Most likely an autoimmune disease
Over the last couple of weeks, my husband and I have noticed Butters progressively having more trouble with chewing. At first, I thought he was just trying to swallow his treats too quickly, but he has been having increasing trouble with smaller and smaller treats over the last several days. Yesterday he started having difficulty swallowing water. We found him attempting to drink for several minutes, getting more water on his ears than in his mouth and drooling over his bowl. Needless to say, we made an emergency appointment with the vet.
On our visit to the vet today, Butters could not open his mouth for the exam. I have never had this difficulty with him before, but had noticed at home that he was getting more fussy with brushing his teeth. He also had 2 very swollen mandibular lymph nodes on either side of his neck. The vet pointed out that he has significant localized muscle atrophy around the jaw and temples, something that I had never noticed before. Looking at his pictures, it is difficult to really tell when that started.
He goes tomorrow for additional testing. The major consideration the vet initially had was focal myasthenia gravis. He is planned to have a chest x-ray, basic blood work, and an endoscopy (to look for megaesophagus vs foreign bodies or other possible pathology in the mouth/nose/esophagus) in the morning. However, looking further into his symptoms, I am increasingly worried that he may have masticatory muscle myositis (which Cavaliers are at increased risk for)... especially with the planned endoscopy (I have read that forced manual retraction of the jaw is contraindicated). This possible diagnosis did not come up during our visit today, but he really fits the picture. We plan to discuss this other possibility with the vet in the morning, and hope that we can come to the right diagnosis and treatment plan quickly.
My husband and I are right now absolutely feeling devastated. Butters is still his happy self at the moment, but watching him struggle when he goes to eat and drink is heartbreaking. He is trying so hard, and I can't help but sob watching him struggle. He is so young, at only 1.5 years, and my husband especially is having a rough time (this is his first dog, and they are inseparable).
I guess I am looking for anyone who has additional information/suggestions/feedback, particularly related to our situation and/or the potential diagnosis of MMM. I have read that having preexisting muscle atrophy is consistent with a chronic form, but his presentation otherwise really looks like an acute flair. He has never had symptoms like this before. Anyone have a similar situation, and did your cav improve? worry about the fact that the chronic form, most often identified by atrophy (with associated muscle fibrosis), has a worse prognosis with less likely improvement. What else should we think about discussing with our vet?
Also, we are most likely looking at a period of Butters being on high dose steroids (for MMM he would be on 2mg/kg to start, from my literature search)... and the side effects that go with them. Right now Butters sleeps on the bed. Since urinating in sleep can be an issue, should we start transitioning into a different arrangement? Should we arrange doggie diapers or a waterproof bed to lay on our comforter? What sorts of adjustments should we anticipate and plan for?
Thanks for reading and any feedback