Small Animal Flashcards
What is the key feature of distinguishing which limb in a forelimb lameness?
Head and weight goes down on sound limb- sinking.
Why does a forelimb lameness give the appearance of a degree of lameness in the hindlimb?
Tend to balance diagonally therefore if e.g. lame on R TL and so on L TL for longer, also likely to be on R HL for longer
What are the key features of distinguishing which limb in a hindlimb lameness?
Iliac crest/ gluteal area sinks on sound side. Tarsus (calcaneus) acts as a spring- sinks on sound side
Why is grading the lameness important?
Graded out of 10. Regrade in a few weeks following tx
What is the presentation of bone disease in small animals?
Young animals. Deviation of limbs, poor posture, weakness. Axial and appendicular. Dietary problems. Comparison with littermates. Pathological fractures. Generalised dz.
Define osteomyelitis
Infection of the cortical bone and medullary cavity
Define osteitis
Inflammation of the cortex w/out involvement of the red/ yellow BM, can be septic/ aseptic
Describe the acute presentation of osteomyelitis
Occurs in LAs and SAs
Single limb lameness rapid onset, short duration
Often hx of laceration or sx
Describe the clinical exam findings for an acute presentation of osteomyelitis
Heat, pain, swelling on palpation of bones
Joints structures may be normal
Febrile
Describe the chronic presentation of osteomyelitis
Occurs in LA and SA.
Moderate/ intermittent lameness of days/ weeks duration
Often a hx of laceration or sx
Describe the clinical exam findings for a chronic presentation of osteomyelitis
Possible heat, pain, swelling on palpation of bones Joint structures may be normal Pain, discharge, sinus tract formation Pathological fracture (becomes acute)
In bone disease, the combination of pathogenic process and bones reaction leads to what two things?
Bone loss (lysis) Bone formation
What are some diagnostic options/ plans for bone disease?
Radiography. C+S (tracts, pieces of necrotic material). Biopsy (chronic osteomyelitis and OSA will look similar on radiograph, this helps distinguish between the 2). Radionuclide scan
What is the tx for osteomyelitis?
Early intervention w/ BS abx (change of culture and consider local delivery)
Surgical debridement, immobilisation, lavage
Rehabilitation of entire limb
Why it is important to get a bone biopsy when presented w/ radiographic appearance of osteomyelitis?
OSA and chronic osteomyelitis are radiographically similar (combo of lysis and formation of bone)
With suspected bone neoplasm, what should be included in the investigation?
Clinical evaluation (LN, degree of disability)
Radiography
Swab tracts, C+S on samples
Biopsy (jamshidi needle, get a no of planes)
Ddx based on biopsy and culture
Staging/ evaluation of px
Why is it important to get multiple planes of the lesion in a bone biopsy?
You need to get a representative sample of the lesion in order to help the pathologist make a ddx
What are some tx options for OSA?
Amputation (4m) Amputation and chemo (12-14m) Limb sparing and chemo (12-14m) Radiotherapy (palliative only) NSAIDs/ bisphosphonates (palliative only) Euthanasia
Define dysplasia.
It is an abnormality of development.
Describe hip dysplasia.
Hereditary disease that causes ligament hypertrophy (slack ligaments), subluxation, destruction of cartilage and changed shape of the joint surface. This leads to secondary osteoarthritis (bony AND fibrous) in the joint.
What are the clinical signs of hip dysplasia in puppies less than 6 months of age?
Generally only an abnormal gait is noticeable, caused by subluxation of the hip joint.
What are the clinical signs of hip dysplasia in puppies 6-16 months of age?
Progresses from just abnormal gait due to subluxation, to damage and inflammation causing pain and lameness as well.
What are clinical signs of hip dysplasia in dogs 16 months and older?
Abnormal joint with secondary OA causing pain and lameness, OR muscular/fibrous stabilization of the joint, resulting in pain free joint with restricted range of motion.
What is the treatment for hip dysplasia for puppies 0-6 months old?
Conservative; diet and exercise.
What is the treatment for hip dysplasia for dogs 6-16 months old?
- Conservative; diet and exercise (consider pain relief)
- Surgical; anatomical correction (arthroplasty)
What is the treatment for hip dysplasia for dogs 16 months old and older?
- Conservative; diet and exercise (pain relieving drugs)
- Surgical; hip replacement (arthroplasty)
What are some examples of osteochondrosis?
- Osteochondritis dessicans; detachment of a chondral or osteochondral fragment from the articular surface
- Subchondral bone cysts (SBCs)
- Peri-articular fragmentation/fracture; detachment of a chondral or osteochondral fragment from the peri-articular area
What is canine elbow dysplasia and what conditions are included?
Elbow dysplasia is a generalized incongruency of the elbow joint in young, large, rapidly growing dogs that is related to abnormal bone growth, joint stresses, or cartilage development. Humeral osteochondritis dessicans, fragmented coronoid process, united anconeal process, 2ry osteoarthritis
What joints can be affected in fast growing high performance dogs?
Elbow
Shoulder
Stifle
Tarsus
What conditions can be seen in fast growing high performance dogs?
- Osteochondritis dessicans
- Fragmented coronoid process
- Ununited anconeal process
Name the two types of synoviocytes.
Type A and type B
Describe the role of type A synoviocytes.
These are non-fixed cells that can phagocytose actively cell debris and wastes in the joint cavity, and possess an antigen-presenting ability; they are derived from blood-borne mononuclear cells, can be considered resident macrophages (tissue macrophages.
Describe the role of type B synoviocytes.
These are involved in producing the synovial fluid found in joints (hyaluronan, collagen, fibronectin).
Describe joint fluid.
It is a dyalisate from plasma, and is filtered by vascular endothelium and synovial interstitium. It contains proteins, electrolytes, enzymes, water, and HA, as well as synovial lining cells.
What are the classifications of arthritis?
Non-inflammatory (WBC less than 3000/ul) and inflammatory (WBC greater than 3000/ul).
What are the different types of non-inflammatory arthritis?
- Traumatic
- DJD
- Hemarthrosis (bleeding into the joint space)
What are the different types of inflammatory arthritis?
- Infectious (bacterial, viral, fungal, rickettsial, protozoal, borrelial, mycoplasma)
- Non infectious (immune based and non-immune based)
What are the different types of non-infectious immune based canine arthritis?
Erosive or Non-erosive
Name some causes of erosive immune based arthritis
Rheumatoid arthritis
PA of greyhound
Feline chronic progressive PA
Name some causes of non-erosive immune based arthritis
SLE Idiopathic PA/PM syndrome PA/ meningitis syndrome PA of akitas
What posture will a dog w/ a CCL rupture assume when sitting down?
The dog will abduct the injured leg out when asked to sit down as painful to flex stifle
What clinical sign is very distinctive to IMPA?
Affected animals look like they walk on eggshells. Painful to flex tarsus. Sit w/out putting weight at the back
What clinical sign would be associated with hip dysplasia?
Flex/ extend hips, so swing when walking
What can be used to diagnose joint disease?
Radiography
Arthrocentesis
Joint fluid analysis (cytology, cell count, chemical analysis, culture)
Describe how joint fluid is obtained via arthrocentesis?
Sedation/ GA
Sterile technique
Use of landmarks to determine where joint capsule is
What does presence of macrophages in joint fluid cytology mean? And neutrophils?
Macrophages- non-inflamm process (DJD)
Neutrophils- inflamm process (look at degenerate vs non-degenerate)
When is therefore decreased glucose in joint fluid?
Septic arthritis
When is there increased TP in joint fluid?
Inflammatory arthritis
How reliable is culture of joint fluid and what can be done to improve it?
23% false -ve
Be careful w/ false +ve also. If really suspect infectious but culture -ve then can use synovial membrane biopsy. Special culture media incr change of +ve culture
How do bacteria gain entry to the joint?
Direct penetration (trauma)
Spread from adjacent tissue
Haematogenous
OA- reaction in joint predisposes to infection
What are common pathogens in bacterial joint infection?
Staphylococcus
Streptococcus
Pasteurella
Why is radiography useful in dx of joint disease?
Erosive vs non-erosive- won’t see bony changes on radiography w/ non-erosive
Acute- effusion
Chronic- degenerative changes + OA
What diagnostic test can be used for infectious arthritis or when suspecting IMPA?
Serology for infectious agents- Lyme dz, Ehrlichiosis, Leishmania
When suspecting erosive PA, what test can be done to definitively diagnose?
High titres for Ab against IgG in rheumatoid arthritis (up to 70%) along w/ radiographic changes
What is the ANA titre test used to diagnose?
Systemic lupus erythematosus (which will cause other clinical signs incl PA)
What are the diagnostic criteria for SLE?
Major signs- skin lesions, glomerulonephritis, PA, haemolytic anaemia, polymyositis, leukopenia, thrombocytopenia
Minor signs- fever of unknown origin, CNS signs, seizures, oral ulcerations, lymphadenopathy, pericarditis, pleuritis
Serologic evaluation- ANA, lupus erythematosus cell preparation
What should you do when you suspect an immune-mediated polyarthritis?
Radiograph affected joint(s) Rheumatoid factor ANA titres Image body cavities (rads, US, CT) And depending on signs, CSF, muscle biopsy etc
How many limbs are involved in septic arthritis?
Usually only one