Today on the emDOCs cast with Brit Long, MD (@long_brit), we cover Guillain-Barré syndrome focusing on the history, examination, and ED evaluation. Part 2 will cover management.
Episode 111: Guillain-Barré Syndrome Part 1
Background:
- GBS is an immune-mediated disease affecting peripheral nerves.
- An inciting event creates antigens that look like normal host cells or proteins, which confuses the immune system and results in antibodies that attack the myelin sheath of peripheral nerves.
- Infectious triggers: upper respiratory infection or GI illness caused by Campylobacter jejuni,Haemophilus influenzae, E. coli, influenza, HIV, EBV, and COVID-19 have all been implicated.
- Noninfectious triggers: vaccinations, checkpoint inhibitors for cancer treatment, surgery, pregnancy, or myocardial infarctions
- ~100,000 cases occur worldwide annually, making it the most common cause of generalized neuromuscular paralysis.
- Most patients are 50-70 years old.
Presentation:
- Symptoms start 5 days to 6 weeks after the inciting event.
- The first symptom is a sensory change, such as paresthesias or burning pain in the distal extremities, followed by weakness that progresses proximally.
- Cranial nerve involvement occurs in over half of patients, affecting ocular, facial, or oropharyngeal muscles.
- The Miller-Fisher syndrome is one of many GBS variants. It is characterized by ophthalmoplegia, ataxia, and areflexia, with less limb weakness.
- Often occurs in four phases:
- Acute phase (first 2 weeks): subtle sensory changes/paresthesias
- Progressive phase (2-4 weeks): weakness gets worse and spreads proximally
- Plateau phase (4 weeks): can last weeks to months
- Recovery: can take months to even years
Exam:
- The sensory exam is typically normal, with no numbness.
- Weakness is symmetric and ascending, starting in the feet. It progresses proximally and can involve the abdomen, chest wall, and diaphragm.
- Hyporeflexia or areflexia are key exam components. ~90% of patients will have a change in their deep tendon reflexes.
- ~⅔ of patients have dysautonomia, resulting in HR and BP fluctuations.
Diagnosis:
- GBS can be a clinical diagnosis, but lab tests and imaging should be performed to rule out other causes of weakness.
- Labs:
- BMP: hypokalemia and hypophosphatemia can result in weakness.
- CSF cell count and protein
- Albuminocytologic dissociation with elevated protein (50-1,000 mg/dL) and normal cell count suggests GBS. Over half of GBS patients will not have this in the first few days of symptoms. However, after 2-3 weeks, over 80% will.
- Imaging:
- MRI can show anterior nerve root enhancement and should be obtained of the spine regions corresponding to symptoms.
- Electromyography is the most sensitive and specific test 1 to 2 weeks from symptoms onset.
Who needs an LP?
- Anyone with ascending weakness and/or a change in reflexes should be discussed with neurology, and LP should be completed.
- For patients with symmetrical distal sensory changes that have been getting worse over a week’s time, especially if there is some sort of trigger, discuss the case and the need for an LP with neurology (since LP may be negative at this early stage.)
- For patients with symptoms that have been present for over a month and that haven’t progressed, that’s probably not GBS, and LP is likely unnecessary.
How do I differentiate between GBS and other causes of weakness?
- Rate of symptoms: Symptoms progressing over days to weeks are suggestive of GBS. Faster or slower timelines are not.
- Symmetry: GBS is usually symmetric.
- Sensory involvement: GBS has mild sensory changes and occasionally pain but no severe sensory change.
- Fever: GBS does not usually have fever as symptom onset.
- CSF: Elevated protein after one week with cell count less than 50.
- Progression: GBS generally is progressive over the first few weeks. If the motor or sensory level is stable, it suggests something other than GBS.
- Bowel/bladder dysfunction: These occur later in GBS and come with severe ascending weakness. If present at onset, it would argue against GBS.
References:
- Madden J, Spadaro A, Koyfman A, Long B. High risk and low prevalence diseases: Guillain-Barré syndrome. Am J Emerg Med. 2024 Jan;75:90-97. Epub 2023 Oct 28. PMID: 37925758
