Neurology: Peripheral Neuropathies Flashcards
Describe Wallerian degeneration in its most basic sense.
When a peripheral nerve is cut, the distal end degenerates and is recycled by the immune system.
Describe the functions of small and large fiber peripheral nerves.
Small Fiber: poorly myelinated, pain and temp sensation, ANS signaling
Large Fiber: heavily myelinated, descriminiative touch, vibration, proprioception, REFLEXES
What are the #1 and #2 risks for polyneuropathies?
- Diabetes Mellitus
2. Alcoholism
Component that causes sensory or autonomic polyneuropathy from overuse of vitamin supplements.
Pyridoxine
Define: hypesthesia, hyperesthesia, dysesthesia, and paresthesia
Hypesthesia - decreased sensation
Hyperesthesia - increased sensation
Dysesthesia - unpleasant, abnormal sensation produced by normal stimulus
Paresthesia - perverted, abnormal sensation like burning, prickling, formication (crawling)
2 conditions that lead to cranial neuropathies.
- Guillain Barre Syndrome
2. Diptheria
5 conditions that lead to ANS neuropathies.
- Diabetes M.
- Amyloid (insoluble fibrous aggregates of protein inside cells, usually neurons)
- Guillain Barre
- Porphyria
- Thallium Poison (rare)
6 conditions that lead to mononeuropathy multiplex.
- Diabetes M
- Vasculitis (from RA or polyarteritis nodosa)
- Trauma
- Plasma Cell Dyscrasia (plasma cell cancers)
- Leprosy
- Sarcoidosis
Describe Guillain Barre Syndrome
Ascending demyelinating motor polyneuropathy often caused by acute inflammation.
Etiology of Guillain Barre
Unknown, leading hypothesis states that the immune system reacts to a cancer or infecitous agents that resembles the bodies nerves and an autoreaction occurs.
Why does Guillain Barre syndrome that results from a Campylobacter jejuni infection take longer to recover than most other forms?
This form of Guillain Barre attacks the axons, not the myelin
What distinguishes Guillain Barre from: 1. Polio 2. Myelitis 3. Botulism in the DDx?
- Polio: bug has been eliminated
- Myelitis: hyper-reflexia, GB has arefelxia
- Botulism: descending motor, GB is ascending
Describe two treatments for Guillain Barre.
- Plasmapheresis: wash the bad Abs out of the blood and return it to patient
- IV IgG: overdose with Abs to shut down the immune system
Describe Uremic Polyneuropathy
Renal failure leads to progressive, painless, symmetrical, sensorimotor polyneuropathy. Patients have parasthesia and restless legs at night.
Treatment can be a renal transplant.
Describe Alcoholic Polyneuropathy
Combination of direct toxicity of alcohol and vitamin deficiency lead to symmetric sensorimotor neuropathy.
Treat with proper nutrition and stop drinking
Most common cranial nerve neuropathy caused by diabetes.
CN VII
Name common symptoms of Autonomic Polyneuropathies.
Genitourinary and Gastrointestinal symptoms, impotence, impaired sweating and vascular regulation
Describe symptoms of a radiculopathy.
PAIN, usually restricted to a dermatome (mostly thoracic) due to poor diabetic control and weight loss.