Primary Secretory Otitis Media (PSOM) in Cavalier King Charles Spaniels & Treatment
Primary Secretory Otitis Media (PSOM) is an important differential diagnosis in Cavalier King Charles Spaniels with signs of pain involving the head and neck, and possible neurological signs as well. This breed can also have a Caudal occipital malformation syndrome (COMS), which also presents with similar clinical signs. Caudal occipital malformation syndrome (COMS) is a congenital malformation of the caudal occipital region of the skull, leading to overcrowding of the caudal fossa and compression of the cervicomedullary junction at the level of the foramen magnum.
Diagnosis of PSOM can made by examination of the tympanic membrane and middle ear with the OtoPet-USA Video Vetscope. A bulging, but intact, tympanic membrane is found in most cases. While patients are under general anesthesia, a myringotomy is performed and a highly viscous mucus plug is found filling the middle ear. This condition is also referred to as “glue ear.” Treatment consists of removing the mucus plug via a myringotomy and flushing the middle ear. The myringotomy can be performed with visualization using the OtoPet-USA Video Vetscope. The ear can be flushed using the OtoPet-USA Earigator. An MRI is needed to diagnose COMS.
The Video Vetscope is used to visualize the tympanic membrane. The Video vetscope probe is inserted into the horizontal ear canal and is used as a working channel to perform the myringotomy.
A myringotomy is performed at the 5:00 (left ear) or 7:00 position (right ear) in the ventral portion of the pars tensa at the ventral most portion of the attachment of the eardrum to the annulus. In an already diseased eardrum, a myringotomy may be performed by applying pressure to a tomcat catheter and perforating the eardrum. If the eardrum is thickened or hard to perforate, the end of a 5 Fr. polypropylene catheter is cut at a 45 degree angle so that there is a point at the tip. Long, thin spinal needles are more expensive, but may also be used for myringotomy. The tip is then directed to the puncture site and is pushed through the eardrum to remove mucous from the middle ear. Using these locations for myringotomy prevents disruption of the blood supply to the eardrum and does not disrupt sound transmission from the malleus to the cochlea.
Once the myringotomy is performed, the mucous plug should be suctioned from the same perforation site using a 5 Fr. catheter and a 3 cc syringe. Finally, irrigation and suction of the bulla can be done using the OtoPet-USA Earigator (link here).
In most dogs, small myringotomy incisions completely heal within a month.
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