Overview
Botulism is a severe rare condition produced by a neurotoxin called Clostridium botulinum. It is known worldwide as the most poisonous bacterial toxin, and approximately one milligram is lethal to humans.1,2 The toxin affects many body systems leading to life-threatening illnesses such as severe respiratory and muscular paralysis, difficulty breathing and even death, if not treated immediately.3 There are different types of botulism, but each case is considered a medical emergency and must be treated via the use of antitoxins, to reduce the risk of further complications. According to the NHS, foodborne botulism affects all age groups, and there are different avenues for developing this rare condition, including foodborne, wound or infant botulism.4
What causes botulism?
Clostridium botulinum is a bacterium that produces spores that are heat-resistant and exist in natural environments such as soils, seawater, and rivers. In anaerobic environments, or in other words, in environments where there is a lack of oxygen, the spores continue to multiply and grow (also called germination), and excrete toxins, in this case, botulinum toxins.3 The botulinum toxins are particularly known for being neurotoxins attacking the nervous system, and causing paralysis.4 If not treated immediately, the paralysis can spread to muscles that control breathing, also known as respiratory paralysis. According to the NHS, botulism is fatal in around 5 to 10 % of cases.4
Risk factors
Certain activities can increase your chances of having botulism including:5
- Injecting illicit drugs
- Eating contaminated food
- Drinking certain kinds of homemade alcohol (also known as ‘pruno’ or ‘hooch’)
- Inhaling or being injected with too much botulinum toxin
Types of botulism
Botulism is mainly a foodborne intoxication, however, there are different types of botulism.3 According to the NHS website, there are three main types of botulism, foodborne, infant, and wound botulism.4 There is no human-to-human transmission. There has to be direct consumption or access to an open wound for a person to start experiencing the symptoms of botulism.3
Foodborne botulism
Clostridium botulinum can be found in natural environments such as soils, seawater and rivers, which can further transmit to commercially produced foods such as canned products, ready-to-eat meals, and certain vegetables. Thus, the bacteria can already produce toxins within these foods before it has been consumed. But also Ill-prepared foods can cause foodborne botulism, particularly when making home-bottled or home-canned foods.3 The incubation period for foodborne botulism ranges from 18 to 36 hours.2 The incubation period is defined as the time between infection of the botulinum toxin and when signs or symptoms of botulism start to occur.6
Symptoms of foodborne botulism include:2,3, 7
- Abdominal pain/swelling
- Nausea
- Vomiting
- Diarrhea
- Dry mouth
- Blurred or double vision
- Difficulty swallowing or speaking
- Fixed and dilated pupils
- Sore throat without fever
- Abdominal swelling
- Constipation
Infant botulism
Within infant botulism, heat-resistant forms of bacteria, known as spores, are consumed. The bacteria multiply, or in other words, germinate in the infant’s intestines, and over time release toxins which cause illnesses to surrounding organs and spread to other areas of the body. It is extremely important to treat infant botulism immediately because infants are young and have not fully developed their immune systems. Therefore, their natural defence systems are not as strong as seen for healthy older children or adults. Therefore, they are more likely to develop illnesses a lot faster. The incubation period can vary from days to weeks.7-8
Infant botulism has similar symptoms to foodborne botulism, as well as:7
- Weak cry
- Poor feeding
- Weaking sucking reflex
- Loss of strength of neck and limb muscles
Wound botulism
Wound botulism is less common in comparison to food-related botulism. However, there has been a rise in wound botulism due to an increase in drug use, especially among those who use heroin and cocaine. Wound botulism is where the botulinum toxins are produced and released in a contaminated and opened wound. The incubation period varies from 7 to 21 days.2,3 Symptoms are like what is seen with foodborne botulism except the symptoms that relate to food digestion, absorption, and excretion of waste products from the digestion system (also known as the gastrointestinal system).
Other types of botulism
There have been other cases of botulism, which include iatrogenic botulism, inhalation botulism, and adult intestinal toxaemia.
Iatrogenic botulism
This type of botulism is a result of receiving treatment that has botulism toxins in its highly purified but diluted form. Treatment is received in the form of injections for medical or cosmetic purposes, such as botox injections to prevent wrinkles.2,3 Iatrogenic botulism can occur when an individual has too many botulinum toxin injections, and experiences similar to foodborne botulism such as:9,10
- Dropping of the eyelids
- Double vision
- Blurred vision
- Slurred speech
- Fatigue
- Hoarseness of voice
- Difficulties of swallowing, speaking or breathing.
Inhalation botulism
Inhalation botulism involves inhaling the aerosol form of botulinum toxins.11 A study has stated that laboratory workers have been reported to have inhalation botulism. This could happen accidentally or due to intentional events such as bioterrorism.11 Symptoms are similar to ingesting the bacteria and they become visible after 12 to 72 hours of inhalation exposure.2 The incubation period might take longer for lower levels of intoxication. If inhalation botulism is suspected, one must immediately follow decontamination protocol such as:3,11
- Prevent additional exposure
- Remove clothing worn during exposure. The clothing should also be stored in a plastic bag until it can be washed thoroughly with soap and water
- Shower
Adult intestinal toxemia
Adult intestinal toxaemia is the adult version of infant botulism. However, there is a need for more research to understand why this type of botulism occurs in adults.12,13
Diagnosis of botulism
A person experiencing symptoms of botulism should seek medical help immediately to prevent developing lifelong and fatal conditions such as muscular and respiratory paralysis.4 Diagnosis begins with a physical examination; however, this does not confirm that an individual has botulism. Also, if the diagnosis is related to foodborne or infant botulism, doctors will ask more questions about what types of food were eaten within the past several days. This is to check whether the foods consumed could potentially contain Clostridium botulinum or its toxins.3,14
Laboratory tests are also performed to confirm that the botulinum toxin is present in blood and/or stool samples before treatment methods are discussed. For food-related botulism, the foods in question can also be tested to see whether they contain the toxin. But also further investigation can be done to understand how to prevent bacteria from growing and producing harmful toxins in the sampled foods.3,14
Some other diseases or conditions share similar symptoms to botulism such as a stroke, meningitis or an opioid overdose.3,14 More information can be found in the study.2 Hence it is important to also make sure to perform other laboratory tests to confirm that the toxin is present before proceeding with treatment, such as an electromyography (EMG), imaging scans such as CT scans or MRI scans or a spinal fluid test.15-19
Treatment methods for botulism
Antitoxins are useful in preventing the toxins from causing further harm.3 It is also important to note that the antitoxins do not immediately heal the damage that has already been caused by the toxins. Hence it is vital to have early treatment to prevent severe damage that might take weeks or even months to gradually heal. If treatment is not received early, some patients might require surgery to remove the source of bacteria. Also, if patients are experiencing respiratory problems, a breathing machine, such as using mechanical ventilation, will help improve breathing due to damage caused by toxins before treatment.20
For wound botulism, if the wound is severely damaged, it might be useful to have wound debridement. Wound debridement is where the dead skin cells are removed and the removal will also involve taking the source of the botulinum toxins. This is normally followed up by the use of antibiotics.19 A botulism vaccine can be administered to certain people, for example, military personnel or laboratory workers.2 However, it is worth mentioning that the vaccine could lead to severe side effects and there is not a lot of evidence on its effectiveness to prevent a person from having botulism.3
Complications of botulism
As it is impossible to see, smell or taste the botulinum toxin, it is vital to make sure that prevention strategies are considered because the smallest amount of botulinum toxins can be lethal. Also, early treatment via the use of antitoxins can reduce the likelihood of developing long-term medical complications.2 For those that have experienced paralysis before treatment, it will take time weeks to months to gradually improve and slowly recover.4,21 Some individuals who survive botulism might have fatigue and shortness of breath for several years. Furthermore, they may need long-term therapy and rehabilitation, such as speech, physical and/or occupational therapy, to assist with recovering from botulism.19,20, Thus it is important to consider prevention strategies and guidelines to avoid developing botulism.3-4, 9, 22-23
Summary
Botulism is a lethal and rare condition that if not treated immediately could lead to life-threatening conditions such as severe respiratory and muscular paralysis and even death. There are three main types of botulism including foodborne, wound, and infant. However, there are other types of botulism to consider. It is important to seek medical help should you experience any of the symptoms mentioned above. Antitoxins are the primary treatment for botulism, although depending on the severity of the symptoms experienced, it could take months or even several years to fully recover. Hence, it is important to take heed of prevention strategies and guidelines to avoid experiencing botulism.
References
- Chaudhry, Rama. ‘Botulism : A Diagnostic Challenge’. The Indian Journal of Medical Research, vol. 134, no. 1, July 2011, pp. 10–12. PubMed Central, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3171901/.
- Kobaidze, Ketino, and Zanthia Wiley. ‘Botulism in the 21st Century: A Scoping Review’. Journal of Brown Hospital Medicine, vol. 2, no. 2, Mar. 2023. bhm.scholasticahq.com, https://doi.org/10.56305/001c.72707.
- Botulism. https://www.who.int/news-room/fact-sheets/detail/botulism. Accessed 31 May 2024.
- ‘Botulism’. Nhs.Uk, 17 Oct. 2017, https://www.nhs.uk/conditions/botulism/.
- CDC. ‘People at Increased Risk for Botulism’. Botulism, 9 May 2024, https://www.cdc.gov/botulism/risk-factors/index.html.
- Scallan, E. ‘Disciplines Associated with Food Safety: Epidemiology’. Encyclopedia of Food Safety, edited by Yasmine Motarjemi, Academic Press, 2014, pp. 47–52. ScienceDirect, https://doi.org/10.1016/B978-0-12-378612-8.00025-1.
- CDC. ‘Symptoms of Botulism’. Botulism, 19 Apr. 2024, https://www.cdc.gov/botulism/signs-symptoms/index.html.
- CDC. ‘Clinical Overview of Infant Botulism’. Botulism, 16 May 2024, https://www.cdc.gov/botulism/hcp/clinical-overview/infant-botulism.html.
- Centre for Health Protection, Department of Health - Botulism. https://www.chp.gov.hk/en/healthtopics/content/24/44865.html. Accessed 31 May 2024.
- CDC. ‘Harmful Reactions Linked to Counterfeit “Botox” or Mishandled Botulinum Toxin Injections’. Botulism, 16 May 2024, https://www.cdc.gov/botulism/outbreaks/harmful-reactions-botox-injections/index.html.
- CDC. ‘Bioterrorism and Botulism: The Threat’. Botulism, 16 May 2024, https://www.cdc.gov/botulism/bioterrorism/index.html.
- Cherington, Michael. ‘Clinical Spectrum of Botulism’. Muscle & Nerve, vol. 21, no. 6, June 1998, pp. 701–10. DOI.org (Crossref), https://doi.org/10.1002/(SICI)1097-4598(199806)21:6<701::AID-MUS1>3.0.CO;2-B.
- CDC. ‘Botulism Prevention’. Botulism, 16 May 2024, https://www.cdc.gov/botulism/prevention/index.html.
- CDC. ‘Testing for Botulism’. Botulism, 16 May 2024, https://www.cdc.gov/botulism/diagnosing-treating/index.html.
- ‘Peripheral Neuropathy - Diagnosis’. Nhs.Uk, 3 Oct. 2018, https://www.nhs.uk/conditions/peripheral-neuropathy/diagnosis/.
- ‘CT Scan’. Nhs.Uk, 18 Oct. 2017, https://www.nhs.uk/conditions/ct-scan/.
- ‘MRI Scan’. Nhs.Uk, 23 Oct. 2017, https://www.nhs.uk/conditions/mri-scan/.
- ‘Lumbar Puncture’. Nhs.Uk, 24 Oct. 2017, https://www.nhs.uk/conditions/lumbar-puncture/.
- CDC. ‘Clinical Overview of Botulism’. Botulism, 1 May 2024, https://www.cdc.gov/botulism/hcp/clinical-overview/index.html.
- CDC. ‘Treatment of Botulism’. Botulism, 16 May 2024, https://www.cdc.gov/botulism/treatment/index.html.
- Welcome to the Infant Botulism Treatment and Prevention Program. https://www.infantbotulism.org/. Accessed 31 May 2024.
- CDC. ‘Home-Canned Foods’. Botulism, 17 May 2024, https://www.cdc.gov/botulism/prevention/home-canned-foods.html.
- ‘Botulism - Symptoms and Causes’. Mayo Clinic, https://www.mayoclinic.org/diseases-conditions/botulism/symptoms-causes/syc-20370262. Accessed 31 May 2024.