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

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myelopathy - details of historymyelopathy - details of history

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

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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

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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

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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

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NMJ - details of historyNMJ - details of history

l Exposure_ botulism_ snake bites

l fatigue

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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

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MyopathiesMyopathies

l Periodic Paralyses

l Electrolyte Abnormalities_ Hypermagesemia_ Hypophosphatemia

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Metabolic AbnormalitiesMetabolic Abnormalities

l Periodic Paralysesl Hypermagesemial Hypophosphatemia

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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