma


Lynette K. Cole, DVM, MS, DACVD



BASIC INFORMATION



Description


An aural hematoma is the accumulation of fluid or blood within the ear flap (pinna).



Causes


An aural hematoma occurs when scratching the ear or shaking the head causes a blood vessel in the ear to rupture and blood leaks into the tissues of the pinna. Occasionally, hematomas also arise from trauma and bite wounds.



image Clinical Signs


A noticeable swelling is present in the pinna that may be either firm or soft. The swelling may be small, or it may involve the entire pinna and extend into the ear canal. Aural hematomas occur most often in dogs but can also occur in cats.



image Diagnostic Tests


An aural hematoma can often be diagnosed from the typical clinical appearance. In some instances, the swelling may be aspirated with a needle to obtain cells that can be examined under the microscope. Your veterinarian may recommend other tests to investigate an underlying cause of the hematoma, such as an external ear infection.



TREATMENT AND FOLLOW-UP




image Treatment Options


Aspiration of the fluid can be attempted. This is the simplest and most conservative method of treatment. It is effective in relieving any associated pain, but recurrence of the aural hematoma is common following aspiration.


Surgical drainage of the fluid also decreases pain, and there is less likelihood of a recurrence. Several surgical methods are available, including the following:


• Silastic drain placement: A drain is inserted into the top and the bottom of the hematoma to allow blood to drain from the hematoma.

• Teat cannula placement: A teat cannula is a small tube with holes at both ends that can be inserted into the opening of the nipple on the udder of a cow. In this instance, the tube is inserted into the bottom part of the hematoma to allow drainage.

• Closed suction catheter system: A catheter is inserted into the bottom of the hematoma. One end of the catheter is attached to a container that collects drainage from the hematoma.

• Incisional drainage: An incision is made from the top to the bottom of the hematoma, and stitches are placed on either side of the incision, all the way through both sides of the pinna.

• Laser procedure: A laser is used to make multiple circular skin incisions that allow the hematoma to drain.

Any ear infection that is present is treated with appropriate topical medications. If underlying allergic disease is present, such as atopic dermatitis or adverse food reactions (food allergy), these diseases also must be controlled to prevent head shaking and scratching.



image Follow-up Care


Sutures are removed in 10-14 days, whereas drains are usually removed in 3 weeks. An Elizabethan collar may be used to prevent premature removal of the sutures or drains.



Prognosis


Most hematomas resolve without complications after surgical drainage. Some hematomas recur; however, even with surgical drainage. Although it is uncommon, disfigurement of the pinna can occur after surgical drainage, and it is more noticeable in animals with erect ears. Pinnal scarring and disfigurement are more common with untreated and recurrent hematomas.




SPECIAL INSTRUCTIONS:



Deafness


Lynette K. Cole, DVM, MS, DACVD



BASIC INFORMATION



Description


Deafness can be divided in to several classes based on the specific problem, as follows:


• Conductive hearing loss results from failure of sound energy to be translated into mechanical energy in the outer and middle ear structures.

• Sensorineural hearing loss is caused by loss of electrical energy transfer from the cochlear sensory receptors or cochlear nerve.

• Central-mediated hearing loss is failure to process auditory information at the level of the brain.

• Presbycusis is old age–related hearing loss that is not associated with a specific pathologic process but arises from degeneration of the inner ear structures.


Causes


Conductive hearing loss may be caused by outer ear diseases such as otitis externa, ear wax impaction, foreign bodies, cancerous tumors, benign inflammatory polyps, and trauma. Middle ear diseases such as infectious otitis media, primary secretory otitis media (PSOM), foreign bodies, and tumors are also causes.


Congenital, hereditary sensorineural deafness occurs in some dogs and cats with white coat color and blue eyes. It also affects numerous purebred dogs, such as the Dalmatian, Australian blue heeler, English setter, Argentine dogo, bull terrier, Australian shepherd, Jack Russell terrier, and Cavalier King Charles spaniel.


Acquired sensorineural deafness may develop from certain systemic drugs (aminoglycoside antibiotics) and topical otic medications (ceruminolytic agents), trauma, tumors, or presbycusis.



image Clinical Signs


Conductive hearing loss can occur at any age, depending on the underlying cause. It rarely results in complete hearing loss. Congenital, hereditary deafness is present soon after birth. With acquired deafness, hearing loss may be sudden or slow in onset; in some cases, balance (vestibular) problems may be detected.



image Diagnostic Tests


Physical examination findings are usually normal. Specialized hearing tests are used to confirm deafness, to pinpoint where the hearing loss is occurring in the hearing pathway, and to determine whether the hearing loss is conductive or sensorineural in nature. For the best results, these tests are often performed with the animal sedated or anesthetized, and they are usually available only at veterinary specialty or university hospitals. Examples include the following:


• Impedance audiometry is performed by inserting ear plugs into the ear canal and measuring the change in mobility of the eardrum (tympanic membrane) and the involuntary contraction of the muscles in the middle ear. This test helps to assess the integrity of the middle ear.

• The brainstem evoked auditory response (BAER) test measures specific components of the hearing pathway and can be used to characterize conductive and sensorineural hearing loss.


TREATMENT AND FOLLOW-UP




image Treatment Options


Conductive hearing loss is usually reversible and requires removal of any obstruction, such as wax from the external ear canal or mucus from the middle ear (especially in dogs with PSOM). Congenital hereditary sensorineural hearing loss and presbycusis are not treatable and are irreversible. Drug-induced hearing loss is usually permanent but may improve once the drug has been discontinued.

Related posts:

  1. 6: Endocrine System
  2. 8: Reproductive System
  3. 2: Cardiovascular System
  4. 15: Infectious Diseases

Stay updated, free articles. Join our Telegram channel
Tags:
Sep 11, 2016 | Posted by in SMALL ANIMAL | Comments Off on 14: Diseases of the Ear

Full access? Get Clinical Tree
Get Clinical Tree app for offline access