45 Questions
What is the most common cause of unilateral facial paralysis?
Bell’s Palsy
Which virus is thought to be responsible for the reactivation leading to Bell’s Palsy?
Herpes virus
What is the characteristic clinical feature of Bell’s Palsy?
Hyperacusis (increased sensitivity to sound)
Why is surgery not a primary treatment for Bell’s Palsy?
Ineffective in resolving symptoms
Which of the following is NOT a symptom of Bell’s Palsy?
Blurred vision
What is the proposed mechanism of nerve compression in Bell’s Palsy?
Edema and inflammation
Which population group is more commonly affected by Bell’s Palsy?
Older adults
What percentage of Bell’s Palsy cases tend to resolve spontaneously over time?
>80%
What is the Uhthoff sign associated with in multiple sclerosis (MS)?
Blurry vision
Which symptom is NOT common in MS patients?
Loss of bowel control
What can cause a temporary worsening of neurological function in MS patients?
All of the above
What is a stereotyped worsening of neurological function among MS patients associated with?
Core body temperature increase
Which of the following symptoms is NOT commonly worsened by heat in MS patients?
Constipation
MS patients can experience an "electric shock" running down their back and legs in an unpleasant manner. What is this phenomenon called?
L'hermitte's phenomenon
What is the most common mechanism of injury in central nervous system demyelination?
Autoimmune mechanism affecting oligodendrocytes
Which type of neuropathy involves damage to Schwann cells in the peripheral nervous system?
Guillain-Barre syndrome
What is the main pathophysiologic mechanism involved in nerve compression-related neurological damage?
Vascular injury leading to nerve ischemia
Which term refers to a condition characterized by self-reactive antibodies or T-cells damaging Schwann cells in the peripheral nervous system?
Guillain-Barre syndrome
What defines multiple sclerosis (MS) as an immune-mediated disease in the body?
Autoimmune response directed against the CNS
Which of the following is the most common demyelinating disease?
Multiple sclerosis
What distinguishes between the pathologic appearance of an active and an inactive plaque in central nervous system demyelination?
The inflammatory activity in active plaques
Which condition involves genetic deficits impairing Schwann cells' ability to produce myelin sheaths?
Hereditary sensory and motor neuropathy
What is the typical presentation of Guillain-Barre Syndrome?
Acute polyradiculopathy
What happens to the Schwann cells after 2-3 weeks of demyelination in Guillain-Barre Syndrome?
They begin to proliferate
Which nerve is most at risk of being involved in Guillain-Barre Syndrome if the condition progresses to a life-threatening state?
Phrenic nerve
What is the treatment approach for severe Guillain-Barre Syndrome cases that can progress to loss of function including cervical spinal cord?
Plasmapheresis
What is a common feature of most compressive neuropathies in the peripheral nervous system?
Reduction or loss of motor function
What is a distinguishing characteristic regarding the progression of symptoms in Guillain-Barre Syndrome compared to other conditions?
Ascending muscle weakness
What is the genetic etiology of multiple sclerosis?
HLA-II gene (DRB1/DRB15) responsible for 10% of disease risk
What is a characteristic of inactive plaques in multiple sclerosis?
Loss of axons with limited leukocytic infiltration
What is the role of helper T-cells in the pathogenesis of active plaques in MS?
Recruit cytotoxic T-cells and macrophages into white matter
What do hematoxylin and eosin (H&E) stains show in MS inflammation?
Perivascular infiltration of inflammatory cells
How do acute flares in MS contribute to worsened neurological symptoms?
Attack on white matter components by helper T-cells and cytotoxic T-cells
What is a common feature of active plaques in multiple sclerosis?
Presence of MBP-specific B-lymphocytes producing anti-MBP antibodies
Which immune cells are involved in initiating an immune response against myelin in MS?
$CD4+$ Th cells and B cells
Which of the following is NOT an autoimmune disease?
Charcot Marie Tooth disease
Match the following symptoms with their descriptions in compressive neurological damage:
Weakness or flaccid paralysis = Loss of muscle strength or tone Numbness or anaesthesia = Loss of sensory function resulting in inability to feel touch or pain Tingling or dysaesthesia = Pins-and-needles sensation Urinary retention or erectile dysfunction = Loss of autonomic nervous system function
Match the theories of compressive nerve damage with their descriptions:
Direct mechanical damage to the nerve = Results in loss of axonal function, especially in crush injuries Compression of the vessels in the perineurium = Causes decreased blood flow and reduced nerve function due to ischemia Impingement of the nerve = Inability for the nerve to glide along its course, leading to position-dependent symptoms Compressive defects in axonal transport = Prevent proper transport of proteins from cell body to axon, affecting nerve function
Match the potential consequences of compressive neurological damage with their descriptions:
Death of the nerve = Occurs only in severe cases of direct mechanical damage Survival of the nerve = Usually happens unless compression is severe Decreased blood flow to the nerve = Results from compression of vessels in the perineurium Inability for proper protein transport = Caused by compressive defects in axonal transport
Bell's palsy is caused by compression of _______ nerve
Facial
MS symptoms progress in a gradual manner
False
Guillian Barre Syndrome is characterized by acute and rapid radiculopathy
True
Guillian barre syndrome typically occrus after an ______
infection
Hammer toe is characteristic of.....
Charcot Marie Tooth Disease
______ is a very common feature of most compressive neuropathies
Pain
Study Notes
Here are the study notes:
Demyelinating Diseases
- Demyelination can occur in the central or peripheral nervous system
- Central demyelination: damage to oligodendrocytes or their processes that myelinate axons, commonly caused by autoimmune mechanisms (multiple sclerosis)
- Peripheral demyelination: damage to Schwann cells, commonly caused by genetic deficits or autoimmune mechanisms
Multiple Sclerosis (MS)
- Immune-mediated disease directed against the central nervous system
- Genetic polygenic etiology: candidate genes include HLA-II gene (DRB1/DRB15) responsible for antigen presentation, and variations in IL-2, IL-7, and IL-17 genes
- Other factors: link to viral infections (e.g., Epstein-Barr virus), and reduced vitamin D levels
- Pathogenesis: two phases - active plaques (inflammation, demyelination, and axon damage) and inactive plaques (loss of axons, oligodendrocytes, and myelin)
- Gross pathology: well-circumscribed, irregularly shaped plaques in white matter areas
- Signs and symptoms: vision problems, weakness, numbness, fatigue, heat and activity intolerance, Uhthoff sign
- Diagnosis: clinical diagnosis, aided by characteristic lesions on brain and spinal MRI, and presence of certain antibodies in CSF
- Treatment and prognosis: no cure, immunomodulators can be used for chronic treatment, steroids for acute flares, prognosis varies depending on the pattern of progression
Guillain-Barre Syndrome
- Acute onset immune-mediated demyelinating neuropathy
- Pathogenesis: typically occurs after an infection, immune system mistakenly attacks the nerves
- Clinical features: acute onset of weakness or flaccid paralysis, loss of autonomic nervous system function, loss of sensory function
- Diagnosis, treatment, prognosis: clinical diagnosis, EMG and nerve conduction studies, treatment with plasmapheresis and immunoglobulins, prognosis generally good
Compressive Neurological Damage
- Theories of compressive nerve damage: direct mechanical damage, ischemia, and impingement of the nerve
- Examples of compressive disorders: carpal tunnel syndrome, ulnar nerve entrapment, thoracic outlet syndrome, and disk herniation
Other Neurological Disorders
- Charcot-Marie-Tooth disease: hereditary sensory and motor neuropathy, characterized by demyelination of peripheral nerves
- Bell's palsy: idiopathic paralysis of the facial nerve, thought to be caused by compression of the facial nerve during inflammation
I hope this helps! Let me know if you need any further clarification.
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