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DISEASES OF MUSCLES, LIGAMENTS AND TENDONS
Muscles are the organs that move bones and thusly lead to movement of the cat. 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 cat. ((Muscles))
A sprain infers damage to a ligament(s). This should not be confused with a strain, which defines an injury to a tendon and 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 care.
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 deformity to the region. Diagnosis of sprains is made through history, physical exam and 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 for several days, followed by a week of restricted and controlled exercise until the cat is moving normally. Wraps and dressings are sometimes used but rarely are of much value. Cortisone or torbutrol can be used for pain but caution should be exercised that the cat not feel "too good" and be inclined to run, jump 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 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 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, most feline patients are so small, and thusly are their ligaments, that exacting repairs of most areas is nearly impossible. Often times, surgical approximations and localized tightening of related tissues are 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 classified in a manner similar to that of sprains.
Mild strains 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 anti-inflammatory 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 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 young cats of a few select breeds due to genetic imperfections. As this condition is considered inherited, cats with the defect should not be used for breeding. Older cats usually will acquire this condition secondary to some type of trauma to the leg. Patellar luxations are normally graded 1-4 as follows, based on the clinical signs: ((Patellar Luxation))
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 cat 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 unless 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 cats that have suffered injury to the leg. The level of symptoms will vary greatly from cat to cat despite the grade of deformity present.
TREATMENT OF PATELLAR LUXATION
Many cats will be asymptomatic until later in life when degenerative changes caused by the patellar luxation precipitates into lameness. These need little or no care until such time. Some cats 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 rarely the caudal ligament, can lead to lameness and degenerative joint disease in the cat. 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 cats while they jump off a couch, bed, stairs or fence and the leg twists slightly. This is an uncommon injury in the cat but most small animal veterinarians will have diagnosed a few cases.
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.
Rarely 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. Some joints will stabilize without surgical intervention, but this may increase the likelihood that degenerative joint disease will begin and progress. While outwardly a damaged joint may appear stable, the net effect will be to leave the cat with a partially functional and painful limb. Surgical repair is highly advised by this author but other experts do advise confinement and letting injured joints heal as they may.
Post surgery, most cats will rehabilitate quickly and can be aided with passive manipulation of the limbs, light and controlled exercise and the use of Adequan, Synovicre or Cosequin to help rebuild joint surfaces. Occasionally cats 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, cats can rupture the Achilles tendon, or it can tear away from where it attaches to the ankle; the injury often occurring with the influence of outside trauma. Most injuries of this type occur in outdoor, older cats while they are running or jumping. Clinical signs include sudden, severe lameness in the hindleg which in time may seem to get better as the cat 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 cats 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 cats being in some type of splint for several weeks after surgery. The long-term prognosis is excellent with proper treatment and aftercare.
Polymyositis is an uncommon inflammatory disease of the muscles. Causes can include immune-mediated disease, toxoplasmosis and secondary to thymoma being present. Cats with low blood potassium levels also exhibit signs of polymyopathy. 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 muscles, weight loss, pain, fever, loss of appetite and sometimes a noticeable change in the cat's meow.
Diagnosis is based on clinical signs, blood serum analysis, physical examination and X-rays. Special neurologic testing may also be performed, but most cats will have normal nervous system function (reflexes etc.) and abnormal muscle function. A biopsy of diseased muscle tissue will be the ultimate diagnostic test.
TREATMENT OF POLYMYOSITIS
Most cats respond promptly when given cortisone type drugs, esp. prednisolone. Some animals will also be given cyclophosphamide or azathioprine that 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 cats 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. Treatment for any specific initiating cause will also be needed.
Under certain circumstances, muscle inflammation will occur when the cat 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 cat 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.
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 do 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.
Cats 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. These types of hernias are common in the dog but less commonly seen in the cat. Diagnosis is based on physical examination and X-rays. ((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 cat, the spermatic cord, to pass from inside the body. Uncommonly found in cats, this ring may be too large and fat or intestine may fill the groin area. In some cases, herniation occurs on both left and right sides. Diagnosis is based on physical examination and X-rays. When present, inguinal hernias have likely been caused by some sort of trauma.
Most common in older cats, perineal hernias occur as muscular and connective tissues break down secondary to chronic straining. The area between the anus and point of the pelvis nearest the tail will be the location of the defect. The condition is most commonly seen secondary to megacolon, feline urologic syndrome, chronic colitis, perianal tumors and previous perineal urethrostomy. Clinical signs include swelling near the anus that makes defecation or urination difficult as, in many cases, the rectum and/or urinary bladder pass into the hernia. This can be so severe as to even block urination or defecation completely. Hernias on both sides occur in some cases. Diagnosis is based on physical examination and X-rays.
TREATMENT OF HERNIAS
Most all hernias, whatever the cause, need to be surgically repaired. Cats with small hernias through which little material passes may be ignored if they do not enlarge. Cats used for breeding should have these repaired to prevent future tears. Larger hernias, too, always need repair and replacement of organs to their proper location. Cats with perianal hernias most always need to have a surgical repair although it is difficult to properly repair this particular type of hernia. Hernias in odd locations most commonly associated with traumatic events most always need repair to restore proper function.
