AUTOIMMUNE HEMOLYTIC ANAEMIA (AIHA)

In hemolytic anaemia's, a loss of red blood cells (rbcs) occurs due to destruction of the rbcs. The destruction occurs due to antibodies which stick to the rbc and cause the body to react, leading to destruction of the cell. This can be the direct result of a drug, toxin, blood parasite, virus or other primary cause or it can be an unexplained immune mediated reaction. It can occur inside the blood stream (intravascular hemolysis) or outside the bloodstream (extra vascular hemolysis). In most cases in dogs, hemolysis occurs outside the blood stream in the spleen, liver and bone marrow. The destruction of red blood cells often leaves recognizable cellular debris in the blood stream. In particular, a form of damaged rbc known as a spherocyte occurs. Finding spherocytes on a blood smear almost guarantees that some form of hemolytic anemia is occurring. It does not really give a clue as to whether the IMHA is due to a primary cause or if it is occurring for no apparent reason, though. Since this disorder does not stop the production of red blood cells, there are usually immature red blood cells in the bloodstream which can be detected on the blood smears as well (a regenerative anemia).

The mechanism by which the immune system mistakes red blood cells for a "foreign invader" varies somewhat according to the cause. It usually involves adherence of the offending agent (parasite, drug, toxin, etc.) to the surface of the rbc. The immune system wishes to attack this agent but manages to injure the rbc as well.

Dogs with IMHA usually experience a sudden onset of clinical signs, including depression, lethargy, pale gums or conjunctiva, sometimes jaundice or a heart murmur and bruising. Vomiting or abdominal pain may be present. It is unusual for overt blood loss to occur, such as nose bleeds or excessive bleeding from a minor injury. Death can occur rapidly, even with appropriate treatment.

The combination of clinical signs and spherocytes on a blood smear give a strong indication of this condition very rapidly. It can be confirmed using a Coomb's test to check for antibodies adhered to red blood cells. This test is usually done at body temperature and at a colder temperature (4 degrees Celsius). A small percentage of dogs that have IMHA will not test positive on the Coomb's test.

This condition will often respond well to very high doses of corticosteroids, such as prednisone. These medications suppress the immune system, allowing the rbcs to escape destruction. Improvement usually occurs within 1 to 3 days, if the dog is going to respond. If signs of icterus (jaundice) are present, the prognosis is usually worse. Dogs with this symptom may benefit from very aggressive treatment with anticoagulants and cyclophosphamide, a potent immune system inhibitor. Blood transfusions can be used in dogs with IMHA if necessary but they can make the condition worse so most vets reserve this approach for dogs that appear to be in imminent danger of dying due to severe anemia. It is necessary to treat most dogs for a fairly long time to prevent recurrence of the disease and some dogs seem to require lifelong use of corticosteroids or other immunosuppressants. Splenectomy is done in resistant cases since it is a major site of red blood cell destruction.

This condition the heart is enlarged and compensatory mechanisms are acting to maintain blood flow. The dog will initially have no clinical symptoms but will eventually exhibit lethargy, will tire easily (heart can't pump enough blood), start coughing (fluid in lungs), etc. Basically the symptoms of congestive heart failure.

There is no cure for dilated cardiomyopathy but there are treatments that will improve cardiac function which will deninish the clinical symptoms. The typical treatment consists ofenalapril (angiotensin converting enzyme inhibitor), lasix (diuretic),and digoxin (improves the contractility of the heart, i.e. functions better). The treatment, in addition to lessening the clinical manifestations of the disease, may prolong the dog's life. Since cardiomyapathy is a progressive disease. Treatment prior to the appearance of clinical symptoms may slow down the progression and increase the dog's life expectancy.

Hypothyroidism is a relatively common endocrine disease of dogs which results from progressive loss of functioning thyroid tissue. While epidemiological studies are few and somewhat conflicting, it appears that hypothyroidism occurs more frequently in certain breeds and lines, especially in large breed dogs. It is usually caused by lymphocytic thyroiditis (most likely an immune-mediated disease) or idiopathic thyroid atrophy (shrinking of thyroid tissue from unknown causes). The disease can occur in either sex and usually becomes apparent in young adults (1-3 years of age) or middle-aged dogs (4-9 years of age). Clinical signs may include hair loss, seborrhea, bacterial skin infections, excessive skin pigmentation, lethargy, obesity, muscle or nerve weakness, slow heart rate and reproductive disorders. Abnormal blood tests may reveal mild anemia and an increase in lipids, especially cholesterol. 

In addition, interpretation of diagnostic tests for hypothyroidism can be confusing and not specific for thyroid dysfunction. Also, there is variation within normal thyroid hormone concentrations which must be considered when evaluating any test results. Younger dogs will have higher thyroid hormone concentrations than older dogs. Certain breeds, such as the greyhound, normally have lower thyroid hormone concentrations. At this time, there is no ideal test, which is readily available and affordable, that is specific for diagnosing hypothyroidism.

The most commonly used thyroid tests are those that evaluate thyroid gland function by measuring thyroid hormone concentrations in the blood. The Total T4, Total T3, Free T4 and TSH concentration tests measure various hormone concentrations at rest.

Unfortunately, diagnosing hypothyroidism isn't so easy. Yes this is possible hypothyroidism, but it could be normal. Depends on several things. Since the thyroid gland affects the body in its entirety, diagnosis must also be done as a whole rather than a simple course of tests. Many of the effects are diffuse and easily confused with other problems (one reason why I think it is over diagnosed). Skin problems and weight problems are most commonly over diagnosed as hypothyroidism.

Several other factors may point to a possible thyroid problem: 

weight gain (even though food is not increased or exercise reduced - though see the next one for complications of this)

lethargy, listlessness, general lack of enthusiasm, loss of appetite, hair loss or thinning (especially on the body), hypothyroid dogs are , constantly cold and seek out any warm place, skin problems - excessive dryness, thickening of the skin, puffiness in the face, high cholesterol 

Altogether, these signs in conjunction with the thyroid blood levels can determine a problem with the thyroid. Taken separately, they may mean little or point to some other condition entirely. Once the dog is put on thyroid medication, follow up must be done in order to determine if, in fact, it was thyroid problems. Thyroid problems do exist but it's not the only cause of these very diverse conditions. Thyroid blood tests are easy to conduct so they should be done in the beginning if hypothyroidism is suspected but that shouldn't be taken as the final word. Putting your dog on a lifetime drug should not be taken lightly nor with a simple series of tests.

Hip dysplasia literally means an abnormality in the development of the hip joint. It is characterized by a shallow acetabulum (the "cup" of the hip joint) and changes in the shape of the femoral head (the "ball" of the hip joint). These changes may occur due to excessive laxity in the hip joint. Hip dysplasia can exist with or without clinical signs. When dogs exhibit clinical signs of this problem they usually are lame on one or both rear limbs. Severe arthritis can develop as a result of the malformation of the hip joint and this results in pain as the disease progresses. Many young dogs exhibit pain during or shortly after the growth period, often before arthritic changes appear to be present. It is not unusual for this pain to appear to disappear for several years and then to return when arthritic changes become obvious.

Dogs with hip dysplasia appear to be born with normal hips and then to develop the disease later. This has led to a lot of speculation as to the contributing factors which may be involved with this disease. This is an inherited condition, but not all dogs with the genetic tendency will develop clinical signs and the degree of hip dysplasia which develops does not always seem to correlate well with expectations based on the parent's condition. Multiple genetic factors are involved and environmental factors also play a role in determining the degree of hip dysplasia. Dogs with no genetic predisposition do not develop hip dysplasia.

At present, the strongest link to contributing factors other than genetic predisposition appears to be to rapid growth and weight gain. It is likely that the laxity in the hip joints is aggravated by the rapid weight gain.

The calcium/phosphorous to calorie ratios in adult dog food are such that the puppy will usually end up with higher than desired total calcium or phosphorous intake by eating an adult food.

If clinical signs of hip dysplasia occur in young dogs, such as lameness, difficulty standing or walking after getting up, decreased activity or a bunny-hop gait, it is often possible to help them medically or surgically. X-ray confirmation of the presence of hip dysplasia prior to treatment is necessary.

Once a determination is made that hip dysplasia is present, a treatment plan is necessary. For dogs that exhibit clinical signs at less than a year of age, aggressive treatment may help alleviate later suffering. In the past a surgery known as a pectineal myotomy was advocated but more recent evidence suggests that it is an ineffective surgical procedure. However, administration of glycosaminoglycans (Adequan Rx) may help to decrease the severity of arthritis that develops later in life. Surgical reconstruction of the hip joint (triple pelvic osteotomy) is helpful if done during the growth stages. For puppies with clinical signs at a young age, this surgery should be strongly considered. It has a high success rate when done at the proper time.

Dogs that exhibit clinical signs after the growth phase require a different approach to treatment. It is necessary to determine if the disorder can be managed by medical treatment enough to keep the dog comfortable.. If medical treatment is insufficient then surgical repair is possible.

The best surgical treatment for hip dypslasia is total hip replacement. By removing the damaged acetabulum and femoral head and replacing them with artificial joint components, pain is nearly eliminated. This procedure is expensive but it is very effective and should be the first choice for treatment of severe hip dyplasia whenever possible.

An alternative surgery is femoral head ostectomy. In this procedure, the femoral head (ball part of the hip joint) is simply removed. This eliminates most of the bone to bone contact and can reduce the pain substantially.

Hip dysplasia may not ever be eliminated by programs designed to detect it early unless some effort is made to publish the results of diagnostic tests openly. This is the only way that breeders will be able to tell for certain what the problems have been with hip dysplasia in a dog's ancestry.

When an older dog is exhibiting signs of pain associated with this condition it is often possible to help them dramatically through medication and simple steps like providing a warm bed or warm spot to rest during the day. There is no advantage to pain and steps should be taken to ensure that the older dog is not in pain. Regular exercise can be very helpful and weight loss can have dramatic effects on the amount of discomfort a dog experiences.

Working with your vet to come to the best solution for your dog and your situation will enable you and your dog to enjoy life to its fullest, despite the presence of hip dysplasia.

All the above information is taken form vWD literature.