Common Diseases in Pets A-B

The most common Adenoviruses in pets are the Adenovirus-1 and the Adenovirus-2.  The latter causes respiratory disease in dogs.  The former is the causative agent of Infectious Canine Hepatitis.

Adenovirus-1 has a predilection, once in the body, to replicate and cause disease in the lungs, liver and spleen.  Its pathological effects can also result in blood clotting issues.

Infectious Canine Hepatitis is most commonly seen in young dogs; since their immune system is so immature.  It is not commonly seen, since most dogs in the U.S. are vaccinated against it by use of the attenuated adenovirus-2.  Many animals show no signs but can shed the virus from anywhere from 6 months to a year in their urine.  Dogs are infected by the ingestion of contaminated urine and feces.  Animals usually present with a low grade to mid grade fever.  They often are anorexic and display petequial hemorrhages on their bodies due to deficiencies in the clotting mechanisms.

A CBC and Chemistry Profiles should be performed.  A low white cell count, clotting difficulties and a high fever are often diagnostic hallmarks of the disease.  Absence of vaccination status may also point the diagnosis in the direction of ICH.

A tentative diagnosis of ICH is usually made by the presence of a relatively high fever and blood clotting disorders seen over the body.  The absence of vaccination against ICH and clinical signs seen in young animals may point the diagnosis in the right direction.

ICH is caused by a virus hence no antibiotic is going to kill it.  Treatment is via supportive care only; which includes antibiotics to prevent secondary bacterial infections as well as blood transfusions if the patient is anemic or has clotting issues.  Animals that are very ill are hospitalized  with intravenous fluids and other supportive care.

The prognosis depends upon the severity of the disease and age of the animal presented.  Dogs presented with higher body temperatures often have a more severe form of the disease therefore the prognosis is much more guarded compared to a mildly infected dog.  Vaccination of all dogs for ICH would prevent a lot of suffering.  This vaccination is included in the “annual boosters” that veterinarians administer.

Adenovirus

The cause of Addison’s disease is unknown although there may be an immune-mediated side of it.  The disease is also known as hypoadrenalcorticism.  This means a deficiency in hormone production in the adrenal glands.

Adrenal glands (in the cortex) produce several important hormones known as mineralocorticoids and glucocorticoids.  The most important mineralocorticoid is aldosterone which is responsible for sodium regulation.  Cortisol is the most important glucocorticoid found in the body responsible for many physiological effects.  A deficiency in one or the other or both lead to the clinical signs seen in the dog.  This is rarely seen in cats.

Clinical signs of Addison’s disease can be insidious and difficult to diagnose.   This disease is seen most commonly in young to middle aged dogs.  Making it difficult, is that only vomiting, diarrhea, weight loss and anorexia may be seen before the animal goes into shock.  Aldosterone not only regulates sodium levels but also potassium levels.  A deficiency leads to elevated serum potassium levels which leads to a slowdown in the heart rate and eventual shock and renal failure.  Some dogs may also show similar signs due to additional depletion of cortisol.

The most commonly used diagnostic test is the ACTH Stimulation Test.  0 hour samples and 2 hour blood samples show extremely low levels of cortisol.

Diagnosis is made by the history, physical exam and diagnostic responses to the ACTH Stimulation Test.

The majority of dogs only lack aldosterone.  An acute case of Addison’s disease is a medical emergency and requires hospitalization with intravenous fluids and glucocorticoids that will repair the hypotension and sodium levels.  Fluids will also lower the excess potassium levels but sodium bicarbonate may also be used for such purpose.  After all animals are stable, homonal replacement therapy is in order.  The most commonly used drug is Percorten®, which is administered every 26-28 days.  Dogs that are deficient in glucocorticoids are given varying doses of prednisone or prednisolone.

The prognosis for Addison’s disease is very good.  Dogs live normal lives while on hormonal replacement therapy.  The crucial role of the owner is to obtain monthly hormonal replacement therapy plus regular visits to the hospital for electrolyte levels; mainly sodium and potassium.

Addison’s Disease

The causes of allergies are too numerous to be mentioned but an allergy be it acute, chronic, food related, contact or inhalant is a response to the presence of a foreign protein named an allergen.  The most common types of allergies are:  parasitic (fleas and ticks), food (different types of meat or grains), horticultural (tree and grass pollen), insect bites (spiders and ants) plus to vaccines and their components.  Each individual is different and any protein can cause an allergic reaction in any animal!

Allergies can effect any part of the body.  Once a foreign allergen invades the body via inhalation, direct contact, or ingesting food, the allergen sets up a reaction.  This reaction involves special cells in the blood known as macrophages (and others) that release histamine.  This leads to the root of all allergic reactions.  These reactions can be acute (anaphylactic shock) or delayed and can be manifested in a myriad of different ways such as asthma (breathing difficulties), itching of the skin (flea and food allergies), ear infections and many more.

The most common clinical sign of allergies is scratching and digging at the skin.  The skin is the largest organ in the dog and cats body and itch (also known as pruritus) can lead to interrupted sleep patterns, hairloss, inflamed skin plus bacterial skin infections once the skin surface is broken.  Ears also are “skin” and many pets suffer from ear infections.  Other allergies such as reactions to vaccines and insect bites can cause an acute swelling of the eyes, lips and limbs (if bitten by a wasp such as a yellow jacket).  These require immediate medical attention.  These are the most common signs.  Finding the cause is the difficult part.

If an animal is suspected of having a form of allergy it makes sense to do a CBC and Chemistry profile to make sure the dog or cat is healthy and to check the level of eosinophils; one of the 5 types of white cells.  Eosinophils are almost always elevated in allergies.  In an attempt to figure out exactly what is causing the allergy, an allergy blood panel is done.  To do this right, all dogs have to be off of all forms of corticosteroids for at least 2 months!  One of the best testing programs is offered by Heska.  Once the cause is found, immunotherapy (a vaccine) can be started.

Diagnosis is made by the physical exam, the time of year plus the breed of dog.  Breeds such as Pit Bulls, Retrievers, West Highland Terriers, Shar-Pei’s, English Bulldogs and others are predisposed to allergies via a genetic path.  In many parts of the country it is cold in fall in winter.  Most plant allergens and insects are dormant.  Noticing an itchy dog in the winter is either dry skin, food allergy or the Cheyletiella mite in puppies.  In South Florida, where I live, it never gets cold so insect and tree allergens are a constant year round problem.  Surgical skin biopsies, using a biopsy punch, may be taken to rule out other non allergy causes of skin irritation.

Treatment goals are based on:  avoiding the allergen causing the problem, controlling the inflammation and itch associated with the allergy plus a long term plan to manage allergy manifestations.  Avoiding the allergen is difficult.  I often commented to my clients in Ohio (which has a high pollen count on average) that to avoid atopic dermatitis they would need to move to Phoenix!  Very difficult.  The only thing that provides immediate relief to allergy suffering is corticosteroids.  These go by the name of prednisone (oral) or DepoMedrol® (injectable).  These drugs should be used sparingly as long term use can lead to Cushing’s Syndrome and, being an immunosuppressant, more prone to picking up other infections such as cystitis.  Over the counter antihistamines such as Benedryl® do nothing other than make the dog sleepy.  Avoid antihistamines in cats.  Hyroxyzine is the only antihistamine that works to control itching in cats.  It is by prescription only.  Atopica® (manufactured by Novartis Animal Health) is also another effective way to control itchy, red skin caused by atopic dermatitis.   Antibiotics may be needed to control secondary infections known as pyodermas.  Medicated shampoos are great and relieve some itching and lift off scale and other debris so that the skin can “breathe”.  Always bathe animals in cool water.  It also numbs the skin making the animal feel better.  Never use hot water.  Regardless if fleas or other parasites are seen, flea control should always be started.  Fleas can make a dog or cat suffering from grass allergies worse since the immune system is already primed and anything can set it off.  Many allergies are seasonal and I have treated many dogs for the same thing within a day or so the following year.  Long term management entails using special prescription hypoallergenic diets such as manufactured by Hill’s® Canine, Hills® Feline or Royal Canin® Canine and Royal Canin® Feline.  Environmental control is crucial.  This means control of fleas and other parasites by using professional sprays and foggers plus changing the home air handler filter more often.  Washing and or changing animal bedding also helps rid the “allergy hot spot” where an animal hangs out or sleeps.  Tired of it all?  Try investing in immunotherapy offered by your veterinarian via Heska.

With modern high tech veterinary medicine, the prognosis for the management of allergies has never been better!  Research is continually being done to make pet lives more full-filling through the advances in veterinary science.  Most dog and cat allergies can be controlled via numerous means and the overall prognosis is good.  In my 30 plus year career, I have only had to euthanize only a few animals suffering from chronic, debilitating atopic dermatitis.

Allergy

When anal gland material is not able to flow from the gland to the rectum, the gland enlarges and like a balloon will pop!  This usually creates a small opening about 4 mm in width at the base of the gland.  The body does this trying to rid the glandular contents to the outside since there is an obstruction the other way.

Clinical signs are similar to that of anal gland sacculitis.  Scooting on their back ends plus chewing at their front paws is characteristic.  The only difference is the presence of the opening or fistula opening up to the exterior skin surface.  The animal is in greater discomfort than a straight blocked anal sac.

Anal gland fistulas can be difficult to heal or resolve.  It is always a good idea to culture the glandular contents so that a specific antibiotic can be selected to cure the condition.

Diagnosis is usually made in a small or toy breed of dog that is scooting on its hindquarters.  Looking at the perineal area will show the fistula.

Treatment of the anal gland fistula is very similar to the basic gland impaction.  The anal gland materials are emptied from both sacs and the area is disinfected.  Dogs are put on an appropriate antibiotic for at least 2 weeks.  If the infection and gland are not healed, most veterinarians will put the dog on cyclosporine (immunosuppressant) that will aid in the sealing and healing of the anal gland fistula.  Glandular excision is also possible.

The prognosis for anal gland fistulas is excellent.  They may be difficult to heal but cyclosporine usually works in most cases.  In those where it doesn’t, the gland can be excised.

Anal gland discomfort is analogous to hemorrhoids in humans.  Both cause an intense inflammation and itch.  Dogs do not get hemorrhoids and humans do not have anal glands.

Anal Gland Fistula

Anemia is defined by a decrease in the amount or numbers of circulating red blood cells.  Without red cells, there could not be any life!  Anemias can be broken down into regenerative and non-regenerative anemias.  The former usually bounces back to normal levels and the latter does not.  A lot of cancers cause a non-regenerative anemia.  Causes of regenerative anemia are many.  Parasites such as babesiosis cause an anemia.  Poor diet and autoimmune disorders can cause an anemia.  Hemorrhaging of any type also does the same.  Anemia is a hallmark of many disease processes.

Inside of the red cell is a hemoglobin molecule which has iron at its center.  Around it, like spokes on a bicycle, are oxygen molecules.  Red cells carry this oxygen to all tissues in the body.  A decrease in their numbers cause the associated clinical signs.

The most visible sign of anemia is the general poor pallor noticed.  The gums will be pale as well as the conjunctiva.  The skin and foot pads may appear pale if the skin pigmentation is light.  A decrease in circulating red cells causes the heart and lungs to work harder hence their rates will be elevated.  An animal will be tired and no longer has the energy to do much hence lethargy is common.  Anorexia occurs since the dog or cat is too weak to go to the food bowl.  Other clinical signs occur dependent upon the disease in question.  For example, a dog with hemolytic anemia will usually have jaundice; a clinical sign of bilirubin buildup in the blood.  Bilirubin is a breakdown product of hemoglobin metabolism.

The most important lab test to perform is a CBC.  This informs the veterinarian of not only the numbers of circulating red cells but their size, shape and concentration of such (hematocrit).  Red cell morphology may change.  An example are the spherocytes (abnormal red cells) seen in auto-immune red cell diseases.  A chemistry profile and urinalysis also are important.  These two let the veterinarian know if any internal organs are affected. Further diagnostic tests dependent upon the suspected disease are done, such as radiographs.

Diagnosis made by noting the light pallor of tissues during a physical exam plus any lab work performed such as a CBC and other diagnostic tests.

Treatment of anemia is often based on the actual disease causing the anemia.  Regardless, treatment of the underlying anemia is the same.  If the red cell count is low, a dog or cat may be transfused with whole blood or blood byproducts.  If blood is not readily available; high molecular weight fluids such as dextran and hetastarch may be given IV.  Animals are also given iron, B12 injections to speed up red cell production if the bone marrow is cranking out red cell precursors.

The prognosis for general regenerative anemia is good.  Dogs and cats that suffer from autoimmune hemolytic anemias have a more guarded prognosis until their red cell counts start to climb.  Animals with a non-regenerative anemia such as cancer patients have a much more unfavorable prognosis.

Anemia

Anorexia simply means a lack of desire or appetite for food.  It is a hallmark of many diseases.  An animal may not have an appetite due to an underlying disease condition or unable to eat even though the dog or cat has a desire to eat.  Usually this entails a mechanical or physical ailment of the cervical and or head area.  Conditions that cause true anorexia are:  fevers of whatever origin, poisonings, liver and kidney disease, immune-mediated diseases, any process that causes vomiting and many types of neoplasms or cancers.  Types of anorexia due to mechanical or anatomical issues are:  a sore infected tooth or periodontal disease, enlarged salivary glands, stomatitis, lesions on the tongue or oral cavity.  Any type of pain or discomfort in the body or jaw can cause this type of anorexia.

All mammals have to eat & drink to obtain calories for all of the body’s metabolic processes to occur.  This maintenance is called the homeostatic response.  If food or water are not consumed, the body must find the calories elsewhere.  This leads to initial metabolism of fats than carbohydrates and muscle tissue.  This leads to chronic wasting and metabolic disorders.  Lack of water leads to dehyrdration at the cellular level and electrolyte issues.  Lack of fluids will lead to circulatory collapse and renal failure.  Bottom line is, that all mammals have to eat and drink to survive!

Clinical signs of anorexia are highly dependent on the actual cause of the anorexia.  In general, the majority of anorexic dogs and cats have lost weight.  Making matters worse, anorexic cats lose weight extremely fast.  They will literally lose weight overnight.  If a cat does not eat within 3 days, they will start to develop liver disease.  No ifs or buts about it.  In addition to the weight loss, many animals will be weak and lethargic.  Anorexia is not disastrous if it occurs for a day or so but long term it can be problematic.

A CBC and Chemistry profile are important to note any electrolyte imbalances secondary to the anorexia plus to point the way trying to figure out the original cause.  That primary cause of anorexia will determine any further lab work needed.

Figuring out the cause of anorexia is the most important part of the diagnosis.  Initially, a good history and physical exam and weight loss history will shine light on the diagnosis.

Diagnosis and Treatment of the primary cause of anorexia is crucial in reversing the overall medical problem but treatment of the anorexic condition is the same.  If the animal is vomiting, it is imperative that it be stopped.  If a dog or cat is vomiting, food and water can not stay down.  Drugs of choice include injections of Cerenia® or ondansetron.  Once the GI tract is quiet, providing appetite stimulants is appropriate.  Oral and or injectable B-complex vitamins, mirtazapine and or cyproheptadine are all used for this purpose.  Nutrical® is a high quality energy and vitamin packed gel that is given all the time to provide calories initially to the dog or cat.  Mixing that with some Hill’s® Prescription A/D works wonders.  That can be fed via a syringe or the animal can eat it if able to.  That diet is for both dogs and cats.  If an animal will not eat, an esophageal or stomach tube may be inserted.  One year ago, I had a severely anorexic dog recovering from Autoimmune Hemolytic Anemia and I brought from home chunks of rotisserie chicken from the night before.  The dog literally attacked my hands getting to the meat!  When, a dog or cat starts to eat on their own, you know they are on their way.

Prognosis of anorexia is dependent upon the original cause of it.  If it caused by a basic respiratory virus, than the prognosis is excellent.  If it is caused by an internal medical condition, than the overall prognosis depends upon the treatment of the primary cause.

Anorexia

Asthma is akin to a severe allergic reaction also known as allergic bronchitis.  Asthma is caused by a myriad of agents including:  dust, dust mites, pollen, smoke and many other irritants.  Anything can trigger an asthmatic attack and figuring out what that anything is, is the hard part.  Asthma also has a genetic route, being seen in Pomeranians and Himalayan cats.  Asthma is exacerbated in obese animals plus those that have a bracheocephalic skull type; like the Pug, Bulldog or Persian cat.

When an irritant enters the respiratory tree via inhalation it sets up a severe allergic reaction which translates into a dramatic inflammatory response once histamine takes over.  This sort of inflammation via a flea bite may be innocuous but when it is present in the airway (trachea, brochi and lungs) it can be life threatening.

The most common clinical signs are coughing and shortness of breath.  The pet is reluctant to move and is weak because insufficient oxygen is being sent to body tissues.  Breathing is labored and difficult.  In severe cases the tongue and mucous membranes turn a shade of blue known as cyanosis.  This means a severe depletion of oxygen in the body.  Many cats will open mouth breathe when in distress.  Excitation and panic can exacerbate these signs.

X-Rays and other imaging procedures are the first diagnostic procedures done.  This assesses the degree and severity of asthma.  A CBC and Chemistry profile are done to rule out infectious components and internal organ involvement.

Asthma is diagnosed by clinical appearance, physical exam and a good medical history.  The time of year is important as certain irritants (allergens) are predominant at certain times of the year.  The pet may have had a prior history about the same time of year.  Trying to figure out the exact allergen causing the asthma can be difficult but blood allergy tests can be performed such as provided by Heska®.

The first order of business is insuring a patent airway.  Make it easier for the animal to breathe.  This involves the use of parenteral and oral corticosteroids, bronchodilators (theophylline), adrenalin and nebulization therapy.  Some animals are so panicked that to decrease oxygen demand, they have to be lightly sedated (Telazol®).  Pure oxygen is administered to patients that are cyanotic. Once the animal is stable antibiotics and other supportive measures may be prescribed depending on the results of the blood work.  Home care involves administering inhaled or oral corticosteroids and avoidance of suspect allergens.  This means using air conditioning, changing the air handler filters more often and cleaning any bedding the animal lies on.  Vacuuming more often is recommended as well as losing weight if obesity is an issue. Some veterinarians will supply several injectable doses of adrenalin to be administered in acute home cases that reoccur.

The prognosis for acute asthma, that is uncomplicated, and recognized early, is quite good.  With chronic asthma, there is a scarring of the respiratory tract which narrows any openings through which oxygen passes; all the way from the bronchus down to the alveoli (final exchange of oxygen in the blood).  Prognosis for these patients is guarded.  Sometimes the sclerosis and over reactive inflammatory response may be fatal.

Asthma

An auricular hematoma is the accumulation of blood and blood by-products between the ear cartilage and skin of the ear.  It is most commonly caused by ear infections, trauma, ear mites and anything else that can irritate a dog or cats ear pinna (flap).

With the infection or irritant present in the affected ear, the animal constantly shakes its head trying to alleviate the discomfort in the ear.  Constantly doing this causes the rupture of capillaries in the ear allowing blood to flow in the area.  This produces a heavy, pendent ear.  This makes the dog feel even worse so it shakes its head even more.   A vicious cycle ensues.

All pets are bothered by auricular hematomas.  When presented, they will constantly shake their heads.  A swollen ear will be noticed.  An otic exam of the ear will show an infection, ear mites or the owner may mention that the pet was involved in a car accident while the owner was driving.  Some pets will also have a mild infection.  Blood is a magnet for bacterial growth hence often producing an additional infection to deal with.

A CBC is required to assess the degree of infection and or elevated white cell count.  Since the majority of these cases require repair under a light general anesthetic, a chemistry profile is in order to make sure the internal organs are functioning well before putting the animal under.

Diagnosis is by simply noticing the enlarged ear pinna.  Sometimes one ear is involved or both at the same time.  Sometimes one ear is affected than months later, the other.

Surgical repair is the only way to correct auricular hematomas.  Just draining the blood from the ear by using a syringe is a waste of time.  It might provide temporary relief but the ear fills up with blood again.  The goal in surgery is to relieve the pressure and contents of the blood buildup plus to allow drainage to continue post operatively.  The ear is bandaged tightly to prevent blood from flying all over the owners car and home.  It also cushions the ear making it more comfortable for the animal.  Antibiotics are always provided and an ear culture is taken at the same time.  If ear mites are present, they can be treated with ivermectin or other preparations.  Surgery is curative.  Sutures are removed in two weeks.

The prognosis for auricular hematomas are excellent.  They are all different but with surgical intervention all animals respond well.

Auricular Hematoma

Autoimmune hemolytic anemia is a disease involving the animal’s immune system.  Autoimmune disorders create antibodies to normal body tissues such as red cells.  These disorders could potentially effect any cell type but in this disorder the red cell antigens lock horns with circulating anti red cell antibodies.  The body is essentially attacking itself!  Most cases are caused by a mix up in the dogs immune system.  Erroneously, it targets normal red cells.  In a less common version the surface antigens of the red cell change tricking the immune system into thinking they are foreign, hence development of antibodies against them.  This can occur in cancers as well as parasitic disorders of the blood.

When circulating anti-red cell antibody confronts the surface antigen of a red cell, the two combine with the eventual destruction of the red cell in the blood vessel itself or in the spleen or liver.  This destruction releases the red cell hemoglobin where it is converted into bilirubin in the liver and than circulates in the animal’s circulatory system.  This destruction of red cells and accompanying metabolism of hemoglobin produces the majority of clinical signs seen in the dog.  Cats rarely develop this disease.

Clinical signs are associated with the resultant anemia.  Animals become debilitated early.  Signs of weakness, anorexia, pale mucous membranes, jaundice, dehydration and clotting difficulties (DIC) are common.  Oxygen depletion also makes the dog depressed and often acts like it is in another world.  Excess bilirubin spills over into the tissue giving it a yellow appearance (jaundice).  It is also secreted in urine giving it a dark yellow/orange appearance.  Since the red count is so low, the heart and respiratory rate elevate trying to compensate for a low saturated amount of oxygen.

The definitive lab work needed is:  CBC and Chemistry profile, Coombs test, clotting panel & urinalysis to start.  Most dogs have a hematocrit of about 18-20 when diagnosed and it creeps downward, even though treatment has commenced, eventually bottoming out.  Serum bilirubin is elevated and the urine is 4+ direct (conjugated) bilirubin.  Liver enzymes are often elevated and a CBC will show a marked regenerative anemia with spherocytes often present in a blood smear.  Because of the altered blood chemistry, DIC (Disseminated Intravascular Coagulopathy) is present.  The blood appears watery and will not clot.  This can be life threatening in itself.

Diagnosis of AIHA is made by a complete physical exam, blood work and the acute onset of the disease.  This is very common in tiny or small breeds such as:  maltese, toy poodles and wheaten terriers.

Treatment of AIHA is geared towards stopping the autoimmune destruction of red cell and clinical signs associated with red cell destruction.  Many of these animals are vomiting and intravenous doses of Cerenia® are required.  This condition is a medical emergency and all patients are hospitalized.  Intravenous fluids help maintain circulatory pressure and perfusion of vital organs plus maintain renal function.  Corticosteroids (usually dexamethasone SP) are administered daily to break the immune mediated red cell destruction.  Other supportive measures such as adding dextrose to the fluid line, caloric replacement and B12 vitamin supplementation are done.  Antibiotics may be administered if an infection is suspected.  Blood transfusions are contraindicated until the animals immune system has been suppressed.  Premature blood transfusion is like throwing gasoline on a fire.  Excess red cell antigen is thrown in and further red cell destruction ensues.  Under such conditions, it is not unusual for a transfusion to cause a drop of 4-5 points in an animals already low hematocrit.   Once the emergency has been alleviated (often taking several days) the animal’s red cell destruction tapers off and over time the dog starts feeling better.  In time animal’s start to drink on their own and develop a ravenous appetite!  It is very rewarding to turn these animals around.  Animals are discharged on oral prednisone and Azathioprine (Imuran®). The latter is extremely effective at suppressing the immune system and allows a lower dose of prednisone to be used so as to prevent iatrogenic Cushing’s syndrome.  At home, owners need to maintain a weekly CBC visit to the hospital, insuring that the hematocrit continues to climb.  Post hospital management usually takes about 4 months.  The long term goal is to wean the dog off of all drugs with monthly or quarterly CBC’s for the duration of the animal’s life.

The prognosis for AIHA is guarded until the immune mediated reaction stops and the hematocrit starts to rise.  It becomes more favorable as the animal responds to therapy and starts to eat and drink on its own.  With continued therapy at home and periodic CBC evaluations the prognosis is good as long as the dog stays in remission and its immune system stays quiet.  A normal high quality of life can be expected.

Autoimmune Hemolytic Anemia