Peripheral Neuropathies Flashcards
symmetric distal sensory loss with burning or weakness
polyneuropathy
Disease usually provoked by preceding infection, acute inflammatory demyelinating polyneuropathy
Guillain-Barre Syndrome (GBS)
Sx include symmetric muscle weakness w/ absent or decreased DTRs, respiratory muscle weakness requiring ventilatory support, severe back pain, Dysautonia***
Guillain-Barre Syndrome
Tx for Guillain-Barre Syndrome
plasmapheresis or IV immune globulin
Diagnostic test of choice for Guillain-Barre and its results
Lumbar puncture- elevated protein w/normal WBC count
Glycolipid antibodies to gangliosides
Likely cause of Bell’s Palsy
Herpes simplex activation
Sx include: unilateral facial paralysis, Decreased tearing, Eyebrow sagging
Bell’s Palsy
TImeline of progression and resolution of Bell’s Palsy
Progressive w/ maximal paralysis within three wks of onset. Recovery of some degree by 6 months
Pharm tx for Bell’s palsy
short term glucocorticoid. if severe add valacyclovir
Autoimmune disorder characterized by weakness and fatiguability of skeletal muscle. Autoantibodies against acetylcholine receptors
Myasthenia Gravis
Key symptom of Myasthenia Gravis
Fluctuating skeletal muscle weakness
Sign seen in myasthenia gravis characterized by unilateral ptosis
Curtain Sign
Mainstay of tx for myasthenia gravis in symptomatic patients
Anticholinesterase agents-Pyridostgigmine (Mestinon)
Tx for a myasthenia crisis
Plasmapheresis, IV immunoglobulin, removal of thymus
Most common etiology of polyneuropathy
DM
pattern of weakness in polyneuropathy
stocking and glove distribution
Results of electrodiagnostic tests for polyneuropathies
Reduced amplitude of evoked compound actions potentials. Preservation of nerve conduction studies
Neuropathy pathogenesis that results in length-dependent “dying back” axonapathy and Involves the distal portions of the longest mylenated and unmylenated sensory axons
DM polyneuropathy
late findings of DM polyneuropathy
widespread loss of reflexes and motor weakness
4 Factors needed for adequate absorption of B12 (cobalamin)
pepsin, pancreatic proteases, intrinsic factor, and Ileum w/ Cbl-IF receptors
Cause of polyneuropathy that leads to a defect in myelin formation and subacute degeneration of dorsal (posterior) and lateral spinal columns
Vitamin B12 deficiency
Axonal neuropathy complicated by demyelination when there is coexisting nutritional deficiency
Alcoholic Polyneuropathy
An example of a common direct neurotoxin
ETOH
Sx include: Pareshesias, ataxia w/ loss of vibration and position sense, can progress to severe weakness, spasticity, clonus and paraplegia
Vitamin B12 deficiency polyneuropathy
Tx for vitamin B12 deficiency polyneuropathy
IM B12 injections 1000microgms twice weekly for 2 weeks followed by weekly for 2 months and then monthly
Spinocerebellar syndrome with variable peripheral nerve involvement
vitamin E deficiency
Most common etiologies of vitamin E deficiency
cholestasis and pancreatic insufficiency
Tx of vitamin E deficiency
large doses of alpha-tocopherol then daily oral vitamin E
neuropathy associated w/ calf cramps, muscle tenderness, and burning feet, autonomic neuropathy may be present
Dry Beriberi
high-output CHF + neuropathy
Wet beriberi
Bugs commonly responsible for Guillan-Barre
Campylobacter jejuni, CMV, and EBV
has the advantage of being an antidepressant as well as helping control pain
Duloxetine (Cymbalta)
medication that is targeted for diabetic polyneuropathy
Pregabalin (Lyrica)
medication that reduces pain associated with polyneuropathies
Gabapentin (Neurontin)
Has NO abnormalities beyond motor function of CNVII
Bells Palsy
In Myasthenia Gravis what happens to sensation and DTRs
Sensation is normal and there are no reflex changes
More common in pregnancy and DM
Bell’s Palsy
