UMEM Educational Pearls

  • When dealing with weakness and sensory complaints in the ED, the time course of symptoms and physical exam findings help identify emergent conditions.
  • We often talk about upper motor neuron vs. lower motor neuron signs that distinguish whether a lesion is in the central or peripheral nervous system.
  • Characteristics that differentiate between central vs. peripheral nervous system pathology include:
  Central Nervous System Peripheral Nervous System
Pattern of Symptoms
Hemibody involvement
Weakness of UE extensors
Weakness of LE flexors
Distal involvement in polyneuropathy
Distal and proximal involvement in polyradiculoneuropathy
Proximal involvement in polyradiculopathy
Sensory often precedes motor symptoms 
Pure proximal>distal weakness may be due to myopathy or NMJ disorder
Sensory Symptoms
• Central poststroke pain (hyperalgesia, allodynia)
• Sensory level in spinal cord pathology 
• Proprioception involved early in dorsal column disorders
Neuropathic pain (burning, tingling, shock-like) 
Ascending sensory loss involving distal BLE>BUE in polyneuropathy
Proprioception involved late in polyneuropathy
Hyperreflexia in affected limb(s) after acute period
Positive Babinski’s sign
Hyporeflexia in affected limb(s)
Tone Increased after acute period Decreased
UE = upper extremity
LE = lower extremity
NMJ = neuromuscular junction
Bottom Line: A systematic approach to the evaluation of weakness and sensory complaints in the ED help differentiate between central vs. peripheral nervous system pathology.



London ZN. A structured approach to the diagnosis of peripheral nervous system disorders. Continuum Minneap Minn) 2020;26(5, Peripheral Nerve and Motor Neuron Disorders):1130-60.
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