Neuromuscular Disorders Flashcards
What are Upper motor neuron signs?
Weakness, Spastiticity
Increased Tendon Reflexes
Pathological WEaknesses
Hyperrreflexia, Babinkski’s Sign
Loss of Dexterity and Muscle Stiffness - slowness from stiffness
What are lower motor neuron signs?
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
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?
Large Fibers go into the Dorsal columb bringing, proprioception, vibration and light touch
Small Fibers into Lateral Spinothalamic Tracts bringing in pinprick and temperature.
Difference between Motor Unit and Motor Neuron Pool?
Motor Unit - motor neuron innervates one set of muscle fibers
Motor Neuron Pool - many motor neurons each innervates a motor unit within the muscle
What are the different pathologies of Peripheral Nervous system affecting NEURONS??
Idiopathic - ALS
Hereditary - Spinal Muscular Atrphy, Kennedy Disease
Infections - Poliomyelitis, West Nile encephaliitis
What happens in ALS? What is the presentation?
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!
What are the 2 diseases of the Anterior Horn Cells? Who gets which one? How do they present?
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)
What genes are involved in Spinal Muscular Atrophy? How is it inherited?
Spinal Muscular Atrophy is Autosomal Recessive Mutation on the survival motor neuron gene on Chromosome 5
How is Kennedy Disease inherited? what are the genetics? Other findins?
Adult onset for problems in the Androgen Receptor Gene
Inherited X-Linked Recessive
get CAG repeats leading to Adult spinobulbar atrophy and Androgen insensitivity
What is a radiculopathy? What are symptoms and signs?
**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
How many Nerve routes are in the body and why types?
31 pairs of nerve routes
8 - cervical
12 - thoracic
5 - lumbar
-5- sacral
1- coccygeal
Relationship between Dermatome and Myotome
Myotomes tend to be more proximal and distribution does not correspond to sensory distribution for same muscle!!!
What are common causes of RAdiculopathy? What are the most common radiculopathies?
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
What are the common symptoms and causes of plexopathy?
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
What is the number 1 cause of peripheral nueropathy worldwide?
[note neuropathy is a set of symptoms and not a diagnosis!]
Diabetes!!!
Used to be Leprosy :(
What are the sensory symptoms of peripheral neuropathy?
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
What’s the difference between large and small fibers in sensory?
Large Myelinated Fibers - joint position and vibratory sensation
Small Myelinated and Unmyelinated - Temperature sensation and hyperalgesia
What are the motor signs and symptoms with peripheral neuropathy?
weakness
cramps in muscles
fasciculations
tremors/myoclonus
See atrophy, fasciculation/fibrillation
Myokymia
What are the Autonomic Signs and Symptoms of PEripheral Neuropathy!?!?
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
What is the typical pattern of peripheral neuropathy?
Stocking and Glove Distribution!!!!
Decreased Deep Tendon Reflexes bc lose afferent branch
(see attached picture)
Breifly name all the different types of Diseases of Neuropathy that we discussed in class:
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
What is Carpal Tunnel Syndrome? Presentation? Diagnosis? Causes?
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
What are the Hereditary Demyelinating Neuropathies? What are their clinical findings?
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
What aare the acquired Demeylinating neuropathies?
AIDP - from GBS
CIDP - Chronic GBS
Neuropathy associated with paraproteins
(anti MAG or POEMS)
What are the 3 disorders of the NMJ?
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
What is Lambert Eaton and how does it present?
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***
What is Botulism? how does it present?
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
What is Myasthenia Gravis and how does it present?
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
What are the signs and symptoms of Myopathies?
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)
What are the different causes of Myopathy that we discuss?
Inflammatory - polymyositis, dermatomyositis, inclusion body myositis
Muscular Dystrophy - duchenne
Toxic Myopathy - Statin
What are the clinical signs to delineate between the 3 inflammatory myopathies?
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
