Diseases of Peripheral Nerves Flashcards
What are the big categories of peripheral nerve disease?
Inflammatory Neuropathies
Infectious polyneuropathies (more than one nerve affected)
Hereditary neuropathies
Acquired metabolic/toxic neuropathies
What is Guillain Barre syndrome?
What type of neuropathy is this?
Any Treatments?
What is the prognosis?
Guillain Barre Syndrome is an inflammatory neuropathy of the PNS
- It starts as a flue-like illness but develops into paralysis that is ascending (starts at feet and moves up)
- Eventually gets to respiratory system and becomes life-threatening
-Good prognosis, resolves with time
What are the locations of the most intense Guillain Barre syndrome?
How does it happen?
What are the treatments like?
Most intense in Spinal and cranial nerve motor roots and adjacent nerves
-Usually in the PNS
- This is immune-mediated (T-cell mediated)
The T cells tell macrophages to attack myelin on neurons that have been mislabeled with antibodies
This usually occurs after an infection (usually the flu)
Treatment: get rid of the antibodies and allow the nerves to remyelinate
How do you diagnose Guillain Barre Syndrome?
Elevated CSF protein
-There will not be lymphocytes in the CSF though!
Leprosy (Hansen Disease)
-What type of neuropathy is this?
-What causes it?
What does it do?
- This is an infectious neuropathy (both skin and nerves) caused by Mycobacterium leprae
- You will get granulomas to fight the mycobacterium because it has to be surrounded and walled off since it is so small
- If it is not killed, it can cause disabling deformities
What is Mycobacterium leprae?
What other types are there?
- Bacteria that stains via Acid-fast staining
- Likes warm temperature but hard to culture
- Does not gram stain!
Many different kinds:
-Tuberculoid: More localized with scaly skin lesions and nerve degeneration
Lepromatous leprosy (see other flash card)
What is Lepromatous leprosy?
How does it compare to the other leprosies?
What is auto amputation?
Another infection of mycobacterium leprae but the patient’s immune system just can’t fight it off.
- This is more severe and widespread
- Skin, nerves, eye, mouth , testes, hands, feet, etc.
- Can result in auto amputation where the limb just falls off due to lack of vascularizations
What are hereditary neuropathies?
These are neuropathies that stem from a genetic defect
- Genetic defect –> disorder in amyloid deposition or metabolic disorder in the neurons
- Usually sensory and motor neurons are affected but it can include autonomic nerves as well.
What is the most common hereditary neuropathy?
Hereditary Motor and Sensory Neuropathy Type 1 or “Charcot-Marie-Tooth disease”
- This is a demyelinating disease that results in repetitive demyelinating and remyelinating
- Characterized by motor weakness and loss of sensation but still pain
- It starts in the feet and moves up
- Patients usually have normal life spans but still need someone to take care of them
- Signs/symptoms?: High arches, hammer toes, muscle atrophy
How many patient’s with diabetes have peripheral neuropathy?
What is it like?
What type of neuropathy is this?
- 50% will have neuropathy
-This is loss of sensation and decreased pain in the distal extremities
The loss of sensation/pain stems from destruction of distal sensory and motor nerves.
- This is an acquired neuropathy
What are some of the symptoms of Guillan-Barre Syndrome
-Symmetric ascending paralysis
Rapid-onset weakness and loss of deep tendon reflexes
Loss of sensation can occur too
How is Mycobacterium leprae transmitted?
It is transmitted through respiratory droplets
What is the Varicella-Zoster Virus?
- Where does the virus lay dormant?
- What happens after it wakes later in life?
This is the viral Chicken Pox virus but commonly infects the PNS
- After you have the CP, the virus lays dormant in sensory ganglia of the spinal cord and inside the brainstem
- After it wakes again in life, it creates a painful, vesicular, rash that follows dermatomes
What is the most common cause of mononeuropathy (only a single nerve affected)?
Neoplasm malignancies: The tumor can press down on a single nerve.
Lung neoplasms –> Brachial plexopathy
Pelvic neoplasms –> Obturator Palsy
Brain tumors –> Cranial Nerve Palsies
When suffering from a malignancy, is polyneuropathy a direct result of the tumor?
No, polyneuropathy is a paraneoplastic effect
-Paraneoplastic = a problem that is indirectly due to effects of the tumor farther away in the body.
