Diagnosis of Guillain-Barré Syndrome
The diagnosis of Guillain-Barré Syndrome is primarily clinical, based on a careful assessment of symptoms, history, and neurological examination. As no single test definitively confirms the diagnosis of Guillain-Barré Syndrome, doctors rely on a combination of physical findings, electrodiagnostic tests, and supportive laboratory evidence.
Given the potential severity of GBS and its rapid progression, prompt and accurate diagnosis is crucial. Early recognition allows for immediate treatment, reducing the risk of complications such as respiratory failure or permanent nerve damage.
Clinical Evaluation
The diagnostic process begins with a detailed medical history and neurological examination. Doctors will ask about:
Recent infections, particularly gastrointestinal or respiratory illnesses
Vaccinations or surgery within the past few weeks
Onset and progression of weakness
Sensory symptoms, such as tingling or numbness
Reflex changes and mobility difficulties
Key clinical signs pointing toward GBS include:
Symmetric, ascending muscle weakness
Reduced or absent reflexes (areflexia)
No fever at onset of neurological symptoms
Rapid progression (hours to days)
The presence of these features usually raises strong suspicion for GBS and warrants urgent testing.
Diagnostic Criteria
The most widely accepted diagnostic framework is from the National Institute of Neurological Disorders and Stroke (NINDS). Essential criteria include:
Progressive weakness in more than one limb
Areflexia (loss of tendon reflexes)
Progression over hours to 4 weeks
Symmetry of symptoms
Exclusion of other causes
Supportive findings may include:
Facial or cranial nerve involvement
Mild sensory symptoms
Autonomic dysfunction
Lumbar Puncture (Spinal Tap)
A lumbar puncture helps confirm the diagnosis by analysing cerebrospinal fluid (CSF). In GBS:
CSF shows elevated protein levels
White blood cell count is normal or very low
This is known as albuminocytologic dissociation
It may take several days for protein levels to rise, so a normal early result does not rule out GBS.
Nerve Conduction Studies and Electromyography (EMG)
These tests measure how well electrical signals move through nerves and muscles:
In GBS, conduction velocity is slowed, reflecting demyelination
EMG shows reduced muscle activity
Abnormalities confirm nerve dysfunction and help identify the GBS subtype
These tests are highly valuable but may be less useful in the earliest stages of the illness.
Blood Tests and Imaging
Blood tests are not specific for GBS but are used to:
Exclude infections, metabolic disorders, or autoimmune conditions
Check inflammatory markers, electrolytes, and vitamin levels
Imaging (such as MRI) may be done to:
Rule out spinal cord compression, tumours, or other structural issues
Assess inflammation in spinal nerve roots (seen as enhancement on MRI)
These tools help eliminate alternative explanations for neurological symptoms.
Antibody Testing
In specific cases, especially with Miller Fisher Syndrome, antibody tests may detect:
Anti-GQ1b antibodies, linked to eye muscle paralysis and ataxia
Other antiganglioside antibodies, such as anti-GM1, GD1a, or GT1a
These tests support the diagnosis but are not required in every case.
Differential Diagnosis
Conditions that may resemble GBS include:
| Condition | Key Differences |
| Myasthenia gravis | Fluctuating weakness, no sensory symptoms, normal reflexes |
| Poliomyelitis | Asymmetric weakness, fever present |
| Transverse myelitis | Sensory level, bowel/bladder dysfunction, spinal MRI changes |
| Chronic inflammatory demyelinating polyneuropathy (CIDP) | Slower progression over 8 weeks or more |
A thorough assessment ensures that serious alternatives are not missed.
Diagnosis in Children
Paediatric cases may present differently:
More pronounced pain or refusal to walk
Irritability or crying when legs are touched
May appear clumsy or weak without clear description of symptoms
Doctors must rely more on physical exam and parental observation when diagnosing GBS in younger children.
Timing and Urgency
Because GBS can progress rapidly, clinicians often begin treatment before test results are complete, especially if:
The child or adult has progressive weakness
Reflexes are lost
Breathing or swallowing becomes difficult
Starting treatment early improves outcomes and may shorten the duration of hospitalisation.
Conclusion | Diagnosis of Guillain-Barré Syndrome
Doctors diagnose Guillain-Barré Syndrome by looking for a clear pattern of symptoms—such as sudden weakness, loss of reflexes, and quick worsening over days. In addition, they use tests like a spinal fluid (CSF) analysis and nerve studies to confirm the diagnosis. These tools help doctors start treatment with confidence. Since Guillain-Barré Syndrome can be life-threatening, early diagnosis is crucial. Acting quickly not only improves the chances of recovery but also lowers the risk of long-term disability.
