Info
🌱 來自: Huppert’s Notes
Neuromuscular Disorders🚧 施工中
Neuromuscular Disorders
Motor Neuron Diseases
Amyotrophic lateral sclerosis (ALS)
• Pathophysiology: Degeneration of upper and lower motor neurons leading to a combination of hyperreflexia/spasticity and atrophy/fasciculations
• Diagnosis: EMG; rule out mimics with MRI brain/C-spine, B12/MMA, TSH, PTH, Lyme ab, heavy metals
• Treatment: Riluzole (survival benefit of 2–3 months)
Peripheral Neuropathies
Exam is notable for LMN signs (hypo- or areflexia, decreased tone, atrophy, fasciculations); may be symmetric or asymmetric. Axonal neuropathy is typically length-dependent, demyelinating neuropathy is patchy.
Mononeuropathy
• Etiology: Usually due to nerve compression (e.g., carpal tunnel, cubital fossa). Progressive sequential mononeuropathy suggests mononeuritis multiplex and requires an urgent work-up
Polyneuropathy
• Etiology: Approximately 1/3 due to complications of diabetes, 1/3 due to complications of chronic alcohol use, and 1/3 due to other causes including:
- Immune mediated (Guillain-Barré, chronic inflammatory demyelinating polyneuropathy [CIDP])
- Metabolic (thyroid disease, uremia, vitamin B12 deficiency, paraproteinemia)
- Rheumatologic (SLE, vasculitis)
- Malignancy/monoclonal gammopathy (paraneoplastic, leukemia, MGUS, amyloid)
- Infection (HIV, syphilis, lyme, leprosy)
- Toxin/medications (heavy metals, amiodarone, chemotherapy)
- Inherited (Charcot-Marie Tooth disease)