Lecture 27: Developmental Bone Disease (Exam 3) Flashcards
1
Q
What are some primarily inflammatory dev bone diseases & who are they seen in
A
- Panosteitis
- Hypertrophic osteodystrophy (HOD)
- Appear during growth period of large & giant breeds
2
Q
Define canine panosteitis
A
Disease of young dogs causing lameness, bone pain, endosteal bone production & occasional periosteal bone production (There is an infiltration of eosinophils)
3
Q
Describe the pathophysiology of canine panosteitis
A
- Etiology is unknown
- Osseous compartment syndrome (more dominant etiology theory)
- Disease of adipose bone marrow
4
Q
What is osseous compartment syndrome
A
- 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
5
Q
What is the common signalment of panosteitis
A
- Male large breed dogs
- young dogs < 2 Y
- Older dogs occasionally dx
6
Q
What is the common hx of px w/ panosteitis
A
- Shifting leg lameness
- Pain on deep bone palpation
- May present as acute lameness on single limb or of chronic intermittent shifting leg lameness
7
Q
What is seen on a PE if the px has panosteitis
A
- 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
8
Q
Describe the use of radiographs for assessing panosteitis
A
- Make dx w/ radiographs
- Clinical signs may precede radiographic changes by up to 10 D
- Repeat radiographs in 7 to 10 D
9
Q
What are the radiographic findings for a px w/ panosteitis
A
- Widening of Nutrient foramen
- intramedullary radiocapicity (radiopaque patchy or mottled bone; blurring & accentuation of trabecular patterns)
- Endosteal thickening
- Periosteal new bone
10
Q
What is this Xray showing
A
Intramedullary radiocapacity (cloudy)
11
Q
How is panosteitis treated
A
- 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
12
Q
Define hypertrophic osteodystrophy (HOD)
A
- Disease causing disruption of metaphyseal trabeculae
- Usually in the long bones of young rapidly growing dogs
13
Q
What is the etiology of HOD
A
- 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)
14
Q
What is the pathophysiology of HOD
A
- 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
15
Q
What is the common signalment of px w/ HOD
A
- Young rapidly growing large breed
- Male > females
- Usually sx @ 3 to 4 M old
- Seen early as 2 M old
- Weimaraners @ increased risk
16
Q
What is the common hx of px w/ HOD
A
- Acute onset of lameness
- May be severely affected (not able to walk)
- Inappetence & lethargy
- Hx of recent diarrhea may precede lameness
17
Q
What will be seen in the PE of a possible HOD
A
- 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)
18
Q
What are the radiograph findings w/ HOD
A
- 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”
19
Q
Label A & B
A
- A: active physis
- B: osteolysis
20
Q
What is this showing
A
The progression of HOD
21
Q
What is the treatment of HOD
A
- 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)
22
Q
What is the prognosis of a px w/ HOD
A
- Most recover fully in 7 to 10 D (can have relapses)
- Severe debilitation or multi severe relapses = consider euthanasia
23
Q
Describe Retained Ulnar cartilaginous core (AKA Retained endochondral cartilage core)
A
- 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)
24
Q
What is the clinical presentation of retained ulnar cartilaginous core
A
- 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
25
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
26
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
27
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.
28
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
29
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
30
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
31
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
32
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
33
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
34
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
35
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
36
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
37
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
38
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
39
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
