CURRENT RESEARCH - PRIMARY SECRETORY OTITIS MEDIA (PSOM)

OVERVIEW ~ ENROLL ~ SYMPTOMS - Interim Report (9/6/2007)

The American Cavalier King Charles Spaniel Club Charitable Trust is very pleased that through the generous donations of our supporters, we have been able to help fund and make possible this research to be done by Dr. Lynette Cole, Ohio State University College of Veterinary Medicine.

OVERVIEW OF THE STUDY by Dr. Lynette Cole:
A recent report in the veterinary literature has documented an otitis media (middle ear infection) that appears to affect the CKCS breed in particular. Due to the mucoid nature of the ear disease the condition has been referred to as primary secretory otitis media (PSOM) or "glue ear."

The clinical signs associated with this disease (head and neck pain, neurological signs, deafness) are similar to some of the other diseases recognized in the CKCS (syringomyelia, progressive hereditary deafness). Thus it is likely that some dogs with PSOM have been misdiagnosed with other diseases. PSOM is a treatable disease with a significantly more favorable prognosis than syringomyelia or progressive hereditary deafness. There may be a number of owners with CKCS that have this disease, but do not seek medical attention and diagnostics, thinking their CKCS has an "untreatable Disease." The purpose of this study is to find a reliable test or series of tests for the diagnosis of this disease. Once this has been established, large numbers of CKCS can be screened for the disease, appropriately treated, and future studies designed to determine the cause of the disease.

Enrollment of dogs in the study will begin September 2006. If after reading the article below, you are interested in possibly enrolling your CKCS dog in the study, please contact Dr. Cole at the telephone number listed below. Since the clinical signs are variable, and dogs with PSOM rarely have signs of an ear infection there are no set symptoms that the dog must exhibit to be eligible for enrollment. Details of the study will be given individually on the phone.
Primary Secretory Otitis Media (PSOM) or "Glue Ear"

Dr. Lynette Cole DVM, MS, Dipl. ACVD
Dr. Andrew Hillier BVSc, MACVSc, Dipl. ACVD
Dermatology Service, Veterinary teaching Hospital
The Ohio State University, 601 Vernon L. Tharp Street,
Columbus, OH 43210.
Tel: (614) 292-3551

What is PSOM?

PSOM is a form of otitis media (inflammation of the middle ear) that seems to affect the Cavalier King Charles spaniel (CKCS) in particular. Due to the mucoid nature of the disease and the fact that it is uncommonly associated with disease of the external ear canal, the condition has been referred to as PSOM or "glue ear".

What are the signs and symptoms of PSOM?

PSOM has been described in 43 CKCS dogs in one retrospective study in the veterinary literature (Stern-Bertholtz W, Sjostrom L, Wallin Hakanson N. Primary secretory otitis media in the Cavalier King Charles spaniel: a review of 61 cases. J Sm Anim Pract 2003; 44: 253-256). The presenting signs described from most to least common included pain localized to the head and neck, neurological signs (ataxia [incoordination], facial paralysis [drooping of the ear or lip, drooling saliva, inability to blink the eye], nystagmus [involuntary rapid movement of the eyeball], head tilt, seizures), itching around the ears, infections of the external ears, impaired hearing, and fatigue. These are some of the same signs seen with syringomyelia or progressive hereditary deafness which are diseases also identified in the CKCS. At the current time, there are no specific clinical signs that are associated with PSOM only.

How does PSOM differ from the more common infectious otitis media?

The biggest difference between PSOM and infectious otitis media are the prior infections of the external ear (otitis externa) seen in dogs with infectious otitis media. Infectious otitis media is usually due to an extension of an infection of the external ear (otitis externa) through the ear drum (tympanic membrane) into the middle ear. The most common clinical sign of infectious otitis media is recurrent otitis externa, which may manifest as discharge from the external ear, odor, redness of the external ear, pawing or rubbing the ear, head shaking and pain on palpation of the ear. In some instances, neurological signs may be present, as described for PSOM.

How does PSOM cause hearing loss?

There are two types of hearing loss, one is conductive and the other is sensorineural. Sensorineural hearing loss is due to an abnormality of the cranial nerve responsible for hearing, while conductive hearing loss is due to something impeding the ability of sound to get into the inner ear to the cranial nerve. The mucus present in the middle ear in CKCS with PSOM can cause conductive hearing loss by impeding sound from getting to the inner ear. Once the mucus is removed, hearing is restored. Hearing loss may recur if the mucus accumulates in the middle ear again. In the aforementioned study, the middle ear had to be flushed of mucus on more than one occasion in most dogs. Therefore, at the present time, we are unsure of the recurrence rate of PSOM after a middle ear flush.

Can hearing loss due to PSOM cause behavioral problems or changes?

Hearing loss in children due to secretory otitis media (SOM), a disease that appears to be similar to PSOM, has been associated with changes in speech, language, cognition and behavior. Therefore, it is possible that the hearing loss due to PSOM in the CKCS could result in behavioral problems or changes.

How do I know if my CKCS has PSOM?

As stated above, the clinical signs can be quite variable. Neurological signs described above or acute loss of hearing would be an indication to seek veterinary attention.

What should I do if I think my CKCS has PSOM?

The first step would be to schedule an appointment for your CKCS with your veterinarian for evaluation. However, diagnosis of PSOM and distinguishing the clinical signs from other diseases usually requires the expertise of a veterinary neurologist and/or veterinary dermatologist. Your veterinarian should be able to help you find a neurologist and/or dermatologist in your area who can further evaluate your CKCS.

Is PSOM unilateral or bilateral?

It appears that most CKCS have bilateral involvement, but it is possible for the disease to be unilateral.

What is the age of onset of PSOM?

In the above retrospective study, most of the dogs (86%) were between 3 and 7 years of age at presentation, but the ages ranged from 2 to 10. At the present time we are unsure if it occurs in puppies, and do not know how long it has to be present before clinical signs occur.

How can PSOM be diagnosed?

At the present time, the best test for diagnosis of PSOM is a CT scan or MRI. However, these tests will only tell you if there is material (fluid, mucus, pus, or a mass) in the middle ear. Plain radiographs (x-rays) may be helpful, but are not as sensitive as CT or MRI, meaning that a dog may have material in the middle ear, but it would not be identified on the radiograph. To specifically identify the material seen on the CT scan or MRI as mucus, a myringotomy (incision into the ear drum) must be performed if the ear drum is intact. For these procedures as well as the myringotomy, the dog must be under general anesthesia. Most of the CKCS with PSOM have an intact, bulging ear drum. However, a non-bulging tympanic membrane does not rule out the disease. A video otoscope is preferred to the conventional hand-held otoscope for the ear examination, since the video otoscope magnifies and illuminates the ear canal and ear drum to allow for a more thorough evaluation of the ear canal and a complete view of the ear drum. However, a normal ear exam does not rule out PSOM. Functional auditory tests may be useful in the diagnosis of this disease and include brain evoked auditory response testing (BAER, or hearing test) as well as impedance audiometry (testing to determine the status of the ear drum and middle ear), but to date the predictive value of these tests has not been studied. We are in the process of getting funded for a study to evaluate numerous tests for the diagnosis of PSOM.

What happens if PSOM goes undiagnosed for an extended period of time?

Currently we do not know how long a CKCS may have PSOM before clinical signs occur, so we are unsure if any complications may occur the longer the disease is present. Further, it is possible that the condition may be present in some dogs who may never show any clinical signs of the disease.

How can PSOM be treated?

Treatment is aimed at removal of the mucus from the middle ear. This is done by flushing the mucus out of the middle ear with the aid of a video otoscope or operating microscope and suctioning the mucus out of the ear canal. The mucus can be challenging to remove from the middle ear and external ear canal. In most instances, the mucus appears to be sterile, however, I recommend culturing the mucus to determine is there is a secondary infection present in the middle ear.

Are there any medical treatments for PSOM?

In the aforementioned study, after the middle ear flush, a number of treatments were utilized (topical and oral corticosteroids, topical and oral antibiotics, mucolytics), but their efficacy in prevention or treatment of the disease is unknown. To date, the only treatment with known efficacy is middle ear flushing.

What complications may occur as a result of flushing the middle ear?

Complications secondary to the ear flush include facial nerve paralysis, Horner's syndrome (elevation of the third eyelid), balance problems (falling over, difficulty rising), and deafness. These complications are usually uncommon and can be minimized by having this procedure performed by a veterinary dermatologist that has experience in middle ear flushing.

What is the cause of PSOM?

At the present time, the cause of PSOM is not known. Due to its similarity to secretory otitis media in children, there may be an underlying Eustachian tube dysfunction causing the disease. The Eustachian tube is the structure that connects the middle ear to the nasopharynx and allows equalization of pressure (ventilation) in the middle ear with atmospheric pressure, drains secretions produced within the middle ear into the nasopharynx, and protects the middle ear from nasopharyngeal sound pressures and secretions.

Is PSOM a genetic disease?

It would appear that this breed is genetically predisposed to developing the disease, but the mode of inheritance in not known.

Continuing research such as this is made possible through the donations of people who are interested in improving the health and the lives of our beloved Cavaliers. Please make your donation today to the ACKCSC Charitable Trust to support continuing health research for Cavaliers. 

INTERIM REPORT PRIMARY SECRETORY OTITIS MEDIA RESEARCH  (added to website 9/6/2007)

FUNDED BY THE AMERICAN CAVALIER KING CHARLES SPANIEL CLUB CHARITABLE TRUST

Project Title: Diagnosis of Primary Secretory Otitis Media (PSOM) in the Cavalier King Charles Spaniel (CKCS)

Investigators: Cole LK, Hillier A, Wagner S, Samii VF, Rajala-Schultz PJ Account #: 60009836

Primary Secretory Otitis Media (PSOM) is a middle ear disease reported almost exclusively in the Cavalier King Charles Spaniel (CKCS) and may affect 40% of CKCS. Because the clinical signs associated with this disease in the CKCS, such as head and neck pain, neurological signs (facial paralysis, balance problems, etc.), and hearing impairment are similar to some of the symptoms of other diseases recognized in the CKCS (syringohydromyelia, progressive hereditary deafness), it is possible that examining veterinarians have misdiagnosed some CKCS with these other diseases when in fact the CKCS had PSOM. It is important to be able to accurately diagnose PSOM, because once the mucus has been removed from the middle ear, the clinical signs resolve.

In a previous study, the diagnosis of PSOM was made based on visualization of a bulging ear drum with an otoscope. Utilization of otoscopy alone has a low sensitivity for the diagnosis of otitis media (inflammation of the middle ear). Currently, computed tomography (CT, Cat Scan) appears to be the best diagnostic test for evaluation of a dog with suspected otitis media. Disadvantages of CT include cost, availability, use of ionizing radiation, and the requirement of the dog to be under general anesthesia. Other less costly and more available diagnostic tests, such as tympanic bulla ultrasonography, pneumotoscopy, impedance audiometry, and brain-stem auditory evoked response test (BAER) are possible alternatives for the diagnosis of PSOM.

In this study, 75 CKCS will be enrolled, placed under general anesthesia, and the following diagnostics performed: CT scan, tympanic bulla ultrasonography, BAER test, impedance audiometry, otoscopic examination, and pneumotoscopy. If the CT scan is suggestive of otitis media (i.e. a soft tissue density present in the tympanic bulla-the bony part of the middle ear), then a myringotomy (incision into the ear drum) will be performed and the mucus flushed out of the middle ear. Cytology and bacterial cultures will be performed on the mucus from the middle ear. A BAER and CT scan will be performed post-middle ear flush on those CKCS with PSOM.

The study began in September 2006. Since this is a 2-day study, and from start to finish on the second day, including time to recover from anesthesia, the procedures take most of the day, at most I can enroll one CKCS per week. In addition, I have to coordinate the procedures with 2 other investigators and 2 technicians, so there are times when a dog cannot be enrolled, due to one of the investigators being out of the office. To date, 13 CKCS, 9 female (6 spayed) and 4 male (3 castrated), have been enrolled and completed the study. There were 5 Blenheim, 4 Ruby, 3 Tricolor and 1 Black and Tan. Their age when presented for enrollment into the study ranged from 5 months to 9 years old. The CKCS came from all across the United States: Arizona (n=1), Florida (1), Illinois (1), Indiana (1), Michigan (1), Minnesota (2), Ohio (3), Pennsylvania (1), Tennessee (1), and Virginia (1). Eight (62%) CKCS had PSOM (6 had PSOM in both ears, 2 had PSOM in one ear) and 5 (38%) did not have PSOM. Enrollment of the remaining CKCS is ongoing and I have 3 CKCS signed up for the month of September 2007. Once all of the CKCS have completed the study, the results of the diagnostic tests will be compared to the results of the CT scan for the diagnosis of PSOM, to determine which test or group of tests are the best to use for the diagnosis of PSOM.