Musculoskeletal Arthritis Flashcards
osteoarthritis
older patients
progressive erosion/degen or articular cartilage
morning stiffness
Rheumatoid arthritis
Chronic inflammatory disorder
Autoimmune HLA DRB1
Juxta-articular osteopenia/narrowing joint space
What are the RA critieria (7 Items)
Morning stiff
Arthritis in 3+ joints
Arthritis of hand joints
Symmetric arthritis
Rheumatoid nodules
Positive Serum RF+
Radiographic Changes
What does the synovium look like in RA
Thickened, hyperplastic
Histology of RA
dense perivascular inflammatory cells
lymphoid aggregates
What is gout
tissue accumulation of uric acid
What are tophi
large aggregations of urate crystals with inflammatory reaction
What is pseudogout
Sporadic and idiopathic aggregation of calcium phosphate
What organisms can cause infectious arthritis
Suppurative bacteria
TB
Lyme Disease
Parvovirus B19, Rubella, HCV
Clinical Presentation of Infective Arthritis
Sudden onset of pain Usually happens at a single joint
What are the two classes of muscle diseases?
Denervation (Neurogenic Change)
Myopathy (Primary muscle disease)
What is a motor unit?
The lower motor nerve and the muscle fibers it innervates
What determines the muscle fiber type?
The motor unit neuron
What type is slow twitch, weight bearing movement?
Type I
What type is fast twitch, puposeful movement?
Type II
What is a motor neuron disease?
Any disease affecting motor neurons Upper Lower Combined
What is a primary motor neuron disease?
Idipathic or inherited
Secondary motor neuron disease?
Infectious Toxic Metabolic
Multisystem motor neuron disease?
Motor neuron disease + other disease process
What does ALS stand for?
Amyotrophic Lateral Sclerosis
What is the average age of ALS onset? Are men or women affected more?
60 years Men 1.5:1
What are the clinical symptoms of ALS
Early: Asymmetric hand weakness
Late: Progressive muscle weakness spreading to respiratory muscles
What happens microscopically to ALS patients
Anterior spinal nerve roots shrink and atrophy
Brain is normal but if it is affected it would be pre-frontal gyrus
Why is it called Lateral Sclerosis?
Because there is degeneration of the myelinated fibers in the corticospinal tracts (lateral to the grey matter)
What are some clues to look for when performing a muscle tissue biopsy?
Fiber size variation
Degeneration/myonecrosis +/- regeneration Hypertrophic Fibers Vacuoles or intracytoplasmic deposits
Late: Fibrosis and fatty infiltration
What are some general myopathic findings
Degeneration Regeneration Fibrosis
What is the issue with Duchenne Muscular Dytrophy?
Dystrophin is completely absent
What is the cause of Becker MD?
Dystrophin is reduced
Clinical signs of MD
Proximal weakness
Calf pseudohypertrophy
CK elevated early, and then drops as muscle is destroyed
Death from respiratory and cardiac failure
Why are boys affected by MD and not girls?
The gene affected is X linked
When looking at histology for dystrophinopathies what does the normal control look like?
Honey comb with a solid border
What does the DMD look like?
Faded honeycomb missing the dark border
What does BeckerMD look like?
Openings with cell nuclei will be present
What are the typical indicators for inflammatory myopathy?
Proximal weakness Pain Elevated CK
What work up is critical to the diagnosis?
Rheumatological
Polymyositis
Dermatomyositis
McArdles Disease
What myopathy is induced by steroids
Type II Fiber Atrophy
What myopathy is induced by Statin Drugs
Sinble myocyte necrosis with no inflammation
What myopathy is induced by Colchicine
Toxic Vacuolar Myopathy
What myopathy is induced by alcohol
Rhabdomyolysis
What is Critical Illness Myopathy?
ICU/Steroids/vent with neuromuscular block
What Causes This?
Carnitine palmityl transferase deficiency
Which parent would you inherit a mitochondrial myopathy from?
Mom
What special sense organ could be affected by mitochondrial myopathies?
Eye
This “hot” myopathy is caused by Ion channels and a RYR1 gene mutation
Malignant hyperthermia
What can trigger malignant hyperthermia?
Anaesthesia….and it happen to totally healthy people who have never had surgery before
What are the clinical signs of Myasthenia Gravis?
Muscle weakness
Women younger than 40
Weakness is worsened by exercise but helped by rest
Drooping eyelids
Double vision
Labored breathing
What causes myasthenia gravis?
Immune mediated loss of Ach receptors post-synaptically
What disease is caused by antibody response to presynaptic voltage gated Ca receptors?
Lambert Eaton Syndrome
How can you DDx lamber eaton from Mya Gravis?
In Eaton syndrome Ach agents will not improve symptoms because the signal is being stopped before it ever gets to the NMJ
