Diseases of peripheral nerves Flashcards
Motor nerve damage symptoms
usu. associated with muscle weakness
may also see painful cramps, fasciculations, muscle atrophy
Sensory nerve damage symptoms
various symptom patterns can include loss of vibratory sense, stocking-glove sensation, loss of reflexes, loss of position sense, loss of temperature sensation, pain
Autonomic nerve damage: aka small-fiber neuropathies symptoms
Excess sweating, heat intolerance, inability to expand
and contract small blood vessels regulating blood pressure, gastrointestinal symptoms
What is the most common cause of a single nerve injury?
Trauma
What is the most common cause of polyneuropathy in the US?
Diabetes
What is the most common inherited neurological disorder?
Charcot-Marie-Tooth
Peripheral Neuropathy evaluation
*Medical history (symptoms, triggers, possible causes)
* Physical with full neurological exam
*Blood work (looking for deficiencies, dysfunction, infection, metabolic dx, autoimmunity).
*CSF
*Genetic testing
Physiologic tests of nerve function
- Nerve conducsion velocity (NCV)- Tests signal strength and speed
- Electromyography (EMG)-Tests electrical activity, rest/contraction (differentiates between nerve and muscle issue.
What is the gold standard for small fiber neuropathies
Skin biopsy
What is a QSART?
Used for small fiber neuropathies, test sweat ability, Acetyl-choline
Imaging for peripheral neuropathy evaluation
- MRI (Compression/mass/soft tissue/structural)
- CT (Mass/solid tissue/structural)
conservative treatments for peripheral neuropathy
- Manage potential causes i.e diabetes, smoking habits, drinking habits, diet, exercise
Managing specific symptoms:
Motor-Orthotics, mechanical aids
Autonomic-Accupuncture, massage, CBT/psychotherapy
Sensory-Behavioral strategies
*Transcutaneous electrical nerve stimulation (TENS)
Medication treatments for peripheral neuropathy
- TCA’s
- SSRI’s
- Gabapentin
- Topiramate
- Duloxetine
- Topical/local anesthetics
- Capsaicin
- Implanted spinal cord pumps with lidocaine, bupivicaine
- Opioids
Surgical treatments for peripheral neuropathy
- Remove compression
- Cutting the nerve-replaced with stimulation
Complex Regional Pain Syndrome (CRPS)
Chronic (>6 months) pain condition that usually affects one limb, typically after an injury.
Characterized by prolonged or excessive pain and changes in skin color, temperature, and or swelling.
Type I CRPS
Without a confirmed nerve injury
Type II CRPS
With an associated, confirmed nerve injury.
Who is most commonly affected by CRPS?
- Women
*Peak at age 40 - More common in patients with other inflammatory or autoimmune conditions.
Pathophysiology of CRPS
- Peripheral nerve abnormality involving small, unmyelinated/thinly myelinated sensory nerve axons carrying pain messages. Also affects nerves communicating with blood vessels.
- Vascular effects
*Immune system effects
Presentation of CRPS
- Prolonged severe pain described as “burning”, “pins and needles” sensation, or “squeezing” sensation.
- Pain can spread from area of onset
- Often will see sensitivity to area.
*Skin temp, color, swelling changes - Abnormal movement
- Abnormal sweating pattern
CRPS treatment therapies
- Rehab and PT
*Psychotherapy
*Sympathetic nerve block
*Surgical sympathectomy
*Intrathecal drug pumps
*Spinal cord stimulation
CRPS medicinal treatment
- Bisphosphonates
*Anti-Inflammatory meds (NSAID’s, Corticosteroids) - Neuropathic pain meds (gabapentin, pregabalin)
- Botox
*Opioids (CAUTION)
What is the role of Vitamin B12 in the body?
- Important in cellular metabolism and nervous system maintenance/integrity.
- Important in synthesis of DNA and cell division
What is the most common etiology of vitamin B12 deficiency?
Lack of intrinsic factor (pernicious anemia); a common finding in the elderly.
Vitamin B12 neuropathy
Deficiency of B12 associated with impaired erythropoiesis and nervous system demyelination.
Additional causes of Vitamin B12 deficiency neuropathy
*Autoimmune
* Malabsorption
*Dietary insufficiency
B12 Neuropathy physical exam
- Good history on gastro/neuro findings (Chrons or celiacs disease at greater risk)
- Pallor/fatigue (consistent w/ macrocytic anemia)
*Neuro eval (Dementia, mental status, peripheral neuropathy, ataxia/loss of proprioception. - Jaundice
- May also see glossitis, diarrhea, headaches, peripheral neuropathy, neuropsych disturbances.
B12 Neuropathy Evaluation
- CBC w/ peripheral smear
*Serum B12 - Folate
- Methylmalonic Acid
- Homocysteine
If negative - GI work up
If both negative likely autoimmune - Anti-intrinsic factor antibodies
What is the most common cause of B12 deficiency?
Macrocytosis
B12 neuropathy treatment
Supplementation
*oral for vegans
* Intrinsic factor deficient IM once per week for four weeks initially, then once per month
* Routine monitoring w/ celiacs and chrons
Complications of B12 deficiency
- HF
- Severe neurological deficits
- Inc risk gastric cancer
- Inc risk autoimmune disease
Guillain-Barre Syndrome
Rare neurological disorder in which the bodys immune system mistakenly attacks peripheral nervous system.
Guillain-Barre pathophys
Cause unknown, most cases begin a few days or weeks following a respiratory or GI viral infection.
Can also be seen occasionally following surgery, rarely with vaccinations.
Guillain-barre presentation
*Symmetric weakness
*Rate of onset (days to up to four weeks)
*Abnormal sensations
* Absent or diminished deep tendon reflexes
* Recent viral infection or diarrhea
* In children deep pain, refusal to ambulate d/t pain
Acute inflammatory demyelinating polyneuropathy (AIDP)
Most common type of Guillain-Barre in US. Immune response damages myelin coating and interferes with the transmission of nerve signals.
Acute motor axonal neuropathy (AMAN)
Axons themselves damaged by the immune response
Miller-Fisher syndrome
Rare, acquired form of Guillian-Barre Syndrome
Guillain-Barre treatment
- Admit and treat in ICU: plasma exchange or high dose immunoglobulin therapy (one or the other)-effective if started within two weeks of symptom onset
- Supportive care
*Close monitoring respiratory/cardiology
*Later, PT (muscle strengthening), OT, Voc. Therapy (Adaptive equipment and tech)
