Applied Physiology: Lecture 3 - Neuro Cont'd (Disease)

Question 1

What is Myasthenia Gravis?

Answer 1

Chronic autoimmune disorder. 1:7500

Occurs at a rate of 1:7500.

Question 2

What demographic is most affected by Myasthenia Gravis?

Answer 2

Women aged 20-30 years; men over 60 years.

Question 3

What causes Myasthenia Gravis?

Answer 3

Decrease in functional AcH receptors at NMJ due to circulating antibodies.

Question 4

What is the implication of the thymus gland in Myasthenia Gravis?

Answer 4

Thymus gland is implicated in the unknown origin of antibodies.

Question 5

What percentage of AcH receptors can be lost in Myasthenia Gravis?

Answer 5

Up to 70-80 percent.

Present as very weak, and unhealthy. Typically no muscle mass.

Question 6

Which muscles are most vulnerable in Myasthenia Gravis?

Answer 6

Muscles innervated by cranial nerves. Facial muscles you will see it

Question 7

How is Myasthenia Gravis classified?

Answer 7

Depends on skeletal muscles involved and symptom severity.

Question 8

What characterizes Type 1 Myasthenia Gravis?

Answer 8

Involves extraocular muscles only (10%).

Question 9

What is Type 2A Myasthenia Gravis?

Answer 9

Slowly progressive, mild form, respiratory muscle sparing. Good response to ACH esterase and steroid therapy

Question 10

What distinguishes Type 2B Myasthenia Gravis?

Answer 10

More rapid than 2A, less response to pharmaceuticals, respiratory muscles may be involved.

Question 11

What is Type 3 Myasthenia Gravis?

Answer 11

Acute onset, rapid deterioration, skeletal muscle strength loss within 6 months.

Question 12

What characterizes Type 4 Myasthenia Gravis?

Answer 12

Severe, progresses from Type 1 or 2.

Question 13

Differential Diagnosis of Myasthenia Gravis

Answer 13

Look at Stoetlings 7th or 8th Edition (this chart is older)

Question 14

What is the primary treatment for Myasthenia Gravis?

Answer 14

Thymectomy (surgical treatment).

Question 15

What is the main anticholinesterase therapy used for Myasthenia Gravis?

Answer 15

Pyridostigmine.

Question 16

What is the onset and duration time for oral Pyridostigmine?

Answer 16

30 minutes.
Peaks in 2 hours
DOA 3-6 hours

Question 17

What is a Cholinergic Crisis?

Answer 17

Overabundance of AcH.

High doee of Pyridostigmine can cause it

Question 18

What occurs during a Cholinergic Crisis?

Answer 18

Stimulation of nicotinic and muscarinic AcH receptors.

Question 19

What can cause a Cholinergic Crisis?

Answer 19

Organophosphate poisoning.

Question 20

What is a Myasthenic Crisis?

Answer 20

Severe life-threatening complication of myasthenia gravis.

Question 21

Cholinergic Crisis vs Myasthenic Crisis

Answer 21

Myasthenic Crisis
Severe life threatening complication of myasthenia gravis. Worsening muscle weakness, effecting muscles of respiration. May require intubation and mechanical ventilation.

Triggered by stress, surgery, infection.

Treatment: IVIG, plasmapheresis.

Cholinergic crisis
Overabundance of AcH.

Stimulation of nicotinic and muscarinic AcHreceptors.

Organophosphate poisoning.

Leads to muscle weakness, respiratory distress, BLUDS

Question 22

Cholinergic Crisis vs Myasthenic crisis (Differentiation)

Answer 22

Both can occur in a patient with Myasthenia Gravis.

Myasthenic crisis: Not enough AcH

Cholinergic crisis: too much AcH

How do we differentiate the 2?

Edrophonium test:
Edrophonium is an AcHesterase inhibitor

2mg Edrophonium: If symptoms get better then its Myasthenic crisis. If symptoms get worse: Cholinergic crisis.

Question 23

What is the Edrophonium test used for?

Answer 23

To distinguish between Myasthenic crisis and Cholinergic crisis.

Question 24

Anesthetic Considerations when taking Pyridostigmine and MG

Answer 24

May need post op vent support (talk about it in preop)

Dose of pyridostigmine daily? Surgery type? Severity of Dz, concomitant COPD, OSA?

Increases sensitivity to NDMRs, increased resistance to Succ.

Sugamaddex may be the best choice. Or if you can avoid any NMJ blockade, that would be ideal.

More Sux, less Roc?? (LOOK UP)

Question 25

Myasthenia Gravis and Atracurium

Answer 25

Dose response curve to Atracurium Left shift from normal Sensitive to NDMR

Question 26

What is Myasthenic Syndrome also known as?

Answer 26

Lambert Eaton Syndrome.

Question 27

What antibodies are involved in Myasthenic Syndrome?

Answer 27

Immunoglobulin G antibodies to Ca channels. Acquired autoimmune disease

Question 28

Myasthenic Syndrome

Answer 28

Skeletal muscle cell depolarizes, but no Calcium enters the cell. No muscle contraction ACHesteraseinhibitors are not effective in Myasthenic syndrome Sensitive to NDMRS and Succ Polyneuropathy that develops in elderly patients should always arouse suspicion of undiagnosed cancer. Myasthenic (Eaton-Lambert) syndrome may be observed in patients with carcinoma of the lung.

Question 29

Myasthenic Syndrome vs MG

Answer 29

Question 30

What is Myotonic Dystrophy?

Answer 30

Hereditary condition without NMJ involvement, instead a repetitive prolonged discharges of repetitive muscle action potentials. Stems from abnormal Calcium metabolism GA, Regional, NDMB not helpful in relieving contractures.

Question 31

What is the characteristic of Myotonia Congenita and Schwartz-Jampel syndrom?

Answer 31

A type of myotonic dystrophy.

Question 32

Anesthetic considerations with Mytonic Dystrophy?

Answer 32

Avoid Succ: Prolongs skeletal muscle contraction. NDMR okay. No increased/decreased sensitivity or resistance What about reversal? Watch for hypersomnolence effect of narcotics and benzos. (central respiratory depressive effects + weak respiratory muscles) Assess for cardiomyopathy, respiratory muscle weakness. How do your anesthetics make cardiomyopathy worse? Normothermia, avoid shivering

Question 33

What is Schwartz-Jampel Syndrome?

Answer 33

A type of myotonic dystrophy.

Question 34

What anesthetic should be avoided in myotonic dystrophy?

Answer 34

Succinycholine.

Question 35

What are Non-depolarizing muscle relaxants (NDMR) in myotonic dystrophy?

Answer 35

Okay to use; no increased/decreased sensitivity or resistance.

Question 36

What should be monitored in anesthetic considerations for myotonic dystrophy?

Answer 36

Hypersomnolence effect from narcotics and benzodiazepines.

Question 37

What is Muscular Dystrophy?

Answer 37

Painless degeneration and atrophy of skeletal muscles; progressive and linear. Skeletal muscle weakness but muscles remain innervated. Reflexes and sensation remain in tact

Question 38

What is Duchenne's Muscular Dystrophy? (pseudo hypertrophic)

Answer 38

Most severe, childhood progressive type; X-linked recessive. 3:10,000 births, X linked recessive. Can be seen in 2-5 YO males Most severe, childhood progressive type

Question 39

What are the initial symptoms of Duchenne's Muscular Dystrophy?

Answer 39

Waddling gait, frequent falling, difficulty climbing stairs (pelvic muscle weakness) Affected muscles fill with fat. Appear large (pseudo hypertropic)

Question 40

What is the typical age for patients to become wheelchair-bound in Duchenne's Muscular Dystrophy?

Answer 40

By age 8-10 years. Long bone fractures, mental retardation often accompanies

Question 41

What is the serum Creatine Kinase level in Duchenne's Muscular Dystrophy?

Answer 41

Elevated 20-100x normal.

Question 42

What is the typical age of death in Duchenne's Muscular Dystrophy?

Answer 42

By age 15-25 years.

Question 43

What anesthetic considerations are there for Duchenne's Muscular Dystrophy?

Answer 43

Cardiopulmonary involvement and may require post-op intubation. Delayed gastric emptying Weak laryngeal reflexes (aspiration) No Succ (undiagnosed). Roc (extreme caution?) No volatile agents

Question 44

What is Guillan Barre?

Answer 44

Acute Idiopathic Polyneuritis; an Autoimmune disorder mistakes healthy neurons for bacteria or virus.. Mostly age >50yo

Question 45

What are common causes of Guillan Barre?

Answer 45

Includes Campylobacter, Influenza, HIV, Syphilis, Zika, Epstein Barr, Hepatitis A, B, C, E.

Question 46

What is the initial pattern of weakness in Guillan Barre?

Answer 46

Acute onset weakness begins in lower limbs and spreads cephalad. Since the invention of the polio vaccine, GB has become the most common cause of acute paralysis 1-2:100,000

Question 47

What type of paralysis occurs in Guillan Barre?

Answer 47

Flaccid paralysis with loss of reflexes (lower motor neuron involvement) Autonomic nervous system involvement as the spread moves cephalad.

Question 48

What is the treatment for Guillan Barre?

Answer 48

Supportive treatment including plasmapheresis and IVIg therapy.

Question 49

GB Anesthetic Considerations

Answer 49

Do they have ANS involvement? Thorough preop eval! Yes, they do, BP can fly around based on sitting up or laying down, etc. Limited to Lower Motor neuron Dz? Avoid Succ(increased risk of hyperKdue to denervated muscles) Roc okay, may need lower dose (from my experience) Post op intubation? Assess your patient preop. Will probably come with a tracheostomy (always look for a cuff)

Question 50

What is Multiple Sclerosis?

Answer 50

Demyelination disease in the axonal CNS with demyelinated plaques.

Question 51

Are genetics implicated in Multiple Sclerosis?

Answer 51

Yes, but no clear genetic correlation. No clear understanding on which nerves and why will be affected. 2X women than men

Question 52

What are the types of Multiple Sclerosis?

Answer 52

Includes Relapsing remitting and Chronic progressive (usually after 35 yos) Clinical manifestations depend on which CNS nerves are affected. How does remission occur? Do the nerves re-myelinate? Treatment: Interferon B

Question 53

What anesthetic considerations are there for Multiple Sclerosis?

Answer 53

GA okay; avoid spinal (could be toxic with no myelin sheath); epidural probably okay; regional okay. Avoid factors that cause exacerbation Temperature increase Fever Infection Prolonged response to NDMRs (Roc) has been observed (decreased muscle mass) Exaggerated response to Succ leading to hyperkalemia is possible If patient on corticosteroid therapy, may need to stress dose Post op evaluation

Question 54

What is CIDP? (WONT TEST ON THIS)

Answer 54

Autoimmune disorder targeting myelin sheath on PERIPHERAL nerves. Progressive weakness, sensory and motor loss. Usually progresses from extremities and moves proximal Closely related to GBS Considered to be the long term form of GBS Treatment is similar to that of GBS

Question 55

What anesthetic considerations exist for CIDP? (WONT TEST ON THIS)

Answer 55

Avoid or limit muscle relaxants. Effects can be prolonged Avoid Sux. Demyelinating lesion! Regional is okay Reversal with Sugamadexis a good choice. If a patient is on steroids, might need a stress dose. Consult with attending and surgeon. This is a pretty rare disorder, the data isn’t out there. But we use or logic and common sense from understanding the pathogenesis and pathophysiology of the disease.

Question 56

What is Parkinson's Disease?

Answer 56

Neurodegenerative disorder with loss of dopaminergic fibers. Loss of Dopaminergic fibers in basal ganglia, results in depletion of dopamine Results in unopposed AcH stimulation in this system

Question 57

What is the single largest risk factor for Parkinson's Disease?

Answer 57

Increasing age.

Question 58

What are symptoms of Parkinson's Disease?

Answer 58

Skeletal muscle tremor, akinesia, rigidity, dementia, and depression. Dementia and depression often concomitant

Question 59

What is the treatment for Parkinson's Disease?

Answer 59

Dopamine precursor is the treatment: Carbidopa/Levodopa. Increases concentration of dopamine in CNS. Carbidopa prevents break down of levodopa before it reaches CNS. DBS is the surgical approach. Proper way to do this anesthetic? 2 ways? Carbidopa class? Levodopa SE?

Question 60

Anesthetic considerations for Parkinson's?

Answer 60

Must continue their Parkinson's medication regimen. Long case…how can you administer Carbidopa/Levodopa to the patient? Might need to administer via the NG/OG tube since it is oral Avoid Droperidol. (Recent pulled off shelves at HCA), Haloperidol. Dopamine antagonist. Your choice of anesthetic DBS anesthetic?

Question 61

What is Deep Brain Stimulation (DBS)?

Answer 61

A surgical approach for treating Parkinson's Disease.

Question 62

What anesthetic options should be avoided in Parkinson's patients?

Answer 62

Droperidol and Haloperidol.

Question 63

What is Ankylosing Spondylitis?

Answer 63

Chronic progressive inflammatory disease involving articulations of spine joints Begins at SI joint and moves toward cranium.

Question 64

What are the symptoms of Ankylosing Spondylitis?

Answer 64

Loss of lordosis and exaggerated kyphosis.

Question 65

What is the treatment for Ankylosing Spondylitis?

Answer 65

NSAIDs such as indomethacin, diclofenac, and Infliximab.

Question 66

AS anesthetic Considerations

Answer 66

Difficult intubation. Plan ahead. Thorough preop airway exam Awake fiberoptic? CMAC? Airway in…What about positioning? Can they lay flat? Restrictive lung pattern from costochondral rigidity

Question 67

What is Complex Regional Pain Syndrome (CRPS)?

Answer 67

Usually occurs after an injury or surgery, most commonly a limb. But can also occur with no obvious injury Burning, stinging, tearing type of pain. Inconsistent location of pain is also seen.

Question 68

What is the etiology of CRPS?

Answer 68

Unknown; may involve overactivation of inflammatory cascade, dysregulation of pain mediating neuropeptides, CNS sensitization, SNS dysregulation, possible genetic role.

Question 69

What are anesthetic considerations for CRPS?

Answer 69

Have to do good Pre-Op evaluation as they are typically on extremely high pain meds. 200-300 mgs of Ketamine... have to plan with pharamacy Must have a plan in place for surgery on the affected limb.

Question 70

CRPS anesthetic considerations

Answer 70

Is the surgery on the affected limb? IE is CRPS located in the ankle and are you doing an ankle surgery on the same side? Must have a plan in place. These patients may be followed by a pain clinic/doctor. Look at what they are taking. And Don’t underestimate hyperalgesia in this patient population. Thorough preop evaluation. Multimodal approach, including NSAIDS, pregabalin, NMDA, Alpha 2 agonism, opiods, regional. Set expectations and make PACU aware of this patient..

Question 71

What is Diabetic Neuropathy?

Answer 71

Condition from long-standing uncontrolled diabetes causing neuronal ischemia. Microvascular damage leading to neuronal ischemia, glycosylated neurons, denervation, reduced nerve conduction velocity.

Question 72

What are the symptoms of Diabetic Neuropathy?

Answer 72

Sensory loss in distal extremities, commonly the feet. Tingling and numbness very common. ANS dysfunction: Gastroparesis, resting tachycardia, urinary retention, impotence. More prone to positioning injury due to already compromised nerves.

Question 73

What is the Sorbitol-Aldose Reductase Pathway?

Answer 73

Pathway where aldose reductase reduces glucose to sorbitol. High glucose levels in the blood leads glucose into this pathway vs the insulin pathway. Sorbitol Dehydrogenase oxidizes sorbitol to fructose. High glucose levels over activate this pathway leading to excess sorbitol levels in the cells, leading movement of water into cell (osmosis) which leads to cell swelling. Build up in retinal tissues, renal tissues, lead to diabetic nephropathy and diabetic retinopathy.

Question 74

What are the consequences of high glucose levels?

Answer 74

Leads to diabetic nephropathy and diabetic retinopathy.

Question 75

What are aldose reductase inhibitors?

Answer 75

Medications such as Epalrestat, Sorbinil, Tolrestat, and Ponalrestat.

Question 76

Anesthetic considerations Diabetes

Answer 76

Thorough Preop Eval Assess kidney function, NPO status, degree of lability of blood glucose levels Assess current glucose level, last insulin dose. If having surgery on the diabetic extremity, assess neuro status. Most patients despite not feeling much will tell you they feel everything. Pick which anesthetic suits the patient best. Safest most effective option. Understand how your medicines work in renal disease if that is appreciated. Ensure adequate perfusion. Increase MAPS. Diabetes is a very very deep rabbit hole. We will stop here for now.

Question 77

What should be assessed during preoperative evaluation for diabetic patients?

Answer 77

Kidney function, NPO status, blood glucose levels.

Question 78

What are positioning considerations for diabetic patients?

Answer 78

More prone to positioning injury.

Question 79

What can diabetic patients expect during surgery?

Answer 79

Most report they feel everything despite not feeling much.

Question 80

What is the anesthetic choice for diabetic patients?

Answer 80

Choose the anesthetic that suits the patient best.