The major clinical symptoms and signs include progressive limb weakness and areflexia (Table 208.1). Such weakness usually presents over a period of several hours to days. About half of patients will have ascending involvement of lower extremities followed by upper extremities. However, a variant presenting with descending paralysis starting in cranial nerves or upper limbs can be seen in about 14% of cases. Limb weakness does not usually progress beyond 4 weeks and half of the patients experience a nadir within 2 weeks. Frequently patients complain of limb paresthesias and dysesthesias concomitantly or preceding limb weakness that is sometimes accompanied by lower back pain. On physical examination practitioners encounter areflexia or severely decreased myotatic reflexes and usually symmetric limb involving both distal and proximal muscles. On exam, the most common cranial nerves involved are facial, glossopharyngeal, and vagus nerves. Thus patients will have facial weakness (usually bilateral) and oropharyngeal
dysfunction manifested by dysphagia and dysarthria. Compromise of the cranial nerves innervating the extraocular muscles (i.e., III, IV, and VI cranial nerves) is less common and is usually part of a Guillain-Barré syndrome variant also known as Miller Fisher variant. The latter
can present with ophthalmoparesis or ophthalmoplegia and areflexia followed by respiratory failure. The progression and severity of GBS are variable with 33% of patients requiring mechanical ventilation.