Neuromuscular Disorders

Question 1

What are Upper motor neuron signs?

Answer 1

Weakness, Spastiticity

Increased Tendon Reflexes

Pathological WEaknesses

Hyperrreflexia, Babinkski’s Sign

Loss of Dexterity and Muscle Stiffness - slowness from stiffness

Question 2

What are lower motor neuron signs?

Answer 2

Weakness - (but difference is much more muscle loss/atrophy)

Fasciculations! (involuntary single nerve twicthes under the skin - contration and relaxation of individual muscle fibers)

Muscle Atrophy

Question 3

What fibers go into the Dorsal column and what information do they bring?

What fibers go into the lateral Spinothalamic tracts? What information do they bring?

Answer 3

Large Fibers go into the Dorsal columb bringing, proprioception, vibration and light touch

Small Fibers into Lateral Spinothalamic Tracts bringing in pinprick and temperature.

Question 4

Difference between Motor Unit and Motor Neuron Pool?

Answer 4

Motor Unit - motor neuron innervates one set of muscle fibers

Motor Neuron Pool - many motor neurons each innervates a motor unit within the muscle

Question 5

What are the different pathologies of Peripheral Nervous system affecting NEURONS??

Answer 5

Idiopathic - ALS

Hereditary - Spinal Muscular Atrphy, Kennedy Disease

Infections - Poliomyelitis, West Nile encephaliitis

Question 6

What happens in ALS? What is the presentation?

Answer 6

ALS is the most common adult onset neurodegenerative disease characterized by progressive motor neuron dysfunction

Progressive muscular paralysis reflecting degeneration of both Upper and Lower motor neurons

Presentation: Limb weakness (asymmetric, then symetric, then spread) Muscle cramps and fasciculations, Muscle atrophy and spasms, See Bulbar symptoms (slurred speech, dysphagia)

UMN: Hyperreflexia and stiffness

LMN: atrophy, fasciculations and weakness

*FTD in some patients leads to disinhibited behavior!

Question 7

What are the 2 diseases of the Anterior Horn Cells? Who gets which one? How do they present?

Answer 7

Spinal Muscular Atrophy - Floppy Babies –> pediatric disease where babies never sit/stand/walk and can see Fasciculatins in Tongue

Kennedy DIsease - Adult onset Spinobulbar muscle atrophy and LMN signs (+ androgen insensitivity)

Question 8

What genes are involved in Spinal Muscular Atrophy? How is it inherited?

Answer 8

Spinal Muscular Atrophy is Autosomal Recessive Mutation on the survival motor neuron gene on Chromosome 5

Question 9

How is Kennedy Disease inherited? what are the genetics? Other findins?

Answer 9

Adult onset for problems in the Androgen Receptor Gene

Inherited X-Linked Recessive

get CAG repeats leading to Adult spinobulbar atrophy and Androgen insensitivity

Question 10

What is a radiculopathy? What are symptoms and signs?

Answer 10

**Radiculopathy is a disorder of the nerve root **

Symptoms: Pain, Tingling, numbness - severe radiating back pain

weakness

Clinical Examination shows weakness (with atrophy if chronic), sensory Loss and Hypoactive Reflexes

Question 11

How many Nerve routes are in the body and why types?

Answer 11

31 pairs of nerve routes

8 - cervical

12 - thoracic

5 - lumbar

-5- sacral

1- coccygeal

Question 12

Relationship between Dermatome and Myotome

Answer 12

Myotomes tend to be more proximal and distribution does not correspond to sensory distribution for same muscle!!!

Question 13

What are common causes of RAdiculopathy? What are the most common radiculopathies?

Answer 13

Common causes are compression/Disk Herniation, Trauma (avulsion) tumors, autoimmune, or Infectious (HSV, Lyme, HIV)

Most Common Cervical - C7

Most common Lumbosacral - L5 or S1

Question 14

What are the common symptoms and causes of plexopathy?

Answer 14

Brachial - Trauma, neoplasia, post-radiation, immune/inflam

Lumbosacral - trauma, neoplasia, Pregnancy - labor, Hematoma, Abscess, Radiation, Immune/Inlfam

Signs and symptoms are mixed and variable sensory and muscle weakness depending on distribution of underlying disorder

Question 15

What is the number 1 cause of peripheral nueropathy worldwide?

[note neuropathy is a set of symptoms and not a diagnosis!]

Answer 15

Diabetes!!!

Used to be Leprosy :(

Question 16

What are the sensory symptoms of peripheral neuropathy?

Answer 16

Numbness (Hypoestesia/hypoalgesia)

Paresthesia - abnormal sensation like creeping, crawling, pins and needles

Dysesthesia - unpleasant sensation like burning skin in sunburn

Allodynia - experience pain to normally inocuous stimuli (sheet on skin for ex)

Hyperpathia - prolonged painful response to repetitve stimuli

Question 17

What’s the difference between large and small fibers in sensory?

Answer 17

Large Myelinated Fibers - joint position and vibratory sensation

Small Myelinated and Unmyelinated - Temperature sensation and hyperalgesia

Question 18

What are the motor signs and symptoms with peripheral neuropathy?

Answer 18

weakness

cramps in muscles

fasciculations

tremors/myoclonus

See atrophy, fasciculation/fibrillation

Myokymia

Question 19

What are the Autonomic Signs and Symptoms of PEripheral Neuropathy!?!?

Answer 19

Orthosatic Hypotension and symptoms

Anhydrosis distally with Hyperhydrosis in upper trunk

Siccas’ Sydrome

GU/GI dysfunction

Sexual Dysfunction - impotence

tonic pupils

Absence of HR variation with deep breathing

Question 20

What is the typical pattern of peripheral neuropathy?

Answer 20

Stocking and Glove Distribution!!!!

Decreased Deep Tendon Reflexes bc lose afferent branch

(see attached picture)

Question 21

Breifly name all the different types of Diseases of Neuropathy that we discussed in class:

Answer 21

Mononeuropathy - Carpal Tunne of Median nerve

Systemic Disorders - DM, Vitamin B12 deficiency, vasculitis, infection with hIV

Genetic - Charcot Marie Toocth Disease

Inflammatory Demyelinating Polyraducloneuropathy - GBS acute and CIPD GBS chronic

Drug induced

Question 22

What is Carpal Tunnel Syndrome? Presentation? Diagnosis? Causes?

Answer 22

Carpal Tunnel Syndrome is the most common entrapment neuropathy of the Median Nerve

Symptoms include nocturnal paresthesia in hand/wrist/forearm, shaking of hand, pain with activity, sensory disturbance on first 3.5 fingers, weakness/atrophy of thenar muscle

Dx with Phalen maneuver and Tinnel Sign

Associated causes/conditions = pregnancy (water retenetion), occupational, Ra, DM, Hypothyroidism, Acromegaly

Question 23

What are the Hereditary Demyelinating Neuropathies? What are their clinical findings?

Answer 23

Charcot Marie Tooth Disease Type 1A most common and demyelinating

• Inverted Champagne leg, Atrophy of hand, Glove and stocking distribution

Hereditary Neuropathy with Liability for Pressure Palsy (HNPP)

• potato=pickers disease of focal compression with focal deficits

Question 24

What aare the acquired Demeylinating neuropathies?

Answer 24

AIDP - from GBS

CIDP - Chronic GBS

Neuropathy associated with paraproteins

(anti MAG or POEMS)

Question 25

What are the 3 disorders of the NMJ?

Answer 25

Lambert-Eaton - Ab against P/Q Type Ca Channel (presynaptic)

Myasthenia Gravis - Ab against Ach Receptor (postsynaptic)

Bolutsm - cleaves Synaptobrevin/SNARE proteins so no Ach vesicle release at junction

Question 26

What is Lambert Eaton and how does it present?

Answer 26

Lambert Eaton - IgG antibodies to pre-synaptic calcium channels so can’t get in calcium to release Ach Vesicles for fusion

Presents with Proximal muscle weakness, bulbar and ocular muscle weakness

Reduced tendon reflexes

Autonomic dysfunction

***TRANSIENT IMPROVEMENT AFTER BRIEF EXERCISE

***ASSOCIATED WITH SMALL CELL LUNG CANCER***

Question 27

What is Botulism? how does it present?

Answer 27

Botulism is from exotoxin from clostridium botulinum found in spres and can be in honey that babies drink or improperly canned foods

Toxin blocks presynatic release of Ach at somatic and autonomic synapses

Floppy baby with constipation and big pupils

Muscle weakness, blurred vision, diplospia, dysarthria

Parasymp Dysfunciton - ileus, constipation , decreased salivation

Question 28

What is Myasthenia Gravis and how does it present?

Answer 28

Autoantibodies against the post-synaptic Ach Receptor blocking its action

Fluctuating weakness and fatiguability that worsens with exertion or over the course of the day

symptoms exacerbated by elevated temperature, infection, menses, stress

Ocular and Bulbar muscles frequently affected leading to pstosis, diplopia, dysarthria, dysphagia

Proximal muscles > Distal

Question 29

What are the signs and symptoms of Myopathies?

Answer 29

Often associated with elevated serum creatine kinase (esp if necrosis however will NOT see if have functional disorder …ex. mitochondrial)

Positive: Mylagia, Cramp, Contractures, myotonia, myoglobuirua

Negative: Weakness, Fatigue, Exercise intolerance, Atrophy

Weakness typically Symmetric Proximal Limb Girdle Muscle Weakness with no sensory loss (ex. trouble combing hair, brushing teeth, stairs, standing off of toilet)

Question 30

What are the different causes of Myopathy that we discuss?

Answer 30

Inflammatory - polymyositis, dermatomyositis, inclusion body myositis

Muscular Dystrophy - duchenne

Toxic Myopathy - Statin

Question 31

What are the clinical signs to delineate between the 3 inflammatory myopathies?

Answer 31

Polymyositis - older women with Proximal Muscle WEakness

Dermatomyositis - older women with proximal muscle weakness AND RASH!!! Heliotrope Rash (face/eyelids/chest) and Gottrons Sign (papules on knuckles)

Inclusion body - old men problems with finger flexion and knee extension weakness