Our German Shepherd (KING) has developed front leg muscle loss on his left leg. He has been to several vets!! He has had blood tests, MRI, acupuncture, chiropractor, vitamins. No results at all. He is limping very badly !!
This is just a wild shot in the dark, but have they done a urinalysis on him. While not a muscular problem, Mac was treated for a stubborn bone infection that took six months to get under control with clindamycin. The infection came back and this time my vet did a urinalysis (the type where they insert a needle into the bladder to draw it out) and found he had an e-coli infection from a puncture in his intestines that infected his blood (I "suspect" it was from catching and killing tresspassing chickens ... either a beak, feather tip or toenail ... something sharp).
It's the first time I've seen your thread, and I'm so sorry about Kingy. A very painful time for you.
I hope you don't mind me asking but did King have any feeling in his leg,
because one of my GSD's suddenly started holding his leg up, and 2 years later the Vets (2 seperate practices) couldn't find out why.