SAM 1 - Red Material

How can you differentiate primary muscle disease from neuromuscular disease based on gait and neurologic examination?

Patients with primary muscle disease are not ataxic, and postural reactions and reflexes are usually normal.

How do patients with generalized muscle disease commonly present?

They commonly present with muscle weakness.

What is the target of the IgG autoantibodies in masticatory muscle myositis (MMM)?

A unique myosin component of the masticatory muscles called the 2M fibers.

Is masticatory muscle myositis painful or nonpainful?

Painful.

What percentage of acute MMM cases are positive for circulating 2M autoantibodies before steroid treatment?

Approximately 85–90%.

What test can be performed on a muscle biopsy to diagnose MMM?

Immunohistochemistry.

Why is forceful stretching, tearing, or opening of the mouth under anesthesia not recommended in chronic MMM?

The fibrotic masticatory muscles can be damaged by forced opening, so this old-school treatment is not recommended.

What are the two broad categories of canine idiopathic polymyositis?

It can be primary/autoimmune or secondary.

How severe can weakness be in canine idiopathic polymyositis?

Weakness can range from mild to severe.

How high can CK be elevated in canine idiopathic polymyositis?

CK can be elevated approximately 2–100 fold.

What enzyme besides CK is elevated in canine idiopathic polymyositis?

AST.

What is the definitive diagnostic test for canine idiopathic polymyositis?

Muscle biopsy.

When evaluating canine polymyositis, what type of underlying disease should you consider?

Neoplasia, including paraneoplastic disease secondary to lymphoma.

What is the treatment principle for secondary canine polymyositis?

Rule out or treat the underlying disease based on the diagnostic findings.

How common is feline idiopathic polymyositis?

It is rare.

What common acquired causes of diffuse weakness should be ruled out in a cat suspected of having feline idiopathic polymyositis?

Hypocalcemia and thiamine deficiency.

What percentage of cats with feline idiopathic polymyositis are mildly hypokalemic?

Approximately 70%.

What medication is preferred for treatment of feline idiopathic polymyositis?

Prednisolone.

Which breeds are classically associated with dermatomyositis?

Collies and Shelties.

Which muscles are commonly affected by fibrotic myopathy?

The gracilis and semitendinosus muscles.

What category of acquired myopathy is common according to the lecture?

Endocrine and metabolic myopathies.

Is tetanus considered a disease of the muscle?

No, tetanus is not a muscle disease.

How high can CK become in feline muscular dystrophy?

It can be markedly elevated, often greater than 30,000.

What major muscle abnormality is associated with feline muscular dystrophy?

Marked muscular hypertrophy.

What tongue abnormality can occur with feline muscular dystrophy?

Protrusion of the tongue.

What are the two major categories of joint disease?

Non-inflammatory and inflammatory.

What are the major categories of non-inflammatory joint disease?

Developmental, degenerative, neoplastic, and traumatic.

What are the major categories of inflammatory joint disease?

Infectious and noninfectious/immune-mediated disease, including erosive and non-erosive disease.

What clinical features are characteristic of inflammatory joint disease?

Very painful joints, systemic signs of disease, and commonly multiple joints affected.

What clinical feature distinguishes degenerative/non-inflammatory joint disease from inflammatory joint disease?

Reluctance to exercise without systemic signs of illness.

When should radiographs be used for initial evaluation of joint disease?

When only one joint is clinically affected or when joint palpation reveals crepitation, instability, or restricted range of motion.

When are radiographs not recommended in a patient presumed to have IMPA?

When the patient has a rapid and complete response to treatment.

Why is arthrocentesis useful in diagnosing joint disease?

It has minimal risk and a high diagnostic yield.

How many joints should be sampled when polyarthritis is suspected?

At least 3–4 joints.

What aseptic precautions should be used when performing arthrocentesis?

Always aseptically prepare the site and wear gloves.

How many white blood cells should normally be present in synovial fluid per 40× high-dry-power field?

No more than 3 WBCs.

What percentage of neutrophils should normally be present in synovial fluid?

Less than 10%.

What are the most commonly identified underlying causes of degenerative joint disease?

Joint instability, trauma, and developmental orthopedic disease.

Do patients with degenerative joint disease typically have systemic signs of illness?

No.

What is the overall treatment approach for degenerative joint disease/osteoarthritis?

Multimodal therapy.

What is the minimum recommended washout period between NSAIDs?

72 hours.

Why are NSAIDs considered useful for long-term treatment?

They have a favorable safety profile.

What gastrointestinal adverse effects can NSAIDs cause?

Gastrointestinal side effects ranging from erosion to ulceration.

In which patients should NSAIDs be avoided?

Dehydrated patients, hypotensive patients, patients receiving concurrent steroids, and geriatric patients with comorbidities.

Why should NSAIDs be used with extreme caution in cats?

Cats have limited hepatic glucuronidation.

Which NSAIDs are specifically mentioned for use in cats?

Meloxicam and robenacoxib.

How should NSAIDs be incorporated into treatment of feline osteoarthritis?

They should be used judiciously as part of a multimodal therapy plan.

What omega-6 to omega-3 fatty acid ratio is recommended?

Approximately 3:1 or 4:1.

Which opioids are specifically mentioned in the lecture?

Hydromorphone, morphine, buprenorphine, and tramadol.

What receptor system is gabapentin associated with?

NMDA receptors.

What is an important route of infection for septic arthritis?

Direct inoculation.

What type of wound commonly results in a single-joint septic infection?

A penetrating wound involving the joint.

Which organisms are most common causes of septic arthritis in dogs?

Staphylococcus, Streptococcus, and coliform organisms.

Which organism is most common in feline septic arthritis?

Pasteurella.

What are common clinical signs of Lyme/tick-borne polyarthritis in dogs?

Lameness and/or myalgia, joint swelling in one or more joints, and painful joints on palpation.

Are most dogs infected with Lyme disease symptomatic?

No, most infected dogs are asymptomatic.

What class of antibiotics can be used to treat acute tick-borne infections such as Lyme disease?

Tetracyclines such as doxycycline.

Why must steroids be used cautiously with acute tick-borne infections?

Immunosuppressive doses can exacerbate the infection.

What CBC abnormality is commonly associated with rickettsial polyarthropathy?

Thrombocytopenia.

What percentage of non-erosive immune-mediated polyarthritis cases does reactive polyarthritis account for?

Approximately 25%.

How is idiopathic immune-mediated non-erosive polyarthritis diagnosed?

By ruling out other causes of polyarthritis.

In which species is idiopathic immune-mediated non-erosive polyarthritis the most common immune-mediated form?

Dogs.

What does a rapid and complete response to antibiotics suggest in a patient suspected of having IMPA?

It makes IMPA unlikely.

What is the cornerstone of therapy for IMPA?

Prednisone.

What are the five most common developmental orthopedic diseases in dogs listed in the lecture?

Hip dysplasia, elbow dysplasia, medial patellar luxation, shoulder osteochondritis dissecans (OCD), and panosteitis.

What type of disease is canine hip dysplasia?

A multifactorial disease involving genetic and environmental factors.

What is the first proposed mechanism for canine hip dysplasia?

Primary joint laxity due to abnormal collagen type or fiber development in the joint capsule and ligament of the femoral head.

What is the second proposed mechanism for canine hip dysplasia?

Abnormal endochondral ossification of the acetabulum resulting in joint incongruency, joint effusion, and secondary subluxation and laxity.

What is the gold-standard diagnostic projection for canine hip dysplasia?

The PennHIP distraction projection.

Why is the PennHIP distraction projection useful in younger animals?

It is accurate in young dogs, including around 6 months of age.

What are disadvantages of the PennHIP distraction projection?

It requires certified users, special equipment, and multiple views.

What is the pathophysiology of osteochondrosis/osteochondritis dissecans (OC/OCD) in elbow dysplasia?

A disturbance in endochondral ossification.

What are the proposed causes of fragmented coronoid process (FCP) or medial coronoid disease (MCD)?

Multiple different proposed causes.

What is the underlying abnormality associated with ununited anconeal process (UAP)?

A hereditary abnormality in the growth plate.

Which dogs are predisposed to panosteitis?

Large-breed dogs.

Which regions of the long bones are affected by panosteitis?

The diaphyseal and metaphyseal regions.