Some of the most common ones include: STRUVITE.  This urolith is diagnosed in almost  half the cases of bladder stones. It is also called MAP (Magnesium-Ammonium- Phosphate),   or triple phosphate.  It is the predominant stone type in female dogs of all  breeds. Several factors predispose dogs to getting struvite uroliths:

1. Excess struvite crystals in the urine that set the stage for the urolith. Some  
   breeds have a genetic predisposition to forming excess amounts of these
   crystals in the urine.

2. Urinary Tract Infection (UTI) - some bacteria produce a byproduct called
   urease.  Urease will increase the pH of the urine and promote ammonium
   in the urine.

3. The formation of an alkaline (pH greater than 7.0) urine from the diet or
   urease producing bacteria will case the struvite crystals to precipitate out
   of solution and begin the formation of a urolith. 

4. Urine that stays in the bladder longer than usual gives the struvite crystals
   further opportunity to precipitate out of solution and form a urolith.

5. Struvite uroliths come in many different shapes and sizes, are radiodense,
   and form in the alkaline urine.

This is the second most prevalent type of urolith after Strive, making up around 30-50% of the uroliths, especially in male dogs of all species. They come in two versions; the monohydrate and the dihydrate. Sometimes the two are found together, sometimes they are found with other uroliths like calcium phosphate, Strive, or ammonia urate.

This is a problem most commonly in older male dogs. It is suspected that there is a correlation with hormone changes that occur as a pet ages. The Yorkshire Terrier is prone to these along with many other breeds.

Several predisposing factors work together to increase the chance of this urolith forming:

• Increased calcium in the bloodstream (hypercalcemia)

• Increased calcium in the urine (hypercalciuria) with no increase in hypercalcemia

• Concurrent Cushing's disease

• Use of cortisone

This is a common urolith found in some breeds around middle age, with males affected much more often than females. This is because they metabolize protein differently in the liver, with the end result being uric acid buildup in the urine. They are found in Yorkshire terriers. There does not seem to be a connection with a urinary tract infection, and they tend to form in an acidic urine.
 
Urate stones are radiolucent. If they get large or covered with other minerals they might become radiopaque. Urate calculi tend to be small and occur as several stones. These stones usually form in the bladder, and when passed through the urethra, can become lodged.

Dogs with immonium urate bladder stones might have ammonium urate crystals in their urine and a low specific gravity (dilute urine). These stones might not be seen on a radiograph because they are radiolucent. This same radiograph might also show a small liver, an indication of PSS. This small liver is due to the diverted blood flow to the liver. Dogs with PSS will commonly have abnormalities in the blood sample to give us further clues.

Compound Uroliths

Most bladder stones are caused predominantly by one type of mineral. The more common ones have been described above. In a small percent of cases, the bladder stone is caused by a combination of minerals in similar quantities. These stones are called mixed uroliths. Some bladder stones consist of a core mineral surrounded by a lesser amount of a different mineral in a different layer. These are called compound uroliths.

Why some minerals form mixed uroliths and others form compound uroliths is not understood. Compound uroliths form when the factors that predispose to one type of stone formation have now changed to factors that favor a different type of stone formation. If a struvite stone is treated with antibiotics and urinary acidifiers the problem tends to resolve. The change in urine pH might promote excess calcium in the urine, resulting in a shell of calcium oxalate formation around the core struvite stone. The opposite can occur also- a struvite stone can form over a calcium oxalate stone.

In general, these stones are removed surgically and an effort is made to medically prevent the mineral that is at the core of the stone.

Miscellaneous Uroliths --- There are other uroliths that occur, although they are relatively uncommon. They include cystine, silica, calcium phosphate, and miscellaneous minerals.
 

Inheritance considered: Unknown
 

Commonly mistaken for Parvovirus, but needs different treatment. It's a BACTERIAL imbalance in the digestive tract. It is a disease that produces acute infectious diarrhea in puppies and kittens. This is NOT a new form of Parvo. Parvo tests will show a LOW positive & subsequent tests will continue to show low positives, will be inconclusive, or will give erratic results. This disease is so similar to Parvo, that some dogs have tested in the low positive for Parvo. But they do not have Parvo, and it has been recommended that three parvo tests are needed to exclude Parvo.

This disease can be tested for specifically, so if you have an affected dog that appears to have Parvo, but in your mind know that, that could not be possible, have them tested for "Camby". It is important to note that this disease can be transferred between humans, dogs, cats and other livestock. It starts with fecal mucus sheath & continues to get progressively softer until it is watery and contains blood. It then becomes explosive. Vomiting may accompany and may or may not also contain blood. Feces have a sweet/flowery aroma along with a "slaughterhouse on a summer day" smell (similar to parvo diarrhea but with a floral hint). Feces are usually mustard colored. Dogs dehydrate at an astounding rate.
Inheritance: Environmental factors
 

Wrists are congenitally out of joint; first appears at 3 weeks, the gene is allelic to the gene for hemophilia A (in the same place on a chromosome)
Inheritance: Recessive; sex-linked.
 

Shortened, deformed front legs, with a typical downhill stance
Inheritance: Autosomal recessive

Alopecia (hair loss) related to dilute coat color is a recognized condition in dogs. The currently accepted medical terminology for this condition is Color Dilution Alopecia (CDA). The condition may affect any dilutely pigmented dog, regardless of coat color. This condition was previously known as Blue Balding Syndrome, Blue Doberman Syndrome, Color Mutant Alopecia, Congenital Alopecia, etc. The term Color Mutant Alopecia arose because dilutes were at one time mutations from the deep pigment occurring in wild canines. Dilutes are now a regularly occurring form of pigmentation in many breeds and have been for hundreds of years. The term mutation is therefore not applicable to dilute individuals. References to Doberman Pinschers or blue hair coats arose because the condition is common in blue individuals of this breed, but it is not limited to either blue dogs or Dobermans. The term congenital means present at birth, but CDA affected dogs are born with normal hair coats.

The dilute (also known as Maltese) gene also appears in both mice and cats, and interestingly enough, is not associated with any abnormal coat conditions in those species. Color Dilution Alopecia (CDA) has been recognized in dilute individuals of many breeds of dogs including Chow Chows, Dachshunds, Doberman Pinschers, Great Danes, Irish Setters, Italian Greyhounds, Standard Poodles, Salukis, Whippets, and Yorkshire Terriers Dilute individuals carry a recessive genotype of dd and are characterized by blue, bluish-grey, lavender or flesh-colored noses, lips and eye rims. The coat colors may include blue, fawn, blue-fawn, bronze, taupe or some variation of these. These dogs are usually easily distinguished from their deeply (non-dilute) pigmented counterparts. Deeply pigmented individuals carry a dominant genotype of Dd or DD and have black or liver noses, lips and eye rims. Coat colors may include black, red, red-fawn, liver or variations thereof.

CDA is characterized by loss of hair from dilutely pigmented areas. Coats are normal at birth, and onset of hair loss usually begins between six months and three years of age. Hair loss usually begins along the dorsal midline (middle of the back) and often spares the head, tail and limbs. The pattern seems to vary from breed to breed. It has been suggested that darker colored (steel blue) individuals are less likely to be affected, may be less severely affected or may start to lose hair later in life than lighter colored dogs. This suggests that the severity of the disease may be related to the amount of dilution present. Deeply pigmented or white areas of coat are unaffected. In blue dogs with tan points (Yorkies and Dobermans) the tan areas retain a normal appearance. In piebald (white spotted) individuals, the white areas are unaffected by the hair loss. The hair loss may be total or partial and any remaining hairs are usually sparse, rough and easily broken or removed. The skin in the affected areas is usually scaly and may occasionally develop bacterial infections. Pruritus (itching) is usually absent, unless a bacterial infection has set in.
 
Diagnosis of CDA requires first ruling out other causes of hair loss. Diagnostic tests should include fungal cultures, skin scrapings to check for parasitic mites, etc. CDA often closely resembles endocrine (hormone related) hair loss and the dog should be carefully examined for any other abnormalities, and tested for normal thyroid function. Presence of dilute pigment and a characteristic course of disease also aid in making the diagnosis. Microscopic examination of hairs and\or skin biopsies can be used to confirm the diagnosis.
 
There is no cure for CDA. Treatment is limited to controlling the scaliness and any associated pruritus with various shampoos or topical treatments.

The cause of CDA is not clearly understood. Microscopic examination of hairs of dilute individuals reveals that the pigment (melanin) forms large granules (macromelanosomes) which are rarely found in deeply pigmented hairs. In dilute individuals with normal appearing coats, these macromelanosomes are not grouped or clumped and cause no distortion of the cuticle (outer covering) of the hair. Dogs with CDA have many large groups or clumps of macromelanosomes which tend to distort the cuticle of the hair. It is hypothesized that this distortion of the cuticle causes the hairs to break easily, resulting in the short stubby hairs commonly found in affected individuals.  It is further hypothesized that the rupture of the hair releases byproducts of pigment formation, which are toxic to the hair follicles. Regrowth of broken hairs is reduced because of damage to the follicles caused by these toxins.
 
Why in some dilute dogs the macromelanosomes are clumped and in others they are not, is an interesting question at this time. The relationship between dilute pigment and hair loss is clear, but why are some dilute individuals unaffected? Weimeraners as a breed are dd, all individuals are dilute, yet the disease is unreported in this breed. In Dobermans, the dilute individuals comprise only 8-9% of the breed, yet 50-80%6 of the dilute dogs have CDA. Many individuals are dilutes, the IGCA health survey reported only 71 affected individuals among the approximately 2200 dogs included in the survey. If half the dogs included in the survey were dilutes, the incidence of CDA in IG's would be around 7% of the dilute population, as opposed to the 50-80% affected dilute Dobermans.

A third allele (dl) which is associated with CDA has been proposed.  While this is a long way from being proven, it could help explain why some dilute animals are unaffected. Dogs with a genotype dd would be normal coated dilutes, ddl would be intermediates (mildly affected?) and dldl would be CDA affected. A genotype of Ddl should represent deeply pigmented dogs which were carriers of CDA.

In Yorkshire Terriers it is known to affect extremeties such as the ears, dorsal nose area. It is also related to flank alopecia characterized by symmetrical hair loss on each flank in an equal diameter pattern. There is sometimes a hormonal or seasonal causation due to a lack of melanomin in these individuals.
Inheritance: Unknown but closely related to the inheritance of the blue gene in coat colours

 
A diarrhea disease caused by a species of coccidia commonly found in the feces of puppies, and occasionally, adult dogs. Coccidia are not worms; they are microscopic parasites which live within cells of the intestinal lining. Because they live in the intestinal tract and commonly cause diarrhea, they are often confused with worms.
Inheritance: Environmental factors
 

 
Collapsing Trachea is a problem common to Toy Breeds. The trachea is a long tube that carries air from the neck to the chest. It is reinforced with rings of cartilage that help keep it rigid as air moves in and out of the tube. When the cartilage weakens, the trachea may collapse while the dog is breathing. While many affected dogs do fine, this isn't the case in all of the Toy's. The round cartilage rings may flatten, forcing the dog to try to breathe through an extremely narrow opening.
 
The symptoms of the condition---shortness of breath, coughing, fatigue---usually appear after the age of five, although they can begin as early as birth. Generally young dogs tolerate collapsing trachea pretty well until they get older.
 

(Immunoproliferative small intestinal disease) Persistent, nervous diarrhea; may be immune-mediated
 

Inheritance: Unknown
 

Crusts on back due to plugged hair follicles, itching.
 

Cushing's Syndromeis also known as 'Hyperadrenocorticism' and is a combination of clinical and chemical abnormalities resulting from chronic exposure to excessive amounts of glucocorticoids. It is a condition that occurs in most species but is most commonly encountered in the dog and the horse. Cushing's disease is the result of the overproduction of cortison, an natural steriod hormone, by the adrenal glands. It is rare in dogs under five years old. In about 80 percent of the dogs the disease is caused by a lesion in the pituitary gland at the base of the brain that overstimulates the adrenals, while in about 20 percent of cases one of the adrenal glands itself will have a tumor that excretes cortisol independent of what's happening in the body. About half of those tumors are maliganant and spread, and about half of them are benign and generally tend to stay small.

Glucocorticoid have many functions and are essential for life being responsible or indirectly responsible for a range of metabolic functions including blood glucose levels, fat production and distribution, protein metabolism, inflammation, thirst, counteracting shock, the skin and the immune system. The list goes on.

Cushing's Syndrome is a collection of symptoms caused by an excess of a hormone called cortisol. There are three main causes of Cushing's Syndrome: a tumor on the pituitary gland; a tumor on the adrenal gland; or veterinarians who over-prescribe corticosteroids to treat itching skin. It is, as yet, unknown whether there is an inherited predisposition to Cushing's Syndrome in Yorkshire Terriers.

In the base of all our brains is a small grouping of cells which constitute the pituitary gland. This gland has many functions and is the 'director' of much of the bodies function. It gathers information about body hormone levels and then produces its own regulatory hormones that through 'feedback' mechanisms govern their production. One of its functions is to govern the level of glucocorticoids in the blood stream. It does this by producing a hormone called ACTH that flows through the blood stream to the adrenal glands. The adrenal glands are very small pockets of specialized cells sitting behind each kidney that are responsible for producing the bodies glucocorticoid. ACTH stimulates the production of glucocorticoid in the adrenal gland.

Excessive production of ACTH in the pituitary will produce excessive glucocorticoid production. Similarly, an abnormality in one or both adrenals will cause an overproduction and both conditions will produce Cushing's Syndrome. The principal cause of overproduction is due to tumours growing in either the pituitary gland (usually benign, small and unlikely to cause other symptoms) or the adrenal gland (50% benign, 50% malignant and spreading to other areas of the body).

Diagnosis is based on clinical symptoms and confirmed with selective blood tests. Symptoms are varied but includes increased thirst with subsequently increased urine output, an excessive appetite, abdominal distension, often skin changes, with hair loss on flanks, dandruff, thickened and pigmented skin. The dogs become weak and lethargic with muscle wastage. Diabetes can be a secondary symptom. Confirmatory blood tests are many and varied but can be used to produce a diagnosis and then used to determine where in the body the problem lies.
 
The symptoms of Cushing's disease can also appear if a dog is taking steriods for a medical condition and ends up with too much in his system. Steroids are found in a lot of creams, eye ointments and ear ointments, and if you get overzealous with their administration, that can cause these signs as well. When you stop using the products, these symptoms will go away. The typical signs of Cushing's disease are increased thirst and urination, panting, hair loss (usually on the trunk) and weakness.

Symptoms:

• He is drinking huge amounts of water and urinating frequently

• He is losing coat

• His skin is darkening

• His muscles are atrophying and he develops a pot belly.

Cryptorchidism is the failure of one or both of the testicles to descend into the scrotum. Normal descent is often complete by 6 to 8 weeks of age but may be delayed to as late as 6 months of age. The undescended testicle may be found within the abdominal cavity, in the inguinal canal or under the skin next to the penis. The condition is considered hereditary in most breeds. There is not complete agreement on the mode of inheritance. Because of the increased incidence of cancer in retained testicles, cryptorchid dogs should always be neutered. A neutered cryptorchid dog should have no other expected health risks due to this condition. Bilateral cryptorchid is sterile, unilateral fertile but barred from showing.
 

Inheritance: Threshold, possible recessive
 

Extra row of eyelashes, usually on lower lid but appearing at times on upper; irritates the cornea causes excessive tearing
 

KCS or "dryeye" is an eye disease caused by abnormal tear production. The lacrimal glands produce the watery secretions that make up the bulk of the tears. A deficiency in this secretion causes KCS in small animals.

Normal tears are essential for the health and transparency of the cornea (the surface of the eye). Tears cleanse and lubricate the cornea, carry nutrients, and play a role in the control of infection and in healing. Deficient tear production as in KCS causes chronic irritation of the cornea and conjunctiva. Corneal ulcers and eventually corneal scarring occur, and blindness can result.
 
There is a predisposition to this condition in some breeds as listed below. KCS can also occur in any breed as a result of viral infection, inflammation, drug-related toxicity, or immune-mediated disease. Congenital KCS (ie. the dog is born with the condition) is rare. It may be one-sided and has been seen in toy breeds such as the Yorkshire terrier, pug, Pekingese, and Chihuahua. These dogs have very small or absent tear-producing (lacrimal) glands which leads to eye damage and potential blindness.

Inheritance: Unknown
 

Abnormal covering of the neural transmitters in the brain/spine; various nervous signs or tremors; may not be progressive and may improve with age

Inheritance: Unknown
 

Multiple cartiliage bumps on the bones near joints; if sever can cause lameness

Inheritance: Unknownn

 
Renal tubules degenerate, leak suger then proteins and slats in urine; leads to complete renal failure

 
Inheritance: Autosomal recessive
 

 
Caused by a protozoan of the giardia species. Giardia are one-celled organisms that live in the small intestines of dogs and cats. Dogs get the infection from drinking water from streams or other sources contaminated with infective oocysts. Young dogs can develop diarrhea that may be acute or chronic, intermittent or persistent, and may be accompanied by weight loss.

Inheritance: Environmental factorss

• Valvular Endocardiosis is a degenerative change of unknown cause affecting the subendocardial valve leaflets and chordae tendineae in the middle aged to elderly dog. Smaller breeds are predisposed. And it is relatively common in Yorkshire Terriers. Also known as chronic myxomatous valvular heart disease, this disorder is the most important cause of heart disease in veterinary practice.

• Cardiomyopathy, is another heart disease identified with Yorkies and other small toy breeds.

• Patent Ductus Arteriosus (PDA) At birth, mammals must adapt from living in a fluid environment (the amniotic fluid) and acquiring oxygen through the mother's blood, to breathing air and acquiring oxygen through their own lungs. The ductus arteriosus is very important in the adaptation process. This is a small communicating blood vessel between the pulmonary artery (which carries blood to the lungs), and the aorta (which carries blood to the rest of the body). Before birth, most of the blood from the fetal heart bypasses the fetal lungs via the ductus arteriosus. The lungs gradually become functional fairly late in fetal development. At birth, the blood supply from the mother is of course cut off, the dog (or other mammal) begins breathing on its own, and blood flow through the ductus arteriosus decreases dramatically. Within a few days, the ductus closes off completely. Where the ductus does not close, the dog is left with a patent ductus arteriosus (PDA). The extent to which this affects the dog depends on the degree of patency, or opening, of the ductus.

Abdominal contents bulge out under skin most commonly in the groin area of females although some males are affected. In males it can be in conjunction with the retention due to cord length of one or both testes. Umbilical or rupture or "outie"
Bulging of abdominal contents in sac at umbilicus; common; usually harmless unless very large.
 

Particularly dangerous to the toy and smaller breed dogs. Any kind of bacterial diarrhea can quickly dehydrate a dog, and the tinies are at greater risk, as they have little weight to lose before they are dehydrated and need IV rehydration. Your dog can get infected anywhere. Then it can be from 2-10 days after exposure, that your dog can come down with this problem. The symptoms start with vomiting, lethargy, refusing to eat, and progressing to mucous covered stool, loose stools, severe diarrhea and bloody diarrhea. It is important to have a culture done first so that you know exactly what bacteria you are treating, and get them started on antibiotics. DO NOT waste time, especially with the tiny toy dogs , as they do not have the spare fluids to lose thru diarrhea, especially bloody diarrhea.
 

Inheritance: Unknown

Hypoglycemia is when the blood sugar levels (glucose) fall well below normal. Glucose is what the body uses as fuel and is necessary for the brain tissue and muscles to function. Hypoglycemia is often seen in toy breeds, and frequently in young toy puppies. It can cause your puppy to become confused, disoriented, drowsy, have the shivers, stagger about, collapse, fall into a coma, or have seizures. Typical signs are listlessness, depression, staggering gait, muscular weakness, and tremors -- especially of the face. Puppies with a severe drop in the blood sugar develop seizures or become stuperous and go into a coma. Some puppies may only exhibit weakness or a wobbly gait, and occasionally a puppy that seemed just fine is found in a coma.  Most of the time the symptoms can be controlled by eating, or by giving some glucose such as Karo syrup mixed with water to the puppy.  If the puppy is in a coma, don't try to get it to swallow anything. Dip your finger in Karo and rub it under the tongue then get to the vet immediately.  If not treated, it can result in death.

Inheritance: Unknown

 
With hydrocephalus there is an abnormal build-up of cerebrospinal fluid (CSF) in cavities ( the ventricles) in the brain. The resulting increased pressure on the brain causes the clinical signs that occur with this condition.

Hydrocephalus can be primary (congenital ) - the animal is born with the condition, or secondary - the condition is acquired later in life due to some disease process that blocks normal drainage of the CSF. The primary form, discussed here, is seen most often in brachycephalic (dogs with a shortened head) and toy breeds.

Puppies with severe hydrocephalus often die at a very early age due to pressure from the increased fluid in the brain. In other less severely affected pups, the signs gradually become apparent over the first few months of life, and in some mild cases the condition is only diagnosed later in life.

Symptoms

Generally the signs gradually worsen, although by 2 years of age they may stabilize. To minimize brain damage, the condition must be recognized and appropriate treatment begun early. However, affected animals will likely always be slow and have a limited ability to learn.

Inheritance: Polygenic; complex
 

Hypothyroidism is an underproduction of hormones by the thyroid gland. It is characterized as an underproduction of TSH and an iodine deficiency, can be lethal if untreated.. It occurs in many breeds, including Yorkshire Terriers. Diagnosis is done by a blood test for complete thyroid activity. Symptoms include poor haircoat, infertility, lethargy, and cold intolerance. Treatment with synthetic hormones is very successful in controlling this condition. Blood tests to evaluate dosage is important on a yearly basis. However Yorkies are in the low precedence for TGAA testing.

Symptoms

• Abnormal loss of coat (often bilateral and symmetrical), poor coat condition, fading of coat color

• Chronic skin disorders and infections, skin allergies, dry or scaling skin

• Weight gain

• Infertility or reproductive problems

• Fatigue, lethargy

• Intolerance of cold

It is important to determine the exact cause of your dog's hypothyroidism before embarking on a course of treatment. Your veterinarian must run a full thyroid panel and have the blood tested at a laboratory which uses canine thyroid values (suggestion Michigan State University). Do not be tempted to start thyroid treatment without proper veterinary supervision. The balance of the endocrine system is critical to your dog's health and you can cause an otherwise healthy thyroid gland to atrophy by giving medication improperly.

Inheritance: Unclear
 

 
Intussusception is a problem with the intestine (bowel), wherein one portion of the bowel slides into the next, much like the pieces of a telescope. When this occurs, it creates an obstruction in the bowel, with the walls of the intestines pressing against one another. This in turn can cause dangerous inflammation, swelling, and decreased blood flow to the intestines involved.

Intussusceptions generally occur as a secondary problem to some disorder or disease that causes increased intestinal mobility or inflammation. Chronic parasite infestation may be the most common cause but anything that causes chronic intestinal disease can lead to an intussusception. There are times when intussuceptions occur for no apparent reason so it is likely that primary intussusception can occur. They have been reported following ingestion of foreign bodies, trauma, ovariohysterectomy surgery, infiltrative or inflammatory bowel diseases and other conditions that cause intestinal irritability.

Intussusception can be chronic sometimes. It can also be a "come and go" problem -- intussuscpetions occasionally will resolve on their own and then recur. I have removed one surgically, put the remaining intestinal ends back together and watched a new intussusception form right at the same site.

Inheritance: Unknown
 

 
Fluid filled cysts in kidneys may be with or without symptoms and will lead to renal failure without treatment.

Inheritance: Unknown 
 

Aseptic Necrosis of the Femoral Head

Legg-Perthe's disease is a degeneration of the hip joint occurring in young dogs. It is also known as Legg-Calve-Perthe's Disease, Perthe's disease, Calve-Perthe's disease, or in medical terminology, avascular necrosis of the femoral head and neck. The former names recognize the original researchers in the disease as it occurs in humans.

Most of the time the clinical signs of this disease occur in 4 to 11 month old dogs and usually consist of lameness of one leg only. Pain may be mild to very severe. Some dogs have mild forms of this condition and do not require medical care. In other dogs, the condition cause sufficient pain and deformity of the hip joint to require surgical intervention. Atrophy of the muscles of the affected leg is not uncommon. If this is severe it can slow the recovery period considerably and may make medical therapy less likely to work.
.
Definitive diagnosis is made by X-rays. As changes to bone occur slowly, X-rays taken early in the course of the disease may appear normal. Repeating the X-rays in 3 to 4 weeks will reveal the bony changes. A dog affected with LPD suffers a loss of blood supply to an area of the femur (thigh bone) known as the neck. Because the bone loses its blood supply, it dies. As a result of the loss of bone tissue, the neck of the femur collapses. The neck attaches the head of the femur to the body of the femur. When the neck collapses, the head of the femur is moved, and may also become deformed. These changes are readily apparent in X-rays. The head of the femur is the "ball" which sits in the "socket" on the pelvis, making up the hip joint. Therefore, changes to the head result in disruption of function of the hip joint which causes the pain and lameness. The term "avascular necrosis" means death of tissue due to lack of blood supply. In most dogs, only one hip is affected, and males and females are equally affected.
.
Treatment of this condition varies according to the severity of the signs seen. In mild cases, enforced rest may be sufficient to allow healing of the damaged areas to occur. In some cases, immobilization of the affected limb using an Ehmer sling may be beneficial to recovery. Many dogs have advanced cases of this disease by the time they are examined by a veterinarian and medical treatment is not likely to work. In these dogs, excision of the femoral head (ball portion of the hip joint) is often beneficial. Removal of this section of the bone diminishes painful bony contact in the hip joint. Recovery from this surgery can be slow with recovery periods of up to one year sometimes occurring before good use of the affected leg returns. If muscle atrophy is not present at the time of surgery the recovery time is usually much less. Pain relief and anti-inflammatory medications may be beneficial.

There is a stronger tendency to treat this as a medical condition prior to surgery right now. A general rule of thumb is to allow non-surgical therapy a month to show a beneficial response. If one is not seen, surgical repair should be considered more carefully..



Prevention of the disease is only possible through genetic means. Affected animals should not be bred. Breeding stock should have their hips X-rayed to insure that they are not affected with mild LPD, the symptoms of which went unnoticed during the dog's adolescence. Extreme caution should be used when considering breeding animals that have produced LPD, or have LPD affected littermates.

This condition is often referred to as a "liver shunt" but the current favored term appears to be portosystemic shunt. These have also been referred to by more exact terms since there are specific types of shunts that vary slightly.
 
There are three shunt types: intrahepatic, extrahepatic, or microvascular. The most common is Portosystemic shunt (PSS) occurs in many dog breeds the Yorkshire Terrier is one. It is an abnormal flow of blood between the liver and the body. Since the liver is responsible for detoxifying the body, metabolizing nutrients and eliminating drugs, the blood bypassing the liver can cause indications of a possible PSS which might include, but are not limited to, neurobehavioral abnormalities, anorexia, hypoglycemia, intermittent gastrointestinal symptoms, urinary tract problems, drug intolerance, unthriftiness and stunted growth.

Signs of PSS usually appear before two years of age, but later onset has been recorded. If an animal has a confirmed PSS, corrective surgery can be helpful in the long-term management of these animals. Dietary manipulation is also important in maintaining PSS animals. Mode of inheritance has not been established.

Symptoms:

 
Most shunts cause recognizable by the time a dog is a young adult but once in a while one is diagnosed at a later time in life. Since the severity of the condition can vary widely depending on how much blood flow is diverted past the liver it is possible for a lot of variation in clinical signs & time of onset for the signs to occur. Often, this condition is recognized after a puppy fails to grow, making an early diagnosis pretty common.

Signs of portosystemic shunts include:

* poor weight gain
* sensitivity to sedatives (especially diazepam)
* depression
* pushing the head against a solid object
* seizures
* weakness
* salivation
* vomiting
* poor appetite
* increased drinking and urinating
* balance problems
* frequent urinary tract disease or early onset of bladder stones.
* If these signs increase dramatically after eating, it is a strong supportive sign of a portosystemic shunt.

Most dogs will be diagnosed with port-systemic shunts under one year of age, but dogs as old as eight have been diagnosed with the condition. Animals are usually stunted, thin, depressed, have trouble gaining weight, and are usually characterized by the owners as chronic "poor doers". In most affected dogs there will be some degree of behavioral signs ranging from listlessness, apathy, or depression to more severe signs of circling, head pressing, stupor, drooling, blindness, or convulsions, some leading to coma.

These behavioral changes are due to an accumulation of toxins (especially ammonia) that affect the brain causing a condition called Hepatic Encephalopathy. These toxins are most abundant in the blood stream following the dog eating, especially a high protein meal, and may remain high for hours afterward. Not all dogs with the shunt will show this meal associated behavioral change, but in 25% of the affected dogs that do, the diagnosis becomes clearer. A high percent of affected animals show an intolerance to anesthetics or tranquilizers, and will show increased recovery times following use of these products. Even anti-convulsants used to control seizures may be potentially dangerous if allowed to concentrate in a dog with functional shunt.

Approximately 75% of affected individuals will show digestive system symptoms including poor appetite, ascites, vomiting, drooling, diarrhea, or occasionally deranged appetite (eating paper, etc.). Urinary system symptoms may include increased thirst and urination, & in a majority of porto-systemic shunt cases, there will be crystals or stones formed in the urinary tract. These crystals will be either uric acid or ammonium urate (ammonium biurate or thorn-apple crystals.). There can be bladder stones formed or crystals may be noted on the hair around the prepuce or vulva.

* In virtually all porto-systemic shunts there will be a significant rise in the bile acid levels over normal. The use of bile acids in screening clinically normal dogs for liver shunts is not currently being advised due to the variation of normal bile acid levels in Yorkshire Terriers, and other breeds as well.

* Routine performed serum chemistries are fairly nonspecific toward confirming the diagnosis of porto-systemic shunts, but there may be a decreased total protein (primarily albumin), decreased blood glucose, decreased cholesterol, and decreased blood urea nitrogen (BUN). The uric acid levels may be elevated in a significant number of affected individuals. Acid levels are extremely important in the diagnostic screening of symptomatic potential shunts. Fasting and 2-hr. post meal blood samples are evaluated for bile acid levels.
 
* Liver function testing with Bromosulfaphthalein (BSP) or ammonia tolerance testing are sensitive and reliable if performed correctly. These tests measure the liver's ability to excrete/detoxify known agents, and thus measure liver function accurately.

* Radiography. Radiography is one of the most important methods of establishing a diagnosis of porto systemic shunt, and is currently the only universally accepted method of confirming a shunt, short of major surgery. Injection of a radiopaque dye into the spleen (Splenoportograpy) will show the shunt on radiographs and allow accurate assessment for surgical correction.
 
* Nuclear Medicine. The placement of a radiopharmaceutical agent (radioisotope) specific for the liver into the colon for absorption through the mucosa has been gaining favor because of its noninvasive diagnostic value. This procedure requires expensive equipment and the diagnosis is based on the distribution of the radionuclide in the lung or heart compared to that in the liver. This procedure also does not identify the exact location of the shunt for surgical correction if required.
 
* Until recently, ultrasound was fairly unreliable for nonsurgical diagnosis of porto-systemic shunts. With the advent of Color Flow Ultrasound, there is the potential for diagnosis of this condition on non-anesthetized animals. At the present time, this technology appears to be the diagnostic procedure of choice. If currently undertaken research confirms its value, Color Doppler Ultrasound will soon be the preferred screening and diagnostic tool. At the present time, Hepatic Porto-Systemic shunts are considered to be UNQUESTIONABLY genetic by some of the leading canine experts, but the mode has not been identified at the present time; research is being conducted at Michigan State University to identify this pattern (See the Yorkshire Terrier Foundation page and the Joint Research Project between the YTCA Foundation and the CTCA Foundation).

Genetic disorders in dogs can spread relatively rapidly if a dog, whether affected or a carrier, is a well-respected animal in either conformation or ability, and is used extensively for breeding. This is especially true in the case of the male that can produce hundreds of offspring during his breeding life. If the cause of such a condition can be discovered, then a working strategy can be implemented to control and eliminate the disorder. The Yorkshire Terrier Club of America Foundation, Inc. is currently funding research into both the genetic nature of the problem and into the use of Color Flow Doppler Ultrasound as a diagnostic & screening tool.

Inheritance: Unknown, assumed to be polygenetic recessive

This is a dramatic, rapid inhalation and exhalation of air through the nasopharynx. Dogs may do this when they have a mild irritation at the back of their throat. Often confused with seizuring or gasping for air, it is usually a harmless event. Reverse sneezing isn't really a health problem, but something that dog owners should be aware of as it is very common in toy breeds. It is characterized by honking, hacking or a snorting sounds. It usually happens when a dog is excited or can sometimes happen after drinking, eating, running around, or while pulling on the leash. The dog will usually extend his/her neck while gasping inwards with a distinctive snorting sound, it is reverse sneezing. Usually by gently rubbing the throat of your dog, the spasms will stop after they swallow a couple of times and that's the end of it. Other dogs respond well by taking them outside for some fresh air. Or you can plug the nose holes forcing the dog to breathe through her mouth and that will usually stop an episode as well. Reverse sneezing is a harmless condition and medical attention is not necessary. It is important to not confuse reverse sneezing with a collapsing trachea.
 

Inheritance: Unknown
 

Open belly at birth with abdominal organs on outside, usually fatal any living should be neutered/spayed for the animals well being.

Inheritance: Unknown