Diseases #26
Pannus is also known as chronic superficial keratitis. It is a chronic inflammation of the cornea; which is the front clear part of the eye. The cause is an immune-mediated reaction and is seen classically in German Shepherd dogs.
In pannus, an immune-mediated reaction is thought to occur. This inflammatory response leads to chronic corneal inflammation that can lead to blindness if left untreated.
The most common sign associated with pannus is a red, fleshy piece of tissue seen over the left or right eye. Many times, both eyes are involved. These lesions are usually seen on the outer corners of the eye farthest from the nose (lateral canthus). Over time, the lesions start to advance over the cornea and become pigmented. This impairs sight and dogs can have impaired vision if not corrected.
An eye exam will be performed and a fluorescein strip will be employed to assess the integrity of the cornea and rule out corneal ulcers. All animals should be screened for glaucoma with a tonometer.
Diagnosis is made by physical exam and the presence of the typical corneal lesions present; particularly if the animal presented is a German Shepherd.
Pannus can not be cured but it can be controlled if treated before it becomes chronic. Most dogs are place on a topical corticosteroid for life. Topical antibiotics may be prescribed if there is a secondary bacterial infection. Dogs respond well with treatment. Signs may actually regress but the treatment must continue for the remainder of the animal's life.
The prognosis for pannus is good. As long as medications are put in the eye, as directed, signs of pannus can be arrested for a prolonged period of time.
Parainfluenza is one of the common viral causes of tracheobronchitis in the dog. It is also known as one of the causative agents of kennel cough.
Parainfluenza is commonly seen in young animals that are kept in close quarters such as boarding facilities or shelters. Most young, unvaccinated animals have an immature immune system and frequently get the virus from respiratory droplets or secretions that transmit it from one animal to the next.
Clinical signs in dogs are respiratory in nature. Animals may have a fever, be off their appetite, a hacky cough plus eye and nose secretions. Some animals may have conjunctivitis. Some animals may be exposed to the virus and not demonstrate any clinical signs! They develop antibodies that neutralize the virus.
A CBC is always run to keep an eye on the white cell count. Young animals are always susceptible to secondary bacterial infections. Radiographs may be taken if the bronchi are suspected of being involved.
Diagnosis of parainfluenza is made by historical findings and a physical exam. Often by just touching the larnyngeal or tracheal areas, dogs will produce a severe, hacky cough. Chest films will also demonstrate characteristic tracheal and brochial lesions.
The goal of treatment is supportive in nature. Most animals are young and require fluid therapy and antibiotics to prevent secondary bacterial infections. In basic cases, animals are discharged on antibiotics and cough suppressants. In severe cases, associated with bronchitis, animals are always hospitalized with intravenous fluids and nebulization that is performed at least 4-5 times per day initially. They should be kept separate from other canine patients due to the contagious nature of the disease. Animals get exhausted from constant coughing. Butorphanol is routinely used to suppress cough and allow an animal to rest. Dogs that recover are discharged on antibiotics and Hycodan® syrup for cough. It is important that those animals be rechecked with followup X-Rays.
The prognosis for parainfluenza is excellent. In many dogs, the disease is self limiting and often does not produce any serious clinical signs. Animals that are aggressively treated usually do well.
The key is preventing parainfluenza in the first place. Parainfluenza is part of the core vaccine program that is administered to all dogs beginning at 6-8 weeks. This program includes subsequent boosters. The vaccine protocol should be followed exactly as prescribed by the veterinarian.
Paralysis is the inability to move a limb, several limbs or even all limbs of an animal's body. Certain internal organs can become paralyzed such as the larynx. Paralysis can be caused by many things. One of the most common is car accidents (trauma). Others include: tick bites in Coonhound dogs, tumors, disk prolapses, firearm wounds, discospondylitis, congenital, distemper virus, any disease of the spinal cord and myastenia gravis amongst others.
Many times we take for granted our ability to get out of bed and walk to the kitchen. That basic motion requires a complex mechanism to be continuously repeated. The Central Nervous System is composed of the brain, brain stem and spinal cord. Spinal nerves leave the cord and innervate (connect to) many different types of tissues including muscle. If there is an impediment to the flow of those nerve impulses from the brain to the spinal cord to the tissue; paralysis can be the result. Paralysis is the inability to move a limb. Paresis is a weakening or decrease in the ability to move a limb. Certain parts of the body become paralyzed depending upon the location of the spinal lesion. Lesions in the lumbar vertebrae may lead to paralysis of the hind limbs. This must be differentiated from circulatory issues such as a saddle thrombus in cats.
Every paralyzed animal is different. In general terms, a paralyzed animal is not able to move the affected limb. There may be some sensation but the animal can not move that part of the body. In spastic paralysis of the hind limbs, the quadricep muscles are in a constant state of contraction and the animal holds its hind quarters underneath itself. Other animals have a flaccid paralysis in which the muscles are limp and weak and remain where they are. The problem is not just the clinical signs of paralysis but the inability of the animal to get to a food or water bowl. The inability to go out to the bathroom means an animal may soil itself unintentionally. It is the lack of mobility that leads many animals to be put down. That is the last resort, as I will discuss under treatment.
Radiographs do not show spinal cord damage except a complete severing of the spinal cord secondary to extreme trauma as a result of being hit by a car. They may also show a decrease in the intervertebral disk space. Myelograms and CT scanning may show lesions. A CBC and Chemistry profile plus other tests may be done to rule out individual causes of paralysis.
A diagnosis of paralysis may be made during physical exam but figuring out its cause can be difficult. This will take a lot of time. The client has to tell the veterinarian of any trauma to the animal. Did it get hit by a car? Did it fall down a flight of stairs? Did the animal travel where ticks were numerous? It is just those types of questions that need to be answered to try to find the actual cause of paralysis. Many times a history can not provide that, so many tests will have to be performed to rule out the many causes. The veterinarian will also test the reflexes in the affected limb. Reflexes will be checked on top of the lower limb as well on the bottom of the lower limb. The presence of some withdraw of the limb on any testing is good news.
Treatment of paralyzed animals can be difficult. One of the most common questions veterinarians get asked in these situations is if the animal will ever have normal use of the limb(s) again. My usual answer is that "I do not know". That is an honest answer but does not stop me from trying to make that happen!
To treat paralysis is to understand the underlying cause of the issue. If it is a disk causing spinal pressure, a laminectomy or corticosteroids may be needed to take pressure off of the spinal roots. If the paralysis is caused by ticks, extreme measures are taken to rid the animal and environment of ticks and provide supportive care. Animals with paralysis that are unable to urinate or defecate on their own are difficult cases. In my experience, if an animal is going to regain reflexes and an ability to ambulate, an animal needs a period of 2 weeks to show improvement. Other therapies are acupuncture that may provide benefit to the animal.
If the animal remains paralyzed it will require a lot of dedication from the owner. The animal needs to be kept on a thick, soil proof mat that comforts the animal and prevents "bed sores" from developing. Animals can not turn over and sores may be produced by the pressure of the body on a hard surface such as a wood floor. Food and water bowls need to be kept close and anchored to the floor. They may be easily tipped over by animals attempting to get to them.
Do not give up on animals that are paralyzed in the hind quarters; even if they are fecal and or urinary incontinent! Think about purchasing or leasing a cart from K9 Carts. I once applied a cart to a dachshund that was built by my brother. It was amazing to see the dog not only immediately steer itself on the clinic sidewalk but to run over the curb so it could get to its owner! The motion of the dog and the pressure applied by the supportive belts is often enough to stimulate defecation or urination. Most veterinarians will show you how to manually empty a bladder on a dog or cat.
The prognosis for paralysis varies with the cause of the problem. Animals that have suffered a complete separation or luxation of the spinal cord have a poor prognosis. Even if the paralysis can not be treated or corrected, animals can lead a happy life; as long as the owner is committed to taking tender care of the pet as it ages.
Parvovirus is a debilitating virus that is highly contagious and is spread rapidly amongst the unvaccinated canine population.
Over the years, there have been several serotypes of Parvovirus but the one thought causing the majority of canine disease is CPV-2b. Regardless of the serotype, it is a debilitating virus that affects all unvaccinated dogs. Dogs under the age of 6 months are the most commonly infected. Doberman Pinscher and Rottweiler dogs, or their crosses, get this disease more than any other breed of dog. A lot of this is based upon the immune status of the animal. This is under genetic control.
Parvovirus is spread from one animal to another via the oral-fecal route. Feces contaminated with the virus are ingested by the unvaccinated dog. What makes Parvo extremely dangerous is that the virus can be carried on the soles of shoes and other inanimate objects such as food and water bowls. This can transfer the virus readily from an infected household to another. Making matters worse, is that Parvovirus does not act like most viruses. The majority of viruses can not survive if there isn't a new host for it to replicate in. They die off in a few days. Not Parvo. It can sit in a snow drift for months. When the snow melts, the virus is still active!! That is why I treated a bunch of cases in late winter in my OH practice.
The Parvo problem really started in full force in 1979. I started practice in 1981 and half of a days case load was treating Parvo dogs. Every dog was coming down with it. It still exists today, particularly in shelters, but nothing like it was 30 years ago. You can give thanks to vaccines that were introduced around 1983. What we did figure out, before Parvovirus vaccine was available, that dogs could be immunized against Parvovirus by injecting them with the Cat Distemper vaccine!! It worked and prevented the disease in many a dog as a result of that heads up thinking!
The clinical signs associated with Parvovirus are usually associated with a hemorrhagic gastroenteritis. The virus replicates in the cells lining the small intestine. These cells die leading to clinical signs. Vomiting and a foul smelling bloody diarrhea are the usual initial signs. Parvo hits a dog overnight. The period of incubation is usually 5-7 days. Once a dog shows signs it goes downhill rapidly. The presence of parasites or other concurrent infections will drag a Parvo dog down even quicker. Bacteria will produce toxins that can damage kidney function and make the dog extremely ill, even septic. As the disease progresses, dehydration and further sepsis ensue. Death is rapid; usually within 24-72 hours of the first typical clinical signs. In a very few puppies there will be an immediate death due to a severe myocarditis; a severe infection of the cardiac muscle. I have only seen a few of these in my career.
Once a Parvovirus dog is presented blood work is immediated done to show the extent of the viral infection. A CBC and Chemistry profile are always performed. A low white cell count is characteristic of all Parvo dogs. There may be a neutrophilic left shift indicating a concurrent bacterial infection. These infections can be life threatening because all Parvo dogs have an absolute obliterated immune system. Not all dogs present with hemorrhagic enteritis have Parvovirus. There is an ELISA (CITE) test that is performed in most animal hospitals to confirm the diagnosis. Radiographs may also be taken to check the gastrointestinal integrity.
Parvovirus is suspected in ANY dog, but particularly those under 6 months of age, that has not been vaccinated and shows signs of hemorrhagic enteritis. Some just present sick but almost always are limp as a rag and have pale gums indicating impending circulatory collapse. If it is a Doberman Pinscher or Rottweiler, it probably IS Parvo. I have treated countless LITTERS of Dobermans or Rottweilers for Parvovirus over the years. The diagnosis can be confirmed by an in house Parvovirus ELISA test.
Treatment of Parvovirus is supportive. There is no specific drug that will cure the viral infection. All animals receive intravenous fluids that build up the circulatory system and helps to maintain kidney function. Animals are treated for vomiting and diarrhea. Parvovirus is extremely painful and all dogs are administered pain killers such as butorphanol. This is a great drug that alleviates a lot of that "visceral pain". Antibiotics are usually given to treat and or prevent bacterial infections that almost always show up in any immunosuppressed animal; particularly puppies that have an immature immune system to begin with.
Most dogs respond to treatment within 48 hours. Easily digested diets and small amounts of oral fluids are administered to eventually wean the animal off of intravenous fluids. Dogs are sent home on medical prescription diets or they can make their own chicken and rice meals for the dog. Sports drinks are also recommended to help replenish lost electrolytes. Freezing a sports drink and tossing a few ice cubes into the animal's water bowl will prevent over consumption of fluids. Antibiotics and other supportive products are always prescribed for home use.
The prognosis for most dogs with Parvovirus is good. My track record over the years is about 85% saved. The key is getting a dog with early clinical signs to an animal hospital. Do not wait over night because the animal may be far too gone in the morning. It is a medical emergency.
Half the battle is treating the dog, the other half is getting rid of the virus and starting a vaccine program for the sick animal plus any dogs that the sick animal may have been in contact with.
- Getting rid of the virus in the home and yard area is crucial. A solution of one part bleach to 3 parts water will kill the virus. All floors should be disinfected along with animal toys, water and food bowls or anything else the animal may have been exposed to.
- Pick up all feces in the yard to prevent other animals in the neighborhood from picking up the disease.
- All healthy pets that were in contact with the sick dog should immediately be taken to a veterinary office for exam and vaccination against the disease.
- If a pet dies, DO NOT introduce a new pet into the home for at least 4-6 weeks. Do not let any dog from anywhere enter the home for that period.
- Dogs that recover from Parvovirus may very well have a lifetime immunity to the virus but it is not worth a challenge to prove it! Wait a minimum of one month before the puppy is vaccinated for the disease. The animal's immune system has just basically been wiped out by the disease so time is needed to build it up again.
- There is an issue of maternal antibody (passive) interfering with initial immunization but all dogs should receive their first Parvovirus immunization between 6-8 weeks of age. It than is boostered every 3-4 weeks UNTIL the dog is at a MINIMUM of 16-18 weeks of age. It is than boostered annually. It is crucial that dog owners comply with and finish a complete vaccination protocol. It is very well known that dogs that have not received boosters after 14 weeks have a 25% chance of picking up the disease. I have seen this numerous times.
- People can not get Canine Parvo Virus. I mentioned that dogs used to be vaccinated against Parvo by using the Cat Distemper vaccine before the current vaccine became available in the early 1980's. Dogs can not get Feline Distemper and cats can not get Canine Parvovirus.
The patella or kneecap protects the knee from injury and is also embedded in the tendons that connect the quadricep muscles of the thigh to the tibial crest of the tibia. A patellar luxation is one that is caused by the patella slipping out of its normal location on the distal femur. The cause of this is almost always congenital. It is seen most frequently in: Toy Poodles, Chihuahuas, Maltese, Yorkshire Terriers and other toy breeds or their crosses.
In an animal with congenital patellar luxation, the patella that normally resides in a groove on the lower femur is extremely shallow allowing the patella to slide over to one side or the other. Some cases are permanent on one side or the other. Some may flip over to one side and than reseat itself back in the femoral groove. This is known as a patellar subluxation and almost always is medial in presentation. That means the patella slips to the inner side of the dogs hind leg.
Animals with patellar luxation usually present with a history of intermittent or constant lameness in the affected hind limb. Some animals will hold their leg out to the side. In severe cases, animals will look like they have just gotten off of a horse. They actually look bowlegged.
Orthopedic specialists may perform a CT scan as well as assess general radiographs for signs of bone dysplasia elsewhere.
Diagnosis of a patellar luxation is diagnosed by manual palpation of an unstable or unseated patella out of its normal femoral groove. Other imaging procedures will aid in the diagnosis.
Treatment of patellar luxations varies with the severity of the condition. This disease is staged in 4 different ways with grade 1 being the least problematic to stage 4 where the patella can not and will not return to its femoral groove. Many toy breeds may often require mild anti-inflammatory drugs if an animal hurt itself by running or climbing stairs. This is often the case in toy breeds. It and observation are the usual ways to go. In stage 2 through 4, specialists may perform surgical procedures that deepen the groove where the patella sits or move the tibial crest where the quadricep muscles attach. This latter procedure (transposition of the tibial crest) realigns the anatomy.
The prognosis for patellar luxations is generally good. Even if surgery is not performed, animals live a normal happy life. One great thing about dogs and cats that I have mentioned to clients over the years is that animals are lucky to be able to run around on 4 limbs! If one is affected, it usually does not slow an animal down!! Humans? You bet it will slow you down!
As the dog ages, the remaining cartilage that should hold the patella in place erodes over time. This can set up an arthritic process as the animal ages. These signs can be controlled with anti-inflammatory drugs such as Rimadyl®.
The ductus arteriosis is the vessel that carries blood from the aorta to the pulmonary artery in the unborn animal. Normally, this vessels closes when the animal is born. In patent ductus arteriosis it does not. This is a congenital defect and animals are born with it.
The ductus arteriosis plays an important functional role in the unborn animal. A dogs lungs are not functional while in the amniotic sac inside the mother. Hence, deoxygenated blood can not pass through them. Blood flows from the aorta to the puppies pulmonary artery than to the mother's circulation to get oxygenated again than back to the puppy. When the animal is born and the lungs expand, the ductus arteriosis is supposed to close and start the normal flow of deoxygenated blood from the pulmonary artery to the lungs for oxygenation. When this does not completely seal, a fair amount of blood is diverted from the aorta thru the ductus to the pulmonary artery. This puts extra strain on the left side of the heart leading to eventual congestive heart failure. This is a very common genetic disorder seen in females the majority of the time.
Most animals that are born or very young rarely show signs of patent ductus arteriosis since they are so small. Even though there is a defect, the animal is okay since there is enough oxygen to go around. As the animal starts to gain weight, it tires more frequently, does not have the typical energy of a puppy, it may cough and have difficulty breathing. A characteristic machinery murmur is produced over the mitral valve (left heart valve).
The most common lab procedures are producing several radiographs to observe typical heart changes. The best approach is a cardiac ultrasound where blood flow can be observed.
Hearing an intense, loud machinery murmur over the left side of the heart is almost diagnostic. It can be confirmed with a cardiac ultrasound where blood flow can easily be observed.
The only treatment is surgical. Before surgery, supportive care like oxygen should be administered so that the animal is at the best anesthetic risk as possible. This is thoracic surgery and requires Positive Pressure Ventilation (PPV). Without that, the lungs would collapse during surgery. The patent ductus arteriosis is ligated (tied off) and dogs can resume normal activity in about 2 weeks.
The prognosis for animals born with PDA is very good; as long as it is diagnosed before the onset of signs of congestive heart failure. The animal should be stabilized and surgery undergone as soon as possible. Animals than can lead a normal life.