AMSAN is usually severe with quadriplegia, respiratory insufficiency and delayed, incomplete recovery. EMG NCS... Sensory and motor axonal involvement. CMAP and SNAP amplitudes low F and H responses were absent Conduction block and temporal dispersion seen in demylenating neuropathy I,e AIDP Reduce Recrument Reduce interference pattern After 3 weeks denervation and neurogenic changes. Acute Motor Axonal Neuropathy (AMAN).... Characterized by acute/subacute onset of relatively symmetric limb weakness, diffuse

1. Guillain-Barré syndrome (GBS)
By Faizan Abdullah

2. Topics
• Introduction
• Pathophysiology
• Clinical feature
• Diagnostic tests
• Variants of GBS and
electrophysiological findings
• Treatment

3. History
• In 1916, George
Guillain, Jean-Alexandre
Barré, and André Strohl
described acute and
progressive limb weakness
causing major difficulty in
2 soldiers they examined in
an army hospital during the
battle of the Somme
(northern France, World
War I).
• The key features were the
discovery of an unusual
cerebrospinal fluid (CSF)
finding of isolated albumin
elevation.

4. Introduction:-
 Guillain–Barré syndrome, is an acute polyradiculoneuropathy,
 a disorder affecting the peripheral nervous system.
 Ascending paralysis, weakness beginning in the feet and hands and migrating
towards the trunk, is the most typical symptom,
 some subtypes cause change in sensation or pain as well as dysfunction of the
autonomic nervous system.
 It can cause life-threatening complications, in particular if the respiratory
muscles are affected or if there is autonomic nervous system involvement.
 GBS is characterized by weakness and numbness or a tingling sensation in the
legs and arms and possible loss of movement and feeling in the legs, arms,
upper body, and face. along with complete loss of deep tendon reflexes.

11. Varients of Guillain Barre Syndrome
Types Symptoms
1. Acute Inflammatory Demyelinating
Polyradiculo neuropathy (AIDP)
Most common variant, 85% of cases.
Primarily motor inflammatory
demyelination ± secondary axonal
damage.
Maximum of 4 weeks of progression
2. Acute Motor-Sensory Axonal
Neuropath
 Initially described by Feasby as
axonal GBS.
 Characterized by acute
quadriparesis (Weakness of all four
limb), areflexia, distal sensory loss,
and respiratory insufficiency
• Motor and sensory involvement with
severe course respiratory and bulbar
involvement. Primary axonal
degeneration with poorer prognosis.

12. TYPES SYMPTOMS
Miller-Fisher Variant Ophthalmoplegia, sensory
ataxia, areflexia.
Pure Sensory Variants Rare occurrence of acute
sensory poly--neuropathy with
elevated CSF protein, and
demyelinating features on EDX
studies.
Rapid onset of large fiber
sensory loss.
Positive Romberg sign,
pseudoathetosis (abnormal
writhing movements, usually of

13. Acute Motor and Sensory Axonal Neuropathy
(AMSAN)
 Initially described by Feasby as axonal GBS.
 Characterized by acute quadriparesis (Weakness of all four limb), areflexia,
distal sensory loss, and respiratory insufficiency.
 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.
 Condition is now labeled acute motor-sensory axonal neuropathy (AMSAN)
 AMSAN is usually severe with quadriplegia, respiratory insufficiency and
delayed, incomplete recovery.

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

15. Miller-Fisher Variant.
 Classical triad of ophthalmoplegia, ataxia, and
areflexia described by C. Miller Fisher in 1956.
 Occurs in about 5% of GBS cases.
 Diplopia usually initial symptom, followed by limb or
gait ataxia.
 Occasionally there may be mild sensory symptoms,
swallowing difficulties, or proximal limb weakness in
some cases.
 Abducens palsy (inability of an eye to turn outward
which results in diplopia) usually initial EOM deficit,
which may progress to complete ophthalmoplegia.

16. CONT’D..
 Ptosis frequent, but pupillary function usually spared.
 Limb and gait ataxia common, although possibly
asymmetric limb involvement initially.
 limb ataxia may resemble that seen with cerebellar
disease
 Areflexia is usual.
 Although CSF protein is mildly elevated.
 EDX shows loss of sensory potentials, with milder axonal
degeneration. Some studies have shown a demyelination
neuropathy, while others suggest purely an axonal
process.
 May clinically resemble brainstem inflammatory or
ischemic disease

17. Pure Sensory Variants:
• Rare occurrence of acute sensory poly--neuropathy with
elevated CSF protein, and demyelinating features on EDX
studies.
• Rapid onset of large fiber sensory loss with resultant
sensory ataxia.
• 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.
• Sensory dysfunction may involve the face and torso in
severe cases.

18. 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.
The initial symptoms are :
SENSORY CHANGES: Paresthesia, numbness; usually mild; 70%
patients have sensory abnormalities on electrodiagnostic .

19. Clinical features..
• DYSESTHESIAS:
• Burning, tingling, shock like, persistent in 5-10%
• WEAKNESS:
• Ascending and symmetrical, lower limbs involved first, distal
muscles involved earlier ; develops acutely and progresses.
• Wide variations in severity.
• Deficits peak by 4 weeks after initial symptoms recovery begins
2-4 weeks after progression stops.

20. Clinical features..
 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

21. 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

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

23. Diagnosis
Two 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.

24. 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.

25. 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.

27. 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.

30. 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.

31. Thank you..