key: cord-022352-yvdpj538
authors: Thomson, Maurine
title: The cat with lameness
date: 2009-05-15
journal: Problem-Based Feline Medicine
DOI: 10.1016/b978-0-7020-2488-7.50050-8
sha: 
doc_id: 22352
cord_uid: yvdpj538

nan

Lameness can occur in any limb, and is defined as interference in the normal locomotion of the cat. It is usually pain related, and is secondary to tissue injury which has caused structural alteration, edema and inflammation.

The severity of the lameness will vary with the severity and type of the injury or insult, varying from a mild to a non-weight-bearing lameness.

Generally periosteum has the densest nerve supply of the deep tissues, and has the lowest pain threshold, followed by the joint capsule, tendon, fascia and muscle.

Mechanical lameness can result from an abnormal limb conformation such as shortening, angulation or a rotational abnormality.

CAT WITH AN ABNORMAL GAIT PART 11 978 • Localized tetanus (p 985)

Occasionally causes paresis or paralysis of a solitary limb in the initial stages, but usually advances to generalized tetanus.

• Viral arthritis (p 983)

Can occur secondary to calici virus exposure or vaccination; also coronavirus.

• Fungal infections (p 984) Histoplasmosis, Coccidiomycosis, Sporotrichosis usually cause non-healing lesions, draining sinuses or osteomyelitis.

• Toxoplasmosis (p 984)

More often causes CNS signs such as ataxia, and paresis but can cause stiff gait, shifting lameness and muscle and joint pain.

• Neospora caninum (p 985)

Causes encephalomyelitis with ataxia and paresis and polymyositis.

• Feline progressive polyarthritis (erosive) (p 985) Rare disease; proliferative subtype occurs as acute onset in 1-5-year-old male cats, deforming subtype occurs as chronic onset in older cats. Usually several joints affected, most commonly carpus and tarsus. Proliferative subtype often has systemic signs of illness. Deforming subtype may be FeLV positive.

• Immune-mediated polyarthritis (non-erosive) (p 985) Rare disease, due to deposition of immune complexes in the synovial membrane. Usually carpus and tarsus affected. May be idiopathic or associated with SLE or chronic infection.

• Fractures, luxation, muscular contusions*** (p 980) Very common cause of presenting lameness.

• Cruciate rupture (p 982)

Occurs much less frequently in the cat than the dog, and usually less symptomatic.

Occurs only rarely in the cat, predisposition in Devon Rex cats.

continued Referred pain is pain felt in a part of the body other than that where the cause of pain is located.

Signs of weakness can be confused with lameness. See The Cat With Generalized Weakness (page 941). Paresis and ataxia can also be confused with lameness. The Weak and Ataxic or Paralyzed Cat See (page 908).

The origin of the lameness may be from bone, muscle, joint or neurological.

Diagnosis requires a good physical examination and orthopedic examination to localize the lameness in the affected limb or limbs.

The most common causes of lameness in the cat are cellulitis or an abscess from a cat bite injury, and motor vehicle trauma resulting in fracture or luxation.

The site of the injury is generally localized by palpation of pain and swelling at the affected site.

Cellulitis is often associated with pyrexia and lethargy.

Motor vehicle trauma is often associated with other signs of external injury such as grazes or scuffed nails, with or without dyspnea or internal injuries.

• Acute lameness of affected limb. • Pain and soft tissue swelling at site of injury. • Often associated with pyrexia, anorexia, lethargy. • Wounds in close proximity to a joint can cause septic arthritis.

Occurs secondary to a penetrating bite wound, and is one of the most common causes of lameness in the cat.

Many bacteria are present in the oral cavity of cats, but Pasteurella, Bacteroides and Fusobacterium are the most common organisms responsible for abscess formation, though a mixture of anaerobes and aerobes may also be present.

Infection may take the form of a discrete abscess or a diffuse cellulitis.

Occasionally L-forms of bacteria which lack bacterial walls are involved.

Acute lameness.

Soft tissue swelling and pain at the affected site.

Often a small scab and evidence of a bite wound can identify the area of penetration.

Associated with variable signs of systemic illness, including depression, pyrexia and anorexia.

L-forms produce a syndrome of fever and persistently draining, spreading cellulitis and synovitis that often involve extremities. Lesion is unresponsive to most antibiotics except tetracycline group.

Clinical signs of penetrating injury.

Abscess formation can be demonstrated by aspiration of purulent material.

L-form bacteria produce a discharge containing predominantly macrophages and neutrophils, but organisms cannot usually be detected cytologically or grown on culture. Response of syndrome only to tetracycline group antibiotics suggests diagnosis.

Soft tissue injury caused by another form of external injury.

Foreign body reaction.

Osteomyelitis often causes swelling and sinus formation. Rare in the cat and usually associated with an open fracture or bite wound.

Abscess formation generally requires lancing, and flush with weak solution of chlorhexidine, followed by course of antibiotics sensitive to Pasteurella, i.e. amoxycillin and clavulonic acid 12 mg/kg for 5 days.

Rarely there may be extensive regions of necrosis, which may require debridement and delayed closure.

Cellulitis treated by broad-spectrum antibiotics, i.e. amoxycillin and clavulonic acid, or cephalosporins.

Osteomyelitis may be a rare secondary complication resulting in sinus formation after initial healing of the abscess.

L-form bacteria respond rapidly to tetracycline (22 mg/kg tid PO) or doxycycline (5 mg/kg bid PO).

Normally excellent, and resolves after initial treatment.

With extensive injury the prognosis is still excellent, although it may require more prolonged treatment.

With septic arthritis some degree of degenerative joint disease will occur, although cats tolerate this with less clinical symptoms than dogs.

• Acute, usually non-weight-bearing lameness of affected limb or limbs. • Soft tissue swelling at the site of injury. • Abnormal movement or angulation of the affected bone or joint.

Usually due to external trauma from a motor vehicle accident.

Can also occur from other external trauma such as dog attack, malicious attack or fall.

Hindlimb lameness in young cats less than 7 months of age is usually due to disruption of the growth plate to the femoral head rather than hip luxation.

Type and location of the fracture or luxation will depend on the type of forces that have occurred at the time the injury was sustained.

Acute lameness of the affected limb.

Pain and swelling localized by physical examination.

Most common sites of fractures are femur, humerus, pelvis, tibia and radius.

Hip luxation is the most common form of joint disruption in the mature cat.

Pain localized to the hip in young cats is more likely due to separation of the femoral head.

Fracture/luxation injuries may be open or closed.

Open shearing injuries of the carpus and tarsus often occur due to the minimal degree of soft tissues covering over these regions.

Usually history of trauma.

Localization by physical examination.

Radiography is normally required to demonstrate exact type and location of the fracture or luxation.

Cellulitis can cause a similar degree of soft tissue swelling and lameness. Usually differentiated by evidence of penetrating wound and pyrexia.

Neoplasia of a bone or joint can present suddenly if associated with a pathological fracture. Very rare in the cat, and usually differentiated on radiographs.

Nutritional hyperparathyroidism in the young cat can present suddenly due to spontaneous fractures. Radiographically will see generalized osteopenia, with history of poorly balanced diet.

Will depend on the location and extent of the injury.

Simple fractures in young animals may be amenable to external coaptation, i.e. splints or casts.

More extensive fractures generally require some form of internal fixation. See relevant textbooks dealing with orthopedic diseases and management.

Joint sprains or other soft tissue injuries usually respond well to brief periods, i.e. 2 weeks or less, of immobilization, or simple rest.

Depends on the location and degree of severity of the injury.

With appropriate treatment most injuries have a very good prognosis for return to normal function.

Excision arthroplasty in the cat for treatment of femoral head separation or fracture has a very good to excellent prognosis following surgery.

Cats are generally less symptomatic for osteoarthritis following joint trauma than are dogs.

• Chronic, insidious lameness of the affected limb. • Lameness may be worse after sleeping, or when first rising. • May have thickening of the affected joint, with decreased range of movement. • Much less common in the cat than the dog.

Generally secondary to joint trauma such as open fracture, or penetrating bite wound.

Can occur secondary to joint conformational abnormality such as hip dysplasia in Persian cats, patellar luxation or cruciate rupture.

May be part of an immune mediated polyarthritis, e.g. systemic lupus erythematosus.

Can occur secondary to septic arthritis from hematogenous spread or direct contamination.

Occasionally occurs in association with acromegaly from excess growth hormone.

Insidious lameness which may be exacerbated by strenuous activity.

Usually some degree of joint thickening and reduced range of motion on physical exam.

Often does not cause any clinical signs of lameness and may be incidental finding.

History of insidious or vague intermittent lameness.

Radiographs demonstrate signs of osteoarthritis such as osteophytes, periosteal proliferation and periarticular joint thickening.

Joint neoplasia, which is very rare in the cat. Usually expect more extensive swelling and consistent lameness.

Most cats are not symptomatic for osteoarthritis, or if associated with a sudden exacerbation of the joint normally respond well to conservative management. This involves rest and short-term non-steroidal antiinflammatory drugs, i.e. aspirin 10 mg/kg every 48 hours or corticosteroids, i.e. prednisolone 0.25 mg/kg daily, or other non-steroidal anti-inflammatory drugs, e.g. carprofen, ketofen or meloxicam depending on availability and registration for use in cats.

Encourage weight loss in fat cats.

In severe cases of osteoarthritis associated with erosive arthritis or joint instability, arthrodesis may be warranted.

With severe polyarthritis long-term prognosis is poor, with most cases relapsing after therapy.

• Much rarer in the cat than the dog. • Usually results from traumatic herniation of the disc. • Clinical signs vary with the location of the disc herniation. • Signs may be acute or progressive in onset.

Usually results from traumatic herniation of the disc, resulting in acute spinal cord compression.

Location of the site of herniation dictates type of clinical signs seen.

Usually associated with paresis of the hindlimbs. See The Weak and Ataxic or Paralyzed Cat (page 908).

Lesion identified by neurological examination.

Confirmation of disc herniation by radiographs, myelography or CT imaging.

• Acute onset of hindlimb lameness.

• May have thickening of the affected joint due to synovitis, with pain evident on palpation of the stifle. • Positive cranial drawer sign or tibial thrust. • Much less common in the cat than the dog.

Usually due to external trauma such as a fall, hyperextension injury of the stifle, or excessive internal rotation of the tibia.

Generally causes rupture of the anterior cruciate, rarely is the caudal cruciate involved, unless there has been major stifle disruption.

Acute lameness of the affected hindlimb.

Generally there will be stifle swelling and pain present on joint palpation.

A positive cranial drawer sign or tibial thrust is generally evident on palpation, though pain may prevent an adequate examination of the joint.

Chronic cases may show a mild intermittent lameness as opposed to the acute injury.

By identification of a positive cranial drawer sign and pain in the stifle.

Traumatic disruption of all stifle ligaments due to excessive trauma. Usually palpation will reveal laxity in a mediolateral direction also if the collaterals have been disrupted.

Degenerative joint disease will usually occur, but this does not normally cause clinical signs of lameness.

In refractory cases the stifle can be stabilized with an extra-articular surgical technique. See relevant texts on surgical management of cruciate disease.

Generally the prognosis is very good to excellent with both conservative and surgical management.

• Can be congenital or acquired secondary to trauma. • Much rarer in the cat than the dog, though a predisposition occurs in purebred cats such as the Devon Rex. • Lameness may be worse after sleeping, or when first rising. • May have thickening of the affected joint, with decreased range of movement.

The congenital form occurs secondary to malalignment of the quadriceps mechanism, generally resulting in a medial luxation of the patella.

Varying degrees of deformity of the trochlear groove and tibial tuberosity can occur depending on the severity of the luxation.

The acquired form can occur secondary to external joint trauma from a fall or motor vehicle accident.

The congenital form is characterized by varying degrees of lameness depending on the severity of the condition. The lameness if often insidious and intermittent.

Usually occurs in young, purebred cats.

The acquired form can occur at any age, usually presenting with an acute lameness.

Palpation of the stifle will demonstrate luxation of the patella.

Palpation of the stifle demonstrates patellar luxation, usually in a medial direction.

Lameness present in the affected limb, which varies with the severity of the underlying disease.

In cats with clinical disease surgery is generally warranted.

Type of surgery varies with the severity of the disease, ranging from lateral imbrication, deepening of the trochlear groove and transposition of the tibial tuberosity.

Generally excellent, despite the progression of some degree of degenerative joint disease.

• Lameness may be of a single limb or multiple. • If all limbs involved will be reluctant to ambulate at all. • Can cause erosive or non-erosive signs radiographically. • Considered rare in the cat as a cause of lameness.

• Generally from a blood-borne infection that arises from a septic foci elsewhere in the body. • Can occur from direct bite wound or open joint injury. • Rarer in cats than dogs. • Can occur in kittens secondary to umbilical vein infections. • Pasteurella species are most commonly identified. • Can be due to bacterial L forms, which are mutant bacteria, which have lost their cell wall.

• Calicivirus polyarthritis can occur uncommonly in young kittens following natural exposure or after live attenuated vaccination. • Lameness usually occurs 7-10 days after mild respiratory tract signs, though can occur in the absence of respiratory signs. • Coronavirus has also been associated with polyarthritis.

• The effusive form of feline infectious peritonitis (FIP) virus occasionally causes lameness, with leakage of fluid into joint spaces. • The granulomatous form of FIP may cause paresis or paralysis as a result of spinal cord inflammation.

• M. gatae is linked to arthritis and tenosynovitis in older cats. • Mycoplasmal infection may incite an antigenic response resulting in the formation of immunemediated disease such as rheumatoid-like (deforming) arthritis.

Acute onset of lameness in one or several limbs.

Usually associated with systemic signs such as pyrexia, lethargy.

May appear weak rather than lame if all four limbs involved.

Usually demonstrate joint pain on manipulation of limbs.

Radiographic signs may demonstrate changes of erosion and periosteal proliferation in advanced cases, but may show no abnormalities initially.

Arthrocentesis generally required for cytology and culture and sensitivity.

Weak or paretic cat can appear similarly. See The Weak and Ataxic or Paralyzed Cat (page 908).

Immune-mediated polyarthritis.

Antibiotics for bacterial infection depending on results of culture and sensitivity.

L form infections respond well to 10-14-day course of tetracycline or doxycycline.

Calicivirus is often self-limiting, and cats recover well.

• More commonly causes CNS signs such as ataxia and paresis. • Can cause a stiff gait, shifting leg lameness, hyperaesthesia on muscle palpation and joint pain.

With Signs of Acute Small Bowel Diarrhea) and page 958 (The Cat With Generalized Weakness).

CNS signs seen most frequently, see The Paretic Cat (page 911).

May cause shifting limb lameness.

Can cause arthritis and myositis.

High IgM titers suggest recent infection, but do not confirm that T. gondii is responsible for the clinical signs in a given cat.

The organism can sometimes be seen in a muscle biopsy or very rarely in CSF.

• Cats less commonly affected than dogs.

• Lameness due to fungal osteomyelitis.

• Can be a single bone involved, or more commonly multiple sites affected. • Spores usually inhaled from the soil. 

Occurrence tends to be location dependent: • Coccidioides: south-western USA, Mexico, Central and South America.

• Blastomyces: small area of distribution mainly in North America and near fresh water. • Histoplasma: widespread in temperate and subtropical regions of the world, not Australia. • Cryptococcus: worldwide distribution. • Sporotrichosis: worldwide distribution.

Result in non-healing tumor-like lesion of the distal limbs and draining sinus tracts (sporothrix) or lameness due to fungal osteomyelitis.

Radiographically, see tumor-like lesions present in the bone with bone bony destruction and proliferation seen.

Organism is often evident in cytological preparation of aspirates or discharge from lesion or in a biopsy section.

Positive fungal titer may aid diagnosis.

• Neurological signs such as ataxia and paresis. • Polymyositis frequently present.

Polymyositis and encepalomyelitis with ataxia and paresis are seen most frequently.

Serum titers and muscle biopsy results are the most common methods of diagnosis.

• Retrograde axonal transport of the toxin from an infected focus. • Can cause paralysis of single limb. • Usually progresses to generalized tetanus.

With an Abnormal Third Eyelid).

Occurs following penetrating trauma and tissue devitilization.

Can see paresis or paralysis of a solitary limb in the initial stages.

Generally advances to generalized tetanus.

History of recent wound and clinical signs.

EMG findings characteristic with persistent electrical motor unit discharges following needle insertion or tapping of muscles.

Serum antibody titer to tetanus toxin compared with control cats may aid diagnosis.

• Are considered rare diseases in the cat. • Can be acute or chronic onset. • Often associated with other systemic signs such as lethargy, pyrexia and anorexia. • Can cause erosive or non-erosive signs radiographically.

• Chronic progressive polyarthritis has proliferative and deforming subtypes. • Proliferative form occurs in male cats aged 1-5 years. • Deforming type occurs more rarely in older cats. • Severe subchondral bone destruction may occur, leading to joint instability and deformity. • Radiographic signs are similar to those of rheumatoid arthritis in other species. • Often associated with feline leukemia viruspositive cats.

• Mycoplasmal products have been postulated to chronically stimulate immune-mediated diseases such as deforming arthritis.

• Can be due to systemic lupus erythematosus, chronic infection elsewhere, or idiopathic. • Due to deposition of immune complexes in the synovial membrane which incites an inflammatory response. • The inciting agent is usually not identified, but if the cat is on medication this may be a potential source and should be discontinued.

Deforming type of progressive polyarthritis has a chronic onset. All other forms tend to be acute onset of lameness and stiffness.

Often affects carpus and tarsus more severely than other joints.

Radiographic signs in erosive forms show marked destruction and deformity of the distal joints often resulting in luxation or subluxation but with minimal periosteal proliferation.

The proliferative form is characterized by periarticular soft tissue swelling in the early stages, then progressing to extensive periarticular proliferation. This is most frequently seen in the carpi, tarsi and smaller distal joints.

Arthrocentesis preferably done on two or more joints. Joint fluid is generally slightly increased in amount, slightly turbid, and with reduced viscosity. Cytology typically reveals a non-septic purulent inflammation, with cell counts in the range of 4000-70 000 nucleated cells/μl, and predominantly non-degenerative neutrophils. A variable number of small and large mononuclear cells may also be present.

Mycoplasma.

Rheumatoid factor, ANA and LE cell tests are consistently negative.

Hematological parameters are generally unremarkable.

Infectious arthritides, such as viral infections.

Causes of weakness and paresis in the cat. See The Weak and Ataxic or Paralyzed Cat (page 908).

Remove the cause if secondary to drug administration or chronic infection.

Treatment consists of immunosuppressive doses of corticosteroids for several months, or in combination with chlorambucil at 1.0-1.25 mg/cat once daily, and prednisolone 10-20 mg twice daily until resolution of clinical signs, then slowly taper the dose of prednisolone over 2-4 months. Continue the chlorambucil at the same dose every other day. Combination of prednisolone and gold salts (aurothioglucose 1 mg/kg by injection once a week) has also been used.

Good initial response to drugs, but greater than 50% of cases are likely to relapse, becoming more refractory to treatment.

Classical signs • Rarer in the cat than dog. • May be acute or insidious onset of lameness. • Usually associated with swelling at site of neoplasia.

Primary bone tumors are rare in the cat. Osteosarcoma is the most commonly identified tumor.

Generally occurs in cats older than 10 years.

Primary bone tumors are much less metastatic in the cat than the dog.

Metastatic spread from carcinomas to bone is very rare in the cat, compared to the dog.

Can get carcinomas of the digits secondary to primary lung tumors.

Joint neoplasias are very rare in the cat, and are due to synovial cell sarcomas or other soft tissue sarcomas.

Multiple cartilaginous exostoses or feline osteochondromatosis can transform to a malignant disease in the cat.

Lameness can also occur from nerve sheath tumors of the plexus or spinal cord, but these are very rare in the cat.

Can be acute or insidious onset of lameness.

Rarely can be associated with pathological fracture.

Usually thickening identified at site of disease, which may or may not be painful.

Radiographically, will see bone lysis in the metaphyseal region of long bones, or joint thickening and proliferation.

Histopathology is required for definitive diagnosis.

Thoracic radiographs should be taken to demonstrate primary lung tumor if multiple digits are swollen, or prior to amputation to rule out metastatic disease.

Osteomyelitis.

Septic arthritis.

If no evidence of metastatic disease, amputation is the treatment of choice.

If a solitary tumor of a digit is present, often this can be removed and the limb saved.

If no evidence of metastatic disease, then amputation is often curative, with median survival times greater than 2 years.

Primary bone tumors in the cat are a lot less aggressive than in the dog and generally not followed with chemotherapy.

• Usually occurs in Persian and long-haired cats. • Usually asymptomatic in cats compared to dogs. • Generally requires only conservative management.

Congenital disorder of Persian and other long-haired cats.

Radiographically, see luxation of the coxofemoral joint, with varying degrees of osteoarthritis present.

Usually no clinical signs of lameness are seen.

Pain may be exhibited on flexion and extension of the hip joints.

Occasionally may show signs of a stiff gait or lameness, which is exacerbated by excessive activity.

Pain on manipulation of the hip joints in a long-haired cat.

Radiographic evidence of hip laxity and osteoarthritis.

Usually conservative management consisting of rest, weight loss and intermittent anti-inflammatory drugs is all that is required in symptomatic cats.

If lameness persists femoral head and neck arthroplasty results in an excellent prognosis.

• Onset of forelimb lameness in the cat less than 1 year of age.

Very rare in the cat.

Has been reported as cause of shoulder lameness.

Occurs due to a defect in osteochondral ossification.

Insidious forelimb lameness in cats less than 1 year of age.

Pain identified on full extension and flexion of the shoulder joint.

Radiographically a thickened flap of cartilage or joint mouse can be identified in the shoulder joint.

Surgical removal of the cartilaginous flap.

Excellent.

• Onset of hindlimb lameness in the cat less than 1 year of age.

Uncommon condition.

Reported in male cats less than 2 years of age.

Idiopathic necrosis of femoral neck.

Vague, progressive hindlimb lameness.

May be bilateral.

Radiographically, see radiolucency of the femoral neck and proximal femoral metaphysis.

Traumatic fracture of the femoral neck.

Femoral head and neck osteotomy.

Excellent.

• Rare inherited disorder in Siamese and Siamese cross cats. • Causes a stiff gait and paraparesis. • Cats also have a broad maxilla, corneal clouding, pectus excavatum and neurological abnormalities.

Rare inherited disorder that occurs as a result of a lysosomal enzyme deficiency in Siamese and Siamese cross cats.

Usually present at less than 6 months of age.

Typically have dysmorphic facial features (a broad maxilla), plump paws (from thickened skin) and corneal clouding.

Generally exhibit a stiff gait and paraparesis with diffuse neurological signs.

Also present with a chronic mucoid ocular discharge and chronic respiratory tract infections.

Constellation of clinical signs suggests the diagnosis.

Radiographs show dysplastic femoral heads and necks and subluxated hip joints.

Excessive granulation of neutrophils, and vacuolation of lymphocytes are suggestive.

Positive urine toluidine test for sulfated beta glycosaminoglycans is consistent with diagnosis.

Definitive diagnosis is via enzyme assays of leukocytes and skin fibroblasts to demonstrate deficient beta glucuronidase activity.

• A defect in osteogenesis results in multiple spontaneous fractures. • Present with multiple sites of bony pain due to fractures, or unwilling to ambulate. • Lameness generally of young cats.

A heritable disease with failure of osteoprogenitor cells to develop into mature osteoblasts.

Results in bones that are very brittle and fracture spontaneously.

Spontaneous fractures can occur in any bones, although the long bones are more commonly affected.

Radiographically the cortical bone is very osteopenic, with multiple fractures present.

• Disease affecting cats with at least one fold-eared parent. • Lameness generally occurs at 5-6 months of age.

Inherited disorder of fold-ear cats.

Get shortening of the coccygeal vertebrae, metacarpal and metatarsal bones and phalanges.

They may develop periarticular exostoses and joint ankylosis.

• A congenital disorder characterized by dorso-ventral flattening of the thorax. • Kittens and cats show variations in respiratory and cardiovascular abnormalities. • Also associated with lateral limb deviation.

A deformity of the sternal and costal cartilages resulting in narrowing of the thorax.

Occurs as a congenital abnormality of cats, with the specific cause unknown.

Can be associated with the so-called "wimmer's"syndrome, in which there is lateral deviation of the limbs and impaired ambulation.

Kittens and young mature cats < 1 year of age may show respiratory and cardiovascular abnormalities associated with flattening of the thorax.

Based on clinical signs and radiographic findings of dorso-ventral flattening of thorax and lateral deviation of limbs. 

Improper closure of the neural tube during embryogenesis occurs, with varying severity of neurological signs seen affecting hindlimb function and urinary and fecal control.

In the Manx cat it is often associated with sacral dysgenesis.

Based on clinical signs, radiographic findings.

• Due to excessive intake of vitamin A, usually from an all-liver diet. • Lameness occurs due to bony exostoses around the cervical vertebrae and ankylosis of joints.

Due to excessive vitamin A intake over several months, usually from an all-liver diet.

Causes bony exostoses of spine and osseous hyperplasia and proliferation at joint margins, particularly the shoulder and elbow joints.

Excess vitamin A causes increased reactivity of the periosteum, resulting in bony proliferation at sites of joint capsule and soft tissue attachments to bone.

Cats are often reluctant to move around, and are very painful.

They often display an abnormal posture with a stiff neck and gait.

Radiographically there is ankylosis of cervical and cranial thoracic vertebra, and new bone proliferation around shoulder and elbow joints.

History of diet almost exclusively of liver.

Correction of the diet, ideally on a balanced commercial diet.

May require short-term analgesics.

Correction of the diet halts the progression of disease, and some remodeling of existing bone may occur. However, bony changes are often permanent and pain may persist.

• Lameness present in multiple sites in young kittens. • Due to a diet deficient in calcium, such as an all-meat diet.

Due to increased parathyroid hormone from persistent hypocalcemia, either from an absolute dietary calcium deficiency or secondary to excessive phosphorus intake relative to calcium.

Causes generalized osteopenia.

Most commonly seen in kittens on an all-meat diet.

Occurs with an all-meat diet even if the kittens have access to milk.

Osteopenia can result in spontaneous fracture.

History of inadequate diet.

Radiographs demonstrate diffuse osteopenia, with or without folding fractures.

Correct the diet by adding calcium, or more appropriately, change to a balanced commercial diet formulated for kittens.

Confine if multiple folding fractures are evident.

Very good if fractures have not resulted in malunion.

Residual deformity of the spine and pelvis may result in chronic partial bowel obstruction with constipation.

• Lameness present in multiple sites in young kittens. • Due to a diet deficient in vitamin D or insufficient mineral content, such as an allmeat diet.

Diet deficient in vitamin D or with insufficient mineral content causes the cartilaginous matrix of the growth plate not to calcify.

Results in osteopenia and widening of the growth plates.

Osteopenia can result in spontaneous fracture.

Abnormalities of the growth plate with rickets can cause angular limb deformities.

Diffuse osteopenia, and may see pathological fractures.

With rickets see widened growth plates and osteopenia.

Correct the diet by feeding a balanced commercial diet, and adequate exposure to light.

May require confinement if multiple fractures have occurred.

Usually excellent prognosis if there is not abnormal limb angulation. Correction of the diet corrects the underlying osteopenia and growth plate defect.

Disease Mechanisms in Small Animal Surgery

Slatter D. Textbook of Small Animal Surgery