Neuromuscular disorders - lec 4

A sense of heaviness or “deadness” is known as _____

numbness

An abnormal sensation of burning, tingling, pins and needles is known as ______

paresthesia

A disturbance in the function of a nerve is known as _____

neuropathy

Pain/paresthesia/numbness along the distribution of a dermatome (referred pain) is known as _____

radiculopathy

A disturbance in the distribution of a nerve plexus, either distal to the spinal roots or proximal to the formation of the peripheral nerves, is known as ______

plexopathy

Primary muscle disorder is known as ______

myopathy

What ways do nerves respond to injury?

damage at axon, disruption of axon and/or myelin sheath (trauma), degeneration of axon and breakdown of myelin sheath (metabolic/toxic)

A complete absence of strength / total paralysis is called _____

-plegia

total paralysis in both limbs, one side of the body is known as ____

hemiplegia

total paralysis in both legs is known as ______

paraplegia

total paralysis in all four limbs is known as _____

quadriplegia

A less severe weakness / incomplete paralysis is known as _____

paresis

What would an abrupt onset of sx suggest?

vascular dz like stroke, toxic or metabolic disturbances

What would a subacute onset of sx over days to weeks suggest?

neoplastic, infectious or inflammatory causes

What would a slow onset of sx over mos-yrs suggest?

hereditary, degenerative, endocrine, or neoplastic

An episodic progression of sx may suggest _____

vascular or inflammatory origin

Steadily progressive sx suggests ____

neoplastic disorder or motor degenerative conditions

A rapid fluctuation of sx over short periods of time is characteristic of what condition?

myasthenia gravis

What should be ruled out if spinal cord pain is worse at night?

malignancy; order urgent CT or MRI

What should be ruled out w/ a hx of trauma?

fracture; start w/ plain films

what should be ruled out w/ bowel or bladder incontinence?

cauda equina syndrome; order urgent MRI

What are the most common causes of total spinal cord transection?

MVA (MC), falls, violence, sports accidents

What condition?

• immediate flaccid paralysis & loss of sensation below the level of injury

• spinal shock → loss of reflex activity; hypotension d/t unopposed vagal tone

  • flaccid areflexia, hrs-wks, eventually recover as hyperreflexia

  • priapism may be present

total spinal cord transection (spinal cord cut)

What imaging should be ordered for total spinal cord transection?

CT & MRI

How are total spinal cord transections managed?

• ICU

• immediate immobilization and surgical fixation

• methylprednisolone → don’t use if penetrating or multi system trauma, or mod-severe TBI

• painful spasms → Baclofen, benzodiazepine

What are possible complications w/ total spinal cord transections?

• CV → neurogenic shock

• Resp → resp failure, pulm edema, PNA

• DVT/PE → all pts should get prophylactic tx

• other → pressure sores, stress ulcer, paralytic ileus, temp control, inadequate nutrition

What is neurogenic shock?

part of spinal shock; distributive shock resulting in low BP occasionally w/ slow HR, attributed to disruption of autonomic pathways in spinal cord causing dec vascular resistance

What condition?

• partial cord transection (hemisection), usually from penetrating trauma

• diminished motor strength and fine touch, position, and vibration sensation on side of injury (ipsilateral)

• loss of pain and temperature sensation on side opposite the injury (contralateral)

• bladder function may be spared

Brown-Sequard Syndrome

Decussates at medulla; proprioception and vibration

dorsal column

Decussate at spinal cord; pain & temp, light tough & pressure

spinothalamic

In Brown Sequard syndrome with injury to T10 on the L side, what would be lost BELOW the injury?

R (C/L): pain & temp, pressure & light touch

L (I/L): vibration, proprioception, D/T, UMN lesion

in Brown Sequard syndrome with injury to T10 on the L side, what would be lost AT THE LEVEL of the injury?

R (C/L): nothing

L (I/L): pain & temp, pressure & light touch, vibration, proprioception, D/T, LMN lesion

in Brown Sequard syndrome with injury to T10 on the L side, what would be lost ABOVE the injury?

nothing

Which lesion?

• flaccid paralysis

• areflexia/hypo

• fasciculations

• weakness

• dec tone

• atrophy

LMN

Which lesion?

• spastic paralysis

• hyperreflexia

• inc tone

• babinski

UMN

What is the treatment for brown-sequard syndrome?

early high dose steroids → methylprednisolone

neurosurgical consult to realign spinal cord via traction

What condition?

• tumor pressing on dural sac; often metastatic

  • T spine MC affected; tender at tumor site

• presents w/ pain, worse at night when pt recumbent

• can cause permanent neuro impairment,

• possible weakness + radicular sensory defects

epidural spinal cord compression

New back pain that worsens when lying down should raise suspicion for ______

tumor

What is the management of epidural spinal cord compression?

emergent CT/MRI & referral to neuro/onc

immediate radiation

rapid tx of tumor required to avoid permanent nerve impairment

A “herniated” disc is also known as _____

intervertebral disc prolapse

What condition?

• nucleus pulposus herniates and presses on nerve root (pinching 1 side of cord)

• radicular sx along nerve distribution on one side

• can be caused by heavy lifting

intervertebral disc prolapse

What condition?

• centrally prolapsed disc that causes bilateral sx (compress both sides of cord)

• variable motor and sensory loss in LEs

• saddle anesthesia, bladder and/or bowel dysfunction

• urgent MRI and neurosurgeon consult

cauda equina syndrome

what is the management for acute disc prolapse?

• plain xrays, CT or MRI depending on presentation

• urgent neuro/surgeon referral if significant radicular S&S (3/5 muscle strength)

• bed rest vs activity vs PT

• pain control → simple analgesics, muscle relaxants, epidural steroid injection

• surgery

What is another name for amyotrophic lateral sclerosis (ALS)?

lou gehrig’s disease

what condition?

• degeneration of corticospinal pathways down to anterior horn cells

  • nerve cells gradually die

• progressive disorder; fatal in ~3 yrs

• mixed UMN and LMN deficit in limbs → weakness, easy fatiguability, normal sensation

• presents b/t ages 30-60

• normal intellect, no sensory/occulomotor defect (just motor issues)

ALS

What are sx of ALS?

tongue fasciculation → classic finding

+difficulty swallowing, chewing, coughing, breathing, speaking

Evaluation of ALS?

nerve bx, muscle bx (may reveal denervation atrophy);

EMG → fasciculations + fibrillations in both UE + LE, normal motor conduction velocity & sensory conduction

what is the treatment for ALS?

Riluzole→ inhibits presynaptic glutamate release, slows progression & prolongs survival (no cure)

other: baclofen, wheelchair, PEG tube, amitriptyline, communicative devices, etc

Which nerve is associated with Bell’s palsy?

facial

which nerve is associated with Saturday Night Palsy?

radial

which nerve is associated with carpal tunnel syndrome?

median

which nerve is associated with funny bone tingling?

ulnar

which nerve is associated with Meralgia Paresthetica?

lateral femoral cutaneous

which nerve is associated with compartment syndrome (surgical emergency)?

deep peroneal

what nerve is associated with Tarsal tunnel syndrome?

posterior tibial

what condition?

• compression of the median nerve as it travels through the carpal tunnel

• pain or paresthesia - first 3 digits and radial half of 4th

• worse at night; provoked by flexing/extending wrist or raising arms

• alternating remission and exacerbation

• F > M

carpal tunnel syndrome

What provocative maneuvers are used to examine carpal tunnel syndrome?

Phalen maneuver → pt fully flexes palms at wrist w/ elbow in full extension (positive = pain/paresthesia in median innervated fingers w/ 1 min wrist flexion)

Tinel test → firm percussion over course of median nerve (positive = pain/paresthesia of median innervated fingers that occurs w/ percussion over median n.)

what is the treatment for carpal tunnel?

surgical decompression for most; splinting w/ glucocorticoid injections or oral tx

What systemic / metabolic disorders can cause multifocal peripheral neuropathies?

vit B12 deficiency, alcoholism, leprosy, DM

what condition?

• autoimmune inflammatory process

• multifocal demyelination of white matter of brain and spinal cord (mostly cervical); asymmetric lesions

• relapsing remitting pattern w/ chronic progressive course

• intention tremors, scanning speech, ataxia, + babinski, clonus, loss of position & vibration sense, emotional decline vision complaints in single eye (triggered by retrobulbar neuritis), etc

• F > M, mid 30s (20-50), caucasian/northern european

multiple sclerosis (MS)

Evaluation of MS?

• MRI > CT → plaques / Dawson’s fingers

• evoked potential test → time for nerves to respond to full stimuli (VER or VEP MC)

• CSF → oligoclonal bands, myelin basic protein inc, etc

• McDonald criteria

What CSF abnormalities are seen in MS?

• inc Ig levels, lymphocytes

• oligoclonal bands (pathognomic)

• myelin basic protein may be elevated

• glucose usually normal

What is the criteria called that is used for diagnosing MS that evaluates # attacks, lesions, and CSF findings?

Mcdonald Criteria

What is the treatment for MS?

directed toward relieving sx

• corticosteroids → main tx for acute attacks

  • alt - plasmapheresis

• disease modifying drugs for relapsing (interferon)

• IVIG

• regular exercise; avoid overwork, fatigue, excessive heat

• spasticity→ baclofen, tizanidine

• neuropathic pain → gabapentin, amitriptyline, etc

• chronic fatigue → amantadine, modafinil

Who has the best prognosis for MS?

females, onset before 40, visual or somatosensory dysfunction (touch or tactile perception) rather than pyramidal or cerebellar

what condition?

• disorder of a body region, usually distal limbs

• pain (out of proportion), swelling, limited ROM, vasomotor instability, skin changes, patchy bone demineralization

• usually follows fracture, soft tissue injury, or surgery

• lasts median 7 mos

complex regional pain syndrome (CRPS)

which subtype of CRPS is WITHOUT peripheral nerve injury and most common?

type I

Which CRPS subtype is WITH peripheral nerve injury?

type II

What is the management for CRPS?

• PT/OT

• pain→ NSAIDs (ibuprofen, naproxen), anticonvulsants (gabapentin, pregabalin), TCA (amitriptyline, nortiptyline), opioids

• treatment most effective early in dz

what is the mnemonic for CRPS dx and tx?

Swelling

Temperature

Agony

Redness

Tremors

Nerve meds

Opioid meds

Work outs

what condition?

• viral infx → destruction of anterior horn cells in spinal cord → LMN sx

• fecal oral transmission; dx from stool / nasopharyngeal secretions

• prodrome- fever, myalgia, URI or GI sx

• weakness or paralysis, can affect resp muscles

• no specific tx

poliomyelitis

What condition?

• reactivation of VZV

• severe pain, may precede rash

• skin lesions similar to chicken pox that follow nerve root distribution (T & L roots MC) → maculopapules evolve into vesicles/pustules

• hutchinson’s sign → lesions on tip of nose, indicates ophthalmic division dz

herpes zoster

what is the tx for herpes zoster?

• antivirals → acyclovir, valcyclovir

• steroids → reserve for severe

• pain relief

• postherpetic neuralgia tx → gabapentin or amitriptyline

What is another name for Guillain-Barré syndrome (GBS)?

acute inflammatory polyradiculoneuropathy

What condition?

• autoimmune disorder → destruction of myelin and/or axon by ganglioside antibodies

• demyelination dz of peripheral nerves; usually an ascending paralysis; moves distal to central

• follows an infx, immunization, or surgery; assoc w/ c. jejuni enteritis

• M > F

Guillain-Barré Syndrome (GBS)

What are ssx of GBS?

• paresthesias of hands and feet → earliest sx

• acute, symmetric ascending weakness of limbs

• gait disorder

• pain common, especially back and legs

• resp muscle paralysis & CN involvement possible

How do you dx GBS?

• LP (CSF) → albuminocytologic dissociation (inc CSF protein w/o inc WBC)

• electrophysiology → marked slowing of conduction

What is the treatment for GBS?

• hospitalization- cardiopulmonary support

• plasmapheresis

• IVIG

• analgesics

What is the prognosis of GBS?

self limiting; 75% make full recovery w/in few mos-yr

What is the most common cause of peripheral neuropathy?

DM

What is the most common peripheral neuropathic syndrome associated with DM that is insidiously progressive & can affect any peripheral nerve (including CN)?

diabetic polyneuropathy

What are ssx of diabetic peripheral neuropathy?

• MC in toes and distal feet

• tingling, burning, abnormal pain and temp sensation

• reduced achilles tendon reflexes & vibratory sense in toes

• hand numbness and sensory loss

• stocking/glove distribution

How is a diagnosis of diabetic peripheral neuropathy made?

serial nerve conduction studies and labs to r/o other causes

How is diabetic peripheral neuropathy treated?

• tight control of serum glucose

• TCA → amitriptyline, nortriptyline

• anticonvulsants → carbamazepine, gabapentin

• lidocaine patch, tramadol

How is autonomic dysfunction treated in diabetic neuropathy?

• orthostatic hypotension → fludrocortisone (volume expander, works like aldosterone)

• gastroparesis → metoclopramide, erythromycin

• diarrhea → loperamide

• urinary incontinence → bethanechol

• ED → sildenafil

• CV risk factors → tight control BP and cholesterol, daily ASA, stop tobacco

What condition?

toxin exposure from contaminated wounds → transported along motor nerves into spinal cord → binds irreversibly to receptors in brain & spinal column → blocks release of GABA → unchecked excitatory impulses, inc muscle tone, spasms, rigidity

Tetanus / clostridium tetani

What is the treatment for tetanus?

tetanus immune globulin; hospitalization for resp/CV support

What condition?

toxin binds presynaptic sides of peripheral cholinergic synapses at NMJ → irreversibly disrupts Ach release → motor weakness or paralysis

(MC after ingestion of home canned food, rarely from wounds)

Botulism / clostridium botulinum

Who is at risk for botulism?

infants

_______ is an ascending paralysis; _______ is a descending paralysis

GBS; Botulism

What condition?

• fulminating weakness 12-72 hrs after toxin ingestion

• symmetric descending paralysis

• diplopia, ptosis, blurred vision, facial weakness, dry mouth, dysphagia or nasal speech, paralytic ileus

• difficulty w/ respiration, postural hypotension

• no sensory deficits

• normal DTRs unless involved muscles are weak

Botulism

What is the treatment for botulism?

antitoxin; supportive care

what condition?

• autoimmune disorder; pure motor syndrome

• blockage of neuromuscular transmission at the ACh post synaptic receptors

• MC in young females

• typically 20-40 yrs but can occur at any age

  • F 3rd decade

  • M 5th-6th decades

myasthenia gravis (MG)

What condition?

• mild and intermittent onset over many years

• crisis lasts hours or days

• characteristic muscular weakness; worse in evening

  • extraocular, pharyngeal & facial, cervical, proximal limbs, resp muscles

• ptosis & diplopia MC sx

MG

What condition?

• defective ACh release from pre synaptic

  • abs against VGCC; SCLC

• increased power with muscle contraction (improved power w/ repeated hand grip) → lambert’s sign

Lambert eaton (myasthenic) syndrome

How is MG evaluated?

• Tensilon test = diagnosis

  • edrophonium 4mg IV improves grip strength w/in 30s

• EP → EMG or single fiber, repetitive stimulation

• IP assay → ACh receptor on antigen

What is the treatment for MG?

• anticholinesterase→ mestinon, prostigmin (neostigmine)

• immunosuppressants→ prednisone, azathioprine, etc

• plasmapheresis

• IVIG

• thymectomy rec for all pts w/ generalized

what condition?

• autoimmune disorder causing inflammatory infiltration of muscles, destruction of muscle fibers

• muscle pain, weakness, and wasting (proximal muscles)

• heliotrope rash

• gattron’s papules

polymyositis / dermatomyositis

What condition?

• set of inherited myopathic disorders

• progressive muscle weakness and wasting

• no specific tx, encourage activity and avoid prolonged bedrest

• PT for contractures and mobility

• Eteplirsen slows progression

muscular dystrophy

what condition?

• permanent non progressive central motor dysfunction that affects muscle tone, posture and movement

• most prenatal & during development

• manage w/ multidisciplinary team; PT/OT

• tx w/ botox for spasticity & hyperreflexia

cerebral palsy