Chronic Inflammatory demyelinating neuropathy (CIDP)

Question 1

Characteristics

Answer 1

• Like GBS but slower and relapses (in 1/3rd)
• Chronic version of GBS
• Can be symmetrical or asymmetrical
• May get headaches
• Gait problems
• Large fibre sensory signs more common
• Behaves more like a normal neuropathy
• Not usually prodrome or respiratory failure
• LMN signs
• LP high protein, NCS demyelination
• Slower progressive (at least 8 weeks to nadir in 2/3rds)

Question 2

Evidence to suggest possible spectrum of diseases (GBS and CIDP)

Answer 2

• Both demyelinating neuropathies
• Similar clinical features
• Investigation results similar
• Both respond to immunosuppression

Question 3

Defining between CIDP and GBS

Answer 3

• Acuteness is an important difference CIDP chronic, GBS acute
• Autonomic dysfunction/respiratory failure GBS
• GBS does not respond to steroids but CIDP does
• GBS symptoms quickly developing over days to weeks, then slowly get better again. CIDP symptoms gradually progress over 2-6 months or more
• GBS typically starts in the legs and can spread to the upper body whereas CIDP typically involves 2 or more limbs on both sides of the body at the same time

Definitions
GBS - progresses to nadir in < 4 weeks
CIDP - progresses to nadir in > 8 weeks
In between time frames = SIDP

Question 4

Important time points in GBS/CIDP

Answer 4

1 week - 75% of GBS reach nadir

12 days - mean time to nadir in GBS

4 weeks - maximum time to nadir in GBS

6-8 weeks SIDP

50 days - average time on ventilator if needed

8 weeks - minimum time to nadir in CIDP

Variable recovery time - weeks to 18/2 in more severe cases

Question 5

Presentation on examination

Answer 5

• Can be symmetrical or asymmetrical
• Gait problems
• ICP headaches
• LMN like GBS
• Large fibre sensory signs more frequent
• Bulbar signs less frequent
• Facial weakness and opthalmoparesis can occur
• Autonomic symptoms and respiratory weakness
• Rarely fatal

Question 6

Investigations

Answer 6

• Similar to GBS
• Look for alternative causes of demyelination neuropathy: proprotiens, inherited, drugs, HIV
• NCS more useful - show demyelination
• Antibodies useful in variants e.g. Anti-MAG
• Rarely nerve biopsy - when NCS does not show demyelination but show clinical characteristics of CIDP

Question 7

Treatment

Answer 7

• Steroids e.g. prednisone
• Steroid sparing agents - e.g. methitrexate
• Intravenous immunoglobulin
• Plasma exchange

Question 8

Prognosis

Answer 8

• Relapsing better than progressive
• 70% recover well from relapses
• 90% respond well to treatment initially
• 70% sustained
• Mortality
• Chronic disease associated with chronic disability
• Much unknown

Question 9

Pathophysiology

Answer 9

• Characteristic onion bulb formation on the nerves
• Sign of remyelination
• Precise mechanism unknown
• Cellular and humoural mechanisms
• Perivascular inflammation with macrophages and lymphocytes
• Evidence of chronic demyelination/remyelination on biopsies

Question 10

SIDP

Answer 10

Subacute inflammatory demyelinating polyneuropathy

around 6-8 weeks

May treat as CIDP or GBS - may get treatment fluctuations