GBS Variants:

-AIDP (Acute inflammatory demyelinating polyneuropathy)- 85-95 % of GBS
-Miller Fisher Variant (5 % US but up to 25 % in Japan)
-AMAN (Acute motor axonal neuropathy)
-AMSAN (Acute sensorimotor axonal neuropathy)

Timing:

Acute (<4 weeks)

Pathophysiology:

Due to molecular mimicry from immune response to preceding infection that cross reacts with components of the peripheral nerve.

Diagnostic Criteria:

1. Progressive weakness of ≥ 2 limbs due to neuropathy
2. Areflexia
3. Disease course < 4 weeks
4. Exclusion of other causes

Supportive criteria:

1. Symmetric weakness
2. Mild sensory involvement
3. Absence of fever
4. Typical CSF profile
5. EMG evidence of demylination

Most common infectious triggers:
-Campylobacter Jejuni (most common), CMV, EBV, HIV, VZV, Mycoplasma, and even Zika virus

Most sensitive physical exam findings in GBS

-Absent/Depressed DTR (90 %)
-Ascending extremity weakness (90 %)
-Paresthesias (80 %)
-Dysautonomia (70 %)
-Facial weakness or bulbar signs (55 %)
-Back/extremity pain, respiratory failure, oculomotor weakness

What do you see on LP?

Albumino-cytologic dissociation (normal WBC with high protein)

Miller Fisher variant TRIAD:

-Ophthalmoplegia
-Ataxia
-Areflexia
Antibodies against GQ1b (anti-ganglioside) present in 85-90 % of patients

Treatment

-Supportive treatment
-IVIG
-Plasma Exchange

Remember that steroids are not effective!