Growth Related Diseases

Growth Related Diseases

Many nutraceuticals are now being encouraged to assist or even prevent many growth related diseases.  Please consult with your veterinarian regarding these products.

Panosteitis (enostosis)

Panosteitis is a disease of bone characterized by the production of scar tissue in the interior of bone and the production of new bone with in the marrow cavity.

Causes are unknown at this time. It may be of a viral origin and is usually a disease of the larger breeds of dog, particularly the German Shepherd.

Clinical Signs:

The disease is often episodic, recurring at intervals.

Dogs are usually 6-18 months old at presentation, but has been reported in animals up to five years of age.

The initial signs are of a relatively severe lameness of acute onset.

The forelimbs are more commonly involved the hind limbs, but the lameness may shift from limb to limb. Recurrence in a previously affected bone appears to be rare.

Lameness may be accompanied by loss of appetite, fever, lethargy, and tonsillitis.

Clinical signs may persist for 2-9 months, but the disease generally disappears by 18 months of age.

Usually the bones affected are the ulna, humorous, radius, femur, and tibia.Loss of muscle may be present over the affected limbs.Pain can be elicited by palpation of the affected area of bone.

Diagnosis:

Diagnosis is confirmed by radiology. Radiographic signs may persist for several months after lameness disappears.

Treatment is supportive and consists of exercise restriction and analgesics (non-steroidal anti- inflammatory drugs) such as aspirin (ascriptin), carprofen, and etogesic.

Prevention:

Prevention may involve nutritional management. Excessive calcium intake can result in hypercalcitonism that may retard bone remodeling.

CERVICAL SPONDYLOMYELOPATHY (WOBBLER SYNDROME)

Cervical spondylomyelopathy is a disorder that is recognized in many large breeds of dog, particularly the Great Dane and Doberman Pincher. The clinical and neurological signs result from compression of the cervical spinal cord.

The compression is caused by the developmental malformations of the vertebrae, vertebral instability or instability associated changes to the vertebrae or associated tissues.

The cause is likely to be multifactoral with genetic, nutritional and biochemical influences. The presence of a large, heavy head on a long neck may create abnormal forces that contribute to abnormal vertebral development.

Nutritional studies in Great Danes have shown that ad libitum feeding of balance diets in young dogs can increase the prevalence of the disorder. Additionally, chronic, excessive calcium intake in young dogs can result in hypercalcitonism, which disturbs skeletal remodeling and ossification and may contribute to abnormal vertebral development.

Compression of the spinal cord may arise from any of the following acting individually or in combination

-stenosis of the vertebral canal-malformation of the processes where they join

-disc disease

-enlargement of the ligament holding the vertebra together

-vertebral mal alignment

The above changes produce constant compression of the spinal cord. This may result from pressure on the spinal cord and usually caused by buckling of the ligament stabilizing the cervical vertebrae or from abnormal alignment if the vertebra in younger dogs.

Pressure on the spinal cord results in neurological signs, most commonly affecting the hind limbs. Compression may be present an single or multiple sites along the spinal cord and there is variation among breeds as to the level of the vertebral column that is most commonly affected.

Chronic compression of the spinal cord may result in damage to the nerve tracts descending down the spinal cord.

Clinical signs:

The disorder is seen more commonly in males than females and the age a presentation may vary from around eight weeks to ten years or older.

There is variation among breeds in the age of onset of clinical signs.

Clinical signs vary considerably in their severity and speed of onset by is usually chronic and progressive.

There is usually the slow onset of paresis and ataxia of the hind limbs, which may progress to involve the forelimbs.

Dogs can present acute onset quadrapariesis or quadriplegia.

Cervical pain may be present.

Diagnosis:

X-rays of the cervical spine may show a number of abnormalities

-tipping of the vertebra into the spinal cord

-stenosis (narrowing) of the vertebral canal

-malformation of the vertebral bodies

-narrowing of the inter vertebral disc spaces with arthritic changes

Myelograms are required to localize the lesions

MRI or CT scans are also now invaluable in diagnosing this disease.

Treatment:

Dogs with mild intermittent signs may be treated conservatively (restricted activity), corticosteroids, feeding from a height and the use of a chest harness rather than a collar and lead.

Dietary adjustment, if necessary, in young dogs

Surgical treatments including decompression of the spinal cord, fusion of the spinal cord, and the placement of screws through the vertebra.

Prevention

This is likely to be a genetic component to the disorder, but correct nutrition during growth and development is important, particularly in giant breeds of dog.

Avoid over feeding and excessive mineral supplementation during growth.

Ununited Anconeal Process

Ununited anconeal process has been reported in numerous large and giant breeds of dog, as well as some chnodrodystrophoid breeds such as Basset Hounds. The most commonly affected breed is the German Shepherd.

The joint affecting the humorous-ulnar area (elbow-illustration of normal elbow) joint is formed by the articulation of the humorous and the ulna. It is responsible for stabilizing the joint and restricting extension of the elbow. The anconeal process fits into the hole of the humorous when the elbow is extended.

In certain breeds the anconeal process which is part of the ulna does not fuse. If not fused by 20 wk. of age this bone will stay ununited.(illustration of ununited anconeal process)

Due to the non-union degenerative joint disease develops as a result of instability in the joint.

Clinical Signs:

Age of onset of clinical signs ranges from 4-8 months, although signs may appear in animals as young as two months and as old as five years.

Males are more commonly affected than females.

May affect both fore limbs and levels of pain and lameness may vary.

Pain is elicited on manipulation of the elbow, particularly extension.

Restricted range of movement in the elbow joint .Swelling of the elbow

Diagnosis:

Radiographs of the elbow show evidence of the disease. Arthritis may or may not be present.

Treatment:

Options include conservative or surgical management. Young dogs may be best managed with surgery.

Surgical options include

-removal of the anconeal process.

-screwing the bones together

-removing part of the ulna

Or a combination of the screwing and removal of bone.

Techniques that preserve the anconeal process may give better long-term success than removal of the process.

Prevention:

This is very likely a genetic dysfunction. Therefore, affected animals should not be used for breeding or the parents of the affected animal.

Over nutrition should be avoided to minimize the risk of ununited anconeal process developing.

Osteochondrosis: osteochondritis dissecans (OCD)

Osteochondrosis is a disorder characterized by abnormal calcification of the joint cartilage. It can affect primary and secondary centers of bone growth, joint cartilage, and growth plate cartilage.

Osteochondritis dissecans is a type of osteochondrosis. The name implies that there is a lesion cutting into the joint cartilage with a secondary inflammation of the affected area and the joint.

The disorder involves a genetic, hormonal, environmental and nutritional factor.

Growth rate, conformation and level of activity may influence the development of the disease.

Genetic studies have suggested that the disease is heritable.

Overfeeding and over supplementation with calcium increase the prevalence of the problem.

Medium and large breeds are most commonly affected including the Rottweiler, Labrador Retriever, Golden Retriever, German Shepherd, Bernese Mountain Dog, Newfoundland, St. Bernard and Great Dane. OCD has also been reported in the cat.

Joints commonly affected by osteochondritis dissecans include the shoulder(normal shoulder, OCD lesion of shoulder), elbow(normal elbow, OCD of elbow), stifle, and hock. Joints are often affected bilaterally.

Clinical Signs:

Signs develop between four and ten months of age, although the disease may the may be subclinical.

The pattern of lameness depends on the joint that is affected and whether the problem is unilateral or bilateral.

Joints in both the fore- and hind limbs may be involved.

Dogs with mild clinical signs may show only stiffness on rising that improves with exercise.

The dog may adopt a characteristic posture, i.e. extended hocks, if these joints are involved, or there may be external rotation of the front feet if the elbows are affected.

Pain is present in manipulation, usually extension of the affected joint.Pain may be elicited by direct pressure over the affected area of the joint, i.e. shoulder joint.

There may be swelling of the affected joint and loss of muscle size if the affected leg.

Diagnosis:Radiography Arthroscopy MRI

Treatment:Treatment of affected joints may be surgical or conservative. The optimum treatment for some joints remains controversial.

Conservative treatment is usually reserved for animals with no or minimal clinical signs or where there is moderate to severe degenerative joint disease.

Surgical treatment consists of removal of the cartilage flap and /or joint pieces floating in the joint.

Prevention:

Avoid overfeeding and over supplementation, especially with calcium, particularly in the large and giant breeds of dog.

Selective breeding

Nutritional Secondary Hyperparathyroidism

Young growing animals have a greater requirement for calcium than adults do to achieve normal mineralization of cartilage and bone.

Nutritional secondary hyperparathyroidism develops if there is a calcium deficiency in the diet, or an increase in dietary phosphorus combined with a normal or decreased calcium, or a deficient intake of vitamin D.

The condition is mainly seen in dogs and cats (especially kittens of Oriental breeds) that are fed all-meat diets or all-grain diets. Meat, offal and cereals are deficient in calcium and rich in phosphorus.

Pathogenesis:

An increased plasma phosphorus level produces a reciprocal fall in the plasma calcium concentrations.

Chronic low calcium levels stimulated the release of parathyroid hormone.

This process of increased parathyroid hormone eventually will cause weakening of the bone resulting in both bone pain and pathological fractures (fractures following relatively minor events such as jumping from a sofa.

Clinical Signs:

Usually seen in dogs and cats under 6 months of age.

Lameness:

Reluctance to move

Bone and joint pain

Unstable or wobbly gait if there are fractures of the vertebrae.

Deformities of the long bones resulting from pathological fractures.

Deterioration of posture, with splaying of the toes and sinking of the carpi and tarsi.

Chronic constipation can develop if there is a narrowing of the pelvis as a result of pathological fractures.

Diagnosis:

The disorder can be suspected from dietary history of affected animals.

Radiographs show a generalized bone density, and the walls of the bones appear thinner than normal. The reduction of bone density will not be apparent until there is at least 30% reduction in the mineral content of the bone.

Pathological fractures may be present.

Laboratory findings:

-low to normal serum calcium levels

-normal to high phosphorus levels

-increased serum alkaline phosphatase

-increase plasma parathyroid hormone level

Treatment:

Correct the dietary imbalance by feeding nutritionally balanced pet food

Animals with skeletal deformities should be confined for the first four weeks of dietary correction to prevent further injury and to limit any progression of skeletal deformity. Corrective osteotomies of long bones can be considered when the skeleton has mineralized to a sufficient level.

Animal with spinal injuries may never recover

Analgesics can be used for pain relief-avoid corticosteroids, which will further lower plasma calcium levels

Many animals will remain stunted in growth even with dietary correction

Prevention:

All young dogs and cats should be fed a balanced diet that contains adequate, yet not excessive, amounts of calcium, phosphorus, and vitamin D. This is best provided in the form of a nutritionally balanced pet food.

RECOMMENDED BOOKS
Arthritis: Veterinary Advice for Dog

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