Vestibular Disease

Email this article Vestibular Disease

 

What on Earth is the Vestibular Apparatus?

In a nutshell, the vestibular apparatus is the neurological equipment responsible for perceiving your body’s orientation relative to the earth (determining if you are upside down, standing up straight, falling etc.), which inform your eyes and extremities how they should move accordingly.

The vestibular apparatus allows us to walk, even run, on uneven ground without falling, helps us know when we need to right ourselves, and allows our eyes to follow moving objects without becoming dizzy.

Copyright VIN 2012

There are two sets of receptors involved: one to detect rotational acceleration (tumbling or turning) and one to detect linear acceleration and gravity (falling and letting us know which direction is up and which is down). Both receptors are located in the middle ear.

Rotation is detected using the three semicircular canals as shown above. These canals contain fluid called endolymph, which moves as your head rotates. Tiny neurological hair cells project into this fluid and are stimulated by the flow. These hair cells are part of sensory nerves that carry the appropriate message to the cerebellum (part of the brain that coordinates locomotion) and to four vestibular nuclei in the brain stem.

Up and down orientation stems from small weighted bodies called otoliths, which are located within the utricle and saccule of the middle ear. These small otoliths move with gravity within a gelatinous medium, stimulating small hair cells as they move similar to the situation described above.

From these centers, instructions are carried by nerve cells to the legs, neck, and eye muscles so that we may orient ourselves immediately. The information about being upside down (or in some other abnormal orientation) is also sent to the hypothalamus (an area of the brain) so that we can become consciously aware of our position. The information is also sent to the reticular formation (another area of the brain – a sort of a volume control on our state of wakefulness. In this way, if we are asleep and start to fall, the vestibular stimulations would wake us up. This is also why rolling an anesthetized animal from side to side is used to hasten anesthetic recovery).

The Signs of Vestibular Disease

A head tilt is seen on Milou, a dog with vestibular disease. At the time this photo was taken Milou was not able to walk, but was nearly normal within 4 days.

If there is trouble in the vestibular apparatus, then you may not properly perceive your orientation. To put it more simply, you won’t know which way is up, whether or not you are standing up straight or slanted, and you’ll feel dizzy.

The following are signs of vestibular disease:

  • Ataxia (lack of coordination without weakness or involuntary spasms – in other words, stumbling and staggering around).
  • Motion sickness.
  • Nystagmus (back and forth or rotational eye movements. The movements will be slower in one direction. This is the side where the neurologic lesion is likely to be; however, nystagmus is named according to the direction of the fast component – i.e. there may be left nystagmus but the lesion is probably on the right side of the vestibular apparatus.)
  • Circling (usually toward the side of the lesion).
  • Head tilt (usually toward the side of the lesion).
  • Falling to one side (usually toward the side of the lesion).
  • Trouble with other nerves controlling the head and face.

Causes of Vestibular Disease

The most common causes of vestibular disease are:

  • Middle ear infection
  • Brain lesion
  • Idiopathic (unknown)

For more info go to veterinarypartner.com

Heartworm

What Happens in Heartworm Disease
By Wendy C. Brooks DVM, DABVP

 

Heartworm Disease vs. Heartworm Infection

Before reviewing the clinical signs seen in heartworm disease, an important distinction must be made between heartworm disease and heartworm infection. Heartworm infection by definition means the host animal (generally a dog) is parasitized by at least one life stage of the heartworm (Dirofilaria immitis). Dogs with heartworms in their bodies do not necessarily have adult worms in their hearts; they may have larval heartworms in their skin only. Dogs with heartworms in their bodies are not necessarily sick, either. Dogs with only larvae of one stage or another are not sick and it is controversial how dangerous it is for a dog to have only one or two adult heartworms. These dogs are certainly infected but they do not have heartworm disease.

On the other hand, dogs with heartworm disease are sick. They not only have the infection but they have any of the problems listed below because of it. Fortunately, heartworm disease is both treatable and preventable. Further sections of this web page explain both treatment and prevention; we will now discuss the damage heartworms can do to a dog’s body.

For more info go to veterinarypartner.com

Fleas

 

Print this article  Email this article

Fleas: Know your Enemy

 

Despite numerous technological advances, fleas continue to represent a potentially lethal plague upon our pets. Current products are effective so there is little reason for this; the problem seems to be one of understanding.
There are over 1900 flea species in the world. Pet owners are concerned with only one: Ctenocephalides felis, the cat flea. This is the flea that we find on our pets (cats, dogs, rabbits, and other species) in 99.9% of cases and in order to understand how to control the damage caused by this tiny little animal, you should learn all you can about it.

What Kind of Damage Can Fleas Cause?

It would be a grave mistake to think of the flea as simply a nuisance. A heavy flea burden is lethal, especially to smaller or younger animals. The cat flea is not at all selective about its host and has been known to kill dairy calves through heavy infestation. Conditions brought about via flea infestation include:

• Flea Allergic Dermatitis (fleas do not make animals itchy unless there a flea bite allergy)

• Flea Anemia

• Feline Infectious Anemia (a life-threatening blood parasite carried by fleas)

• Cat Scratch Fever/Bartonellosis (does not make the cat sick but the infected cat can make a person sick)

• Common Tapeworm infection (not harmful but cosmetically unappealing)

Fleas can kill pets.

This is so important that we will say it again: Most people have no idea that fleas can kill. On some level, it is obvious that fleas are blood-sucking insects but most people never put it together that enough fleas can cause a slow but still life-threatening blood loss. This is especially a problem for elderly cats who are allowed to go outside. These animals do not groom well and are often debilitated by other diseases. The last thing a geriatric pet needs to worry about is a lethal flea infestation and it is important that these animals be well protected.
Also consider that in about 90% of cases where an owner thinks the pet does not have fleas, a veterinarian finds obvious fleas when a flea comb is used. Despite the TV commercials, the educational pamphlets, the common nature of the parasite, there are still some significant awareness problems and a multitude of misconceptions.

For more info go to veterinarypartner.com

Diabetes Mellitus

* Diabetes Mellitus Center

 

What is Diabetes Mellitus?

In order to understand the problems involved in diabetes mellitus, it is necessary to understand something of the normal body’s metabolism.

Illustration by Wendy Brooks, DVM
Illustration by Wendy Brooks, DVM

 

The pancreas is nestled along the stomach and small intestine. It secretes digestive enzymes into the small intestine but it also secretes hormones into the bloodstream to regulate blood sugar.

The cells of the body require a sugar known as glucose for food and they depend on the bloodstream to bring glucose to them. They cannot, however, absorb and utilize glucose without a hormone known as insulin. This hormone, insulin, is produced by the pancreas. Insulin is like a key that unlocks the door to separate cells from the sugars in our bloodstream.

Glucose comes from the diet. When an animal goes without food, the body must break down fat, stored starches, and protein to supply calories for the hungry cells. Proteins and starches may be converted into glucose. Fat, however, requires different processing that can lead to the production of ketones rather than glucose. Ketones are another type of fuel that the body can use in a pinch but the detection of ketones indicates that something wrong is happening in the patient’s metabolism. Ketones may therefore be detected in the urine of starving animals because of massive fat mobilization is required for ketone formation. Ketones can also be detected in diabetic ketoacidosis, a severe complication of unregulated diabetes so it is helpful to periodically monitor for ketones in a diabetic patient’s urine. The point is, for now, that in times of extreme fat burning (such as in starvation), ketones are a byproduct.

For more info go to veterinarypartner.com

Dentistry

Periodontal Disease in Pets

More than 85% of dogs and cats older than four years have periodontal concerns. There are four periodontal types of tissue: the gingiva (gum), cementum, periodontal ligament, and alveolar supporting bone.

Periodontal disease starts when plaque forms; plaque is a transparent adhesive fluid composed of mucin, sloughed epithelial cells and aerobic, and gram positive cocci. Plaque starts forming two days after dental cleaning. If the plaque is not removed, mineral salts in the food can precipitate to form hard dental calculus. The calculus is irritating to the gingival tissue, changing the pH of the mouth and allowing bacteria to survive subgingivally. By-products of these bacteria “eat away” at the tooth’s support structures, eventually causing the tooth to be lost in some cases.

There are two common grading systems commonly used to classify the degree of periodontal disease. The mobility index evaluates the looseness of the tooth. With Class I mobility, the tooth moves slightly. Class II is when a tooth moves less than the distance of its crown width. With Class III mobility the tooth moves a distance greater than its crown width. Class III teeth have lost more than 50% of their support and in most cases should be extracted.

Periodontal disease can also be staged:

Stage 1 gingivitis

Stage 2 early periodontitis-less than 25% support loss

Stage 3 established periodontitis- between 25%-50% support loss

Stage 4 advanced periodontitis- greater than 50% support loss

When periodontal disease is not treated, subgingival bacteria can continue to reproduce, creating deeper periodontal pockets through bone destruction.
Eventually, this progression can cause tooth loss and other internal medicine problems.

Imagine a giant tooth sitting in a 10-foot garbage can containing mud and industrial waste. Continue to pretend it is your job to clean the tooth and you are only supplied with equipment 5 feet long. What happens? The top is cleaned and the bottom is allowed to remain in the toxic waste until it eats through the can. How can you solve this problem? Try opening the side of the can to clean the waste out in order to save the tooth. That is the essence of periodontal surgery.

For more info go to veterinarypartner.com

Cancer

Fighting Cancer

Cancer is the most common natural cause of death in dogs in the United States and Canada. And while the diagnosis is one that every pet lover dreads, the fact is that canine cancer is more treatable than ever before. Even better: Veterinarians now know more about what steps can be taken to help prevent the dreaded disease.

To reduce the risk of cancer in your pet:

  • Adopt a healthy dog who fits into your lifestyle. If you’re considering a purebred dog, know that cancer hits some breeds more than others. Do your homework before deciding on a breed, and work with a reputable breeder who is aware of the health problems of the breed and is working to reduce those problems. Because of the breed-specific health problems in purebred dogs, some believe it’s better to bring a mixed-breed into your home. (Although there’s no guarantee that a mixed-breed dog won’t be stricken with cancer, of course.) Shelters and rescue groups will be happy to help you find your best pet, no matter your choice.
  • Make sure your dog has good nutrition, weight-management and plenty of exercise. Help your dog to maintain a fit body for life. A fit dog will have a wasplike waist and a tucked-in abdomen.
  • Feed your dog a high-quality diet made by a reputable company or a home-prepared diet prepared with the help of your veterinarian. Start with the amount of food recommended for your dog and adjust accordingly with how your pet’s body responds. Cut down on extra calories by substituting baby carrots as treats or by adding volume to meals with green beans.
  • Consider adding omega-3 fatty acids (also known as n-3, found in fish oils and other sources) to potentially to reduce the risk of developing cancer. Add regular exercise, and you and your dog will benefit with greater health and a closer, more vibrant relationship.
  • Spay or neuter your dog early in life. Spaying and neutering have been shown to be an effective method of preventing cancer. Spaying has a significant effect of preventing breast cancer if it is done before a dog goes into her first heat cycle.
  • Choose clean living for your dog. Eliminate exposure to environmental carcinogens such as pesticides, coal or kerosene heaters, herbicides, passive tobacco smoke, asbestos, radiation and strong electromagnetic fields. Each one of these factors has been suggested to increase the risk of cancer in your dog (and in you).

For more info go to veterinarypartner.com

Arthritis

Degenerative joint disease is the number one cause of chronic pain in dogs and cats.  The condition is the result of long-term stresses on a joint, either resulting from an old injury or from natural development of a poorly conformed joint.  While surgery may be able to help in some situations, most of the time the degeneration of the joint cannot be reversed and treatment focuses on preventing progression of damage. Numerous products are available; some are best combined with others and some cannot be combined.  What we do know is that arthritis pain is best addressed by what is called a multi-modal approach, meaning that several approaches combined yield better results than any single therapy.  Here, we focus on medications.

Medications for arthritis pain are divided into two groups: Slow-acting drugs and fast-acting (non-steroidal anti-inflammatory drugs and cortisone-type drugs).

read more at  veterinarypartner.com

Ruptured Anterior Cruciate Ligament

Ruptured Anterior (Cranial) Cruciate Ligament

 

First, the Basics

The knee is a fairly complicated joint. It consists of the femur above, the tibia below, the kneecap (patella) in front, and the bean-like fabellae behind. Chunks of cartilage called the medial and lateral menisci fit between the femur and tibia like cushions. An assortment of ligaments holds everything together, allowing the knee to bend the way it should and keep it from bending the way it shouldn’t.

There are two cruciate ligaments that cross inside the knee joint: the anterior (or, more correctly in animals, cranial) cruciate and the posterior (in animals called the caudal) cruciate. They are named for the side of the knee (front or back) where their lower attachment is found. The anterior cruciate ligament prevents the tibia from slipping forward out from under the femur.

Finding the Rupture

The ruptured cruciate ligament is the most common knee injury of dogs; in fact, chances are that any dog with sudden rear leg lameness has a ruptured anterior cruciate ligament rather than something else. The history usually involves a rear leg suddenly so sore that the dog can hardly bear weight on it. If left alone, it will appear to improve over the course of a week or two but the knee will be notably swollen and arthritis will set in quickly. Dogs are often seen by the veterinarian in either the acute stage shortly after the injury or in the chronic stage weeks or months later.

The key to the diagnosis of the ruptured cruciate ligament is the demonstration of an abnormal knee motion called a drawer sign. It is not possible for a normal knee to show this sign.

The Drawer Sign

The veterinarian stabilizes the position of the femur with one hand and manipulates the tibia with the other hand. If the tibia moves forward (like a drawer being opened), the cruciate ligament is ruptured.

Another method is the tibial compression test where the veterinarian stabilizes the femur with one hand and flexes the ankle with the other hand. If the ligament is ruptured, again the tibia moves abnormally forward.

If the rupture occurred some time ago, there will be swelling on side of the knee joint that faces the other leg. This is called a medial buttress and is a sign that arthritis is well along.
It is not unusual for animals to be tense or frightened at the vet’s office. Tense muscles can temporarily stabilize the knee, preventing demonstration of the drawer sign during examination. Often sedation is needed to get a good evaluation of the knee. This is especially true with larger dogs. Eliciting a drawer sign can be difficult if the ligament is only partially ruptured so a second opinion may be a good idea if the initial examination is inconclusive.

Since arthritis can set in relatively quickly after a cruciate ligament rupture, radiographs to assess arthritis are helpful. Another reason for radiographs is that occasionally when the cruciate ligament tears, a piece of bone where the ligament attaches to the tibia breaks off as well. This will require surgical repair and the surgeon will need to know about it before beginning surgery. Arthritis present prior to surgery limits the extent of the recovery after surgery though surgery is still needed to slow or even curtail further arthritis development.

How Rupture Happens

Several clinical pictures are seen with ruptured cruciate ligaments. One is a young athletic dog playing roughly who takes a bad step and injures the knee. This is usually a sudden lameness in a young large-breed dog.

A recent study identified the following breeds as being particularly at risk for this phenomenon: Neapolitan mastiff, Newfoundland, Akita, St. Bernard, Rottweiler, Chesapeake Bay retriever, and American Staffordshire terrier.

On the other hand, an older large dog, especially if overweight, can have weakened ligaments and slowly stretch or partially tear them. The partial rupture may be detected or the problem may not become apparent until the ligament breaks completely. In this type of patient, stepping down off the bed or a small jump can be all it takes to break the ligament. The lameness may be acute but have features of more chronic joint disease or the lameness may simply be a more gradual/chronic problem.

For more info go to veterinarypartner.com

Obesity

 

Print this article  Email this article

Obesity

 

Obesity has become an extremely important health problem in the Western world, not just for humans but for dogs and cats as well. Obesity in pets is associated with joint problems, diabetes mellitus, respiratory compromise, and decreased life span; recent estimations suggest that up to 35% of dogs and cats in the U.S. suffer from obesity.

Why Obesity is Bad

A common justification for over-feeding treats is that a pet deserves a higher quality of life as a trade off for longevity. While this might on some level makes sense (after all, a pet munching on a treat is certainly getting a great deal of satisfaction from doing so), the other consequences do not make for higher life quality in the big picture. Here are some of problems that obese animals must contend with while they are not enjoying their treats and table scraps.

Arthritis
The over-weight animal has extra unneeded stress on joints, including the discs of the vertebrae. This extra stress leads to the progression of joint degeneration and creates more pain. Weight management alone decreases and can even eliminate the need for arthritis medications. The problem is compounded as joint pain leads to poorer mobility, which in turn leads to greater obesity.

Respiratory Compromise
The obese pet has a good inch or two of fat forming a constricting jacket around the chest. This makes the pet less able to take deep breaths as more work is required to move the respiratory muscles. Areas of the lung cannot fully inflate, so coughing results. The pet also overheats more easily. Many cases of tracheal collapse can be managed with only weight loss.

Diabetes Mellitus
Extra body fat leads to insulin resistance in cats just as it does in humans. In fact, obese cats have been found to have a 50% decrease in insulin sensitivity. Weight management is especially important in decreasing a cat’s risk for the development of diabetes mellitus.

Hepatic Lipidosis
When an overweight cat goes off food or partially off food because of illness or psychological stress, body fat is mobilized to provide calories. Unfortunately, the cat’s liver was not designed to process a large amount of body fat. The liver becomes infiltrated with fat and then fails. A stress that might have been relatively minor, such as a cold, becomes a life-threatening disaster.

Reduced Life Span
A study of age-matched Labrador retrievers found that dogs kept on the slender side of normal lived a median of 2.5 years longer than their overweight counterparts.

Unwillingness to Accept Therapeutic Diets
If the pet should develop a condition where a therapeutic diet is of great benefit, the pet that has been maintained primarily on a diet of table scraps may be unwilling to accept commercial pet food of any kind, much less a food modified to be beneficial for a specific disease process. This unwillingness will hamper treatment.

Increased Surgical/Anesthetic Risk
Obesity poses an extra anesthetic risk because drug dosing becomes less accurate. (It is hard to estimate a patient’s lean body mass for drug dosing if it is encased in a fat suit.) Furthermore, anesthesia is inherently suppressive to respiration and adding a constrictive jacket of fat only serves to make proper air exchange more challenging. And still further, surgery in the abdomen is hampered by the slippery nature of the extra fat as well as difficulty visualizing all the normal structures through the copious fat deposits. One never knows when a pet will require an emergency surgery (to say nothing of regular teeth cleanings).

So is the enjoyment of all those extra treats really worth it?

For more info go to veterinarypartner.com

Epilepsy

Email this article Seizure Disorders

 

What is a Seizure?

Any involuntary behavior that occurs abnormally may represent a seizure. Seizures are classified into several categories.

Generalized (Grand Mal) Seizures
This is the most common form of seizure in small animals. The entire body is involved in stiffness and possibly stiffness/contraction cycles (tonic/clonic action). The animal loses consciousness and may urinate or defecate.

Partial Seizures
This form of seizure originates from some specific area in the brain and thus involves the activity of a specific region of the body. Partial seizures may generalize to involve the whole body.

Psychomotor Seizures
This type of seizure is predominantly behavioral with the animal involuntarily howling, snapping, circling, etc. The abnormal behavior may be followed by a generalized seizure.

Seizures (neurological events) are often difficult to differentiate from fainting spells (cardiovascular events). Classically, true seizures are preceded by an aura, or special feeling associated with a coming seizure. As animals cannot speak, we usually don’t notice any changes associated with the aura. The seizure is typically followed by a post-ictal period during which the animal appears disoriented, even blind. This period may last only a few minutes or may last several hours. Fainting animals are usually up and normal within seconds after the spell.

For more info go to veterinarypartner.com