GUILLAIN-BARRE 

Acute Ascending Polyneuropathy

Guillain-Barré Syndrome is an autoimmune disease that demyelinates the PNS. GB occurs following a viral infection. 

What viral infection?

Usually Campylobacter jejuni-induced diarrhea. But also Mycoplasma pneumonia, CMV, the flu or even vaccinations (that’s pretty rare though).

Why does it follow a viral infection?

Due to molecular mimicry. Campylobacter is coated in a protein that looks very similar to a protein found on the myelin of LMN’s. It takes about 2-3 weeks to build up an army of antibodies that then attack the myelin and Schwann cells. Since antibodies cannot cross the blood-brain barrier, the CNS is spared.

So what are the symptoms?

Subacute onset of ascending LMN damage (flaccid weakness, hyporeflexia, atrophy and fasciculations). It takes about 4 weeks for the symptoms to reach peak intensity. There can be mild sensory changes as well.

Why is it ascending?

Because of how demyelination works. Like a chain, it only takes one chink in an axon’s myelin to disable it. So statistically, the longest nerves are going to sustain damage before the shorter ones. The longest nerves are those that run down to your toes. 

Is it dangerous?

Yeah it’s really dangerous. One third (!) of patients are placed in a medical coma and intubated. 10% die.

Why is it so dangerous?

When weakness reaches the chest, the respiratory muscles fail and they suffocate.

What are the treatments?

It’s self resolving. So the goal is to intubate them until it passes. 15% of survivors end up with chronic weakness, and this phenomenon is called Chronic Inflammatory Demyelinating Polyradiculopathy. Travis Frederick, an all-star NFL lineman for the Dallas Cowboys, was recently forced into an early retirement because of it. 

How to diagnose?

Do a lumbar puncture. The CSF will have increased protein.