Visiting Vet: Hunting for the cause of shoulder pain

Hunter is a seven-month-old Bernese Mountain Dog. Just a puppy, he already weighs 76 wiggly pounds. If you haven’t had the pleasure of meeting a Bernese, this breed is one of several varieties of Swiss Mountain Dogs with an ancient heritage. Their ancestors are thought to have developed two thousand years ago from crossbreeding between mastiffs brought to the region by Roman invaders and local farm dogs that worked driving cattle, pulling carts to market, and being both watchdogs and companions.

These beautiful animals had many names including Farmer’s Dog, Gelbackler (Yellow Cheeks), Vierauger (Four Eyes, because of the facial markings), and my particular favorite, Cheese Factory Dog. In the early 1900s, dog fanciers pronounced them one breed, dubbing them “Durrbachlers,” after the Durrbach region in the canton of Bern. In 1908, Dr. Albert Heim, a professor, geologist, and canine researcher, introduced the name “Berner Sennenhund,” which means “Bernese Alpine Herder’s Dog.” This has remained the breed’s official name in Switzerland to this day, though they are often referred to affectionately as simply “Berners.”

Berners are sturdy, powerful dogs with long, silky black coats highlighted by dramatic rust and white markings. Bred to work, they need both exercise and interesting activity to stay healthy. They do best when exposed to many people when young. Berners are not for everyone. They’re big. They’re hairy. They like to be an integral part of the family and may not do well if left alone long or cooped up in a kennel or small space.

Our friend, Hunter, had plenty of company and exercise, his owners being well aware of a Berner’s needs, especially since his mom is my longtime assistant, Elise. She also knows that Berners have a notoriously short life expectancy, often only seven to eight years, although some lines may live longer and that purebred dogs have a higher risk of genetic disorders than mutts.

There is an old Swiss saying about Berners and related breeds. “Three years a young dog, three years a good dog, three years an old dog.” But the heart wants what the heart wants, and Elise and her husband, Daniel, wanted a Berner.

Last week Hunter spent the day playing at a relative’s house. He seemed fine that evening but next morning woke up lame on his left front leg. Hunter was so thrilled to visit Elise and me at work that day that it took two helpers just to take his temperature as he danced and squirmed on the table. His temperature was a bit elevated, but this is not uncommon in excited, active dogs. After a quick look at his general demeanor I went right to the gimpy leg, beginning with the foot. Owners frequently bring in limping dogs, saying “Maybe he has a thorn in his paw.” This is what comes from making school children read Aesop’s fable of Androcles and the lion. In 30 years of practice, and thousands of limping dogs, I have only seen an actual thorn (or any other foreign body) in a paw a handful of times. Nonetheless, I always check that first.

Hunter’s paw was fine. Working my way up I palpated each bone, and flexed and extended each joint while Elise tried to hold him still. Metacarpals, check. Carpus, check. Radius, ulna, check. Elbow, check. Humerus, check. Shoulder, ch… YOW. Hunter let out a sharp yelp when I hyperextended his shoulder. I let him relax a minute, then tried again. YOW.

I wasn’t being mean. I needed to confirm the reaction was repeatable, indicative of a real problem, not just a fluke. “It’s his shoulder,” I concluded. “Let’s watch him walk.” Hunter’s gait supported my findings. He placed his foot firmly on the ground, without hesitation. Dogs with paw injuries put the foot down tentatively, if at all. But as Hunter moved to bear more weight on that side, it hurt, so he shifted quickly back to the other leg. Voila. Limping Berner. Maybe he sprained it playing, but there was another more serious possibility.

Osteochondrosis dissecans (OCD) is a developmental problem affecting the cartilage that covers the ends of certain bones inside certain joints. Shoulders are most frequently affected, but OCD may occur in elbows, knees, or hocks. Most common in rapidly growing, large breed male dogs between four and ten months of age, no one knows the exact cause, but factors implicated include genetics, over-nutrition, hormones, excessive calcium intake, and trauma.

Imagine the shoulder joint. The top of the big arm bone, the humerus, is shaped like a ball and is coated with a smooth cartilage surface that allows the joint to rotate unimpeded. Now imagine a small area of that coating is abnormal — hard, thickened, and rough. It is more susceptible to injury and inflammation and eventually creates a small flap. Bits may even break free, creating tiny foreign bodies called “joint mice,” and leaving a divot in the surface of the humeral head. The degree of lameness varies with the severity of the lesion and may fluctuate with activity. Definitive diagnosis requires radiographs.

Treatment for OCD can start with conservative medical approach. Mild cases may do fine with just rest and medication, but, depending on the severity, untreated dogs are at risk for ongoing lameness and crippling. These require surgery, the earlier the better, to remove loose fragments, curette the defect, and try to stimulate healing. If one shoulder is affected, the other may be too. It is important to check both sides. Prognosis post-surgically is good, with 75 percent of patients eventually returning completely to normal. Since Hunter would barely hold still for an exam, properly positioned X-rays were going to require sedation.

“Let’s start with rest and pain medication. It may just be a sprain, “I said, optimistically. “If he doesn’t improve, we’ll anesthetize him for radiographs, check for OCD, and send you to the orthopedic specialist if necessary.” Hunter agreed with enthusiasm, wagging his whole body so hard he almost knocked me over. Three years, a young dog. Yup.