Neuromuscular Diseases Lecture Powerpoint

Question 1

Neuromuscular disease definition and most common symptom

Answer 1

• Disease that affects function of muscles due to problems with the nerves and muscles
• Most common symptom is muscle weakness (not general weakness but physical muscle weakness)

Question 2

Myasthenia gravis

Answer 2

Most common neuromuscular transmission disorder, typically acquired by immunological abnormality but sometimes genetic, disorder of post synaptic neuromuscular junction

Question 3

Pathophysiology of myasthenia gravis

Answer 3

• Post synaptic muscle membrane becomes distorted and simplified (loses its normal folded shape)
• This prevents Ach from binding to its receptors properly at the muscle end plate (alongside autoantibodies attaching to the membrane)

Question 4

Myasthenia gravis most common onset age in women vs men

Answer 4

Women in 2nd to 3rd decade of life, men in 7th to 8th

Question 5

Thymus-myasthenia gravis relationship

Answer 5

Many patients with myasthenia gravis have an enlarged thymus (not diagnostic, just a trend - can see enlaraged thymus for a variety of reasons), often triggers and maintains the production of antibodies that block the acetycholine

Question 6

Myasthenia gravis presentation and 2 co-occurring symptoms in some cases

Answer 6

Fluctuating fatigable specific muscle weakness that worsens with activity and improves with rest, often worsening as the day progresses, with prolonged muscle use, with hot temps, stress, or infection. Most often begins with weakness of eye muscles, difficulty swallowing, or slurred speech with initial transient symptoms that gets worst within 1 year

-2/3 also have co-occurring ocular disturbances such as ptosis or ocular muscle weakness OR 1/6 have oropharyngeal muscle weakness (difficulty swallowing or talking)

Question 7

Bulbar area of brain

Answer 7

Cerebellum, medulla, and pons including CN IX, X, XI, and XII

Question 8

2 types of myasthenia gravis

Answer 8

• occular

- generalized

Question 9

Myasthenia gravis diagnostic tests (5)

Answer 9

• Aceycholine receptor antibodies (80% of the time diagnostic)
• if negative then check muscle specific receptor tyrosine kinase (MuSK)
• Tensilon (edrophonium) test that blocks breakdown of Ach
• EMG:electromyogram to assess nerve and msucle function
• Ice pack test, cold decreases breakdown of Ach at the neuromusclar junction resulting in decreased ptosis

Question 10

Myasthenia gravis treatment options (5), are any curative?

Answer 10

• Pyridostigmine (mestinon) that increases Ach available
• Immunotherapeutic agents such as prednisone or cyclosporine
• Plasmapheresis (replace antibody containing plasma with antibody free plasma)
• IV immunoglobulin
• Thymectomy

-(NONE of these are curative, only helpful)

Question 11

Amyotrophic lateral sclerosis (ALS) AKA Lou Gehrig’s disease

Answer 11

Progressive incurable disease that affects nerve cells of the brain and spinal cord causing loss of muscle control resulting in muscle weakness, disability, and death with a median survival of 3 years

Question 12

ALS epidemiology

Answer 12

Slight male predominance for sporadic cases, ALS is sporadic in 90-95% of cases, inherited in 5-10% of patients, increased risk suggested in laborers or military

Question 13

ALS pathophysiology

Answer 13

Nerve cells that control volutnary muscle movements are affected, motor neurons gradually deteriorate and therefore are unable to send signals to muscles, theorized to be due to a complex interaction between environmental and genetic factors

Question 14

ALS clinical findings in upper motor neurons and lower (3 in each)

Answer 14

Upper motor neuron findings (slow speech, jaw jerk, spasticity)
Lower motor neuron findings (atrophy, fasciculations, weakness)

Question 15

ALS presentstion

Answer 15

Most common presentation in 80% is asymmetric limb weakness, 20% have onset in the bulbar segment resulting in dysarthria and dysphagia

Question 16

Dysarthria

Answer 16

Weakness of muscles used for speech resulting in slowed or slurred speech

Question 17

ALS signs and symptoms (7)

Answer 17

• Difficulty walking
• Tripping
• Weakness in hands, legs, and feet (foot drop)
• slurred speech or trouble swallowing
• muscle cramps
• inappropriate crying, yawning, laughing
• cognitive or behavioral changes

Question 18

ALS often starts in the ____ and spreads to ____.

Does it cause pain? What system is not affected?

Answer 18

hands/feet/limbs, chewing/swallowing/speaking, does not cause pain in any stage, sensation and bladder control typically not affected

Question 19

ALS diagnostic criteria (3)

Answer 19

• Upper and lower motor signs
• progressive clinical course
• lack of other etiology

Question 20

ALS diagnostic tests (3)

Answer 20

• EMG
• Nerve conduction study
• MRI

Question 21

ALS prognosis

Answer 21

Time from symptoms onset to typical diagnosis is 14 months, mean survival is 30 months, 30% survival 5 years after diagnosis, significant variability in rate of progression and requires palliative care from onset

Question 22

ALS treatment options (4)

Answer 22

• Riluzole (rilutek) oral increases life expectancy 3-6 months
• Edaravone (radicava) IV infusion
• Meds to manage symptoms
• Therapies such as physical, occupational, nutritional, etc

Question 23

ALS management

Answer 23

Encouraged to have a pre-determined plan before loss of functionality such as respiratory failure or nutritional failure to determine what they will do

Question 24

Muscular dystrophy

Answer 24

Group of diseases that cause progressive weakness and loss of muscle mass, has no cure but meds and therapies can manage symptoms with signs and symptoms beginning at diff ages and diff muscle groups, often due to abnormal genes interfering with production of proteins to form healthy muscle

Question 25

Signs/symptoms of muscular dystrophy (1)

Answer 25

-Main one is progressive muscle weakness

Question 26

Duchenne muscular dystrophy (etiology and presentation)

Answer 26

Most common form of musclular dystrophy that is X linked recessive (more common in boys)
Often seen in 2nd year of life with early clumsiness walking

Question 27

Gower’s maneuver

Answer 27

Refers to a common finding in duchenne muscular dystrophy where a patient has to place 1 hand on knee to assume upright position because of ilitibial bands and heel cords become tight

Question 28

Duchenne muscular dystrophy progression (3)

Answer 28

• By 5-6 stair climbing becomes labored
• 6-7 frequently falls
• 8-10 cease to be able to climb stairs or stand from floor often requiring wheel chair

Question 29

Cardiac, growth, and orthopedic complications from duchenne muscular dystropy

Answer 29

• primary dilated cardiomyopathy and conduction abnormalities resulting in degeneration and fibrosis
• short stature and growth delay
• fractures from frequent falling

Question 30

Duchenne muscular dystrophy pathophysiology

Answer 30

Caused by mutation of gene that encodes dystrophin that helps keep muscles intact (protein localized to inner surface of sarcolemma of muscle fiber) affecting proximal muscles first then distal

Question 31

Duchenne muscular dystrophy visual inspection findings

Answer 31

Thick lower leg muscles due to fat not muscle, thin weak thighs especially in front, weak muscles in front of leg cause foot drop and tiptoe contractures, belly sticks out due to weak muscles, shoulders and arms held back when walking

Question 32

Duchenne muscular dystrophy diagnosis (4)

Answer 32

• DNA studies looking for deletion of dystrophin gene, 30% of patients are negative then
• muscle biopsy is required to establish absence of dystrophin
• Serum CPK levels markedly elevated
• EMG sees myopathic changes

Question 33

Duchenne muscular dystrophy treatment (4)

Answer 33

• PT to keep joints loose as possible and maintain ligament laxity
• night splints and braces can delay progression
• surgery such as reconstruction or tendon release
• prednisolone

Question 34

Duchenne muscular dystrophy prognosis

Answer 34

-16-18 predisposed to fatal pulmonary infections, affected children die from respiratory failure or cardiomyopathy that is resistant to treatment, or aspiration and acute gastric dilation

Question 35

Becker muscular dystrophy differences from Duchenne

Answer 35

Signs and symptoms similar to duchenne but tends to develop more slowly in teens and be more mild perhaps not occurring until mid 20’s or later

Question 36

Cerebral palsy

Answer 36

Group of disorders that affects muscle tone or posture and movement, can range in severity, caused by damage (such as lack of oxygen) to immature brain as it develops most often before birth, most common motor disability in childhood (4/1000) signs and symptoms appear during infancy or preschool years

Question 37

Cerebral palsy causes prenatal (3) and natal (3) and what % does prenatal vs natal be seen as the cause

Answer 37

Prenatal: (70%), infection, anoxia, toxicity
Natal: (5-10%), anoxia, traumatic delivery, metabolic dz

Question 38

Cerebral palsy risk factors (4)

Answer 38

• alcohol consumption
• prematurity
• intrauterine growth restriction or infection
• antepartum hemorrhage

Question 39

4 origin types of cerebral palsy and what determines it

Answer 39

• spastic
• dyskinetic
• ataxic
• mixed

-Based on what part of brain has damage

Question 40

Cerebral palsy signs and symptoms

Answer 40

-vary but all have problems with movement and posture, some may have intellectual disability, visual or hearing defect, etc.

Question 41

Different types of cerebral palsy and what they mean (6)

Answer 41

• monoplegic (1 extremity)
• paraplegic (2 lower extremities)
• Hemiplegic (1 side upper and lower extremities)
• Triplegic (3 extremities)
• Quadraplegic (4 extremities)
• Diplegic (symmetrical left and right either upper or lower extremities)

Question 42

Cerebral palsy diagnosis

Answer 42

-Clinical based on risk factors around birth, ruling out other etiologies, and relying on developmental milestones

Question 43

Cerebral palsy treatment (3)

Answer 43

• physical therapy
• occupational therapy
• pharmacologic intervention to reduce symptoms that impair muscle coordination and control

Question 44

Myasthenia gravis lifestyle modifications (2)

Answer 44

• Avoid overexertion

- Eat foods high in potassium to help maintain muscle strength

Question 45

Fasciculation

Answer 45

Small, local, involunary muscle twitch

Question 46

Cerebral palsy diagnostic studies (3)

Answer 46

Performed by ruling out other etiologies via
-MRI
-Cranial ultrasound
EEG