What happens in Guillain-Berre Syndrome?
1. flu-like illness, usually a virus
2. T-cells cross-react with myelin and macrophages destroy it
3. you get acute ascending paralysis
4. usually resolves with time
The acute demyelination occurs thorughout the PNS, but where is it most intense?
spinal and cranial nerve motor roots and adjacent nerves
What sort of immune cells will proliferate around nerves and venules in Guillain Barre?
mononuclear immune cells - lymphocyes, macrophages, and plasma cells (so basically everything but neutrophils)
What are some physical exam and lab signs of Guillain Barre?
rapid onset weakness, loss of DTRs
some loss of sensation
elevated CSF protein, but no lymphocytes
Demyelination occurs _____ in GUillarin-Barre.
segmentally - it won't just be the whole thing disappearing right away
What bacteria causes leprosy (Hansen Disease)?
How is Mycobacterium leprae transmitted?
probably through responratory droplets - usualy an't even find the bug in the skin lesions
What makes mycobacterium leprae special?
they have a waxy coat so it can't stain with gram stain - have to use acid-fast
only grow intracellularly, so hard to grow in culture
hard to kill by normal immune response
How does the immune system (hopefully) respond to mycobacterium leprae?
forms granulomas around it to wall off and destroy
What are the two forms of leprosy an which is less severe?
Tuberculoid Leprosy is less severe
Lepromatous Leprosy is the bad one
What are the symptoms of tuberculoid leprosy and why is it less severe?
Dry scaly skin lesions and some nerve degeneration
Not as severe because they have the appropriate T cell response to the bug with granuloma formation
What are the symptoms of lepromatous leprosy and why is it more severe?
Affects skin, nerves, eye, mouth, testes, hands and feet (grows bet at 91 degrees - so stays at periphery)
- leonine facies (skin lesions form big dysfiguring nodules on the face)
WOrse because they don't form granulomas
Instead of granulomas, what would you see on histology in lepromatous leprosy?
Where does varicell zoster remain dormant after chicken pox?
the sensory ganglia of the spinal cord and brain stem
What will you see on histology in varicella zoster?
neuronal destruction and multinucleated giant cells (in shingles)
What is another name for Hereditary Motor and Sensory Neuropathy Type 1?
What happens in CMT?
repetitive demyelination and remyelination leading ot muscle and sensation loss (pain intact)
usually lower extremities more affected - high arches, hammer toes, muscle atrophy
What will nerves of CMT patients look like on histology?
they'll have onion bulb formation - this is the remyelination
What is the most common manifestation of peripheral neuropathy in diabetes?
symmetric sensory and motor neuopathy involving distal nerves - hands and feet in sock and glove distribution
- decreased pain sensation
What is the most common cause of a mononeuropathy?
malignancies that press on nerves - brachila plexopathy from lung neoplasms, obturator palsy from pelvis neoplasms and cranial nerve palsies from brain tumors
How does a polyneuropathy occur with malignancy?
it occurs as a paraneoplastic effect related to some cytokine released from the tumor
especially common with small cell lung cancer and plasma cell malignancies