L8peripheral Nerve Disease Flashcards
Most peripheral neuropathies can be subclassified as?
either axonal or demyelinating
Axonal neuropathies:
• caused by insults that directly injure the axon.
• entire distal portion of an affected axon degenerates
• Axonal degeneration is associated with secondary myelin loss,(Wallerian degeneration)
• Regeneration takes place through axonal regrowth and subsequent remyelination of the distal axon.
• morphologic hallmark of axonal neuropathies is a decrease in the density of axons
which correlates with a decrease in the strength of amplitude of nerve impulses
Demyelinating neuropathies:
1-damage to Schwann cells or myelin with relative axonal sparing results in
slow nerve conduction velocities.
2- occurs in individual myelin internodes randomly
( this process is termed segmental demyelination ).
3- relatively normal density of axons and features of
segmental demyelination and repair.
4- presence of axons with abnormally thin myelin sheaths and short internodes.
Polyneuropathies ?
1- affect peripheral nerves in a symmetric length-dependent fashion.
2- Axonal loss is diffuse and more pronounced in the distal segments of the longest nerves.
3- loss of sensation and paresthesias that start in the toes and spread upward to the knees and then involve the hands in a “stocking-and-glove” distribution
Mononeuritis multiplex ?
1- damage randomly affects portions of individual nerves (right radial nerve palsy and wrist drop and at separate point in time, left foot drop) -Asymmetric-
2- caused by vasculitis
Simple Mononeuropathy ?
1- involve only a single nerve most commonly is the result of
traumatic injury or entrapment (e.g., carpal tunnel syndrome).
Disorders Associated with Peripheral Nerve Injury (Guillain-Barré Syndrome):
1-most common life threatening diseases of the peripheral nervous system.
2-rapidly progressive acute demyelinating disorder affecting motor axons that results in ascending weakness that may lead to death from failure of respiratory muscles over a period of only days.
3-triggered by an infection or a vaccine that breaks down self-tolerance thereby leading to an autoimmune response
4- injury most extensive in the nerve roots and proximal nerve segments and is associated with mononuclear cell infiltrates rich in macrophages
5- Both humoral and cellular immune responses are believed to play a role in the disease process.
-Associated infectious agents in Guillain-Barré Syndrome include ?
-Campylobacter jejuni
-Epstein-Barr virus
-cytomegalovirus
-HIV and Zika virus.
Guillain-Barré Syndrome Treatments
1- Plasmapheresis
2- immunoglobulin
3- Supportive care
اللي يعدي من الحالة الacute بيتشافى
most common chronic acquired inflammatory
peripheral neuropathy?
Chronic Inflammatory Demyelinating Polyneuropathy
Chronic Inflammatory Demyelinating Polyneuropathy :
1- symmetrical mixed sensorimotor polyneuropathy that persists for 2 months or more.
2-Both motor and sensory abnormalities (walking, weakness, numbness, and pain or tingling sensations)
3-immune- mediated Like GBR
4-in patients with other immune disorders (SLE and HIV)
5-relapsing-remitting or progressive course عكس الثاني
6-chronically regenerating Schwann wrap around axons onion-skin pattern
7- treated by plasmapheresis and administration of immunosuppressive agents.
8-recover completely but recurrent
9-bouts of symptomatic disease lead to permanent loss of nerve function.
10-peripheral nerves show segments of demyelination and remyelination.
most common cause of peripheral neuropathy?
Diabetes
Diabetic Peripheral Neuropathies ?
• Autonomic neuropathy
• Lumbosacral radiculopathies
• Distal symmetric sensorimotor polyneuropathy ( mostly )
• Autonomic neuropathy is characterized by?
changes in bowel, bladder, cardiac, or sexual function.
• Lumbosacral radiculopathy usually manifests with?
asymmetric pain that can progress to lower extremity weakness and muscle atrophy.
