Central vs Peripheral Weakness?
Brain/Spinal Cord: Upper Spinal Motor Neuro Lesion: Tone goes up, reflex goes up, babinski upgoing, no wasting, no fasiculations. Not really useful in the acute setting.
Motor weakness: look at distribution: clinical localization, proximal vs distal, facial involvement, symmetry, progression. Sensory, reflexes.
If reflexes present, it is NOT: GBS, NMJ blocker, botulism, hypermagnesium.
Guillain-Barre syndrome: acute inflammatory demyelinating polyradioculopathy. Weakness more proximal, Legs>arms, symmetrical. Rapid, ascending. 2-4 weeks after URI/GI illness.
Myasthenia Gravis: 85% eye involvement, gradual. precipitated by medication noncompliance, infection (usually pneumonia).
Spinal Cord: acute compression from epidural compression, epidural abscess, tumor. Acute ischemia/infarct from aortic dissection. Weakness below lesion of lesion, usually symmetric.
Anterior spinal artery syndrome: less of pain/temp sensation lost, others preserved.
Acute Non-traumatic Weakness, Danya Khoujah, The Crashing Patient Conference 2015.