acute peripheral weakness peter shearer, md assistant residency director mt. sinai school of...

Acute Peripheral WeaknessAcute Peripheral Weakness

Peter Shearer, MDAssistant Residency DirectorMt. Sinai School of Medicine

Peter Shearer, MD

ObjectivesObjectives

l Acute Extremity Weaknessl Levels of potential involvement_ Key Elements of History and Physical for

each level• CNS• PNS

l Diagnostic Optionsl Therapy

Peter Shearer, MD

Question #1Question #1

At which level of the CNS can a lesion produce motor weakness without affecting mental status?

A. Brainstem

B. Dorsal root ganglia

C. Spinal Cord

D. Cerebellum

Peter Shearer, MD

Question #2Question #2

Which of the following can differentiate between acute transverse myelitis and Guillain-Barre Syndrome?

A. ascending vs. descending paralysis

B. presence of slight lymphocytosis in CSF

C. increased vs. decreased reflexes

D. acuity of onset

E. presence of a preceding respiratory or GI illness

Peter Shearer, MD

Question #3Question #3

Which of the following does NOT produce a myelopathy?

A. Spinal cord infarct

B. Transverse Myelitis

C. Spinal cord metastasis of lung cancer

D. Tick Paralysis

Peter Shearer, MD

Question #4Question #4

Which of the following illnesses has a well evaluated, prospectively studied therapy?

A. Guillain-Barre Syndrome

B. Acute Transverse Myelitis

C. Acute Spinal Cord Hemorrhage

D. Botulism

Peter Shearer, MD

case-historycase-history

l 30 year old woman l diffuse weaknessl lower extremities > upper extremitiesl over 3 daysl preceding diffuse vesicular rashl difficulty voiding

Peter Shearer, MD

case-historycase-history

l 30 year old woman l diffuse weaknessl lower extremities > upper extremities

ascendingl over 3 daysl preceding diffuse vesicular rashl difficulty voiding

Peter Shearer, MD

case-details of the physicalcase-details of the physical

l BP 140/86, P 90, RR 18, T 99, 99%O2 sat

l CN intactl Motor: 4/5 in UE, 3/5 in LEl Sensory intact but sharp/dull less

pronounced in the LEl Reflexes 3+ in all extremitiesl palpable bladder

Peter Shearer, MD

Case - summaryCase - summary

l Acute ascending symmetrical paralysis following a recent infection with slight sensory impairment and hyperreflexia.

Peter Shearer, MD

Could this be a CNS lesion?Could this be a CNS lesion?

Peter Shearer, MD

Could this be a CNS lesion?Could this be a CNS lesion?

Yes

Can a CNS lesion produce bilateral weakness and sensory deficits and have

a normal mental status?

Peter Shearer, MD

Could this be a CNS lesion?Could this be a CNS lesion?

l CNS = Upper motor neuron_ cerebral cortex to, but not including the

anterior horn cell

l UMN lesions produce:_ increased tone_ increased DTR_ extensor plantars_ no fasiculations

Peter Shearer, MD

levels of the CNSlevels of the CNS

l Cerebral Cortex

l Cerebellum

l Brainstem

l Spinal Cord up to the Anterior Horn Cell

Peter Shearer, MD

Could this be a PNS lesion?Could this be a PNS lesion?

Peter Shearer, MD

Could this be a PNS lesion?Could this be a PNS lesion?

Yes

Where?

Peter Shearer, MD

levels of the PNS levels of the PNS

l Spinal cord - Anterior horn cell of the Lateral Corticospinal tract

l Peripheral nervel NMJ l Muscle

Peter Shearer, MD

MyelopathyMyelopathy

l A Lesion in the cord produces A Level of deficit

l Division of labor_ Dorsal columns - position/vibration_ Lateral corticospinal tract - motor function_ Lateral spinothalamic tract -

pain/temperature

l Preserved mental status

Peter Shearer, MD

Myelopathy - etiologyMyelopathy - etiology

l Infarctl Trauma_ Brown-Sequard_ Central cord syndrome_ Anterior cord syndrome

l Mass lesionsl Inflammation/Infection

Peter Shearer, MD

myelopathy - details of historymyelopathy - details of history

l Acuity of onsetl Traumal Distal > Proximall Pain at sitel Preceding Illness

Peter Shearer, MD

myelopathy - details of physicalmyelopathy - details of physical

l Weaknessl Spasticityl Atrophyl Fasciculationsl Bowel and bladder complaintsl Increased tonel Sensory findingsl DTR’s may be increased (not if ALS)

Peter Shearer, MD

Cord InfarctCord Infarct

l Anterior Spinal Artery_ anterior cord - dissociation of sensory

findings_ symmetric flaccid paralysis_ loss of sphincter tone_ Dorsal columns prevail

l Posterior Spinal Artery_ proprioceptive and vibratory sensation

Peter Shearer, MD

Acute Peripheral NeuropathyAcute Peripheral Neuropathy

l Motor and/or sensory_ disorder of transmission along peripheral

nerve • axon• myelin

_ Guillain-Barre_ Tick Paralysis_ Toxic

Peter Shearer, MD

Acute Peripheral Neuropathy - Acute Peripheral Neuropathy - details of physicaldetails of physical

l Weaknessl Absent DTR’s (all outflow from the cord

is affected)l Affects longer nerves first - ascending

Peter Shearer, MD

Guillain-Barre SyndromeGuillain-Barre Syndrome

l Post infectiousl mononuclear inflammatory infiltrate of

myelinl dymyelinatingl may be axonal injury and degeneration

Peter Shearer, MD

Guillain-Barre SyndromeGuillain-Barre Syndrome

l Symmetric ascending paralysisl areflexicl possible sensory - paresthesias, position

and vibrationl Progression over 1 - 3 weeks - may be

more rapidl 1/3 progress to respiratory failure

Peter Shearer, MD

Guillain-Barre SyndromeGuillain-Barre Syndrome

l CSF - Albuminocytologic dissociationl Stool for C. jejuni

Peter Shearer, MD

NMJNMJ

l Presynaptic - disorder of ACh release_ will affect nicotinic and muscarinic_ weakness_ anticholinergic symptoms

l Postsynaptic - will just be nicotinic_ weakness_ NO anticholinergic findings

Peter Shearer, MD

NMJ - details of historyNMJ - details of history

l Exposure_ botulism_ snake bites

l fatigue

Peter Shearer, MD

NMJ - details of physicalNMJ - details of physical

l Proximal>distal musclesl Bulbar musclesl May have anticholinergic signs if

presynampticl Fatigability

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Examples of NMJ disordersExamples of NMJ disorders

l Myasthenia Gravisl Botulisml Tick Paralysis

Peter Shearer, MD

MyopathiesMyopathies

l Periodic Paralyses

l Electrolyte Abnormalities_ Hypermagesemia_ Hypophosphatemia

Peter Shearer, MD

Metabolic AbnormalitiesMetabolic Abnormalities

l Periodic Paralysesl Hypermagesemial Hypophosphatemia

Peter Shearer, MD

Work upWork up

l CBC and serum chemistry

l CSF for signs of GBS or myelitis

l Radiography_MRI vs CT

Peter Shearer, MD

ManagementManagement

l Corticosteroids_ not supported by prospective placebo

controlled studies