Musculoskeletal Disease Flashcards
What causes Myasthenia Gravis?
Autoimmune destruction of POST junctional nicotinic acetylcholine receptors
Key features of MG are:
Muscle fatigue that gets works as the day progresses
Removal of ______ can improve symptoms of myasthenia gravis
The thymus
What situations exacerbate MG?
What are the early symptoms of MG?
What is the first line treatment for MG?
- ORAL PYRIDOSTIGMINE
- Immunosuppression
- Thymectomy
- Plasmapheresis
What test is used to determine whether muscle weakness is caused by MG?
In terms of NM blockade, MG creates sensitivity to ________ and resistance to _______
sensitivity to non-depolarizers
resistance to depolarizers
In a patient with MG, what is an appropriate dose of Rocuronium?
You should reduce your dose by 1/2 to 2/3 and give repeat doses based on ToF
If you have to give a patient with MG succinylcholine, what dose is appropriate?
1.5 - 2 mg/kg
Will a patient with MG who receives succinylcholine have a decreased or increased duration of action?
Increased. Pyridostigmine is an acetylcholinesterase inhibitor, so break down of Succ will be delayed
All patients with MG are at risk for requiring postoperative ventilation, but this risk is especially high in which circumstances?
What causes Eaton-Lambert Syndrome?
IgG mediated destruction of PREsynaptic voltage-gated CALCIUM channels
What are alternative names of Eaton Lambert Syndrome?
Myasthenic Syndrome
LEMS
How does ELS impact acetylcholine receptors?
It doesn’t! It inhibits PRE synaptic calcium channels, which means Ach is never released into the NMJ
Which muscles are effected by ELS?
The proximal muscles first (opposite of MG)
Eventually the diaphragm and respiratory muscles
Worst in the morning and improves throughout the day (opposite of MG)
What is the treatment for ELS?
DAP, which increases Ach release by presynaptic neurons
Which cholinesterase inhibitor is recommended for ELS?
NONE! Cholinesterase inhibitors are not helpful, and a Tensilon test is not diagnostic
Which NMBA should be used in patients with ELS?
They have increased sensitivity to BOTH
Which comorbidity is present in 60% of ELS patients?
Small cell carcinoma.
If a patient is coming in for surgery to remove an SCC, you should be suspicious they may have presynaptic dysfunction and be judicious with NMBAs
What causes Guillain-Barre syndrome?
Autoimmune destruction of the myelin sheath in peripheral nerves
Action potentials can’t be conducted
When does GBS occur?
1-3 weeks after a flu-like illness
How long does GBS last?
2-4 weeks
What are the most common causes of GBS?
Campylobacter
Mono
CMV
Vaccines
Surgery
Lymph Disease
What are the s/s of GBS?
What is the treatment for GBS?
Plasmapheresis
IVIG
Steroids are NOT helpful
How do patients with GBS respond to ephedrine?
They have an exaggerated response, because sympathetic receptors upregulate in an attempt to improve conduction
What is another name for GBS?
Acute idiopathic polyneuritis