B2W2

Question 1

Mechanism of Action for Myasthenia Gravis

Answer 1

Autoimmune attack on the post synaptic NMJ by blocking of AChR

Question 2

Symptoms of Myasthenia Gravis

Answer 2

-Ocular Symptoms (diplopia, ptosis)
-Bulbar Symptoms (chewing, swallowing, flaccid dysarthia)
-General Weakness

Question 3

Ocular MG v MG

Answer 3

Ocular MG has only ocular symptom presentation

Question 4

MG does not have any ……. symtpoms

Answer 4

sensory

Question 5

How do symptoms progress in a patient with MG

Answer 5

symptoms have fluctuation with a as the day progresses – improving with rest

Question 6

Physical Exam for MG

Answer 6

1. Neurological exam (ptosis, respiratory stress, drooping head)
2. Cranial Nerve exam (dysarthria, blurred vision, worsening ptosis, facial weakness with eyebrow raise, jaw opening and closing)
3. Muscle power testing for fatigue (testing to see if there is recovery after rest period after maximal effort)

Question 7

Diagnostic Testing for MG

Answer 7

-Tensilon Test (injection of AChE to see spontaneous recovery dog video)
-AChR antibody test (if this is negative, then test for MuSK antibodies)

Question 8

Name the Electrodiagnostic Studies for MG

Answer 8

-Nerve Conduction Studies
-Slow RNS
-Single Fiber Electromyography
-Chest Imaging

Question 9

Nerve Conduction Studies Mechanism

Answer 9

General conduction testing of motor and sensory neurons

Question 10

Slow RNS

Answer 10

-rapid, no pt coop needed, completed in weakened muscles
-slow RNS = decrease in SFMAP = decrease in CMAP
-decrease in readily available ACh leading to a decrease in AP generation (depression of EPSP!!)
- anything larger than a 10% difference between 1st and 4th response equates to a NMJ disorder

Question 11

Single Fiber Electromyography

Answer 11

Voluntary SFE (patient coop, done in an activated muscle, the most selective test for NMJ disorders, but not most specific, usually only done when there is a clinical presentation of MG)
Simulation SFE (no patient coop, stimulates muscle and nerve at the same time)

Question 12

Chest Imaging for MG

Answer 12

-looking for thyloma (tumor of thymus which is often seen in (+) ACh serum patients)
-thymic hyperplasia (enlarging of the thymus most often leading to a thymectomy)

Question 13

MG Exacerbation v Crisis

Answer 13

Exacerbation: minor respiratory symptoms without intubation
Crisis: respiratory symptoms leading to intubation innervation or ventilation

Question 14

Causes for MG Crisis

Answer 14

-Medication
-Uncontrolled Disease
-Infection
-Stress (pregnancy, surgery, trauma)

Question 15

Outpatient treatment of MG

Answer 15

-Mestinon (oral tensilon - AChE inhibitor) (GI side effects)
-Prednisone (most common) - (osteopenia, dyspepsia, insomnia, depression, weight gain side effects)
-Steroid sparing immunosuppressants (take longer to affect and usually are used in conjunction with prednisone regiment)
-Thymectomy (removal of thymus)

Question 16

Medication interactions with MG treatment (absolute, contradictions, caution level)

Answer 16

absolute- curare, botox
contradictions- antibacterials, antiarythmics, Mg, antimalarias
caution- antihypertensive, lithium, Statins

Question 17

Inpatient treatment of MG

Answer 17

-Ventilation
-Cardiac Monitoring
-Infection Tx
-Prophylaxis for DVT
-Rescue Therapies
—Plasma Infusions (RISK: spasms, hypotension, sepsis)
—-Immunoglobulin IV (RISKS: renal failure, rash, thrombosis)

Question 18

Lambert Eaton’s Mechanism of action

Answer 18

antibody targeting of presynaptic Ca2+ channels leading to decrease in Ca2+ and vesicle fusion

Question 19

Symptoms of LEMS

Answer 19

• Proximal weakness in extremities
  -Autonomic NS symptoms (orthrostatic hypotension, constipation, dry mouth)
  -Paraneoplastic (small lung cancer) v Non-paraneoplastic (IDDM, Thyroid condition)

Question 20

Clinical Exam of LEMS

Answer 20

-Proximal Weakness
-Ataxia (clumsy movements)
-Areflexia (unable to have reflex movements - recoverable with exercise)
-Dyspnea/Dysphagia

Question 21

Diagnosis of LEMS

Answer 21

1. Anti P/Q VG Ca 2+ channel serum must have conjunction with symptoms because this test also is true for many other neurological presentations
2. RRNS (rapid repetitive nerve stimulation)(seeing a rise from low CMAP to a recovery of AP due to increase in store release from peptide vesicles)

Question 22

Screening/Radiology Evaluation of LEMS

Answer 22

1. CT - abdomen or chest for tumor identification
2. FDG-PET - for highly metabolic areas
3. Serial Screening (to check factors that would make someone more likely to have LEMS based on gender, age, smoking hx, autoimmune hx) (High score = more screening, low score = less screening)

Question 23

Pathophys of Botulism

Answer 23

cleaves SNARE proteins that are involved in synaptic vesicular fusion leading to decrease in quantal content

Question 24

Method of infection for botulism

Answer 24

Ingestion

Question 25

Symptoms of Botulism

Answer 25

-Flaccid dysarthria -Oculobulbar weakness -Descending weakness

Question 26

Testing for Botulism

Answer 26

Stool samples/wound samples

Question 27

Physical Exam findings for botulism

Answer 27

-Fixed pupil dilation (paralysis of the irises) -facial diplegia (paralysis of both sides of the face) -constipation, respiratory failure, descending weakness

Question 28

Tx for Botulism

Answer 28

-ICU admission for respiratory support -HBAT (serum antibodies) -BIG-IV (serum for infants) -prolonged recovery