1. Guillain-Barre Syndrome
December 7, 2009
Lisa Rose-Jones, MD

2. GBS Eponym that encompasses acute immune-mediated polyneuropathies
Peripheral nerve myelin is target of an immune attack
Starts at level of nerve root=conduction blocks & muscle weakness
Eventually get widespread patchy demyel= increased paralysis

3. Pathophysiology Usually postinfectious
Immune-mediated: infectious agents thought to induce Ab production against specific gangliosides/glycolipids
Lymphocytic infiltration of spinal roots/peripheral nerves & then macrophage-mediated, multifocal stripping of myelin
Result: defects in the propagation of electrical nerve impulses, with eventual conduction block and flaccid paralysis
Most patients report an infectious illness in the weeks prior to the onset of GBS

4. Clinical Features: Progressive, fairly symmetric muscle weakness
-typically starts in proximal legs
-10% will 1st develop weakness in face or arms
-severe resp muscle weakness in 10-30% pts
-oropharyngeal weakness in ~ 50%

5. Clinical Features: Absent or depressed DTR
Often prominent severe pain in lower back
Common to have paresthesias in hands and feet
Dysautonomia is very common: tachycardia, urinary retention, hypertenison alternating w/ hypotension, ileus

6. Diagnosis:
Albuminocytologic dissociation: elevated CSF protein w/ normal WBC (80-90% pts)
Electromyography (EMG) helps confirm diagnosis = prolonged or absent F waves
Mass Gen prospective study of 110 pts w/ GBS showed CSF protein elevations ranged from mg/dL in 73% or pts, however protein elev as high as 1000 mg/dL have been described
Prolonged or absent F waves are pathognomonic and reflect demyelination at level of nerve roots

7. NINDS Expert Consensus:
Req’d Features for dx:
Progressive weakness of > than 1 limb
Areflexia
Supportive Features:
~progression of Sx over days to 4 weeks
~relative symmetry
~CN involv esp b/l facial n weakness
~autonomic dysfunction ~EMG features
~elev CSF protein w/ cell count ,10 mm3
NINDS= National Institute of Neurological Disorders and Stroke

9. GBS=heterogenous syndrome w/ variant forms
Think of AIDP as the traditional form as described previously, accts for 85-90%
Miller Fisher Syndrome: opthalmoplegia, ataxia, and areflexia (5%). GQ1b antibody. Only 1/4th w/ extremity weakness
AMAN: selective involv of motor nerves, DTRs are preserved, more common in Japan/China, almost all preceded by Campylobacter infxn
AMSAN: more severe form of AMAN +sensory
GQ1b= ganglioside component of nerve.
Camplyobacter can induce anti-ganglioside antibodies. The virulence of C jejuni is thought to be based on the presence of specific antigens in its capsule that are shared with nerves. Immune responses directed against the capsular components produce antibodies that cross-react with myelin to cause demyelination. Ganglioside GM1 appears to cross-react with C jejuni lipopolysaccharide antigens, resulting in the immunologic damage to the peripheral nervous system. This process has been termed molecular mimicry. Get Ab and complement mediated axonal nerve damage w/o siginficant axonal degeneration
AMSAN= delayated & incomplete recovery

10. DDx of Polyneuropathy:
Arsenic poisoning
N-Hexane (glue sniffing)
Vasculitis
Lyme Disease
Tick paralysis
Sarcoidosis
Leptomeningeal Dz
Paraneoplastic Dz
Critical Illness

12. Supportive Care
Monitor Resp status closely (follow NIFs), up to 30% may req ventilatory support
In severe cases, intrarterial monitoring may be necessary given the gisngifcant blood pressure fluctuations
Neuropathic pain plagues most, often managed w/ Gabapentin or Carbamazepine
a negative inspiratory force (NIF) <-25 cmH2O, more than 30% decrease in either VC or NIF within 24 hours

13. Disease Modifying Treatment
IVIG : typically given for 5 d at 0.4 gram/kg/d (may need to extend course depending on response)
Plasmapheresis: usually 4-6 treatments over 8-10 days
The choice b/w plasma exchange and IVIG is dep on availability, pt contraindications, etc. Because of ease of administration, IVIG is frequently preferred. The cost and efficacy of the 2 treatments are comparable. Glucocorticoids have NO ROLE!!
-IVIG side effects: aspectic meningitis, ARF, rash, and rarely hyperviscosity. IgA defiency = anaphylaxis. Works by likely neutralize circulating myelin antibodies through anti-idiotypic antibodies and down-regulate proinflammatory cytokines, including interferon-gamma (INF-gamma). In addition, may block the complement cascade and promote remyelination
-Plasma exchange side effects: hypotension, sepsis, need central venous access.

14. Outcomes: 65% can walk independently @ 6 mos
Overall, 80% usually recover completely
5-10% have prolonged course w/ incomplete recovery, ~3% wheelchair bound
Approx 5% die despite ICU care
2% will develop chronic relapsing Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP)

15. REFERENCES:
Uptodate 2009.
Plasmapheresis and acute Guillain-Barre syndrome. The Guillain-Barre Syndrome Study Group. Neurology 1984; 2:1296.
Ropper, AH. The Guillain-Barre Syndrome. N Engl J Med 1992; 326:1130.
Sumner, AJ. The physiologic basis for symptoms in Guillain-Barre Syndrome. Ann Neurol 1981; 9 Suppl:28.