Musculoskeletal Flashcards
1
Q
What is scleroderma?
who does it affect most
A
- An initial damage is caused to small blood vessels (unknown what causes this) which leads to tissue ischemia and fibrosis
- fluid leaks out of the vessels, causing an inflammatory response, laying collagen which causes fibrosis
- This can happen to blood vessels anywhere in the body
- Because it is autoimmune, it requires a genetic component AND an environmental trigger
- women 35-45 years old (4:1; women:men)
2
Q
What is an early sign of scleroderma and what can this turn into later?
A
- Raynaud’s is an early sign
- If the perfusion is so poor to the fingers, they will get scars or become necrotic
- eventually can form calcium deposits.
3
Q
What is “limited” Scleroderma?
A
- CREST
- C- Calcinosis
- calcium deposits on skin
- R- Raynaud’s Phenomenon
- spasm of blood vessels in response to cold or stress
- E- Esophageal dysfunction (too stiff to allow food to pass)
- acid reflux and decrease in motility of esophagus
- S- Sclerodactyly
- Thickening and tighetening of the skin on the fingers and hands
- T- Telangiectasia
- Dilation of capillaries causing red marks on the skin surface
- Small, dilated capillaries (if in mouth, can bleed with DVL)
4
Q
What is “diffuse” scleroderma?
A
- Lung fibrosis (leading cause of death in scleroderma
- decrease in diffusion, decrease in compliance
- pulmonary arterial hypertension
- Right heart failure (cor pulmonale); common
- Left heart failure (fibrosis); non common
- pericarditis
- Kidney- baseent membrane fibrosis- decreased GFR & proteinuria (slow)
- scleroderma renal crisis- (rapid)
- Gi tract- hypomotility, malabsorption
- Joint contractures- loss of mobility
5
Q
Systemin Lupus Erythematosus (SLE)
What type of sensitivity?
Who does it affect?
A
- Type III sensitivity
- primarily affects young women (15-30); blacks and hispanics more than whites
6
Q
Systemic Lupus Erythematosus (SLE)
How does this disease work?
A
- Pt has anti-nuclear antibodies
- damaged cells do not go through apoptosis correctly, allowing for release of DNA which the antibodies bind to, leading to further destruction?
- Immune complexes damage blood vessels
- this can happen to any organ
7
Q
How does Systemic lupus erythematosus affect the different systems?
A
- Cardiovascular disease is now the leading cause of lupus now that there is dialysis
8
Q
What are the different parts of muscle fibers?
A
- One cell runs entire length of muscle
- myofibril is made up of A-band, I-band, and z-disk
- A-band and I-band slide together, overlapping, when muscle is contracted.
9
Q
A
- Nerve impulse comes through axon and depolarized calcium channel at end of axon. Calcium causes release of acetylcholine
- Acetylcholine causes ligand dependent Na channel to open and Na moves into sarcoplasm, depolarizing cell.
- Depolarized sarcoplasm opens Na voltage gated channel and further depolarizes.
- Voltage gated Ca channel in sarcoplasm opens which opens calcium channel (dihydropyridine, DHP) in Sarcoplasmic reticulum. (this is where T-tubule is depolarized)
- Calcium moves from SR into sarcoplasm which contracts cell.
10
Q
What is Duchenne muscular dystrophy?
A
- There is not enough Dystrophin, which is a protein that connects the muscle fiber to the endomysium
- Without it, everytime the person uses their muscles, it rips the plasma membrane
- a normal person would recover to be stronger
- person with MD just gets weaker
- High levels of CK from these cellular injuries
- until they no longer have any muscles left to injure
11
Q
Who is most often affected by Duchenne’s?
A
- Young boys
- usually wheelchair bound by 8
12
Q
How does Myesthenia gravis work?
What type of hypersensitivity is it?
A
- Type II hypersensitivity
- Antibodies that react with acetylcholine receptors either prevent the receptors from working or destroy them
- Requires much more ACh to get the same response as a normal person because the ACh has to find the few functioning receptors
- They are strongest in the am when they have higher stores of ACh
- Weakness is improved with acetylcholinesterase inhibitors
13
Q
What is myesthenic syndrome?
A
- Ca++ channel at the end of neuron is blocked by antibody
- Acetylcholine cant get out
- They are weak all day, do not start stronger and get weaker
- weakness is not improved with acetylcholinesterase inhibitors
14
Q
How does curare work?
botulinum toxin?
tetani toxin?
A
- Curare: works by competetively blocking the acetylcholine receptor
- Botulinum: ACh vessicles cant fuse with membrane and cant be released
- very long lasting
- Tetani: uncontrolled fusion of ACh vessicles to the membrane
- causing overstimulation
15
Q
What are osteoclasts?
osteoblasts?
osteocytes?
A
- Osteoclasts- macrophage that breaks down bone
- Osteoblasts: cells that lay down bone
- Osteocytes: mature osteoblasts
- Know the difference between spongy/trebeculae and compact/cortico
16
Q
What kind of genetic disorder is Marfan’s syndrome?
A
- Autosomal dominant
- 20% are spontaneous mutations
- men, women, and all races are equally affected
17
Q
What genes are involved with Marfan’s Syndrome?
A
- FBN1 gene which encodes fibrillin-1
- Fibrillin-1 is essential for the proper formation of elastic fibers
- People with marfan’s syndrome have weac elastic fibers
18
Q
What symptoms are affected by marfan’s syndrome?
A
- skeletal system
- tall, extra long long bones
- scoliosis, thoracic lordosis
- pectus excavatum or protrusion of sternum
- CV
- regurg of the mitral or aortic valves
- dilation of aorta or aortic aneurism
- lungs
- spontaneous pneumothorax common
- eyes
- lens dislocation
- visual problems
- nervous system
- weakening of connective tissue of dural sac around spinal cord
19
Q
What type of genetic disorder is Achondroplasia?
What genes are involved?
Who is most affected?
A
- Autosomal dominant
- 80% spontaneous mutations
- FGFR3 which encodes fibroflast growth factor
- fibroblast growth factor is a negative regulator of bone growth
- mutated form is continually active
- affects long bones, flat bones are ok
- males, females, and all races equally affected
20
Q
How is the skeletal system affected by achondroplasia?
A
- tubular bones are short and thick
- skull is large
- narrow foramen magnum
- relatively small skull base
- narrowed spinal canal
- cervical kyphosis
- stiff neck when intubating
- Dens is short- chance of cervical dislocation
- *some patients dont live past one, but if they do they will have normal lifespan and cognitive abilities
21
Q
What parts of the bone are affected in osteoporosis?
A
- cortical- gets new holes
- trabecular bone- gets thinner
22
Q
What is the basic difference between osteoarthritis and rheumatoid arthritis?
A
- osteoarthritis is NOT inflammatory
- usually found on weight bearing joints, due to life long use
- Rheumatoid arthritis is an autoimmune disorder
23
Q
What sites are most commonly affected by osteoarthritis?
A
24
Q
How does rheumatoid arthritis work?
A
- Immune system attacks joints
- can affect ppl of all ages
- can cause errosion of bone
- fingers will be pulled to one side by tighetening of ligament after errosion of bone
25
What is ankylosing spondylitis?
* Autoimmune disease that affects the entire body
* fusion of neighboring vertebrae
* weight loss
* fatigue
* fever
* aortic regurgitation
* bundle branch block
26
what is spondylosis?
degeneration of the spinal column from any cause, usually osteoarthritis
27
what is spondylolysis?
defect or stress fracture in the pars interarticularis of the vertebral arch, usually in the lower lumbar vertebrae
28
what is spondylolisthesis?
forward displacement of a vertebra over a lower segment, usually L5 or L4
