Interview with Dr. Tobin, DVM
Dr. Stephen Tobin is a holistic veterinarian who provides treatment using homeopathic herbs and nutrition. He speaks with us about hisphilosophy of animal care, pet nutrition, and his experience with the Longlife Program in the treatment of his patients.
The Canine Immune System
The immune system is a complex defense network of white blood cells, antibodies, and other substances that fight off infections and reject foreign proteins. It is a force patrolling the body, designed to distinguish one’s own cells from outside cells by trace markers found on the surface of every cell in the body. It is this ability that causes the bodies of human beings and animals to reject skin grafts, blood transfusions, and organ transplants. Like anything else in life, the immune system can fail, either by not doing enough or by doing too much.
Such is the natural process by which the body responds to so many harmful outside agencies that a breakdown in a dog’s immune system is so destructive. A collapse of the immune system leaves the body open to attack by an opportunistic infection from outside elements. In these situations, lacking the body’s natural defense mechanisms, a dog might suffer terribly from the most ordinary of injuries.
An Auto-Immune Disease, on the other hand, is a different kind of immune system failure. In this situation, the immune system fails to recognize itself, and it begins to attack and reject the body’s own tissue as foreign. One specific tissue type, such as red blood cells, may be affected, or a generalized illness, such as systemic lupus (see below), may result.
Causes of Auto-Immune Disease in Dogs
What causes the immune system to short-circuit and start rejecting normal body tissue? Many theories exist, but the ultimate answer is that no one quite knows. Jean Dodd’s, a veterinarian who specializes in immunology, believes that multivalent modified-live vaccines overstimulate the immune system. Others blame environmental pollutants or food preservatives such as ethoxyquin, an antioxidant found in most dog foods. There is strong evidence for a genetic factor in the development of auto-immune disease in many species. Finally, some cases occur spontaneously, causing damage to kidneys, lungs, or the thyroid gland.
Symptoms of Auto-Immune Diseases
Canine auto-immune disease can be signaled by a multiplicity of symptoms, any of which might signal an onset. Chief among these is an intense soreness certain parts of the body, often demonstrated by a “protecting,” during which the dog behaves as if keeping a certain body part untouched is a matter of life and death. For instance, a protecting of the pancreas (a pale pink glandular organ that nestles just under the stomach) might signal the onset of auto-immune disease. A soreness of the thyroid (a butterfly-shaped gland in the throat) might be cause for concern, as might an irritated or swollen rear quarter, illustrated by a licking or dragging of the left hind paw.
Other symptoms, which otherwise might be overlooked in the larger picture of a dog’s health, include itchy, flaky skin, inflamed ears, excessive licking of the front paws, and swelling of the toes. If any of these symptoms are present, a dog may suffer from Canine auto-immune disease, and should see a veterinarian immediately.
Testing for Auto-Immune Disease / Thyroid Tests
Veterinarians may suggest a thyroid test if a pet has gained weight or is having chronic skin infections, or if an elite breeding dog is experiencing reproductive difficulties, especially if the animal lacks energy or has a scruffy or dull coat. The veterinarian draws the blood and sends it to one of several laboratories with the equipment for conducting the test. The blood sample should be taken when the dog is otherwise healthy, is not approaching a heat cycle, and is not taking pharmaceuticals such as steroids, non-steroidal anti-inflammatories, oranti-seizure drugs. The latest tests include measurement of two forms of the thyroid hormones T3 (triodothyronine) and T4 (levothyroxine) and a search for antibodies that could indicate auto-immune thyroiditis, the genetic form of the disease. Interpretation of the numbers recorded is as important as the numbers themselves, for the relationship between the hormones is complex. In addition, normal ranges of hormones vary somewhat with the breed or mix.
Hypothyroidism in Dogs
When a dog suffers from an auto-immune disease, he or she is at risk for several ailments, most commonly Hypothyroidism. Hypothyroidism is a common disorder in middle-aged to older dogs, characterized by thyroid hormone production.
Thyroid hormones affect almost every organ in the body and thus many signs of this disease are common. These include lethargy, depression, obesity (despite normal feeding amounts), hair loss, skin and ear infections, and weak or torn knee ligaments. Should this disease be suspected, initial screening blood workis performed. Dogs that are hypothyroid have thyroid levels that are almost always below the normal range.
Puppies with severe forms of congenital hypothyroidism are said to have Cretinism. These usually have developmental defects of the pituitary gland and are stuntedmentally, and, with time, are malformed physically.
Breeds Commonly Affected by Hypothyroidism
Many breeds are commonly affected by this disease: Boxers, Cocker Spaniels, Golden Retrievers, Labs, Poodles, Dachshunds, and Miniature Schnauzers. It is likely that some breeds are genetically predisposed. There is no difference infrequency of occurrence between males and females.
Additional Symptoms of Hypothyroidism in Dogs
In addition to the symptoms listed above, some of the other signs of Hypothyroidism include lethargy, mental dullness or behavioral changes, increased weight gain/obesity, cold intolerance (seeking of warm places), poor wound healing, poor skin and hair coat (including hair loss or abnormal hair turnover, or dull or brittle hair), altered pigmentation, oily or dry skin, thickened skin with a “sad” facial expression, odiferous skin that may be pruritic (itchy) because of secondary bacteria, and/or yeast dermatitis/pyoderma (superficial infections) with or without concurrent demodecosis (skin parasite). The last group of symptoms includes seizures, cranial nerve deficits (blind and/or droopy eyelids, or dry irritated red eyes due to paralysis of eyelids), and decreased tear production, which causes eye surfaces to be dry and irritated. In rare cases, the dog might act “drunk”, endure swallowing problems, or endure general weakness.
Pemphigus Disease in Dogs
Three other major potential diseases may result from canine auto-immune disease:
The first is Pemphigus. Clinically, dogs with pemphigus will present with ulcers that affect the oral cavity and skin areas bordering the mouth, nose, eyes, anus, and genitalia. The lesions often progress to involve the skin, especially in areas of friction, such as the groin and armpits. In rare dogs, the lesions are restricted to the skin, to the nose, or to the borders of the nails. Ulcerated skin and mucosal lesions generally are painful; the pets thus are reluctant to eat, and they will begin to lose weight. Deep skin lesions commonly become infected with skin bacteria.
Pemphigus Disease Symptoms
The more common forms of pemphigus produce scaling skin, scabbiness, and sometimes pus-filled sores that look like pimples. Early in pemphigus foliaceus, the disease may be confined to the head and feet, making it hard to distinguish from pemphigus erythematosus. Later it spreads to more of the body. Careful examination of the skin may reveal the presence of blisters, which are very indicative of these diseases. The blisters rupture quickly and may not be seen.
There are several skin disorders within the pemphigus complex. They all have one thing in common, in that the body produces harmful antibodies, this time against the outer layer of the skin.
Breeds Commonly Affected by Pemphigus
Pemphigus foliaceus is the most common of these diseases in the dog. It is seen more often in Akitas, Chow Chows, Dachshunds, Bearded Collies, Doberman Pinschers, Finnish Spitzes, and Newfoundland dogs. Pemphigus erythematosus is second most common and may just be a milder form of pemphigus foliaceus. It is seen more commonly in Collies, Shetland Sheepdogs, and German Shepherds.
Pemphigus Vulgaris Symptoms
Pemphigus vulgaris is the most severe form of the disease. In this disorder, there is severe ulceration of the skin, usually where “normal” skin meets “specialized” skin, around the mouth, anus, prepuce, nose, and vagina. The mouth is almost always affected. Secondary complications are more common with pemphigus vulgaris than other forms of Pemphigus, and can be very severe.
Pemphigus vegetans may be a less severe form of pemphigus vulgaris, but it does look different. In this form of pemphigus there are warty growths that may ulcerate. Many diseases can look like pemphigus disorders.
Testing and Treatment of Pemphigus
Diagnosis of pemphigus is best done by skin biopsy. Sometimes specialized testing must be done on the biopsy samples—often by doing them again. Treatment of pemphigus vulgaris and pemphigus foliaceus can be pretty frustrating. Treatment of pemphigus erythematosus and pemphigus vegetans may not be necessary or is usually possible with topical corticosteroids or low to medium dosages of prednisone. Due to the serious immunosuppressive tendencies of the medications used to treat pemphigus diseases, it is usually necessary to closely monitor the health of pets under treatment. To succeed in keeping a dog comfortable when affected by the more severe pemphigus diseases, the client and veterinarian must cooperate closely. Teamwork is important in treating pemphigus.
Canine Lupus
Canine Lupus: In Latin, “Lupus” means wolf, and the disease Lupus is aptly named; Lupus, in both humans and canines, is the disease in which the body literally attacks itself. The disease takes two forms, Systemic LupusErythmatosus and Discoid Lupus.
Systemic Lupus Erythmatosus
Systemic Lupus Erythmatosus (SLE, or often referred to as simple canine lupus)is a rare autoimmune-mediated disease specific to dogs. Dogs with lupus have unusual antibodies in their blood that are targeted against their own body tissues. Lupus can cause widespread systemic disease of the skin, heart, lungs, kidneys, joints, and nervous system, as well as blood (anemia and/or decreased platelet numbers). Multiple organs are usually affected.
Symptoms of Systemic Lupus Erythmatosus
The condition tends to wax and wane, so your dog will have periods of remission and of flare-up. The kinds of problems you may notice include shifting lameness(varies depending on which joint is affected at any time), weakness and palegums (due to anemia), and/or increased drinking and urination (kidney disease).The face and the feet are the areas of the skin most often affected, with ulcers and loss of pigment on the nose, and ulceration and thickening of the footpads.
From the above paragraph, one might conclude (correctly) that one of the problems with SLE is that it causes such a wide variety of symptoms that it can be confused with a number of different diseases. The signs of SLE may be acute (sudden onset and short duration) or chronic (of long duration and recurring) and are usually cyclic (recurring in a specific pattern or cycle). Some of the symptoms may include a fluctuating fever, shifting lameness, arthritis affecting multiple joints without any evidence of cartilage erosion, multiple painful muscles, anemia, a low white blood count, oral ulcers, symmetrical skin lesions including alopecia (hair loss),skin crusting, lesions, ulceration and scar formation, thyroiditis, (inflammation of the thyroid gland), and splenomegaly (enlargement of the spleen). Pyelonephritis(generalized infections of the kidney), renal failure (kidney failure), septicarthritis (serious infection of the joints), or septicemia (infections of the blood stream) are signs that the disease is in an advanced state.
Diagnosis of Systemic Lupus Erythmatosus
Because SLE can affect many different body systems, diagnosis is challenging. In fact, it is sometimes called “the great imitator”. Once suspected, diagnosis is confirmed by specific blood tests and biopsy for examination by a veterinary pathologist.
Veterinarians should know that the list of rule-outs with SLE is extensive, due to the varied and changeable cutaneous and systemic manifestations of this disorder. Diagnosis is based on signs of multisystem involvement (most common lyanemia, thrombocytopenia, glomerulonephritis, polyarthritis, nasal and footpad dermatitis, fever of undetermined origin), a positive antinuclear antibody test, and histopathologic and immunopathologic evaluation.
Discoid Lupus
Discoid Lupus is an immune-mediated skin disease that is probably related to SLE, but instead of affecting the whole body, as SLE does, it primarily affects the nose and face. There is no known cause of this problem, but it does seem more common in dogs of the German Shepherd, Collie, Brittany Spaniel, Shetland Sheepdog, Siberian Husky, and German Shorthaired Pointer breeds. Discoid Lupus is also called Cutaneous Lupus Erythematosus (CLE).
Symptoms of Discoid Lupus
The disease normally starts as a loss of pigment around the nose. There maybe scabby sores or just scaling of the nasal tissue. The surface of the nosemay change from its typical “cobbletoned” appearance to a smooth surface. As this disease progresses it can cause deep sores on the borders of the nose, where it meets normal skin. Eventually, the sores start to progress up the bridge of the nose.
(Note: Nasal scarring is common with both SLE and CLE. Exposure to ultraviolet light is a factor (especially in CLE), so the condition is seen more often and is more severe in the summer and in sunny parts of the world.)
Ultraviolet light seems to make the sores worse, so the disease may appear to be seasonal. It is more common in areas in which exposure to ultraviolet light is increased, such as high altitudes. If the depigmentation leads to sunburn, squamous cell carcinoma becomes more likely than in other dogs. Topical sunscreens can be very beneficial, although it is hard to get dogs to leave them on. Keeping the dog indoors during peak sunlight hours is probably the most effective wayto prevent excessive exposure to UV light.
CLE is diagnosed through examination of biopsy samples, and by histopathologic and immunopathologic evaluation.
Exposure to ultraviolet radiation worsens the skin lesions in both conditions, so sunscreen is advisable and dogs should be sheltered from peak sunlight (approximately10:00 am to 3:00 pm).
One should note that for many breeds and many disorders, the studies to determine the mode of inheritance or the frequency in the breed have not been carried out, or are inconclusive. Listed here are breeds for which there is a consensus among those investigating in this field and among veterinary practitioners that the condition is significant in this breed.
This, too, is important: Although the mode of inheritance is not known for either discoid or SLE, these conditions run in families. Affected animals should not be bred, and it is prudent to avoid breeding their close relatives as well.
Auto-Immune Hemolytic Anemia
The third and last ailment resulting from auto-immune syndrome is Auto-Immune Hemolytic Anemia (AIHA), a disease in which the body attacks its own red blood cells (RBC). A pet suffering with AIHA will have a lower-than-normal number of red blood cells within the blood. This is termed anemia.
The exact mechanisms which trigger the dog’s immune system to attack and destroy its own red blood cells are unknown. However, the disease process is believed to occur when antibodies coat the surface of the red blood cells, tagging them for destruction by the white blood cells. When the body is invaded by an infectious microorganism or agent, it produces a number of antibodies that range in specificity for that particular invading antigen. Some of the antibodies are highly specific, while others bind with less specificity. In the normal immune system, suppressor-cells ensure that these non-specific antibodies do not react with normal host tissues. However, it is believed that some dogs may have poorly regulated T-cell suppression that allows these non-specific antibodies to attack their own cells.
Breeds Commonly Affected by AIHA and Other Factors
Such a genetic predisposition for AIHA has been suspected in several breeds of dogs, including Old English Sheep Dogs, Cocker Spaniels, Poodles, Lhasa Apsos, and Shih Tzus. Alternatively, some clinical studies exploring potential causative mechanisms have identified several non-genetic factors that may play a role in the development of this disease. For example, the observation that dogs afflicted with AIHA also demonstrate increased antibody titers to viral antigens for canine parvovirus and distemper virus suggests that certain viral infections may triggeran autoimmune reaction. Under such circumstances it is believed that there is adsorption of the virus to the red blood cell. When the immune system launches antiviral antibodies to destroy the virus, these antibodies target and destroy not only the virus, but the red blood cell as well. Similarly, some drugs (such as antibiotics, analgesics, and cardiovascular drugs) as well as viral antigens composing modified-live vaccines are also believed to induce AIHA through this type of mechanism.
Additional Risks of Auto-Immune Hemolytic Anemia
AIHA makes a dog vulnerable to another disease, immune-mediated hemolytic anemia (IMHA). IMHA refers to all anemias that occur when the immune system mistakenly destroys its own blood cells secondary to an immune attack directed against an underlying condition such as cancer, endocarditis, or heartworm, or by unidentifiable causes, as in AIHA.
A veterinarian can diagnose AIHA. The clinical signs of AIHA are usually gradual and progressive, but occasionally an apparently healthy pet suddenly collapses in an acute hemolytic crisis. The signs are usually related to lack of oxygen supply. The hemoglobin in RBC is the primary carrier of oxygen in the blood.
The Role of Blood
Blood is considered an organ. It has its own complex and diverse development, structure and functions. Its unique form, cellular tissue suspended in fluid plasma, allows it to serve as a main distribution system throughout the body. Cellular tissues composing the blood include: the red blood cells, which provide oxygen to tissues of the body; the white blood cells, which prevent invasion of microorganisms or other foreign substances; the lymphocytes, which carry out immune surveillance; and the platelets, which are involved in keeping the components of the blood in balance. Remarkably, all of these cellular components originate from a common source, called stem cells, located in the bone marrow. These stem cells give rise to a mature colony of cells which as they continue to divide and mature undergo a series of changes, a process known as differentiation, and eventually develop into the specialized blood cells indicated above. Anemia is a condition brought on by abnormalities which lead to a deficiency in the number of red blood cells. Although the average life span of a circulating red blood cell is brief in most organisms (approximately 4 months), under normal circumstances the red blood cell mass is maintained at a constant level because new red blood cells are made as old red blood cells are destroyed and removed from circulation by the white blood cells. When this balance is disturbed and the level of red blood cells decreases to a point at which demand exceeds the capacity of the bone marrow to produce them, anemia develops. Because integrity and function of other organs in the body are dependent upon red blood cells to deliver oxygen to their tissues, if the red blood cell number decreases to a point at which the body is unable to compensate for the decrease in oxygen transport, serious and irreparable tissue and organ damage may occur. Conditions which maycause a decrease in the circulation of red blood cells include excessive blood loss (hemorrhage), impaired ability of the bone marrow to produce new red blood cells, or increased rate of red blood cell destruction.
When a large percentage of red blood cells (RBC) are affected, and they are removed faster then they can be replaced, the animal shows external signs of the disease. To the untrained eye, signs include weakness, lethargy, anorexia, and an increase in heart rate and respiration. Heart murmurs, pale mucous membranes(gums, eyelids, etc.), and discoloration in the urine and/or stool may also be present. More severe cases also have a fever and icterus (jaundice), which is a yellow discoloration of the gums, eyes, and skin. This is due to a build up of bilirubin, one of the breakdown products of hemoglobin.
Causes of AHIA and IMHA
Unfortunately, as of now, the veterinary medical field has not discovered why an individual dog gets AIHA/IMHA. Certain breeds, such as Cocker Spaniels and Poodles, are at a higher risk than other breeds. Middle-aged female dogs are also at a higher risk. However, immune-mediated hemolytic anemia may occurring any breed at anytime.
Evidence suggests that recent vaccinations (DHLPP), along with the administration of certain medications like sulfa-trimethoprim antibiotics, may be associated with a higher incidence of IMHA. Dogs with serious infections or cancers in their body may also develop IMHA. The thought for the underlying cause is that something(e.g., vaccine, cancer cells) triggers the immune system to react and to create antibodies. Accidentally, the antibodies also destroy the red blood cells and sometimes also the platelets (idiopathic thrombocytopenic purpura), and therefore, the first sign of illness may be anemia.
Summary
In summary, AIHA/IMHA is a life-threatening immune disease that can caused mage to vital organs through the lack of oxygen supply associated with the resultant anemia. Owners of pets with AIHA/IMHA face a guarded to poor prognosis for the pet at the time of diagnosis. If an underlying disease such as cancerous discovered, the prognosis becomes complicated by the limitations associated with the underlying cause as well.