Demyelinating Diseases

Question 1

What is Guillain Barre syndrome?

Answer 1

Guillain Barre syndrome is a monophasic illness characterized by a cell-mediated immune attack on peripheral nervous system myelin.

Question 2

What is a characteristic of Guillain Barre syndrome?

Answer 2

Cytoalbuminologic dissociation is a characteristic of Guillain-Barre syndrome but is not completely diagnostic.

Question 3

What is cytoalbuminologic dissociation?

Answer 3

Cytoalbuminologic dissociation is the finding of high protein in the cerebrospinal fluid without many (usually less than 6) white blood cells.

Question 4

Define multiple sclerosis.

Answer 4

Multiple sclerosis is a condition characterized by inflammatory, demyelinating lesions in the central nervous system separated in space and time.

Question 5

What causes multiple sclerosis?

Answer 5

• The cause is unknown although the rate is higher in certain families and certain genetic types.
• It is also higher in certain locations (particularly at higher latitudes), but where you spend your first 15 years appears to determine risk (higher the further away from equator).
• There is an immune attack on oligodendroglia, although the trigger is not clear.

Question 6

Can a patient with a single episode of demyelination be diagnosed with MS?

Answer 6

Single episodes cannot be diagnosed as definite multiple sclerosis, although sometimes scans can detect evidence of prior as well as recent events that fulfill criteria.

Question 7

What are the patterns of presentation for MS?

Answer 7

MS may be relapsing remitting, secondarily progressive, primary progressive or rapidly progressive.

Question 8

What are common symptoms of MS?

Answer 8

• Symptoms are scattered in the nervous system.
  
  • Optic nerves (vision loss)
  • Dorsal columns (loss of sensation)
  • Corticospinal tract (spastic weakness)
  • Cerebellar pathways (incoordination, dysarthria)
  • Medial longitudinal fasciculus (double vision on lateral gaze)
  • Spinal trigeminal tract (face numbness or pain)
  • Control of the bladder.
  • Irritation of cervical spinal cord sensory tracts => Lhermitte sign (electric sensation down back and/or legs with neck flexion)

Question 9

Are certain portions of the nervous system not affected by MS?

Answer 9

• MS does not directly damage neuron cell bodies and therefore does not result in basal ganglia symptoms.
• It does not result in LMN damage
• No damage to cranial nerve nuclei, or peripheral nerves.
• Does not produce aphasia or affect memory (until late in the condition).

Question 10

What supportive tests are there for the diagnosis of MS?

Answer 10

1) MRI shows T2 and flair hyperintensities in periventricular distribution in well over 90% of patients.
- Some of these lesions may be enhancing (if they happened in the last 3 months).
2) CSF shows oligoclonal bands and elevated IgG synthesis in over 80% of patients.
3) Evoked potentials that may show problems with sensory systems that are not known from clinical exam.

*None of these (except serial MRIs) can show whether lesions are separated in space and time.

Question 11

What other conditions can produce symptoms similar to MS?

Answer 11

Other conditions producing disseminated lesions:

• Lupus
• Lyme
• HIV
• Sarcoidosis
• Neurosyphilis
• B12 deficiency
• Brucellosis
• HTLV-1.

Question 12

What causes Guillain-Barre syndrome?

Answer 12

Guillain-Barre syndrome may be triggered by certain infections.
- It is a cell-mediated immune attack on nerve roots with a lymphocytic infiltration in perivenous pattern.

Question 13

What laboratory findings are supportive of the diagnosis of Guillain-Barre syndrome?

Answer 13

CSF shows high protein but few white blood cells (cytoalbuminologic dissociation).

Question 14

What is the usual clinical picture for Guillain-Barre syndrome?

Answer 14

• Symptoms develop over days to weeks, usually resolving over weeks to months.
• It often proceeds in an ascending fashion though it may even start in the cranial nerves.
  
  • It can paralyze all muscles (including respiration) and produce autonomic nervous system instability (can lead to respiratory arrest)
  • Infection or pulmonary embolus can be fatal.
• Guillain-Barre syndrome does NOT affect CNS
  
  • Patients usually recover (about 20% have residual).

Question 15

What treatments help in Guillain-Barre syndrome?

Answer 15

Treatment with plasmapheresis or human immune globulin infusions may speed recovery.

Question 16

What is chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)?

Answer 16

CIDP is a condition that has an appearance of chronic and demyelination of peripheral nerves.

• Subacute weakness and sensory loss
• Responds to steroids and other immunosuppressives
  
  • Including plasmapheresis and human immune globulin infusion