Dr. Nishtha Jain provides an overview of Acute Inflammatory Demyelinating Polyneuropathy (AIDP). Key points include: AIDP is an immune-mediated disorder of the peripheral nervous system, often preceded by a respiratory or gastrointestinal infection. Diagnosis involves lumbar puncture showing elevated CSF protein without pleocytosis. Electrodiagnosis can show features of demyelination. Treatment involves plasma exchange or IV immunoglobulin to remove antibodies. Prognosis is generally good, with most patients achieving near-full recovery, though respiratory failure can occasionally occur. New variants beyond classic AIDP have been recognized.

1. AIDP Update
Dr. Nishtha Jain
Senior Resident
Department of Neurology
GMC, Kota.

2. AIDP
• Acute Onset
• Usually Monophasic
• Immune mediated disorder
• Peripheral Nervous System

3. Old Concept
GBS = AIDP
New Concept
Other Variants

4. • First described by Landry in 1859.
• Recognized as GBS since 1916, when Guillain, Barre´,
and Strohl described two French soldiers who contracted
the illness during World War I.

5. • Incidence Rate : 1–2 / 100,000 population.
• The lifetime likelihood of any individual acquiring GBS is
1:1000.
• In Europe and North America : AIDP(90% of the cases).
• In China and Japan : AMAN(most common).

7. • A peak incidence between June–July and Sept–October.
• Western countries - GBS is common in 5th decade.
• India - more common at a younger age.
• Equally common in men and women.

8. • Often follows an upper or lower respiratory illness or
gastroenteritis by 10 to 14 days.
• Approximately 70% of patients can identify a preceding
illness.
• Infections associated with GBS - CMV, M. pneumoniae,
EBV, Influenza A, H. influenzae, Enterovirus,
Campylobacter jejuni and Zika virus.

9. • Cytomegalovirus : most common associated virus.
• Campylobacter jejuni : most frequently associated
bacterial infection.(overall 40%)
• Other less common precipitants are surgery, pregnancy,
cancer, and vaccinations.

10. • Evolves over days, often beginning with numbness in the
lower limbs and weakness in the same distribution.
• Approximately 50% of patients achieve maximum
weakness by 2 weeks, 80% by 3 weeks, and 90% by 4
weeks.
• Progression beyond 4 weeks is unusual.
• Neuropathic pain - 66% patients(localized to the lower
back and thighs).

11. • The weakness begins distally and spreads proximally.
• In rare cases, the weakness may be localized to the legs
only (giving the appearance of paraplegia).
• Sensory examination : normal or show minor
deficiencies in vibration and proprioception.
• All patients have areflexia or at least hyporeflexia at
some time in the illness.

12. • 50% of patients - some degree of facial weakness.
• Weakness attributed to cranial nerves includes ocular
dysmotility, pupillary changes, and ptosis.
• Ophthalmoparesis : approximately 20% of patients with
GBS.

13. • 30% of patients develop respiratory failure from phrenic
nerve disease, requiring intubation and ventilation.
• Autonomic involvement : tachycardia, bradycardia,
hypertension and hypotension, gastric hypomotility, and
urinary retention.

14. Variants of GBS

15. AMAN
• An axonal motor variant of GBS
• Reported in 1993 from Northern China
• So K/As Chinese paralytic illness.
• Can present with transient conduction block without
axonal loss and this led to the term acute motor
conduction block neuropathy.

16. • More common in children during the summer.
• Pure motor without sensory symptoms and signs.
• NCS – decreased CMAP amplitudes, normal latencies
and conduction velocities, and normal sensory studies.

17. AMSAN
• Sensory involvement also occurs
• Later age of onset
• Broader geographic distribution
• A more protracted course
• Slower and incomplete improvement

18. Miller Fisher syndrome
• Acute or subacute demyelinating
polyradiculoneuropathy.
• Clinical presentation differs markedly from typical AIDP.
• Triad of ophthalmoplegia, areflexia, and ataxia.
• Often grouped with Bickerstaff brainstem encephalitis -
similar presentation plus encephalopathy and
corticospinal tract dysfunction.

19. • The prognosis in both Miller Fisher syndrome and
Bickerstaff brainstem encephalitis is favorable.
• Most patients improve within 1 to 2 months and make a
complete recovery in 6 months even without specific
treatment.

20. Acute Pandysautonomic Neuropathy
• Rare
• Sympathetic and parasympathetic nervous systems
involved.
• CVS involvement, Blurry vision, anhydrosis.
• Recovery is often gradual and incomplete.
• Often combined with sensory features.

21. Pathogenesis
• Molecular mimicry plays a major role.
• Molecular mimicry is believed to occur where the
immune system recognizes the myelin epitope as
‘‘foreign’’ and targets it for destruction.

23. Diagnostic
Criteria

26. Laboratory Testing
• Elevated CSF protein - may not be present until 3 weeks
after the onset of the illness.
• Pleocytosis (greater than 5 white blood cells) - not
present in patients with GBS
• 15% of patients -10 to 50 cells per high-power field.
• If a pleocytosis is present, it raises suspicion for an
infectious process; sarcoidosis; or carcinomatous or
lymphomatous meningitis.

28. Electrodiagnosis
• In first few days – NCS may be normal or only show
subtle changes of demyelination, such as prolonged or
absent F waves and H reflexes, and patchy changes in
distal latencies in patients with AIDP.
• As the disease evolves - conduction block, temporal
dispersion, and prolonged distal and F-wave latencies.

29. • Sensory NCS - A characteristic sural nerve sparing.
• Sensitivity of NCS - As low as 22% in early AIDP and
rise to 87% at 5 weeks.
• A conduction velocity of <70% of the lower limit of
normal and a distal latency of >150% of the upper limit of
normal was highly sensitive and had a specificity of
nearly 100% for AIDP.

30. • Needle EMG - Decreased recruitment initially, followed
by fibrillation potentials over weeks 2 to 5 in proximal
and distal muscles simultaneously.

31. • The best electrodiagnostic indicator for a rapid or good
recovery is maintained motor amplitude.
• Patients with an average amplitude >10% of the lower
limit of normal likely have a major component of
conduction block which has the potential to reverse.
• Amplitudes <10% during illness are seen in patients with
a greater degree of axonal injury and a more prolonged
recovery.

32. Imaging Studies
• To assess for gadolinium enhancement of nerve roots.
• To eliminate other causes of quadriparesis, particularly
transverse myelitis, subacute compressive myelopathy,
and infiltrating illnesses of the roots and the spinal cord.
• 95% of children with GBS show enhancement of the
lumbar roots secondary to the inflammatory process.

36. Management

40. Additional predictors
• (1) time from GBS onset to hospital admission of less
than seven days
• (2) inability to lift the elbows or head above the bed
• (3) inability to stand
• (4) ineffective coughing

42. Specific treatment
• Plasma exchange
• IVIg
• Corticosteroids(not approved)

43. Plasma exchange
• First treatment shown to be effective.
• Removes autoantibodies, immune complexes,
complement, and cytokines.
• Boosts T-cell suppressor function.
• Dose - 250 mL/kg divided over 5 alternating days.
• Risks - central venous catheter placement, hypotension,
cardiac arrhythmia, vasovagal spell, allergic reaction to
albumin replacement, hypocalcemia, anemia, and
thrombocytopenia.

44. 2017

45. Patients with mild GBS on admission
should receive 2 PEs. Patients with
moderate and severe forms should
benefit from 2 further exchanges.
Ann Neurol 1997

46. IV immunoglobulin (IVIg)
• Pooled IgG from thousands of blood donors, which
results in a fivefold increase in serum IgG.
• Adverse events - mild infusion-related symptoms
(nausea and headache), aseptic meningitis, rash, severe
rare anaphylaxis, and, in fewer than 2% of cases, renal
failure.
• IVIg may be preferred since it is easier to administer.

47. IVIg is as effective as plasma
exchange.
NEJM 1992

48. Lancet 1997
Combination therapy ?

49. 2016

50. Nature 2015

51. AAN Recommendations
• PE is recommended for nonambulant patients within 4
weeks of onset (level A, class II evidence) and for
ambulant patients within 2 weeks of onset (level B,
limited class II evidence).
• The effects of PE and IV immunoglobulin (IVIg) are
equivalent.
• There is insufficient evidence to recommend the use of
CSF filtration (level U, limited class II evidence).

52. • The evidence is insufficient to recommend the use of
immunoabsorption (level U recommendation, class IV
evidence).
• IVIg is recommended for patients with GBS who require
aid to walk within 2 (level A recommendation) or 4 weeks
from the onset of neuropathic symptoms (level B
recommendation derived from class II evidence
concerning PE started within the first 4 weeks and class I
evidence concerning the comparisons between PE and
IVIg started within the first 2 weeks).

53. • The effects of IVIg and PE are equivalent.
• Corticosteroids are not recommended for the treatment
of patients with GBS (level A, class I evidence).
• PE and IVIg are treatment options for children with
severe GBS (level B recommendation derived from class
II evidence in adults).

55. Novel Immunomodulatory Approaches
• Inhibition of complement using eculizumab prevents
neuropathy in an animal model of Miller Fisher
syndrome.
• Limitations - significant cost and potential complications,
including a high risk of meningococcal infections.
• Other complement inhibitors - APT070, rEV576,
nafamostat mesylate, and soluble complement receptor
1 have been evaluated in animal models.

56. • One possible strategy for axon protection is sodium
channel blockade.
• Supporting this approach are data indicating flecainide
protects axons in an animal model (experimental
autoimmune neuritis [EAN]).
• Another general approach to axon protection, or
enhanced regeneration, is growth factor therapy.

57. • The voltage gated potassium antagonist, 4
aminopyridine represents a potential approach for GBS
patients with residual gait dysfunction.

58. Treatment-related Fluctuations
• Treatment-related fluctuations are defined as worsening
of weakness after an initial improvement or after
stabilization following treatment with IVIg or plasma
exchange.
• Occur in approximately 10% of patients with GBS.
• Usually take place within the first 2 months after
treatment.
• Treated with another course of IVIg or plasma exchange,
and the treatment is often beneficial.

59. • If the patient experiences more than one treatment-
related fluctuation, and particularly if it occurs 2 months
or more after the onset of the illness, then the diagnosis
of CIDP becomes a strong consideration.

60. PROGNOSIS
• The prognosis for most patients with GBS is for good to
excellent recovery.
• Approximately 87% experience full recovery or minor
deficits.
• Most of the improvement in GBS occurs within the first
year, but patients may continue to improve for up to 3
years or longer.

61. • Mortality in GBS is 3% to 7%
• Most often attributable to respiratory failure, infection, or
uncontrollable autonomic dysfunction.

64. Conclusion
• New variants
• Diagnostic and prognostic criteria have come
• Newer treatment modalities under trials

65. Thank You

66. Referrences
• Guillain-Barre´ Syndrome. P D Donofrio. Continuum
2017;23(5):1295–1309.
• Acquired Immune Demyelinating Neuropathies. M M
Dimachkie. Continuum 2014;20(5):1241–1260.
• Immune-Mediated Neuropathies. Y T So. Continuum
Lifelong Learning Neurol 2012;18(1):85–105.
• Guillain-Barré Syndrome. X A Londono et al. Semin
Neurol 2012;32:179–186.
• Inflammatory Neuropathies. J Whitesell. Semin Neurol
2010;30(4):356-364.