Guillain-Barre syndrome (GBS) can be difficult to diagnose, especially in its early stages, because its symptoms can resemble those of other neurological disorders. GBS is primarily a clinical diagnosis, meaning it is based on medical history and physical examination, with tests used to support the diagnosis and rule out other conditions. Initial signs and symptoms can also vary among patients, which provides an extra layer of complexity.
Physicians may conduct a physical examination of the feet, limbs, and hands to check for symptoms such as numbness and weakness. They assess whether symptoms are symmetrical (affecting both sides of the body), which is typical in GBS, and how quickly the symptoms progress.
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Speak to a SpecialistKey components of the diagnostic evaluation include:
1. Physical Exam
This is usually the first step in diagnosing GBS. Physicians typically look for the following:
- Recent onset (within days to up to 4 weeks) of progressive weakness on both sides of the body, often starting in the legs. Most significant weakness occurs within 2 weeks after symptoms start.
- Abnormal sensations such as numbness, tingling, or pain in the feet, which may occur before or alongside weakness.
- Reduced or absent deep tendon reflexes in affected limbs.
- Double vision or difficulty with moving the eyes
2. Electrodiagnostic (Nerve) Tests
Electrodiagnostic tests are used to evaluate how well nerves and muscles function. These include:
- Electromyography (EMG): Measures electrical activity in muscles using small needle electrodes.
- Nerve conduction studies (NCS): Use mild electrical impulses to assess how quickly signals travel through nerves.
In GBS, these tests often show slowed nerve conduction or other abnormalities, indicating peripheral nerve damage.
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3. Lumbar Puncture
In this procedure, a needle is inserted into the lower spine to collect cerebrospinal fluid (CSF) for analysis.
Lumbar punctures help diagnose diseases of the central nervous system, including those of the brain and spine. A typical finding in GBS is elevated CSF protein levels without an increase in white blood cells (albuminocytologic dissociation). This finding may not appear until about 7–10 days after symptom onset.
4. Antibody Tests
Blood tests may be used to detect specific antibodies associated with certain variants of GBS, such as the Miller Fisher variant.
However, these tests have limitations and are not routinely used to diagnose the more common forms of GBS.
Overall, the diagnosis of Guillain-Barre syndrome is based on a combination of clinical features, progression of symptoms, and supportive test results, while also excluding other possible conditions.
