Guillain-Barré syndrome (GBS)

 A 42 year old male presents to the emergency department with progressive weakness in both legs and tingling in the feet over the past 4 days. The weakness has ascended over the past 24 hours, now involving the arms and causing difficulty swallowing. He reports an episode of bloody diarrhea 2 weeks earlier after consuming poultry, suggestive of Campylobacter jejuni infection. On examination, there is bilateral symmetric weakness (MRC 3/5) with absent deep tendon reflexes. Cerebrospinal fluid analysis shows elevated protein with normal cell count. Electrophysiologic studies demonstrate prolonged latency and decreased conduction velocity, consistent with a demyelinating pattern. MRI of the brain and spinal cord is normal. Diagnosis?

Diagnosis is Guillain-Barré syndrome following Campylobacter jejuni infection.

1. Definition

Guillain-Barré syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy and a neurologic emergency, characterized by rapidly progressive symmetric weakness and areflexia.

2. Etiology

1. Preceded by infection in approximately 70 percent of cases
2. Most common trigger is Campylobacter jejuni
3. Other associated infections include:
1. Cytomegalovirus
2. Epstein-Barr virus
3. Mycoplasma pneumoniae
4. HIV
5. Zika virus
6. Hepatitis E virus
4. Noninfectious triggers include:
1. Surgery
2. Autoimmune disorders
3. Malignancy
4. Medications

3. Pathophysiology

1. Molecular mimicry between microbial antigens and peripheral nerve gangliosides
2. Formation of antiganglioside antibodies
3. Activation of complement and macrophages
4. Leads to immune-mediated demyelination

4. Clinical Features

1. Ascending symmetric weakness starting in lower limbs
2. Areflexia or hyporeflexia
3. Distal paresthesias
4. Back or radicular pain

4.1 Cranial Nerve Involvement

1. Facial weakness
2. Dysphagia
3. Ophthalmoplegia in variants

4.2 Autonomic Dysfunction

1. Arrhythmias
2. Labile blood pressure
3. Urinary retention
4. Ileus
5. Symptoms typically begin about 10 days after infection and reach nadir within 2 to 4 weeks

5. Diagnosis

5.1 Clinical

1. Progressive bilateral weakness
2. Reduced or absent reflexes

5.2 CSF

1. Albuminocytologic dissociation
1. Elevated protein
2. Normal cell count
2. Protein may be normal in the first week

5.3 Electrophysiology

1. Demyelinating pattern (AIDP)
1. Decreased conduction velocity
2. Prolonged latency
2. Early studies may be normal, requiring repeat testing

5.4 MRI

1. Usually normal
2. May show nerve root enhancement

6. Management

6.1 Indications for ICU Monitoring

1. Rapid progression
2. Bulbar dysfunction
3. Respiratory compromise
4. Autonomic instability

6.2 Immunotherapy

1. IVIG or plasmapheresis (equally effective)
2. Do not combine therapies
3. Corticosteroids are not beneficial

6.3 Respiratory Monitoring

1. Forced vital capacity (FVC)
2. 20/30/40 rule

7. Supportive Care

1. Respiratory support if needed
2. DVT prophylaxis
3. Physical and occupational therapy
4. Prevention of pressure ulcers and aspiration

8. Complications

1. Respiratory failure
2. Autonomic instability
3. Arrhythmias
4. Aspiration pneumonia
5. Deep vein thrombosis and pulmonary embolism

9. Prognosis

1. More than 50 percent fully recover within 1 year
2. About 80 percent regain independent ambulation
3. Mortality is 3 to 7 percent, higher in severe cases

10. Key Clinical Insight

Ascending weakness + areflexia + recent diarrheal illness + albuminocytologic dissociation = Guillain-Barré syndrome

11. Exam Pearls

1. Campylobacter jejuni is the most common trigger
2. Areflexia is the hallmark
3. CSF protein may be normal early
4. IVIG equals plasmapheresis in efficacy
5. Steroids are not useful
6. Autonomic dysfunction can be life-threatening
7. Progression beyond 4 weeks suggests alternative diagnosis such as CIDP