Acute Peripheral Weakness Acute Peripheral Weakness Peter Shearer, MD Assistant Residency Director Mt. Sinai School of Medicine
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
Peter Shearer, MD
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