1. Dr. Kevin J. Pacheco
Weakness

2. Introduction Weak = decrease in muscle strength or power
Dizzy = lightheadedness, disequilibrium, disorientation, vertigo, or even confusion
Weakness
First, divide into focal or generalized
Then, separate sudden vs. gradual onset

3. History Hints Focal + Sudden
Ischemic CVA/TIA/ICH until proven otherwise
Generalized + Sudden
Occult infections, anemia, and metabolic disorders (hypoxia, sodium, potassium and glucose)
Focal + Gradual
Tumor, peripheral nerve compression, other spinal cord pathology, or autoimmune (MS)

4. Physical Exam Hints Ptosis – myasthenia gravis
Persistent tachycardia – myocarditis (troponin will be positive)
Back pain + weakness – MRI (with contrast if fever) for epidural hematoma/abscess, cauda equina, metastatic cancer, transverse myelitis
Young female and focal neuro – MRI with contrast for multiple sclerosis

5. Can’t Miss Differential
Stroke – hemiplegia, aphasia, visual
Spinal cord compression/ischemia/infection – back pain and true weakness
Electrolytes – sodium, potassium, magnesium, glucose
CNS infection – fever, meningismus, altered mental status
Seizure – post-ictal, tongue laceration, incontinence
Toxic

6. Weakness – Work-Up Orders
Start with CBC, BMP, EKG, VS +/- accucheck if DM and UA if elderly or symptoms suggestive
Consider troponin if presentation or clinical history suggests
Add CT head w/o contrast if sudden or focal and no other explanation
Add TSH if gradual
Then look at MRI of spinal cord or brain

7. Weakness Zebras What are you going to miss with above?
Myasthenia Gravis – blurred vision, diplopia, and ptosis (anti-acetylcholine R Ab)
Guillaine-Barre – ascending paralysis, decreased reflexes, variable sensory deficits (LP + history)
Drug Induced Myopathies – meth in particular - total CK or myoglobin
ALS – mixed picture of weakness and hyperreflexia (rule out others + EMG)
Certain infections – mono (sore throat, monospot), hepatitis (hx +/- jaundice, CMP)
Adrenal insufficiency – chronic steroid use, refractory hypotension (cortisol and ACTH stimulation test – give 100mg hydrocortisone)

8. Often Overlooked Check reflexes
This can increase or decrease suspicion of difficult to diagnosis conditions (example: if reflexes present unlikely Guillain Barre)