P2: Bone Pathology

What can cause low bone density?

rickets, osteoporosis, tumours

What can cause high bone density?

inflammation, productive tumours

Which are the more aggressive periosteal reactions?

sunburst, Codman triangle

What are examples of periosteal reactions?

thin, solid, tick irregular, septated, laminated (onionskin), perpendicular, sunburst, disorganised, Codman triangle

What is hypertrophic osteodystrophy characterised by?

decreased blood flow to metaphysis leading to failure of ossification, and necrosis and inflammation of cancellous bone

When does hypertrophic osteodystrophy typically first present?

2-7 months

What is the diagnosis of hypertrophic osteodystrophy based on?

history, clinical signs, physical exams showing pain and swelling at growth plates, x-rays

What do x-rays show with hypertrophic osteodystrophy?

thin radiolucent line at the metaphysis at the end of the ulna, radius, or tibia;
bony inflammation and bone remodelling may also be seen at these sites (fever and high white blood cell count)

What is the treatment for hypertrophic osteodystrophy

supportive; anti-inflammatories and painkillers

Which types of breeds are mostly affected by hypertrophic osteodystrophy?

fast-growing large and giant breed dogs

What causes nutritional secondary hyperparathyroidism?

puppies fed meat, increasing P, decreases Ca causing increased PTH;
hormonal

What is seen on an x-ray of nutritional secondary hyperthyroidism?

long bone has a thin cortex with an abnormally wide medullary cavity;
decreased bone density;
deformation;
fracture

What happens when growth plates close early in dogs?

trauma in physis causing fractures, subluxation of the elbow joint, arthrosis

Where does early closure of growth plates generally occur?

physia of distal ulna, radiusossification of the

What is seen on an x-ray with early closure of growth plates?

premature cut smaossification of the growth plates

What is the treatment for early closure of growth plates?

cut smaller bone

What is panosteoitis?

inflammatory disease of long bones affecting the medullary cavities and endoost-osteoblastic activity

What is the cause of panosteitis?

imbalanced food diet, high activity

Which breeds are more likely to be affected by panosteitis and when?

large breeds aged 5-12 months

What is the treatment of panosteitis?

balance diet and activity; anti-inflammatories

What is the cause of osteomyelitis?

open fractures (bacteria, fungi);
response to the osteosynthesis material

What are the clinical signs of acute osteomyelitis?

pain, swelling, fever

What are the clinical signs of chronic osteomyelitis?

muscle atrophy, cutaneous fistula, lameness, changes to all structures of the bone: Volkmann, Havers

What is seen in an x-ray with acute osteomyelitis?

indefinite

What is seen in an x-ray with chronic osteomyelitis?

periosteal reaction, increased radiopacity marrow - avascular bone segments

What types of general tumours are there?

benign, malignant, primary, secondary

Which tumours affect bones to cause secondary tumours?

prostate, mammary gland, lung, bowel cancer, blood vessels, lymphatic vessels

What is a tumour of blood or bone marrow called?

multiple myeloma

What is a tumour of cartilage called?

chondrosarcoma

What is a tumour of bone called?

osteosarcoma

What is a tumour of connective tissue called?

fibrosarcoma

What types of osteosarcoma are there?

mixed, productive formation, lytic formation

What is a Codman triangle?

a type of periosteal reaction seen with aggressive bone lesions where bone lesions grow so aggressively that they lift the periosteum off the bone and do not allow it to lay down new bone

What is the treatment of osterosarcomas?

amputation, treatment (radiotherapy, chemotherapy)

How are fractures classified?

by bone, by location (proximal epiphysis, diaphysis, distal epiphysis)

What types of fractures are there?

linear fracture;
transverse fracture;
oblique fracture;
spiral fracture;
incomplete fracture;
complete fracture;
comminuted (multiple) fracture

What is a linear fracture?

fracture parallel to the bone's long axis

What is a transverse fracture?

fracture at right angle to the bone's long axis

What is an oblique fracture?

fracture diagonal to the bone's long axis

What is a spiral fracture?

fracture where at least one part of the bone has been twisted

What is an incomplete fracture?

a fracture in which the bone fragments are still partially joined

What is a complete fracture?

a fracture in which fragments separate completely

What is a comminuted (multiple) fracture?

a fracture in which the bone has broken into several pieces

What are Salter-Harris fractures?

a fracture involving the epiphyseal plate

What is a type I Salter-Harris fracture?

a complete physeal fracture with or without displacement

What is a type II Salter-Harris fracture?

a physeal fracture that extends through the metaphysis, producing a chip fracture in the metaphysis, which may be very small

What is a type III Salter-Harris fracture?

a physeal fracture that extends through the epiphysis

What is a type IV Salter-Harris fracture?

a physeal fracture plus epiphyseal and metaphyseal fractures

What is a type V Salter-Harris fracture?

a compression fracture of the growth plate