Pathophysiology
Myasthenia gravis is an autoimmune disorder affecting this location.
What is the neuromuscular junction?
This is the most common initial symptom of MG.
What is ptosis?
This blood test is first-line when MG is suspected.
What are acetylcholine receptor antibodies?
This acetylcholinesterase inhibitor is first-line symptomatic treatment.
What is pyridostigmine?
This tumor is classically associated with MG.
What is thymoma?
The most common antibodies in MG target this receptor.
What is the acetylcholine receptor (AChR)?
Weakness in MG characteristically worsens with this and improves with this.
What is use (fatigue) and rest?
If AChR antibodies are negative, this antibody should be tested next
What is MuSK antibody?
These medications are used for long-term immunosuppression in generalized MG.
What are corticosteroids?
This class of antibiotics can worsen MG symptoms and should be avoided.
What are fluoroquinolones?
(Also acceptable: aminoglycosides, macrolides)
These antibodies reduce functional receptors by complement activation and this process.
What is receptor internalization and degradation?
Diplopia in MG results from weakness of these muscles.
What are extraocular muscles?
Repetitive nerve stimulation in MG shows this pattern.
What is a decremental response?
This steroid-sparing immunosuppressant is commonly used in MG
What is azathioprine?
(Also acceptable: mycophenolate mofetil)
Differentiating myasthenic from cholinergic crisis may require this short-acting acetylcholinesterase inhibitor (historical test).
What is edrophonium?
This alternative antibody is associated with AChR-negative MG and often causes more bulbar symptoms.
What is anti-MuSK (muscle-specific kinase)?
This life-threatening complication involves respiratory muscle weakness.
What is myasthenic crisis?
All patients with MG should undergo imaging of this structure.
What is the thymus (CT chest)?
These two therapies are used for rapid improvement in myasthenic crisis.
What are IVIG and plasmapheresis?
In contrast to MG, this disorder presents with proximal weakness that improves with repeated use.
What is Lambert-Eaton myasthenic syndrome?
In MuSK-positive MG, complement activation is less prominent because these antibodies are primarily of this IgG subclass.
What is IgG4?
Reflexes and sensation in MG are typically this.
What are normal?
This bedside respiratory measurement helps determine need for intubation in myasthenic crisis (value <20 is concerning).
What is negative inspiratory force (NIF)?
This surgical intervention improves outcomes in patients with AChR-positive generalized MG, even without thymoma.
What is thymectomy?
Lambert-Eaton syndrome is most commonly associated with this malignancy.
What is small cell lung cancer?