From the Research
The most sensitive diagnostic test for Guillain-Barré syndrome (GBS) is clinical criteria, as electrophysiological criteria proposed by the NINDS, Dutch, and Brighton criteria are less sensitive compared to clinical criteria in diagnosing GBS at early stages 1.
Key Diagnostic Features
- Clinical assessment remains crucial, with progressive ascending weakness and diminished or absent deep tendon reflexes being hallmark features.
- Supportive diagnostic criteria include symptom progression over days to weeks, relative symmetry of symptoms, and mild sensory involvement.
- Electrophysiological studies, such as nerve conduction studies, can detect demyelination patterns and conduction blocks characteristic of GBS, but may not be as sensitive as clinical criteria, especially in the early stages of the disease.
Electrophysiological Findings
- The H reflex is the most sensitive test for early GBS, with absent H response, abnormal F wave, and abnormal upper extremity SNAP combined with a normal sural SNAP being characteristic of early GBS 2.
- Sensory nerve conduction studies, including the sural-sparing pattern and the sensory ratio, can be useful in the diagnosis of GBS, especially in establishing the diagnosis and predicting the outcome according to the various subtypes of the disease 3.
Importance of Early Diagnosis
- Early diagnosis is essential as prompt treatment with intravenous immunoglobulin or plasma exchange within the first two weeks of symptom onset can significantly improve outcomes and reduce long-term disability.
- Comprehensive testing, including novel tests such as cutaneous silent periods, long latency reflexes, and contraction-induced H reflexes, can provide diagnostic certainty in most cases of GBS from the very first study 4.