Visiting Vet: Small dogs, the upside and down

Visiting Vet: Small dogs, the upside and down

You know you’re getting old when women your own age, or even younger, start showing up with Little Dogs. We’re talking dogs that fit in your pocketbook — Yorkshire terriers, teacup poodles, Chihuahuas.

As a teenager, my family had a diminutive cocker spaniel I adored, but by college I youthfully dismissed any canine under 50pounds as Not A Real Dog. I longed for a statuesque Irish wolfhound, but settled for an Irish setter husky cross (who, sadly, ended up having the worst traits of both breeds). As an adult I adopted Heidi, a Labrador with diabetes and cataracts, then Sadie, a Samoyed with glaucoma. Both were blind, but both were big. Then when my kids came along, we got Flower, a mixed breed pup who grew large enough to be a passable substitute for the often requested pony. My younger daughter inherited my penchant for large dogs, yearning for a great dane or Swiss mountain dog, both of which I tell her she can have when she has her own house, hopefully bigger than the one we live in now. But the older I get, the more I understand about owning Little Dogs.

Animals intentionally bred for extreme physical characteristics, like being extra big or extra small, are at greater risk for medical problems. Giant breed dogs have notoriously short life spans, as well as a predisposition for problems like bloat. Pug-faced dogs are known for respiratory difficulties from their smooshed-in snouts. Little Dogs…well, they have their own list.

Take Amigo, the Chihuahua, who came in recently for an introductory examination. At six months old, he weighed less than four pounds. “I can’t let him outside unattended,” his mom said. “A big hawk buzzed him the other day. It just came out of nowhere.” I nodded.

Another Chihuahua owner I know was walking her wee one on a Vineyard beach when a red-tailed hawk swooped down, grabbed her pup by the head, lifting it several feet into the air. Whether it was the weight of the dog, or the effect of an hysterical woman screaming and waving her arms frenetically, the big bird lost its grip and the Chihuahua tumbled to the ground. Miraculously, except for several puncture wounds from the talons, the pup was uninjured. Yup. Better not let Amigo run around outside taunting the local raptors.

Examining young dogs always includes checking for congenital defects, i.e., abnormalities they were born with. Amigo looked fine. Eyes, ok. Teeth, no overbite or underbite. I opened his mouth to look for cleft palate. Nope. I ran my hands over the top of his domed head, gently feeling where the various skull bones join across the crown. Except Amigo’s skull bones didn’t all join in the middle. Instead there was a central area about the size of a nickel that was soft and squooshy.

It’s called a fontanel — a membrane-covered opening between the bones of a young skull. If you’ve raised a baby, you know those “soft spots” on an infant’s head that allow it to squeeze through the birth canal. In people, fontanels close gradually between the age of three months up to two years. In dogs, the fontanel on top of the head should close by 12 weeks of age. But in Chihuahuas, as well as several other toy breeds, the fontanel often doesn’t close. Ever.

Chihuahua fanciers call it a “molera,” saying that it is normal for the breed, and it is not considered a defect by the American Kennel Club Breed Standards. In fact, for many years, the presence of a molera was considered proof of the purity of a dog’s Chihuahua blood line. Here’s where breeders and veterinarians may be at odds. Many veterinarians consider any fontanel that does not close by 12 weeks to be an inherited defect and advise that the dog in question not be used for breeding.

There is also some controversy as to the health implications of persistent fontanels. (A brief aside about grammar. Many people call this condition an “open fontanel.” Technically speaking, that is redundant: by definition, a fontanel is open.) Some veterinarians believe that persistent fontanels are associated with greater risk of hydrocephalus — increased accumulation of cerebral spinal fluid inside the ventricles of the brain. This puts pressure on the brain and can lead to seizures, blindness, pressing of the head into corners, and extreme difficulty in house training. Hydrocephalic dogs may also exhibit the “setting sun sign” in which the eyes point downward and sometimes to the outside. They can be treated temporarily with medications to reduce the pressure, but eventually a shunt should be placed surgically to drain the excess fluid. In their “Molera Statement,” the Chihuahua Club of America cites several studies and veterinarians stating that there is “adequate medical evidence” that a molera does not predispose a Chihuahua to hydrocephalus. But I think the jury is still out on this one.

Amigo was well past the 12-week mark for closure of the fontanel, but some Chihuahua sites claim moleras may continue to get smaller until a dog is up to three years old. I do not know if this is true. I do know that since Amigo appeared neurologically normal there was nothing else we needed to do. If he ever showed signs of hydrocephalus, an ultrasound of the brain could be done via the fontanel, but he has a perfectly good chance of leading a perfectly normal life and never having any problems. I advised his owner to take extra care with his head and to never press the soft spot. If she wanted, there were even places she could purchase a tiny helmet for him. I wondered if Amigo would tolerate such headgear. Then I thought how cute he would look and imagined myself toting around a four-pound dog wearing a mini-bike helmet. That could be as cool as having an Irish wolfhound.

The older I get, the more I understand the charm of Little Dogs.

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