Path- 1: Neuro/cytology Flashcards
What happens to the Schwann cells in segmental demyelination?
They have either a disfxn (in hereditary motor or sensory neuropathy) or damage (like in Guillian Barre)
What happens to the axons in segmental demyelination?
NOTHING
What do you see on a microscope with chronic de- and remyelination?
Onion bulbs
“Pissed off shrek in plastic wrap.”
Which cells are absolutely ESSENTIAL for the regeneration of the injured PNS?
Schwann cells
What is the pattern of demyelinatiopn in multifocal motor neuropathy?
Segmental demyelination of a motor axon
In axonal degeneration and muscle atrophy, what happens first and second?
There is primary destruction of the axon and a secondary loss of the myelin sheath.
Define: This is a bundle of muscle fibers that lose innervation from a nerve, so they become small and angular.
Grouped atrophy
What is the process called when there is axonal injury due to transection?
Wallerian dgeneration
What happens in wallerian degeneration at the distal portion of the nerve?
axon breaks down within a day –> Schwann cells begin to destroy myelin and engulf axon fragements –> macrophages FEAST
What happens in wallerian degeneration at the proximal portion of the nerve?
there is degeneration for only 2 or 3 distal internodes, undergoes regenerative activity
What happens to the muscle in axonal transections?
Atrophy
What forms on the nerve “stump” as far as the reinervation process?
It forms clusters of small axons with thin myelin
Define: this is a benign, encapsulated neoplasm that has neoplastic proliferation in the endoneurium with the perineurium forming the capsule. Typically forms around VIII.
Schwannoma
What are the clinical Sx of Guillian Barre?
Can cause resp arrest, ascending paralysis, segmental demyelination of the spinal and peripheral nerves (primary lesion)
it’s like when Neo sticks his hand in that mirror and that mirror shit climbs up his body and then down his troat. Crazayyyy
What causes Guillian Barre?
immune mediated response due to infection of Capylobacter jejune, CMV, mycoplasma pneumo or vaccines.
Is nerve conduction velocity increased or decreased in Guillian Barre?
Decreased
Is CSF protein increased or decreased in Guillian Barre?
increased
What causes HMSN’s?
mutations in genes involved in peripheral nerve function
What is the most femousestestest type I HMSN?
Charcot Marie Tooth
Who does CMT affect?
KIDS or young adults
What is the inheritance of CMT?
AD
What is the clinical presentation of CMT?
Progressive paralysis below knee (peronial muscular atrophy), sensorimotor deficit with orthopedic deficit such as pes cavus, notmal life span
What type of HMSN of Dejerine Sottas?
HMSN tpye III
Where in the doby does Dejerine Sottas affect?
both the trunk and the limb muscles
What is the inheritance of Dejerine Sottas?
AR
What is the clinical presentation of Dejerine Sottas?
infintile onset (1-12mo), large peripheral nerves, demyelination w/onion (skrek) bulbing, more severe than CMT