Botulism Symptoms

It is critical to be able to recognize the signs and symptoms of botulism because if it is not treated in time, the toxin can prove fatal. The botulinum toxin's lethal dose to humans is 1 mcg (micrograms). Put on a different scale, an aerosolized botulism toxin (if intentionally dispersed as a terrorism act) could potentially kill 1.5 million people.

About 90% of botulinum infected people will present at least three of the following symptoms:

• nausea, vomiting, abdominal cramps
• difficulty swallowing
• double vision
• dilated/fixed pupils
• dry mouth

Some of these symptoms can appear as early as six-hours from toxin ingestion but may not be initially linked to botulism (due to its vagueness). Gastrointestinal symptoms tend to be signs of a food-borne infection. Double vision and dilated pupils are some of the first signs of a neurological damage and usually appear within this same time frame. 

An alliteration tool may help people recognize the onset of botulism and the typical progression, in order of appearance:

"The Dozen D's"

• double vision (diplopia) 
• dilated pupils 
• droopy eyes
• droopy face
• diminished gag reflex
• dysphagia (difficulty swallowing)
• dysarthria (difficulty pronouncing words)
• dysphonia (difficulty speaking)
• difficulty lifting head
• descending paralysis
• diaphragmatic paralysis

Half of all diagnosed patients will experience double vision but are otherwise mentally intact. More serious conditions that accompany botulism, such as airway obstruction, lead to delirium and need for critical care.

Sources:
http://emedicine.medscape.com/article/213311-clinical#a0217
http://emedicine.medscape.com/article/829125-clinical#a0217
http://www.mayoclinic.com/health/botulism/DS00657/DSECTION=symptoms
http://www.cdc.gov/nczved/divisions/dfbmd/diseases/botulism/#symptoms