Ascending weakness has not been reported. True sensory changes are not encountered, but hyperventilation may produce paraesthesias. Patients remain fully conscious, as the toxin does not penetrate the blood brain barrier; however, mental numbness may occur, and patients may appear lethargic because of diffuse muscle weakness and difficulty communicating due to bulbar weakness [78] . Urinary retention or GI ileus may occur with abdominal cramping. Postural hypotension may be present. Deep tendon reflexes are intact in the beginning, but decline during a period of days. There are no dermatologic abnormalities.