Peripheral neuropathies Flashcards
Polyneuropathy definition
- causes
- pathophys
- symmetric distal sensory loss with burning or weakness
- can be axonal or demyelinating
- stocking glove distribution
Cause:
- DM
- AIDS
- Vit B12 deficiency
- Toxins: alcohol, chemo
- uremia
Pathophys:
- axonal: MC, injury related to axonal length
- demyelinating: seen in autoimmune and DM polyneuropathy
Guillain-Barre Syndrome
- cause
- clinical features
- sx
Cause: immune-mediated, provoked by preceding infection; Resp tract infection, CMV, EBV, campylobacter jejuni.
-generation of abys to gangliosides that cause axonal injury
Features:
-ascending symmetric muscle weakness w/ absent or decreased DTRs
Sx:
- resp muscle weakness requiring ventilator support
- paraesthesias in hands/feet
- severe back pain
- dysautonia; tachycardia, urinary retention, HTN alternating w/ hypotension, bradycardia, ileus, loss of sweating
Guillain Barre Syndrome
- Tx
- Dx
Tx: plasmapheresis or IVIG x5days
Dx:
- LP; elevated protein and normal WBC
- EMG/Nerve Conduction studies
- sensory does not level
Bells Palsy
- what is this?
- cause
WHat: acute unilateral peripheral facial palsy
- inflammation of facial nerve, compression leading to break down of myelin.
- motor portion of facial nerve is paralyzed
Cause:
- herpes simplex MC cause
- others: EBV, adenovirus, rubella, mumps, influenza B, hepes zoster*, coxsackie virus
- pregnancy
Bells Palsy
- clinical presentation
- course of disorder
- you know its not bells palsy if they have these sx
Presentation:
- sudden onset (hrs)
- eyebrow sagging
- inability to close eye
- disappearance of nasolabial fold
- mouth drawn to non-affected side
- decreased tearing
Course:
- onset in 1-2days, progressive w/ maximal paralysis at 3 weeks, recovery of some degree of function by 6mo
- not everybody gets total function back*
NOT plasy if:
-onset prolonged, relapsing course
Bells Palsy Management
- Glucocorticoid Therapy
- protect the eye via:
- -glasses
- -eye drops
- -eye gel
- -patch
- -paper tape
Patient education: recovery may be disorganized
Myasthenia Gravis
- what is this?
- cause
- peaks at what ages in men and women?
What: autoimmune disorder characterized by weakness and fatigability of descending skeletal muscle
Cause:
-autoabys against ach receptors, block the binding sites of ach, muscles done work
Ages:
- 2nd and 3rd decade in women
- 6-8th decade in men
Myasthenia gravis
-sx
Sx:
- fluctuating* skeletal muscle weakness, worsened by contractile force
- sx ok in AM and worse at night
- ocular: ptosis bilateral or unilateral, diplopia
- bulbar: weakness with prolonged chewing, jaw weakness at rest, dysarthria/dysphagia, nasal regurgitation of liquids
- facial: expressionless, snear
- neck/limb: dropped head syndrome, limb proximal weakness
- respiratory: resp insufficiency and pending resp failure
Myasthenia Gravis:
- Dx
- Tx
Dx:
-serological testing immunologic assays: AChR-Ab, aby to MuSK
- Electrophysiologic studies:
- repetitive nerve stimulation studies
- single fiber electromyography*** most sensitive to MG
Tx:
-Anticholinesterase agents: Pyridostgigmine (Mestinon)
- Chronic Immunotherapies; corticosteroids, immunosuppressive medications
- Rapid immunotherapies; plasmpharesis, IV immunogloblins
Surgery: thymectomy for thymoma
Diabetic Polyneuropathy:
- risk factors
- pathogenesis
Risk Factors:
- duration and severity of hyperglycemia
- increased triglycerides
- BMI
- smoking
- HTN at baseline
Pathogenesis:
- accumulation of glycosylation of end products and sorbitol
- nerve ischemia and damage
- long axons go first
- peripheral nerve repair is impaired in DM
What is the most common neuropathy in the western world?
Diabetic Polyneuropathy
Diabetic Neuropathy:
- PE findings
- Complications
- Tx
PE:
- loss of vibratory sensation and altered proprioception
- impairment of pain, light touch, and temp
- decreased/absent reflexes
Complications: cant walk right and fall, foot ulcers leading to amputation
Tx: tight glycemic control
- Neurontin: reduces pain
- TCA: amitriptyline
- Carbamazepine & Phenytoin = varying success
- Lyrica = targeted towards diabetics
- Cymbalta: antidepressant and controls pain
NO NARCOTICS!!!
Alcoholic Polyneuropaathy
- pathogenesis
- tx
axonal neuropathy complicated by demyelination when there is coexisting nutritional deficiency
(thiamine)
Tx: stop drinking alcohol
Vit B12 deficiency polyneuropathy
- pathogenesis
- cause
- dx
- tx
defect in myelin formation leading to subacute degeneration of nerves
Cause:
- decreased dietary intake
- decreased intrinsic factor by parietal cells
- decreased receptor sites on ileum
- bariatric surgery
dx: serum B12 level(Cobalamin)
- gastrin
- parietal cell abys
- anti-intrinsic factor abys
- h. pylori
Tx:
-IM B12 injections twice weekly for 2 weeks then weekly injections for 2 mo….monthly injections for life or until deficiency resolves
Vit E deficiency Polyneuropathy
- cause
- tx
- pancreatic insufficiency
tx: very very high dose of Vit E
