Important congenital health problems are:

1. Patellar luxation
2. Portosystemic shunt (Liver Shunt)
3. Retinal dysplasis
4. Tracheal collapse

These four disorders are somewhat common in the Yorkie breed and can seriously affect the health of your pet and may require medical or surgical intervention.

Patellar Luxation

The knee cap (patella) normally fits into a groove in the thigh bone (femur). The patella slides up and down in this groove as the leg bends and straightens. Patellar luxation means that the knee cap has slipped out of the groove. There are several reasons why this happens, including malformation of the groove. Luxation may happen only occasionally, or may happen continuously. The knee cap may pop back into the groove on its own, or your veterinarian may need to push it back into place. Your yorkie will be lame when the patella is out of place. Over time your yorkshire terrier may develop other degenerative joint changes, such as osteoarthritis.

Portosystemic Shunt (Liver Shunt)

In a yorkie with a portosystemic shunt (PSS) there is abnormal blood flow in the liver. Blood should flow from the digestive tract to the liver via the portal system into the blood vessels of the liver, and then to the caudal vena cava which is the large blood vessel carrying blood back to the heart. In a portosystemic shunt, as the name implies, portal blood by-passes the liver and goes directly to the systemic venous circulation (caudal vena cava). One important function of the liver is to clear toxins, many of which are by-products of protein digestion, from the blood. In PSS, these toxins are not cleared, and circulate in the body. This causes the clinical signs associated with PSS, many of which are neurological. The complex of neurological and behavioural signs caused by liver dysfunction is called hepatic encephalopathy.

Portosystemic shunts may be acquired secondary to another disease, or they may be congenital - that is the yorkshire terrier is born with a shunt. A congenital shunt usually occurs as a single abnormal blood vessel that is a remnant of normal embryonic development. These shunts are defined as intra-hepatic or extra-hepatic depending on the location of the blood vessel in relation to the liver.

Most yorkshire terriers with congenital portosystemic shunts show clinical signs before 6 months of age. Where signs are subtle, the condition may not be diagnosed until much later

Retinal Dysplasis

The normal retina lines the back of the eye. The retinal cells receive light stimuli from the external environment and transmit the information to the brain where it is interpreted to become vision. In retinal dysplasia, there is abnormal development of the retina, present at birth. The disorder can be inherited, or it can be acquired as a result of a viral infection or some other event before the yorkie pups were born.

There are 3 forms of retinal dysplasia

1. folding of 1 or more area(s) of the retina. This is the mildest form, and the significance to the dog's vision is unknown.
2. geographic - areas of thinning, folding and disorganization of the retina.
3. detached - severe disorganization associated with separation (detachment) of the retina.

The geographic and detached forms cause some degree of visual impairment, or blindness.

Tracheal Collapse

Tracheal collapse is a narrowing of the inner diameter of the trachea, that fluctuates with the stage of the respiratory cycle. The rings of the trachea (made of cartilage) lose their ability to maintain their shape, and collapse when the yorkshire terrier breathes, causing a harsh cough. Most often this disorder is seen in middle-aged toy and miniature breeds. Chronic respiratory infection, obesity, and heart disease can all contribute to the development of the condition, but it appears that there is also a congenital deficiency (ie. a yorkie is born with it) in the make-up of the trachea itself.

Hypoglycemia

Another health problem that all Yorkie owners need to be aware of is hypoglycemia. Hypoglycemia or low blood sugar is a common problem with all toy breed puppies including the yorkshire terrier. Hypoglycemia is the medical term for low blood sugar, which is a condition in which there is a drastic, sudden drop in the level of blood sugar in the puppy. In small breed puppies from post-weaning to 4 month of age, the most common form of hypoglycemia is called Transient Juvenile Hypoglycemia: “Transient” because the symptoms can be reversed by eating; "Juvenile" because it is seen in young puppies. Veterinarians unfamiliar with toys often mis-diagnose the condition as viral hepatitis or encephalitis. As a toy yorkie breeder or pet owner, it is important to recognize the symptoms of hypoglycemia and know how to treat it. Hypoglycemia is easily treatable in the early stages, but fatal if allowed to progress. Many puppies are lost needlessly to hypoglycemia because of ignorance on the part of their owner or veterinarian.

It is important to understand that just because a puppy has an episode of hypoglycemia, it does not mean that the puppy is truly "hypoglycemic." True hypoglycemia is a chronic condition caused by overproduction of insulin by the pancreas. Even though the pancreas may normally function properly, toy puppies can still have an isolated hypoglycemic incident in reaction to stress or fasting. Pups of any breed are more likely to develop hypoglycemia than adults, because their skeletal muscle mass and liver size are smaller and brain size, larger, in proportion to the rest of their body. Therefore, there is less glucose being put out into the blood and more being used by the brain, which is dependent upon adequate glucose in order to function. In small and toy breeds, this discrepancy is more pronounced. Even a brief period of fasting or stress in a toy breed puppy can trigger a hypoglycemic "attack. Yorkie puppies with Transient Juvenile Hypoglycemia have normal liver size and function, but inadequate glucose precursors or glucose in its stored form (body fat). Hypoglycemic incidents are almost always preceded by a stress of some kind. Some examples of common stresses include: weaning, teething, vaccinations, a change in environment, shipping, over-handling, cold temperatures, intestinal parasites, infections, anorexia, etc. Many yorkie puppies simply play too hard and stress their system or forget to eat. I have heard of young males experiencing hypoglycemia when a female in heat is around. They become so worked up over the female that they do not eat and their blood sugar drops.

The first sign of hypoglycemia is the yorkshire terrier puppy slowing down and then acting listless. The puppy will then begin to tremble or shiver. This is a reaction caused as the brain is starved for glucose. More signs of an attack are a weakness, confusion, wobbly gait, frothing or drooling from the mouth - sometimes even a seizure and drain of blood from the head. His body will be limp, lifeless, and a check of the gums will show them to be pale, almost a grayish white in color rather than a healthy bright pink.. The body temperature will be subnormal. After a time, the puppy will become comatose and may even appear to be dead. The puppy can go into shock and, if not cared for properly and promptly, may even die.

If Yorkie hypoglycemia is caught in the early stages, rub Nutri-Cal (Caro syrup will do if you have no Nutri-Cal) on the puppy's gums, under the tongue, and on the roof of the mouth. Get a heating pad or heating blanket and slowly warm the puppy to proper body temperature. If the puppy responds, all is well. Feed a quality, canned food containing, high-carbohydrates and protein right away (you may want to mix it with egg yolk) and then monitor the puppy to be sure that the condition does not recur. Be sure to eliminate the stress that caused the episode if at all possible.

If Yorkie hypoglycemia is caught in the more advanced stages, rub Nutri-Cal or Caro in the mouth, and carefully insert a small amount in the rectum. Slowly warm the puppy to normal body temperature (101-102 degrees F) and keep him warm continuously with light heat. If the yorkie puppy still does not respond, carefully eye dropper dextrose solution or Caro water into the mouth, a little at a time only if the dog can swallow. Call your veterinarian immediately and inform him that you have a hypoglycemic yorkie puppy.