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DISEASES OF MUSCLES, LIGAMENTS AND TENDONS
Muscles are the organs that move bones and thusly lead to movement of the dog. Tendons are the fibrous tissues which connect the muscles to bone; ligaments are fibrous bands which connect bone to bone. Proper attachment, strength and function of these tissues are essential towards smooth, correct movement by the dog.
A sprain infers damage to a ligament(s). This should not be confused with a strain, which defines an injury to a tendon and/or muscle. Ligaments are tight, inelastic fiber bundles that hold bone together. If an external force acts upon a ligament and exceeds the normal stretch of that tissue, then a sprain will occur. Sprains are classified as follows:
First-degree sprains are mild, involve only a few of the fibrous tissues within the ligament and result in little if any functional deficits. They will tend to heal quickly with little or no concern.
Second-degree sprains involve significantly more damage to the ligament(s) without actual rupture of such. There will be loss of normal function in the area affected and treatment will be required to restore function. Patellar luxation involves, at least to some extent, a second-degree sprain.
Third-degree sprains will include damage as in a second-degree sprain, plus a partial or complete rupture of the ligament(s) or the ligament being pulled free from its bony attachment(s) (avulsion). Function of the area will be lost and often some type of surgery will be needed to repair the damage and restore function. Cruciate ligament injury is a common third-degree sprain.
Clinical signs of sprains include lameness, swelling to the area, pain on touch or movement and possibly a deformity to the region. Diagnosis of sprains is made through history, physical exam, gait analysis, manipulation and X-rays. The degree to which there is disuse and instability is used to obtain a diagnosis and chart the proper treatment.
TREATMENT OF SPRAINS
Most first degree sprains can be treated early on by icing the area for 10-30 minutes post-injury, then applying heat packs to the area two or three times daily for a week or so. Animals should be kept confined, walked only outside on a leash to enforce the confinement, followed by a week of restricted and controlled exercise until the dog is moving normally. Wraps and dressings are sometimes used but rarely are of much value. Rimadyl, Deramaxx or similar NSAIDs can be used for pain but caution should be exercised that the dog not feel "too good" and be inclined to run and re-injure the area.
The more moderate second-degree sprain will require significantly more time to heal (6-20 weeks) and some type of physical support may be needed. Veterinarians will generally apply a splint for 2-4 weeks followed by a light wrap for several more weeks after that. Strict exercise restriction is important throughout this time, with passive manipulation of the limb and highly controlled exercise or swimming during the healing phase being very important. If there is significant instability, surgery may be needed to tighten and stabilize the area, followed by splinting and rehabilitation as describe above. Early repair is essential to obtain the best results.
Third-degree sprains most always require surgical repair. If possible, the ends of the damaged ligament are sutured back together with special materials. If a ligament and a piece of bone have pulled away, it may be possible to pin the bone back in place. Unfortunately, many canine patients are so small, and thusly are their ligaments, that exacting repairs of some areas is nearly impossible. Often times, surgical approximations and localized tightening of related tissues is often necessary to affect repair. In some cases, fusion of a joint or area will be the only reasonable treatment to provide stabilization. (arthrodesis) Post-operative treatment for third-degree sprains is similar to that for second-degree damage.
Strains, often called "pulled muscles", can occur along any portion of a given muscle/tendon unit and multiple muscles may become involved in certain injuries. They may be characterized in a manner similar to that of sprains.
Mild strains may produce only minimal lameness and will quickly heal. Moderate strains can result in lameness, localized swelling, alteration of gait and pain upon touch or manipulation. Severe strains will result in obvious lameness, local swelling and more intense pain. This would be most severe if a muscle/tendon has ruptured. Diagnosis of strains is similar to that of sprains and in many cases will be difficult to differentiate.
TREATMENT OF STRAINS
As most strains are minor, they will resolve quickly with rest, icing the area and the use of aspirin or related medications. Surgical repair would be necessary in cases of tearing or rupture. After the initial therapy, no matter how severe the injury, gentle physical manipulation to help the limb remain mobile and stretched out, massage of the muscles to help prevent scaring and contraction and controlled exercise and/or swimming can all be used to rehabilitate the patient.
Luxation of the patella involves movement of the kneecap from the center groove it normally rides in, to be sometimes or at all times caught on one side of the knee or the other. The condition is most common in small breeds due to genetic imperfections in femur (thighbone) development. As this condition is considered inherited in small breeds, dogs with the defect should not be used for breeding. Larger breeds seem to have more difficulty if they have this condition and there may be a genetic relationship there as well. ((Patellar Luxation))
Breeds with congenital patellar luxation often have alterations in femoral angles, a shallow patellar groove and changes in the positioning of the tibia bone as well. With these type abnormalities present, stresses placed on the patella cause it to be pulled away from the centerline of the hindleg and stretch the tendons and ligaments that normally stabilize the area.
Patellar luxations are normally graded 1-4 as follows, based on the clinical signs:
Grade 1: infrequent luxation, infrequent lameness, leg strait, patella tends to be in proper location.
Grade 2: frequent luxation, patella usually out of place, rotation of the limb present but overall the dog does well.
Grade 3: patella luxated and fixed in luxated position, animal still most often uses limb but lameness may be present, abnormal rotations of limb present.
Grade 4: patella luxated and fixed with severe twisting of limb and moderate lameness.
Diagnosis of patellar luxation is based on history, physical examination including palpation of the limb and X-rays. Older animals may do well until moderate degenerative joint disease sets in. Young animals may have quite bad lameness at an early age associated with severe deformity. Cruciate ligament injury may be present concurrently in some dogs. The level of symptoms will vary greatly from dog to dog despite the grade of deformity present.
TREATMENT OF PATELLAR LUXATION
Many dogs will be asymptomatic until later in life when degenerative changes caused by the patellar luxation precipitates into lameness. These need little or no care. Some dogs with mild or intermittent symptoms need rest, confinement and pain medication to allow joint inflammation to subside. More serious lameness and deformity will most always require surgical therapy. Many techniques are used and combined to reset the patella and the angulation of the leg. After surgery, physical therapy and the use of Cosequin, Synovicre or Adequan generally speed joint repair.
Rupture of the cranial cruciate ligament and occasionally the caudal ligament, often leads to severe lameness and degenerative joint disease in the dog. Most commonly the cranial ligament will rupture when abnormal rotation is placed upon the joint while it is flexed. This often occurs in middle age and older dogs while they jump off a couch, bed, or stairs and twist slightly. Sometimes it will occur as the dog wrestles with another dog or vigorously plays a game with its owner.
The cruciate ligaments stabilize the stifle or "knee" joint while it moves in and out of flexion. When damaged, the joint slides along itself and is unstable. While usually not painful unless arthritis has set in, the pet will be unable to bear weight on what has then become a "trick" knee. Clinical Signs include a sudden onset of lameness and sometimes pain in the leg. ((Cruciate Injury))
Diagnosis is based on history, clinical signs and the doctor demonstrating the sliding or "drawer" motion present in the joint. X-rays are needed to determine the degree of degeneration in the joint and rule out other conditions. Partial ruptures are possible but will usually progress to complete ligamentous rupture in a short period of time.
Often associated with cruciate ligament injury are tears to the medial collateral ligament and occasionally tears to the medial meniscus, a cartilaginous/fibrous pad which rests below the femur on top of the tibia. When this tissue becomes torn, the joint will often "click" and this will require removal of the meniscus when the joint is repaired.
TREATMENT OF CRUCIATE LIGAMENT INJURY
There are quite a few differing methods to surgically repair ruptured cruciate ligaments and the best method will vary from patient to patient and surgeon to surgeon. The one fact that is certain is that, if left untreated, degenerative joint disease will rapidly begin and progress. While outwardly this may stabilize the joint, the net effect will be to leave the dog with a partially functional and painful limb. Surgical repair is highly advised.
Post surgery, most dogs will rehabilitate quickly and can be aided with passive manipulation of the limbs, light and controlled exercise, swimming and the use of Adequan, Synovicre or Cosequin to help rebuild joint surfaces. Occasionally dogs can rupture the opposite ligament (opposite leg) but most repairs last the life of the patient. It is advisable to find a surgeon or general practitioner that has performed multiple surgeries and is familiar with the various options of surgical repair.
RUPTURE OR AVULSION OF ACHILLES' TENDON
Although an uncommon injury, dogs can rupture the Achilles tendon, or it can tear away from where it attaches to the ankle, the injury often occurring without the influence of outside trauma. Most injuries of this type occur in larger, older dogs while they are running or exercising vigorously. Clinical signs include sudden, severe lameness in the hindleg which in time may seem to get better as the dog compensates for the injury. Localized swelling may also occur in the area. Diagnosis is based on history, physical examination and X-rays.
TREATMENT OF RUPTURE OR AVULSION OF ACHILLES' TENDON
Most dogs with these conditions require surgery, either to suture the ends of the tendon together or to re-implant the tendon onto the anklebone. Various techniques exist with most dogs being in some type of splint for several weeks after surgery. The long-term prognosis is excellent with proper treatment and aftercare.
POLYMYOSITIS
Polymyositis is an uncommon inflammatory disease of the muscles, generally occurring in larger breeds. There is no known cause although immune-mediated disease has been suggested. When the muscle tissue becomes inflamed, it simply cannot function properly. The symptoms of this condition include profound weakness, lameness, incoordination, muscle tremors, trouble chewing and/or swallowing, swelling or shrinking of the muscles of the face, weight loss, pain, fever, loss of appetite and sometimes a noticeable change in the dog's bark.
Diagnosis is based on clinical signs, blood serum analysis, physical examination and X-rays. Special neurologic testing may also be performed, but most dogs will have normal nervous system function (reflexes etc.) and abnormal muscle function. A biopsy of diseased muscle tissue will be diagnostic.
TREATMENT OF POLYMYOSITIS
Most dogs respond promptly when given cortisone type drugs, especially prednisolone. Some animals will also be given cyclophosphamide or azathioprine, which are immunosuppressive agents. Repeat blood testing is used to monitor the progress of the treatment, with most pets being able to stop medication in 2-4 weeks. Some dogs will achieve a complete remission, while others may require care on and off throughout their lives. Medication should always be tapered off, never stopped abruptly.
EOSINOPHILIC MYOSITIS
This condition involves most commonly an inflammation of the muscles of the head of the dog and much less commonly, limb muscles. No cause has been determined. Usually there is a swelling to the muscles the dog uses to chew (sides of the head), which alters the motion of the jaw. Symptoms include moderate to severe pain upon opening the mouth, the dog may not eat well and a fever is often present. Diagnosis is based on history, physical examination, complete blood counts, serum enzyme analysis, with a muscle biopsy being confirmatory. Relapses are common and if the dog experiences recurrent bouts of this disease, fibrosis and progression to atrophic myositis can occur.
TREATMENT OF EOSINOPHILIC MYOSITIS
Treatment is similar to that of polymyositis, with prednisolone most often being used to treat affected dogs. Relapses are common and unfortunately cause muscle loss (atrophy) and scaring, similar to that of atrophic myositis. Medication should always be tapered off.
ATROPHIC MYOSITIS
This condition is a localized inflammation occurring in the muscles with which the dog uses to chew. Atrophy of these muscles (shrinking) occurs to the extent that most bony prominences on the dog's skull become visible. The condition can be secondary to polymyositis or eosinophilic myositis. Symptoms include shrinkage and fibrosis of the muscles on top of the head, the use of the jaw becomes severely restricted with weight loss and jaw pain also being common. Diagnostic blood tests are usually normal so a muscle biopsy is needed to diagnose what is occurring. ((Atrophic Myositis))
TREATMENT OF ATROPHIC MYOSITIS
As for the other types of myositis, prednisolone is the drug of choice for treatment. As the jaw may be functionally fused in the shut position, opening of the mouth may be necessary under anesthesia, although this may produce a nonfunctional jaw that cannot be closed. Long term prognosis is quite poor.
INFECTIOUS MYOSITIS
Under certain circumstances, muscle inflammation will occur when the dog becomes infected with various infectious agents, including leptospirosis, salmonellosis and certain protozoan parasites. Localized wound infections and generalized viral infections can also lead to this type of myopathy. Clinical signs will be more specific to the illness the dog has, but can then include stiffness, muscle pain, altered gait and fever. Diagnosis is secondary to the primary illness. Treatment is also per the originating cause.
EXERTIONAL MYOPATHY
Any dog who exercises extensively or even more than usual can exhibit symptoms of stiffness, lameness and muscle pain often worse in the hind legs. Most show symptoms like any person would after too hard a workout; simply they are "stiff and sore". Most dogs recover quickly without treatment. In some cases, however, dogs may collapse and die shortly after the exercise period. In these cases, dogs will breathe rapidly, have blue gums and many times be unable to stand. Greyhounds are most commonly affected.
Diagnosis is based on history, physical examination, complete blood counts, serum chemistries and urinalysis. In warm and humid months the condition may be confused with heat stroke. To prevent this problem, dogs should be "warmed-up" before runs or other periods of strenuous exercise and large increases in time of or distance of runs should be avoided.
TREATMENT OF EXERTIONAL MYOPATHY
Most dogs recover quickly with a few days rest, but aspirin can be used to ease pain. Light walking and a gradual return to exercise are highly advisable. Dogs that collapse can die quickly and immediate veterinary attention is required. Intravenous fluids as a treatment for shock, steroids and other medications are used to pull the dog through the crisis. Sometimes, dogs that have experienced this condition and recovered can develop a form of atrophic myositis or muscle atrophy.
Hernias occur when there is some abnormal opening through a muscular wall which allows tissues or organs to protrude through the opening. Some hernias occur due to damage caused from some type of trauma. Most others occur when some normal opening has either failed to close properly or when the opening is stretched or widened by some other means. The main problem with hernias is that, in some cases, organs do pass through the opening and become trapped and/or compressed leading to serious compromise of that organ's function.
The most common hernias include the following:
The diaphragm, which separates the chest and abdominal cavities, contracts and relaxes to cause respiration. If a defect or tear occurs in the diaphragm, abdominal organs can move into the chest cavity. While congenital (birth) defects can occur, most often some type of traumatic injury will lead to a tear in the diaphragm. Clinical signs will vary with the size/severity of the tear and may include trouble breathing, blue lips and gums and inability to get comfortable and death. Diagnosis is based on history, physical examination, X-rays and blood counts with organ chemistries.
Dogs, just like humans, have a navel that tends to be flat, smooth and hidden by hair. If this junction either fails to close properly or the mother is too rough tearing off the umbilical cord, the opening can be wider than normal. With smaller hernias, signs include fat or omentum protruding under the skin. With larger hernias, the intestines or liver can protrude. Diagnosis is based on physical examination and X-ray. ((Umbilical Hernia))
In the groin area where the leg meets the body, a ring of fibrous tissue exists to allow nerves, blood vessels and in the male dog, the spermatic cord, to pass from inside the body. Most commonly found in female dogs of smaller breeds, this ring may be too large and signs of fat or intestine may fill the groin area. In some cases, herniation occurs on both left and right sides. If this type of hernia occurs in a male dog and fat or intestine passes clear into the scrotum, it is termed a SCROTAL HERNIA. Diagnosis is based on physical examination and X-rays. ((Inguinal Hernia))
Perineal Hernia (Perianal Hernia)
Most common in older, non-neutered male dogs, perianal hernias occur as muscular and connective tissues seem to deteriorate with age in the area between the anus and point of the pelvis nearest the tail. Many dogs will show signs of a swelling near the anus that makes defecation difficult as, in many cases, the rectum and urinary bladder pass into the hernia. This can be so severe as to even block urination or defecation completely. Hernias on both sides also occur in some cases. Diagnosis is based on physical examination and X-rays. ((Perianal Hernia))
TREATMENT OF HERNIAS
Most all hernias, whatever the cause, need to be surgically repaired. Dogs with small hernias through which little material passes may be ignored if they do not enlarge. Dogs used for breeding or heavy work should have these repaired to prevent future tears. Larger hernias, too, always need repair and replacement of organs to their proper location. Males with perianal hernias most always need to have a surgical repair plus castration although it is difficult to properly repair this particular type of hernia. Hernias in odd locations are most commonly associated with traumatic events most always need repair to restore proper function.
