What clinical features should I look for to differentiate Guillain-Barré Syndrome from other causes of acute flaccid paralysis?

To differentiate Guillain-Barré Syndrome (GBS) from other causes of acute flaccid paralysis, several clinical features should be considered.

Guillain-Barré Syndrome (GBS) typically presents with a rapidly progressive, symmetrical weakness that often starts in the legs and ascends to involve the arms and facial muscles NICE NG127, Sheikh 2020. A hallmark feature of GBS is the loss of deep tendon reflexes (areflexia) NICE NG127, Sheikh 2020. Patients commonly experience sensory symptoms such as paraesthesia or numbness, although motor weakness is usually more prominent NICE NG127, Sheikh 2020. Neuropathic pain is also a frequent complaint in GBS NICE NG127. Autonomic dysfunction, including fluctuations in blood pressure or arrhythmias, can occur NICE NG127, Sheikh 2020. Bilateral facial weakness is also a common presentation in GBS NICE NG127. The progression of weakness in GBS usually occurs over days to weeks, peaking within four weeks NICE NG127, Sheikh 2020.

In contrast, when considering other causes of acute flaccid paralysis such as Acute Flaccid Myelitis (AFM), there are key differentiating points. While AFM also involves acute onset of flaccid limb weakness and diminished or absent deep tendon reflexes in affected limbs, the weakness is often asymmetrical, unlike the typical symmetry seen in GBS NICE NG127, Murphy & Pardo 2020. Furthermore, sensory loss is typically absent or mild in AFM, which contrasts with the more prominent sensory symptoms commonly observed in GBS NICE NG127, Murphy & Pardo 2020. AFM is also characterized by distinct spinal cord lesions, particularly in the grey matter, which can be identified on MRI NICE NG127, Murphy & Pardo 2020.