Which one of the following is not a feature of Gullain Barre syndrome?

*GBS manifest as rapidly envolving areflexic motor paralysis with or without sensory disturbance. *Deep tendon reflex is attenuated or disappear with in first few days *Bladder dysfunction occur in severe case but is usually transient . *CSF finding are distinctive with elevated protein levels without accompanying pleocytosis Ref Harrison20th edition pg 1234