demyelinating, pns, neuromuscular junction disorders and lumbar puncture - Sheet1

Question 1

What is Multiple Sclerosis (MS)?

Answer 1

A common dysimmune, demyelinating disorder that involves the destruction of CNS myelin.

Question 2

What is the function of myelin?

Answer 2

Myelin helps in speeding up the conduction of nerve impulses.

Question 3

What is the mechanism of MS?

Answer 3

In genetically susceptible individuals, an immune response is triggered by a previous insult (trauma, pregnancy, infection), leading to T-cells becoming reactive to myelin proteins in the CNS.

Question 4

How does MS progress?

Answer 4

Some MS disorders are progressive, while others have periods of exacerbation followed by remission.

Question 5

What are the visual manifestations of MS?

Answer 5

Vision changes (blurred or foggy vision, impaired color perception, diplopia), defective pupillary response, and nystagmus.

Question 6

What sensory changes may occur in MS?

Answer 6

Paresthesia (tingling) of the face, body, or extremities, stiffness, or spasming of the body.

Question 7

What are some motor manifestations of MS?

Answer 7

Dysarthria (slurred speech), facial or extremity weakness, and ataxia (lack of coordination in movements).

Question 8

What are the auditory and vestibular manifestations of MS?

Answer 8

Deafness, vertigo, tinnitus, and vomiting.

Question 9

What are some cognitive and mood manifestations of MS?

Answer 9

Short-term memory loss, word-finding difficulties, and depression.

Question 10

What urinary issue is associated with MS?

Answer 10

Bladder incontinence.

Question 11

How is MS diagnosed?

Answer 11

Based on history and physical exam, lumbar puncture (elevated IgG levels), and radiographic studies.

Question 12

What is Peripheral Neuropathy?

Answer 12

A condition caused by injury to the axons traveling to and from the brain stem and spinal cord, with symptoms usually noted in the hands, feet, and sometimes the face.

Question 13

What are common causes of Peripheral Neuropathy?

Answer 13

Uncontrolled diabetes, autoimmune disorders, alcohol abuse, neurotoxic medications, infections, tumors, inherited disorders, ALS, polio, carpal tunnel syndrome.

Question 14

What are the manifestations of Peripheral Neuropathy?

Answer 14

Paresthesia (numbness, tingling), burning pain, and decreased or absent sensation to temperature, touch, pain, and position.

Question 15

What is Guillain-Barré Syndrome?

Answer 15

An acute autoimmune neuropathy that occurs after a viral or bacterial infection, leading to nerve inflammation and edema, and typically resolves in about one month.

Question 16

What are the key manifestations of Guillain-Barré Syndrome?

Answer 16

Paresthesia, areflexia (loss of reflexes), weakness or paralysis of limbs, autonomic dysfunction (changes in HR, BP, breathing).

Question 17

How is Guillain-Barré Syndrome diagnosed?

Answer 17

Through history and physical exam, electromyography (EMG), and nerve conduction studies.

Question 18

What is Amyotrophic Lateral Sclerosis (ALS)?

Answer 18

A degenerative disorder involving upper and lower motor neurons, causing progressive muscle weakness leading to respiratory failure and death, usually 2-5 years after symptom onset.

Question 19

What are the classic forms of ALS?

Answer 19

Amyotrophic refers to progressive muscle wasting, and lateral sclerosis refers to scarring in the corticospinal tract in the lateral column of the spinal cord (Lou Gehrig’s disease).

Question 20

What is the mechanism behind ALS?

Answer 20

Likely due to a genetic defect on chromosome 21 affecting an enzyme that destroys free radicals. Upper and lower motor neurons degenerate without inflammation, causing axonal degeneration, demyelination, and sclerosis.

Question 21

What are the manifestations of ALS?

Answer 21

Weakness starting in one muscle group and progressing asymmetrically to all muscles except extraocular muscles and the heart. Eventually leads to paralysis, but intellectual and sensory functions remain intact until death.

Question 22

How is ALS diagnosed?

Answer 22

Through history and physical exam, electromyography (EMG), and muscle biopsy.

Question 23

What is Myasthenia Gravis?

Answer 23

An autoimmune neuromuscular junction disorder that reduces the number of available acetylcholine receptors.

Question 24

What is the mechanism of Myasthenia Gravis?

Answer 24

Antibody-mediated autoimmune attack reduces acetylcholine receptors at neuromuscular junctions, preventing acetylcholine from binding effectively.

Question 25

What are the classic manifestations of Myasthenia Gravis?

Answer 25

Weakness and fatigue of the eye and throat muscles (causing diplopia, difficulty chewing, talking, swallowing), and weakness starting in the trunk that spreads to extremities.

Question 26

What can Myasthenia Gravis lead to if untreated?

Answer 26

Aspiration pneumonia (due to difficulty swallowing), and myasthenic crisis (severe muscle weakening leading to respiratory distress).

Question 27

What is a Myasthenic Crisis?

Answer 27

A severe muscle weakening that leads to respiratory distress.

Question 28

What is a Cholinergic Crisis?

Answer 28

Resembles a myasthenic crisis but occurs 30-60 minutes after taking anticholinergic medication.

Question 29

How is Myasthenia Gravis diagnosed?

Answer 29

Through history and physical exam, anti-AChR antibodies, MuSK serum tests, nerve stimulation exams, and anticholinesterase tests.

Question 30

What is the purpose of a lumbar puncture?

Answer 30

To measure ICP, collect CSF for testing, infuse medications, or inject contrast for radiographic studies.

Question 31

Where is the lumbar puncture performed?

Answer 31

Between the L3 and L4 vertebrae.

Question 32

What are the normal CSF values?

Answer 32

Pressure: 70-150 mm H₂O, WBC: 0-5 cells/μL, Protein: 15-45 mg/dL, Glucose: 40-70 mg/dL, Appearance: Clear

Question 33

What is seen in CSF during bacterial meningitis?

Answer 33

Increased pressure, WBC >1,000/μL (mainly neutrophils), Protein >500 mg/dL, Decreased glucose, Cloudy.

Question 34

What is seen in CSF during viral meningitis?

Answer 34

Increased pressure, WBC 25-500/μL (mainly lymphocytes), Protein 50-500 mg/dL, Normal/low glucose, Clear/cloudy.

Question 35

What is seen in CSF during encephalitis?

Answer 35

Normal or slightly increased pressure, WBC 500/μL (neutrophils early, lymphocytes late), Slightly increased protein, Normal glucose, Clear appearance.

Question 36

What is the most common reason for performing a lumbar puncture?

Answer 36

To test for meningitis.

Question 37

Why would glucose levels decrease in bacterial meningitis?

Answer 37

Bacteria consume glucose, lowering CSF glucose levels.

Question 38

What is the characteristic CSF appearance in bacterial meningitis?

Answer 38

Cloudy due to high protein and WBC levels.

Question 39

What is the main difference in WBC types between viral and bacterial meningitis in CSF?

Answer 39

Bacterial meningitis has mostly neutrophils, while viral meningitis has mostly lymphocytes.