Guillain-Barré syndrome (GBS) is an acute immune-mediated polyneuropathy characterized by acute onset of peripheral and cranial nerve dysfunction and progressive muscle weakness. It is caused by an autoimmune reaction directed against peripheral nerves, often preceded by a viral infection. Clinically, GBS presents with rapidly progressive symmetric weakness, loss of tendon reflexes, and sensory symptoms like paresthesia. Electrodiagnostic studies are diagnostic in most cases and show features of demyelination like prolonged latencies and conduction block. Treatment involves supportive care and immunotherapy.

1. ACUTE NEUROPATHIES
BY:
SYED IRSHAD MURTAZA
TRAINEE TECHNOLOGIST
NEUROPHYSIOLOGY
AGA KHAN UNIVERSITY
HOSPITAL KARACHI
DATE: 08-10-2012

2. INTRODUCTION
NEUROPATHY:- Dysfunction or disorder of
peripheral nerves.
The type of neuropathy is always determined by the
temporal course of the disease.
Acute (Days to weeks).
Sub-acute, (Weeks to Months)
Chronic (Months to Years)
Progressive (Getting worse day by day).
stepwise (involving a region completely then next)
and
relapsing/remitting. (Attacking and Recovery)

3. How to obtain temporal course?
By the history alone and often confirmed by
EDX studies.
Acute polyneuropathies are notably less
common.e.g Guillaine-Barre Syndrom
(GBS), Which is immune mediated
acute inflammatory demyelinating
Polyneuro(radiculo)pathy.

6. GUILLAIN BARRE SYNDROME (GBS)
08-10-2012 by
MURTAZA

7. Acute polyneuropathies
In 1916, three French neurologists Georges
Guillain, Jean-Alexandre Barre, and Andre
Strohl described two soldiers with acute
areflexic paralysis followed by recovery,
refferred as Guillain Barr’e Syndrome.
Guillain Barre Syndrome refers to an “acute
immune-mediated polyneuropathy. It is an
acute inflammatory demyelinating
polyneuropathy characterized by acute onset
of peripheral and cranial nerve dysfunction
(and progressive muscle weakness and
areflexia)

8. CONT’D
Other Symptoms and signs include
rapidly progressive symmetric
weakness, loss of tendon reflexes,
facial diplegia, oropharyngeal and
respiratory paresis, and impaired
sensation in the hands and feet

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10. Causes/ PATHOGENESIS
Etiology unknown
May be cell-mediated immunological reaction
directed at the peripheral nerves
Frequently preceded by viral infection, trauma,
surgery or other immune system stimulation.
Humoral factors and cell-mediated immune
phenomena have been implicated in the
damage of myelin and/or the myelin-producing
Schwann cells T-cell sensitization occurs which
causes loss of myelin which disrupts nerve
impulses.

12. CLINICAL FEATURES
Progressive symmetric muscle weakness
Absent / depressed deep tendon reflexes
Weakness starts in the legs in 90% of
cases
Parasthesia in legs and arms is common
Wide range of weakness
• Two-thirds of patients develop the
neurologic symptoms 2-4 weeks after
viral infections

13. The initial symptoms are
SENSORY CHANGES:
paresthesia, numbness; usually mild; 70%
patients have sensory abnormalities on
electrodiagnostic
• DYSESTHESIAS:
burning, tingling, shock like, persistent in 5-
10%
WEAKNESS:
oascending and symmetrical, lower limbs
involved first, distal muscles involved
earlier ; develops acutely and progresses.

14. CONT’D
wide variations in severity;
Deficits peak by 4 weeks after initial
Symptoms;
recovery begins 2-4 weeks after progression
stops.
Hypotonic and areflexia (absence of reflexes)
More than 90% of patients reach the nadir of
their function within two to four weeks, with
return of function occurring slowly over weeks
to months
Involvement of lower brainstem leads to facial
and eye weakness

15. Clinical Features
 RESPIRATORY:
 40% patients have respiratory or
oropharyngeal weakness
AUTONOMIC CHANGES:
 Tachycardia, or bradycardia,
 facial flushing,
 paroxysmal HTN,
 orthostatic hypotension,
 urinary retention,
 Ileus (painful obstruction of the intestine)
dizziness (light-headedness and feeling faint)
more common if severe weakness or
respiratory failure

16. CLINICAL FEATURS (DETAIL)
A. “Typical” GBS
GBS is an acute, predominantly motor
neuropathy involving distal limbs paresthesias,
relatively symmetric leg weakness, and
frequent gait ataxia.
1. Most cases will have subsequent arm
weakness, and possibly weakness of facial,
ocular, and oropharyngeal (oral airway)
muscles.

17. B. Weakness
Weakness is always bilateral, although some
asymmetry in onset and severity is common.
i. Proximal muscles weakness very frequent,
especially initially, with subsequent distal arm
and leg weakness.
ii. GBS with a descending pattern of
weakness seen in 14% cases; onset initially
with cranial nerve or arm muscle weakness,
followed by leg weakness.
iii. In 1/3 of cases, the degree of weakness in
the arms and legs is roughly equal.

18. C. Reduced or absent reflexes characterize
GBS.
i. Early loss of reflexes may be due to
desynchronization of afferent impulses in
reflex arc due to non-uniform demyelination.
ii. About 70% of patients present with loss of
reflexes; less than 5% retained all reflexes
during the illness;
iii. The presence of intact reflexes should
suggest an alternative diagnosis other than
GBS.

19. D. Sensory disturbance
i.>50% will present with symmetric distal limb
paresthesias, before clinically evident limb weakness.
Early finger paresthesias suggest a patchy process,
unlike the pattern seen with distal axonopathies.
1. paresthesias of trunk or face unusual, but sensory
loss over the trunk frequent and a psuedo level may
be evident
a. beware if definite sensory level present as this may
suggest structural cord disease.
3. an early sensory ataxia may not be obscured
(indistinct) by concurrent (simultaneous) limb
weakness

20. E. Pain
i. Some discomfort reported in 2/3 of patients
which may take one of
the following forms:
1. deep muscle aching in back, hips or
proximal legs,
2. sharp radicular pain into the legs,
3. severe burning dysesthetic pain (with
urning, aching and/or tingling sensation) in feet
or hands.
ii. Radicular pain can occasionally be a
presenting complaint obscuring (indistinct) the
true diagnosis.

21. f. Cranial nerve involvement
i. 1/2 of GBS patients have some degree of cranial
nerve dysfunction during their illness.
ii. Facial weakness most common, especially if
substantial (considerable) limb weakness present.
1. normal facial strength in the presence of
marked quadriparesis (all 4 limbs weakness) is
very unusual in typical GBS.
2. facial weakness is usually bilateral but may be
unequal in severity; only rarely truly unilateral.
iii. Ophthalmoplegia is seen in 10-20% of
patients.
1. Abducens palsy/vi cranial nerve palsy most
common; usually bilateral.

22. g. Respiratory dysfunction
Due to diaphragmatic weakness occurs in about 1/3 of
patients.
i. Diaphragmatic weakness common in patients with
severe quadriparesis; may also occur early on in
patients with bi-brachial weakness.
ii. Patients with weakness of neck muscles, tongue and
palate often have concommitant (simultaneously)
diaphragmatic and respiratory muscle involvement.
iii. Pathogenesis of respiratory failure:
1. Atelectasis (collapse of lung tissue) results from
reduced vital (life-sustaining) capacity, inspiratory force
and required volume due to diaphragmatic weakness.

23. h. Dysautonomia
i. Occurs in about 65% of cases
ii. more frequent in patients with severe
paralysis and ventilatory difficulties but may
develop in mild cases.
iii. Most common manifestations include
cardiac dysfunction such as sinus tachycardia,
sinus bradycardia, sinus arrest and other
paroxysmal hypertension, and hypotension etc

24. Variations Of GBS
Followings are the typical variants of GBS
a. Acute Motor and Sensory Axonal
Neuropathy (AMSAN)
b. Acute Motor Axonal Neuropathy
(AMAN)
c. Miller-Fisher Variant
d. Pure Motor Variants
e. Pure Sensory Variants

25. CLASSIFICATION
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26. a. Acute Motor and Sensory Axonal Neuropathy
(AMSAN)
 i. Initially described by Feasby as axonal GBS.
 ii. Characterized by acute quadriparesis (Weakness of all
four limb), areflexia, distal sensory loss, and respiratory
insufficiency.
 iii. CSF with increased CSF;
 EDX shows loss of motor and sensory potentials with
diffuse active denervation. No evidence of primary
demyelination.
 . EDX studies differentiate from typical GBS by showing
evidence of only axonal degeneration , without
demyelination.
 iv. Condition is now labeled acute motor-sensory axonal
neuropathy (AMSAN)
 . AMSAN is usually severe with quadriplegia, respiratory
insufficiency and delayed, incomplete recovery.

27. b. Acute Motor Axonal Neuropathy (AMAN)
I. Characterized by acute/subacute onset of relatively symmetric
limb weakness, diffuse areflexia, facial and oropharyngeal muscle
weakness, and respiratory insufficiency.
iii. Clinically purely motor deficits; normal EOMs. (extraocular
muslce/movement)
iv. EDX studies show evidence of motor axonal loss, sparing
sensory fibers. No evidence of demyelination. Needle EMG
shows diffuse denervation. Elevated CSF protein.
v. Pathogenesis unclear; possible antibody and complement
mediated attack at terminal motor nerve endings
vi. Occasionally, some patients make relatively rapid recovery,
possibly due to reversible changes at nodes of Ranvier, or
regeneration of intramuscular nerve endings.

28. c. Miller-Fisher Variant
 i. Classic triad of ophthalmoplegia, ataxia, and areflexia
described by
C. Miller Fisher in 1956
 ii. Occurs in about 5% of GBS cases. some of what appears
to be Fisher syndrome subsequently incorporate findings of
typical GBS raising the possibility of a clinical spectrum
between GBS and Fisher syndrome.
 iii. Diplopia usually initial symptom, followed by limb or gait
ataxia.
 iv. Occasionally there may be mild sensory symptoms,
swallowing difficulties, or proximal limb weakness in up to
1/3 or 1/2 of cases.
 v. abducens palsy (inability of an eye to turn outward which
results in diplopia) usually initial EOM deficit, which may
progress to complete ophthalmoplegia.

29. CONT’D,,
 1. ptosis frequent, but papillary function usually spared.
 vi. Limb and gait ataxia common, although possibly
asymmetric limb involvement initially.
 1. limb ataxia may resemble that seen with cerebellar
disease
 vii. Areflexia is usual.
 viii. Although CSF protein is mildly elevated, it is less so
than in typical GBS.
 ix. EDX shows loss of sensory potentials, with milder
axonal degeneration. Some studies have shown a
demyelinating neuropathy, while others suggest purely an
axonal process.
 x. May clinically resemble brainstem inflammatory or
ischemic disease

30. 

31. d. Pure Motor Variants
 i. Acute, progressive, symmetric limb weakness, no
sensory loss, areflexia.
 ii. Diagnosis suggested by acute, predominantly distal
limb weakness,
 iii. normal cranial nerve function
 iv. Course and recovery similar to typical GBS.
 v. CSF protein elevated (decreased).
 vi. EDX shows marked axonal degeneration with some
accompanying demyelinating features.
 vii. Differential Dx: poliomyelitis (viral disease that
affects nerve & leads to partial or full paralysis) ,
porphyria (inherited disease where heme, is not made
properly), acute myasthenia gravis, tick paralysis.

32. e. Pure Sensory Variants
i. Rare occurrence of acute sensory poly--
neuropathy with elevated CSF protein, and
demyelinating features on EDX studies.
ii. Rapid onset of large fiber sensory loss with
resultant sensory ataxia.
iii. Positive Romberg sign, pseudoathetosis
(abnormal writhing movements, usually of the finger s, caused
by a failure of joint position sense), tremor,(involuntary
vibratory movement) lesser involvement of
small fiber sensory function; dysautonomia.
iv. Sensory dysfunction may involve the face
and torso in severe cases.

33. Differential Diagnosis
a. Acute peripheral neuropathies
i. Toxic: (thallium, arsenic, lead, n-hexane, organophosphate
ii. Drugs: (amiodarone, perhexiline, etc)
iii. Alcohol
iv. Porphyria
v. Poliomyelitis
vi. Diphtheria
vii. Tick paralysis
viii. Critical illness polyneuropathy
b. Disorders of Neuromuscular Transmission
i. Botulism
ii. Myasthenia gravis

34. Diagnosis
2 ways to diagnose:
1. ELECTRODIAGNOSTIC (EMG/NCs)
2. Clinical Assessment
1. EMG/NCS
EMG/NCs reveals markedly prolonged Or
absent late responses, prolonged distal
latencies with marked decrease in CMAP
amplitudes of upper and lower extremities.

35. 2. Clinical diagnosis –
Clinical diagnosis Must include the
following sign and symptoms:
Progressive weakness in one or more
limb, ranging from minimal weakness to
full body paralysis
Areflexia ranging from biceps and patella
to whole body areflexia.

36. 2. Edx evaluation

37. Electrophysiology (EMG and NCs)
a. Diagnostic in 95% cases
b. May be normal early on perhaps
reflecting involvement of proximal nerve
segments not accessible to conduction
studies.
c. Nature and severity of physiologic
findings dependent on timing of study,
number of nerves studied, and whether
proximal nerve segments investigated.

38. NCS findings
d. Typically, there is multifocal
demyelination affecting proximal and distal
nerve segments.
i. Earliest findings may be abnormalities of F
waves and H reflex latencies. Prolonged or
absent F waves may be initial sole
abnormality in about 30-50% of cases
studied.
ii. Conduction block in about 1/3 of cases;
conduction slowing and temporal dispersion
reflect demyelination.

45. Cont’d NCS findings
e. Evidence of sensory axon demyelination
seen in about 25% of cases when studied in
the first week, increasing to 75% after 3
weeks.
f. Characteristic pattern is abnormal median
and ulnar sensory potentials
with spared sural potentials, reflecting
random, multifocal demyelination.
i. Most important predictor of recovery is the
degree of axonal degeneration, best reflected
by the amplitude of the compound muscle
action potential (CMAP).

46. Cont’d
i. Motor potentials with amplitudes less
than 20% normal suggest a prolonged,
and often incomplete recovery.
ii. No correlation between the degree of
conduction slowing and eventual
recovery.
iii. Electrophysiologic evidence of
demyelination may persist for years,
despite adequate clinical recovery.

47. EMG Findings
Most common needle EMG finding is
reduced voluntary motor unit
recruitment.
i. Active denervation present in 20-64% of
cases by week 4.
ii. Myokymia, reflecting demyelination,
occasionally present.
 Severe axonal GBS will show diffuse loss of
sensory and motor responses with
widespread active denervation.

50. Note
Later in the first week or two, sensory studies
may show so-called sural Sparing (i.e., the sural
sensory response is normal whereas the median
and ulnar sensory potentials are reduced or
absent).
This pattern is very unusual in the typical
axonal, dying-back polyneuropathy.
Many believe that sural sparing in the presence
of a typical clinical picture is virtually diagnostic
of AIDP.

51. Cont’d
Why sural sparing occurs is not completely known,
but it is likely related to the preferential, early
involvement of the smaller myelinated fibers in
AIDP.
Although it is not intuitively obvious, the recorded
sural sensory fibers actually are larger, and
accordingly have more myelin, than the median
and ulnar sensory fibers.
The routine median and ulnar sensory potentials
are recorded distally over the fingers, where the
nerve diameters are more tapered than those of the
sural nerve.

52. Treatment and Management1
Supportive Care
Ventilatory Support
Nutritional support
ii. Intravenous immunoglobulin
(IVIg)
 Plasmaphrasis

53. Prognosis
 a. Majority have progressive illness with nadir of clinical
deficits at 4 weeks.
 i. 3/4 reach nadir by 1 week.
 b. 15% have mild illness, remain ambulatory, and recovery after
few weeks.
 c. 5-20% have fulminant course, develop flaccid paralysis,
ventilator dependence, and axonal degeneration.
 i. Such patients have delayed and incomplete recovery.
 d. Residual deficit (remaining part of the abnormality): about
1/3 of cases require ventilator assistance, 1/2 are either chair or
bed bound, and 7% have trouble walking. The remainder are
ambulatory.
 e. Recovery at 1 year follow-up: 62% had recovered completely,
14% could walk but not run, 9% could not walk without
assistance, 4% remained bed bound or ventilated, 8% died.

54. Poor prognostic features:
i. age greater than 60
ii. history of preceding diarrhea illness
iii. ventilator dependence
iv. greatly reduced CMAP amplitudes or inexcitable
nerves
g. Mortality about 5-10% with aggressive ICU care.
h. About 3-6% of patients with typical GBS have
developed a chronic relapsing course consistent with
CIDP.
i. No distinguishing features.
ii. Most relapses responsive to steroids.

55. Thank you..