Lecture 27: Developmental Bone Disease (Exam 3) Flashcards
What are some primarily inflammatory dev bone diseases & who are they seen in
- Panosteitis
- Hypertrophic osteodystrophy (HOD)
- Appear during growth period of large & giant breeds
Define canine panosteitis
Disease of young dogs causing lameness, bone pain, endosteal bone production & occasional periosteal bone production (There is an infiltration of eosinophils)
Describe the pathophysiology of canine panosteitis
- Etiology is unknown
- Osseous compartment syndrome (more dominant etiology theory)
- Disease of adipose bone marrow
What is osseous compartment syndrome
- Animals one protein rich - high calorie diet (potential cause)
- Excessive protein causes intraosseous edema -> increased medullary pressure & ischemia
- Endosteal bone formed as marrow invaded by bone trabeculae
What is the common signalment of panosteitis
- Male large breed dogs
- young dogs < 2 Y
- Older dogs occasionally dx
What is the common hx of px w/ panosteitis
- Shifting leg lameness
- Pain on deep bone palpation
- May present as acute lameness on single limb or of chronic intermittent shifting leg lameness
What is seen on a PE if the px has panosteitis
- Gait analysis (single or multi leg involvement)
- Severity of lameness varies (wt-bearing lameness)
- Pain on direct palpation of affected bone(s)
- Seen in dogs after growth has ceased
Describe the use of radiographs for assessing panosteitis
- Make dx w/ radiographs
- Clinical signs may precede radiographic changes by up to 10 D
- Repeat radiographs in 7 to 10 D
What are the radiographic findings for a px w/ panosteitis
- Widening of Nutrient foramen
- intramedullary radiocapicity (radiopaque patchy or mottled bone; blurring & accentuation of trabecular patterns)
- Endosteal thickening
- Periosteal new bone
What is this Xray showing
Intramedullary radiocapacity (cloudy)
How is panosteitis treated
- Medical - only if it is self-limiting disease, NSAIDs, Exercise restriction when lame, warn owner that recurrences are common
- Surgical treatment not indicated
- Long-term prognosis is excellent for complete recovery
Define hypertrophic osteodystrophy (HOD)
- Disease causing disruption of metaphyseal trabeculae
- Usually in the long bones of young rapidly growing dogs
What is the etiology of HOD
- Unknown
- Thought to be due to vitamin C def
- Viral causes suspected (usually w/ a hx of recent GI/resp prob, possible relationship to distemper virus, vax protocol assoc w/ dev of HOD, weimaraner pups & irish setters)
What is the pathophysiology of HOD
- Disturbance of metaphyseal BS (Changes in physis and adjacent metaphyseal bone, delayed ossification of physeal hypertrophic zone, increased width of the hypertrophied chondrocyte zone of the physis)
- No bone bormed on calcified cartilage, instead there is inflammatory infiltration of neutrophils & mononuclear cells
- Osteoclastic resorption of recently formed metaphyseal trabecular bone
What is the common signalment of px w/ HOD
- Young rapidly growing large breed
- Male > females
- Usually sx @ 3 to 4 M old
- Seen early as 2 M old
- Weimaraners @ increased risk
What is the common hx of px w/ HOD
- Acute onset of lameness
- May be severely affected (not able to walk)
- Inappetence & lethargy
- Hx of recent diarrhea may precede lameness
What will be seen in the PE of a possible HOD
- Mild to severe lameness of all 4 limbs
- Long bone metastases swollen, warm, & painful on palpation
- Swelling is often present in all 4 limbs
- Swelling in forelimbs may be more obvious (in the distal radial metaphyses)
What are the radiograph findings w/ HOD
- Irregular radiolucent line on the metaphyseal side of physis (“double physis”)
- Widening of the physis - as the disease progresses periosteal new bone formation may span active physis
- Usually on multiple limbs
- “second growth plate”
Label A & B
- A: active physis
- B: osteolysis
What is this showing
The progression of HOD
What is the treatment of HOD
- Self limiting so focus on supportive tx
- Analgesics to control pain - NSAIDs +/- opioids
- Severely affected animals - IV fluid support, corticosteroids, antibiotics, & vitamin C (should be considered & bacteremia needs to be ruled out before corticosteroids)
What is the prognosis of a px w/ HOD
- Most recover fully in 7 to 10 D (can have relapses)
- Severe debilitation or multi severe relapses = consider euthanasia
Describe Retained Ulnar cartilaginous core (AKA Retained endochondral cartilage core)
- Cones of growth plate cartilage
- Projects from distal ulnar growth plate into distal metaphysis
- Consist of viable hypertrophic chondrocytes (retained hypertrophic chondrocytes = failure of growth plate cartilage to convert to metaphyseal bone)
What is the clinical presentation of retained ulnar cartilaginous core
- Large to giant immature canines
- Growth plate manifestation of osteochondrosis (OC)
- If assoc w/ reduced ulnar length growth there will be cranial bowing of radius, rotation & valgus deviation of forepaw, & subluxation of carpal & elbow joint (CARPAL VALGUS)
- Forelimb deformities may be identical to premature closure of distal ulnar & radial growth plates
How to dx retained ulnar cartilaginous core
- Through radiographs
- Determine cause of deformity
- No correlation noted btw/ size of lesion, histopathology, & severity of forelimb deformity
What will be seen on radiographs of a px w/ retained ulnar cartilaginous core
- Radiolucent core (triangle) of cartilage in distal ulnar metaphysis +/- sclerotic zone
- Core can extend 3 to 4 cm into metaphysis
What is the tx of retained ulnar cartilaginous core
- W/ no forelimb deformity = not tx
- Moderate to marked forelimb deformities = surgical correction of deformity may be req, all px should be prescribed well balanced diet, & cores may disappear spont.
What is Legg-Calve-Perthes Dx
- Noninflammatory aseptic necrosis of femoral head
- Found in young px before capital femoral physis closure
- Synonyms - Avascular necrosis of femoral head
What is the causes of Legg-Calve-Perthes Dx
- Collapse of femoral epiphysis caused by interruption of blood flow
- Etiology unknown
- Autosomal recessive gene is the proposed genetic cause
What is the pathophysiology of Legg-Calve-Perthes Dx
- Vascular supply to the femoral head in young animals & comes from the epiphyseal vessels the metaphyseal vessels do not cross the physis to contribute to femoral head vascularity
- Epiphyseal vessels course along the femoral neck surface, cross the growth plate, & penetrate the bone this supplies nourishment to femoral epiphysis
- Synovitis or sustained abnorm limb position - may increase intra articular pressure & collapses fragile veins & inhibits blood flow
- Cell death occurs & reparative process begins
- Bone substance weakened during revascularization process
- Norm physio wt.bearing forces = collapse & fragmentation of femoral epiphysis, incongruence of femoral epiphysis & acetabulum (results in DJD), fragmentation & DJD cause pain and lameness
What is the common signalment of a px w/ Legg-Calve-Perthes Dx
- Young small breed dogs (under 10 kg)
- Peak incidence during 6 to 7 MO
- Ranges from 3 to 13 MO
- Males & females affected equally
- Occurs bilaterally in 10 to 17% of affected px
What is the common hx of a px w/ Legg-calve-perthes dx
- Slow onset of wt bearing lameness worsens over 6 to 8 W
- lameness may progress to non weight bearing (NWB)
- May present as acute onset of lameness - sudden collapse of epiphysis may cause acute exacerbation of lameness
- Other sx - irritability, reduced appetite, & chewing @ skin over the hip
What will be found on the PE of a px w/ Legg-calve-perthes dx
- Hip joint pain
- Limited range of motion, muscle atrophy, & crepitus if it is advanced disease
What DDx should also be considered when looking at the PE of a px w/ Legg-calve-perthes dx
- Physeal trauma & medial patella luxation (MPL)
- Small dogs may have concurrent bilateral MPLs
What will be seen on radiographs of a px w/ Legg-Calve-Perthes Dx
- shows femoral head deformity
- Femoral neck shortening &/or lysis
- Foci of decreased bone capacity w/in femoral epiphysis
What is the medical management of Legg-Calve-Perthes Dx
- Do in early stages of dx if not painful
- If made before collapse of femoral head - limited wt bearing on limb during revascularization to prevent collapse of femoral head
- Conservative tx - NSAIDs, leash limited or NWB exercise, can provide pain relief in small % of px
- Dx often made after collapse of epiphysis
- Results in joint incongruity & DJD
What is the surgical management of Legg-Calve-Perthes Dx
- Most dogs req sx to relieve lameness
- Excision of the femoral head & neck (FHO ) is the tx of choice
What is the postop care for a px w/ Legg-Calve-Perthes Dx
- Limb usage imm after sx (include immediate rehab exercise)
- NSAIDs to reduce pain & encourage early fxn
- Passive flexion-extension of hip done 2x daily
- PT initiated (canine rehab) - small movements & ROM gradually increased over 5 to 10 min
What is the prognosis of px w/ Legg-Calve-Perthes Dx
- Good after FHO - small size of affected dogs
- Slight intermittently lameness may occur - Heavy exercise or period of inactivity
- Poor occasionally w/ - NWB before sx, severe preop muscle atrophy, & incorrect sx technique
