Hip dysplasia occurs when there is insufficient stability to keep the head of the femur (the "ball") within the acetabulum (the "socket") of the hip joint. This may be due to stretching of the joint capsule or weakness in the surrounding muscles, or a failure of the "socket" to develop properly. Because of this instability the hip joint develops abnormally, remodelling of the bones occurs and new bone is deposited around the joint (used to be called arthritis - now called degenerative joint disease). The result is hindleg weakness, pain and functional disability.
It may surprise people to learn that the cause of hip dysplasia is not known ! Hip dysplasia is a complex (called polygenic or multigenic) disease with many factors involved in the cause. The most important are genetic and environmental factors but, based on detailed analysis of inheritance in German Shepherd dogs the disease is only described as being moderately heritable in that breed.
Contributing factors are :
Breed - genetic inheritance, BUT specific genes not yet identified. Also multiple genes involved (polygenic).
Body size - low prevalence - ancestral dog size; greater prevalence -large/giant breeds
Body type - low prevalence - slender and fit. Low subcutaneous fat content (1-2%); greater prevalence- giant breeds, heavy conformation, with acromegaly. Relatively high subcutaneous fat content(5-10%).
Growing pattern - rapid growth rate and excessive weight gain (above the average for the breed) can both increase the likelihood of hip dysplasia occurring.
Increased activity has been associated with increased likelihood of developing hip dysplasia. Possibly increased activity exposes the animal to increased chance of injury, or to excessive biomechanical forces which alter the stability of the hip joints.
Muscle disorder - a muscle disease (developmental myopathy of the pectineus muscle) has been described in German Shepherd puppies with hip dysplasia, but a direct link between the two conditions was not proved, though it may have been present.
Hormone - experimentally a female hormone (the oestrogen relaxin) can induce hip dysplasia due to relaxation of supporting ligaments in dogs, including greyhounds. However there is no evidence of a naturally occurring role for the hormone in the cause of the disease.
Diet does not seem to be important except when excessive calorie intake occurs resulting in too rapid a rate of growth or excessive weight gain.
Hip dysplasia affects humans (1.3 children in every 1000) and ALL domestic
animals including cats and dogs. Body size is an important factor and one
of the of the highest prevalence's of the disease is in large and giant
breeds of dog in which over 30% of some breeds may be affected. The
disease is less common in dogs with a body size similar to the ancestral
dog and it is rare in undomesticated animals.
In the USA screening XRays have indicated that in some breeds over 20% are affected by hip dysplasia including - in descending order : St Bernards (43.2%), Newfoundlands (39.9%), Bullmastiffs (34.5%), English Setters (32.1%), Gordon Setters (32.1%), Old English Sheepdogs (29.9%), English Springer Spaniel (27.3%), Akita (27.1%), Chesapeake Bay Retriever (25.7%), Golden Retriever (27.5%), Norwegian Elkhound (25.6%), Rottweiler (25.4%), the German Shepherd Dog (25.1%), Giant Schnauzer(24.2%), Standard Poodle (23.6%) and the Brittany Spaniel (22.4%). (Reference Riser WH et al J Am Vet Med Assoc (1974) 165:79)
Dogs less than 30.5 cm in height and less than 11.3 kg in body weight rarely develop hip dysplasia.
It is interesting to note that hip dysplasia is extremely rare in racing greyhounds, but it is seen frequently in greyhounds kept as pets. This highlights the fact that environmental factors are important as well as genetics.
Equal numbers of males and female dogs are affected with the hip dysplasia.
The disease affects young animals and dogs are usually aged between 5-12 months when signs are first noted.
Signs include a swaying hindleg gait, hindleg lameness, muscle wastage around the hindquarters, reluctance to exercise, fatigue during exercise, inability to climb stairs or jump up. Sometimes there is a loud "click" heard during exercise. Occasionally affected animals walk in a hunched-up manner with an arched back. In some cases (the worst cases) the dog will wince with pain when it moves it's hindlegs.
It is important to realise that the occurrence of pain is not directly related to the degree of abnormal change that can be seen on XRays.
Remodeling of the hip hip joint can lead to severe deformity. In addition
the instability results in new bone being deposited around the joint -
this can lead to pain, and reduced range of movement. With advancing age,
as degenerative joint disease progresses in the hips, ambulatory function
is gradually lost resulting in great difficulty rising from a lying down
position or negotiating steps and stairs. In large and giant breeds of
dogs an inability to jump up (into cars for example) can present serious
management problems for owners.
Post-operative complications can occur - particularly following the removal (excision) of a femoral head and neck.
Hip dysplasia is diagnosed from the presenting history, physical examination and is confirmed by taking XRays of the hip joints. For accurate interpretation of the XRays the position of the animal is critical and in order to position the animal correctly (lying on it's back) it is necessary to immobilise the patient. This usually requires the administration of a general anaesthetic.
This dog has severe hip dysplasia with secondary arthritic changes- some of which are described below
A Abnormal, square shaped head to the femurs with a broader than normal neck. The head "ball" is not lying properly in the acetabular fossa
B There is a lot of "new" bone around the joints such as this osteophyte lying in front of the acetabulum
C There is a loss of cartilage on the surface of the joint resulting in a loss (or narrowing) of apparent joint space between the head of the femur and the acetabulum
D There is an increase in the radiodensity of the bone lying under the acetabulum articular surface. This gives the bone a very white colour - and is called sclerosis. In addition, the joint space (darker line) appears to be wider because the head of the femur is partially lifted out of the socket created by the acetabulum.
E New bone can be deposited all around the joint, including along the neck of the femoral head.
In young animals genetically predisposed to develop hip dysplasia they should be reared in a cage with minimal exercise as this has been shown to reduce the likelihood of dysplasia developing.
Food intake should be restricted during growth to avoid too rapid a growth or excessive weight gain.
Medical treatment involves the administration of pain killers and rest. Aspirin and other non-steroidal anti-inflammatory drugs can be very successful , but they do have potential side-effects if used over a long period of time. Corticosteroids can also give a clinical improvement but most authors advise that they should be used with caution..
Surgical intervention is possible in young dogs with acute pain - various techniques can be used in an attempt to increase the stability of the hip joint.
Triple osteotomy of the pelvis to increase the surface coverage of the femoral head (the "ball") by the acetabulum (the "socket")
Total hip replacement
Removal of the femoral head and neck (excision arthroplasty)
Changing the angle of the head of the hip - corrective osteotomy
Myotomy - sectioning the pectineus, iliopsoas or or gluteal muscle or muscle attachments to provide pain relief
The prognosis is good for most animals, but as they get older the degenerative joint disease makes locomotion more and more difficult
BLOAT (Gastric Dilation-Volvulus) Also commonly known as Gastric torsion.
What is it?
Gastric Dilation-Volvulus (GDV), or bloat as it is commonly known, is a very serious and life-threatening condition, occurring suddenly and can kill in a matter of hours.
Bloat usually occurs in two parts first the stomach rapidly fills up with air, increasing pressure and causing compression of surrounding organs and shock. Secondly, filled with air the stomach can rotate on itself, pinching off the blood supply. The entire blood supply is disrupted and the dog's condition begins to deteriorate rapidly.
Which breeds are susceptible?
A definite link with the build of the dog has been recognised, and bloat is much more likely to occur in large, deep-chested breeds. Great Danes, Saint Bernard, Weimaraner, Irish Setter and Gordon Setter being among the breeds with the highest incidences, however and deep-chested breed is susceptible. It has been noticed that there is often a tendency for bloat to run in certain lines. Because bloat is correlated to the depth and width of the dog's chest, and genes from the parents determine these traits, if the parents are deep chested then it is most likely that their progeny will also have deep chests and thus be more susceptible to bloat. The problem has been known to occur in small dogs, but very rarely.
What causes bloat?
Bloat appears to be caused by a number of different and unknown reasons, and is usually a combination of events. Studies of the stomach gas that occurs, suggests that dilation occurs as a result of swallowing air. Whilst we normally burp to release excess air, for some reason these dogs are unable to release it.
What are the symptoms?
When gas first starts to accumulate in the stomach, the dog will appear slightly uncomfortable. The stomach then starts to dilate (gastric dilation) and the dog will become anxious and restless, often pacing, and the stomach may be swollen. He may also try to vomit, but will only bring up a white foam, no food.
The next stage is when the stomach twists (gastric volvulus) and the dog becomes extremely restless, whining and panting as well as salivating and trying to vomit every few minutes. He may go on to stand with his legs apart and hang his head down. The stomach is swollen and sounds hollow if tapped.
When the blood supply is cut off, organs become compressed and shock can begin to develop. The dog is unable to stand, or stands very shakily, with his legs apart. The stomach is very swollen and breathing is shallow.
The final stage is shock and heart failure develops, the dogs gums are white or blue and death is imminent.
How is it treated?
The best chance a dog has of surviving is immediate veterinary attention. Sadly, even with treatment, a large percentage of dogs still die, some survive surgery but then die of the shock after treatment.
Your veterinarian must relieve the pressure, decompressing either by using a stomach tube or inserting a large needle into the stomach to release the gas. The less time the pressure is on the stomach and organs the better the dog's chances of survival. Once the dog is stabile, x-rays are taken to determine whether a torsion is present. If it is, then surgery is performed to untwist the stomach, which is then stitched to the abdominal wall to prevent reoccurrence.
How is it prevented?
The cause of bloat is unknown and therefore it is near impossible to determine how to prevent it. Some suggestions are listed below, but there is no guarantee that these will help to prevent bloat occurring.
Divide the day's ration into two or three meals a day, spacing them well apart.
If feeding a dry food, ensure it is well soaked beforehand.
If your dog has a tendency to eat very quickly, gulping his food down, try slowing him down by placing a very large smooth stone (too big to be swallowed) in the middle of the food bowl.
If you have more than one dog and meal times are a competition to see who eats fastest then try feeding them in separate rooms.
Put both the water and food bowls on a stand at head height, thus reducing the amount of air swallowed during eating or drinking.
Do not allow your dog to drink large quantities of water at a time, especially after a meal.
Avoid exercise for about two hours after a meal.
Avoid feeding before or during stressful or exciting situations.
Most important of all, ensure you know and can recognise the symptoms of bloat and act quickly by taking him to the vet immediately.
Cancer is the leading non-accidental cause of death in dogs in this
country. It is common in all breeds and the rate of cancer increases with
Cancer (also known as neoplasia) is caused by the uncontrolled, unrestrained growth of cells in the body. It cannot be considered as a single disease since cancer can arise from any tissue in the body, and some forms have the ability to spread (metastasize) throughout the body. Cancers can be very aggressive and spread rapidly, or they can be slow-growing and non-invasive. The cause of cancer in dogs, as in humans, is largely unknown, although there are many theories involving environmental factors, diet, vaccines, and genetic pre-disposition to specific forms of cancer. At this point, there is not enough conclusive evidence to point to any cause in particular.
Cancers fall into two basic categories:
sarcomas, which are derived from structural tissues such as bone, muscle, or cartilage, and
carcinomas, which are derived from non-structural tissues such as blood, glands, and skin.
Despite its reputation, cancer is considered to be one of the most treatable of all chronic diseases, especially when detected early. The AVMA and the Veterinary Cancer Society have developed a list of 10 common warning signs:
Abnormal swelling that persists or continues to grow
Sores that do not heal
Loss of appetite
Bleeding or discharge from any body opening
Difficulty eating or swallowing
Hesitation to exercise or loss of stamina
Persistent lameness or stiffness
Difficulty breathing, urinating, or defecating.
If your Bullmastiff exhibits any of these symptoms, prompt evaluation by a veterinarian is imperative. Remember, if cancer is found early, it can be treated more effectively.