Collapsing trachea

Collapsing trachea is a problem for Toy dogs of many breeds. The symptoms include coughing, shortness of breath, and exhaustion. Although it appears more often in dogs older than 5 years, an occasional puppy has it from birth. To understand the condition, think of the trachea as a straw made of cartilage that carries air from the neck to the chest. When the cartilage collapses, breathing becomes difficult, kind of like sipping soda through a flattened straw.

Your vet can treat the condition with medication, but if you smoke, your Chi's prognosis may be poor. Secondhand smoke is a proven contributing factor to the problem . . . and smoke tends to settle low, where a little dog's nose is.

Heart murmur

Heart murmurs are relatively uncommon in Chihuahuas and even those that have one usually have the functional type. As in people, that means they can be as active and athletic as they want and live long, normal lives.

Molera

The Chihuahua's molera(a.k.a. fontanel) is considered a breed characteristic and not a defect. Most Chihuahuas (80 percent to 90 percent) have a molera — a soft spot on the top of their head similar to a human baby's soft spot. But unlike babies, most Chihuahuas don't outgrow it. Although it usually shrinks as the dog matures and ends up between nickel- and dime-sized, Pepe's molera won't be a problem as long as you're gentle when petting or handling his head.

In rare cases, the molera remains quite large and can be a sign of a serious problem called hydrocephalus (see the next section). But don't borrow trouble. Hydrocephalus has several other signs besides a larger-than-usual molera.

Hydrocephalus

A dog with hydrocephalus (a.k.a. water on the brain) may have an unusually large head for his size caused by swelling. Other signs of this fatal condition are frequent falling, seizures, a lot of white showing in the eyes, an unsteady gait, and east-west eyes (the opposite of crossed eyes). A dog with hydrocephalus is in pain and won't live long, so euthanasia is the humane solution. (Euthanasia is the medical term for a humane, vet-assisted death.)

Hypoglycemia means low blood sugar and is a common problem in young Toy breed puppies, although most of them grow out of it before they are old enough to leave the breeder. But for a few, it's a danger throughout their lives.

Symptoms of low blood sugar are a staggering gait, glassy eyes, and sometimes either limpness or rigidity. If the dog doesn't receive immediate help, he can suffer seizures, unconsciousness, and finally, death. Treatment involves putting some sugar in your dog's mouth, calling your veterinarian, and heading for the clinic. Once you know your dog has a tendency toward hypoglycemia, you can prevent further attacks by changing his feeding schedule to small amounts several times a day and avoiding sugary treats (check the ingredients before buying dog treats). Too much sugar in his food can put Pepe on a roller coaster ride of sugar highs and lows rather than keeping his blood sugar nice and level.

In dog lingo, subluxation of the patella is called slipped stifles or loose kneecaps. When it occurs, the kneecap (we're talking about the rear legs) slips out of its groove — sometimes often and sometimes rarely — depending on the severity of the problem. If your dog is one of the unlucky few whose kneecaps slip often, surgery may be the solution. A dog with a mild case can live a normal life, kind of like a person with a trick knee. Subluxation of the patella is a relatively common problem in small breeds and some large ones as well