Archive Of Standardized Exam Questions: Botulism


This page is dedicated to organizing various examples of standardized exam questions whose topic is botulism. While this may seem a odd practice, it is useful to see multiple examples of how botulism will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a traditional question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a topic is quite valuable.


When it comes to standardized exams, each topic has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for botulism

Chief Complaints:


  • Nausea/vomiting may be present
  • Dry mouth: due to muscarinic acetylcholine blockade
  • Diplopia/double vision/blurry vision: due to nicotinic acetylcholine blockade
  • Dysphasia: due to nicotinic acetylcholine blockade
  • Generalized weakness 


  • Poor feeding
  • Weakness
  • Loss of muscle tone

Patient History:

  • Ingestion of home canned goods (in the case of adults)
  • Ingestion of honey (in case of children/infants)
  • Exposure to aerosolized compound this toxin can be spread in the air as a biochemical weapon.

Clinical Workup:

  • Mydriasis/dilated pupils can be detected on the physical (due to acetylcholine blockade) that will be poorly reactive to light.
  • Decreased muscle tone/flaccid paralysis is seen in these patients.
  • Decreased compound muscle action potentials (CAMP) will be present on EMG studies (although nerve conduction velocities will be normal)

Question # 1

A 50 year old man comes to the ER because he has been suffering from double vision, ptosis, nausea, dry mouth, and difficulty swallowing. A few hours later, his wife begins to suffer the same symptoms. The both attended a church potluck yesterday, and enjoyed a home-made tomato soup that was created using home-canned tomatoes. What is a possible diagnosis in these patients?

Explanation # 1

Double vision + nausea +  dry mouth + dysphagia + ingestion of canned goods = botulism

Question # 2

A 37 year old female comes to the hospital because she has been suffering from dry mouth, blurred vision, and also has trouble swallowing. The patient’s past medical history is remarkable for major depression. A physical exam reveals the presence of mydriasis, and her pupils are poorly reactive light. EMG studies reveal decreased compound muscle action potentials  (CAMP) but normal nerve conduction velocities. What condition does this patient likely have?

Explanation # 2

Dry mouth + blurred vision + dysphagia + mydriasis (poorly reactive to light) + decreased CAMP on EMG = botulism

Question # 3

A 6 month old male child is brought to the hospital because he has been having issues feeding. His parents also comment that he has been having weakness, and has lost muscle tone in his extremities. The patient is completely up to date on his vaccinations and has no remarkable past medical history. He is mostly breast fed, however also sometimes receives some orange juice and honey. He has also been prescribed vitamin D by his pediatrician. What is the likely diagnosis in this patient?

Explanation # 3

Young infant +  weakness + loss of muscle tone + ingestion of honey = botulism

Question # 4

A 25 year old woman and 20 other victims are brought to the hospital after being exposed to an aerosolized substance. She has developed diplopia, dysphagia, and her gait is unsteady since being exposed to the substance. The patients symptoms worse to the point that she has flaccid paralysis of all four extremities. Her pupils are observed to be 7 mm and do not react to light. Her deep tendon reflexes are decreased bilaterally, and her Babinski sign is negative. The patient’s sensation to pinprick is within normal limits in all extremities. CSF is collected from a lumbar puncture, however it shows no abnormalities. What is the likely diagnosis in this patient?

Explanation # 4

Diplopia + dysphagia + flaccid paralysis + dilated pupils (non-reactive to light) = botulism

Question # 5

A 60 year old male is brought to the ER because he has been suffering from nausea and vomiting for the past 10 hours. He also complains of diarrhea, abdominal pain , and generalized weakness. A thorough history also reveals that the patient has blurry vision, dry mouth, and feels tingling in his legs bilaterally. About a day and a half ago the patent wen to a house party where he ate a pork roast, coconut shrimp, fried rice, and also home-canned jams. His pat medical history is notable for an upper respiratory tract infection that resolved without treatment about 2 weeks ago. He currently does not take any medications, and does not smoke cigarettes or drink alcohol. He is current alert, responsive, and oriented to his name, place, and date. A neurological exam reveals pupils that react sluggishly to light, and appear to be dilated. The patient’s mucous membranes are dry, and his cardiac exam is unremarkable. Muscle strength is diminished in the lower extremities, and deep tendon reflexes are present throughout. What is the likely diagnosis in this patient?

Explanation # 5

Generalized weakness + blurry vision + dry mouth + ingestion of home canned goods + dilated pupils (react sluggishly to light) = botulism


Many questions on standardized exams go beyond simply recognizing the underlying topic. Often there are specific testable facts regarding some aspect of the topic’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:


  • Ingestion of botulism toxin
  • Mechanism of action of toxin: blocks both muscarinic and nicotinic signaling. It prevents the release of acetylcholine at the neuromuscular synapse.
  • How to destroy toxin: using heat (properly cooked food is OK)



Page Updated: 10.03.2017