[Marcia]

My poor Sally has had a hard time. Two weeks ago, after a camping trip, we noticed she yelped while eating a treat. The next day she ate her kibble, but again yelped whe eating her cookie (these are harder than her regular food). My husband & I checked inside her mouth, but couldn't find anything obvious. Our first thought was that she had picked up a foreign body that we couldn't locate - she has that wonderful Basset trait of trying to eat inedible things, like pine cones. We are always prying trash out of her mouth. We made a vet appopintment for the next day after work. When I came home, the whole right side of her face was swollen, including her eye, and she was in a lot of pain. I rushed her over to the vet immediately, he anaesthetized her, and found no foreign body or other problem on visual inspection. He diagnosed her with masticatory myositis, an acute inflammation of the muscles that open & close the jaw. She has been on prednisone ever since - within a day she was much improved, after two days she was behaving & eating normally. The side effects of the pred were hard to deal with - it made her insatiably thirsty and hungry (even more than normal for a Basset!). She drank so much that she lost her house breaking completely - not at all her fault. We are now tapering off the pred - in two more days she will be off completely, and I am terrified she is going to relapse. The vet said there is a chance it will, but as we caught it early she may not. Has anyone else experienced this? I have done some research on the internet, but the information is conflicting on quite a few points. Sally is allergic to bee stings - some of the articles say there is a correlation between this disease and high eosinophil levels in the blood. Betsy - do you have any insight? Sorrt this is so long - please keep paws crossed that this terrible thing won't come back........

 

[Barbara Winters]

Sorry to hear about Sally's jaw problems. I have heard of this condition and have been told by an ER veterinarian and several of the staff at my vets that Roady has the muscle atrophy about the head that is consistant with the atrophic form of eosinophilic myositis. Because he has had no jaw pain or inability to open or close the jaw I have not pursued a more definite dx.

From what I have read the acute form responds readily to corticosteriods, though relapses can occur.

I'm curious if your vet made this diagnosis on the presence of elevated muscle enzymes in the blood or did a muscle biopsy? The reason I ask is that I have heard of bassets having difficulty opening or closing the mouth due to a "wry mouth." I know we discussed this on the forum before but can't recall the details. Any one remember?

From what I have read a number of conditions can produce symptoms similar to masticatory mysotitis but it sounds like your vet has ruled out the most likely causes. I understand the presence of a specific kind of circulating autoantibody gives a definite diagnosis.

I'm sure Betsy will beat me to it, but when I get a chance I'll provide you with some reference materials.

Keep us posted.

[ September 16, 2003, 11:24 PM: Message edited by: Barbara Winters ]

 

[Betsy Iole]

From Autoimmune Disease with Oral Components (WSAVA World Congress, 2001)

Masticatory myositis involves antibodies directed at the type 2M fibres unique to the muscles of mastication: the temporalis, masseter and pterygoid. Embryologically these muscles are derived from mesoderm.(16) By two weeks postpartum, these muscles have developed the unique 2M fibres.
 
There are two distinct disorders in masticatory myositis: 1) acute eosinophilic myositis; and 2) chronic atrophic myositis.
 
Eosinophilic myositis is prevalent in German Shepherds and Dobermans of a young age (less than four years). The acute phase lasts two to three weeks followed by remission and recurrent attacks. Peripheral eosinophilia is noted. Histology reveals large numbers of eosinophils, plasma cells infiltrating the muscles, hemorrhage, and necrosis. Chronic lesions demonstrate scar tissue. Treatment involves use of corticosteroids at 0.5–1 mg/kg.(17)
 
Atrophic myositis has no breed, sex, or age predilection. There is usually a single less dramatic attack followed by progressive atrophy and fibrosis. Peripheral eosinophilia is not a feature. Eosinophils are less predominant in histology. Treatment is less effective and the prognosis is guarded.(17)
 
Masticatory myositis has been described as a result of infection with the protozoa Leishmania infantum.(18) Leishmania is transmitted by the sandfly and is zoonotic. The disease is endemic in the Mediterranean and Portugal with sporadic reports in Europe and the United Kingdom. Muscle fibre necrosis, atrophy, mononuclear infiltrates, vasculitis, and amastigotes within macrophages are histological features. IgG immune complexes have been detected.(18)

Sorry to hear about Sally.

[ September 19, 2003, 01:33 AM: Message edited by: Betsy Iole ]

 

[Marcia]

Thanks Barbara & Betsy for the replies. My vet seems to think that Sally has the eosinophilic type, due to the acute onset. I hope he's right. He did explain the diagnostics such as the 2M antibody assay and the serum creatine kinase concentration, but was reasonably sure of his diagnosis so we went for the corticosteroid treatment without the testing. If she relapses after the steroid treatment is through we will go ahead with further diagnostics. The leishmaniasis connection is too scary. Tomorrow is her last day of treatment . She seems normal now - hopefully she will stay that way....

[ September 18, 2003, 11:41 PM: Message edited by: Marcia ]

 

[Highmeadow]

How is your girl doing? One of my boys went through this recently as well. In all my research (and 4 vets), I never came across the protozoan connection - everything said "no known cause". Interesting!

[ October 21, 2003, 12:30 AM: Message edited by: Highmeadow ]

 

[Marcia]

Highmeadow, Sally is doing fine. After tapering her gradually off the steroids, she went back to normal and the condition never returned - *phew*.
I did a ton of research and only found one reference to the protozoal connection, and my vet hadn't heard of it either. I just hope it never happens again! Can you tell me something about the onset and treatment in your pups case? You are the only one I've found who has experienced this. Thanks!

 

[Highmeadow]

My boy is 10 months old and got it last month. I first noticed when I moved him aside to get another dog out of the xpen (at a show) and he whimpered. Same thing the next day but I couldn't find anything wrong in his mouth, neck, head.

Next day he wouldn't/couldn't eat his breakfast (he's a pig). Later that day I checked his mouth again and when I tried to check his palate he screamed! Off to the vet, on prednisone by night.

Within 24 hours, he lost ALL the muscle on his head. Over the next 2 weeks he lost about 50% of his body muscle and his eyes started to sink into his head to the point where the eyelids were curling in. Meanwhile he had seen 2 other prominent vets, all with the same diagnosis and no new info.

In desperation, I took him to a holistic/homeopathic vet. By this time, my poor boy was so weak he staggered!! I was sure he was going to die. This vet believes it is a type of vaccinosis (vaccines, environmental toxins, drugs). Btw, just prior to the onset he had been on ketoprophen for a broken toe.

Anyway, he took him off the pred, put him on an immune stimulant and herbal cleansing tonic (I felt like the world's biggest sucker) but in 3 days he looked and acted almost normal. It has been 10 days since then and he is completely fine now. I dunno what to make of it, I guess time will tell. I will ask him about the protozoan connection for sure though.

The show we were at (we stayed 3 days) is a sandfly haven. I wonder if the protozoan stays in the dog's system and that's why they relapse (a certain life cycle stage?) or if it can be killed? I will let you know what he says.

 

[Marcia]

Ugh, how horrible for your poor boy. I would be interested in what your vet can add.

 

[Highmeadow]

I asked the holistic vet about the protozoan possibility. He said it made sense as these types of infections are known to cause muscle wasting (ie toxoplasmosis). Ivomec will kill it off. Part of the immune stimulant Paddy was given was a homeopathic equivalent of ivomec.

Interestingly, when Paddy went off the daily immune stimulant after a week, he lost a little ground. He is back on it but just 2 cc once a day instead of 3 times.