Botulism

Original Editors - Elliot Mattingly from Bellarmine University's Pathophysiology of Complex Patient Problems project.

Top Contributors - Elliot Mattingly, Lucinda hampton, Admin, Elaine Lonnemann, Wendy Walker, WikiSysop and Kim Jackson  

Introduction

Botulism is a neuroparalytic syndrome that results from the systemic effects of an exo neurotoxin produced by the rod-shaped, spore-forming, anaerobic bacterium Clostridium botulinum.

• Botulinum toxins are one of the most lethal substances known that can block nerve functions and can lead to respiratory and muscular paralysis.
• Human botulism may allude to foodborne botulism, infant botulism, wound botulism, and inhalation botulism or other types of intoxication.
• Foodborne botulism, caused by consumption of improperly processed food, is a rare but potentially fatal diseasethat requires rapid diagnosis and antitoxin treatment. Homemade canned, preserved or fermented foodstuffs are a common source of foodborne botulism and their preparation requires extra caution.

Etiology

Botulinum toxins are neurotoxic and therefore affect the nervous system. Botulinum neurotoxin is considered the deadliest toxin known due to its high potency and lethality, with a lethal dose of 1 ng to 3 nanograms of toxin per kilogram of body mass. The flaccid paralysis of botulism results from the irreversible inhibition of acetylcholine release at the presynaptic nerve terminal of the neuromuscular junctions.

Spores produced by the bacteria Clostridium botulinum, being heat-resistant and existing widely in the environment, freely germinate grow and then excrete toxins in anaerobic conditions . There are 7 distinct forms of botulinum toxin, types A–G. Four of these (types A, B, E and rarely F) cause human botulism. Types C, D and E cause illness in other mammals, birds and fish.

Botulinum toxins are ingested through improperly processed food where bacteria or the spores survive, then increase in number and produce the toxins. Though mainly a foodborne intoxication, human botulism can also be caused by intestinal infection with C. botulinum in infants, wound infections, and by inhalation.

Transmission

There are three common forms of botulism.

1. Intestinal botulism (most common form). Caused by eating food, or swallowing dust or soil that contains the bacteria, Clostridium botulinum. Infants under the age of 12 months are most at risk, however adults who have certain gastrointestinal problems also at risk. The bacteria multiply inside the gut and produce toxins. Healthy adults have natural defences in their gut that prevent the bacteria from multiplying usually.
2. Food-borne botulism: Caused by eating food contaminated with toxins. Symptoms generally occur between 12 and 36 hours after eating the contaminated food. This form of botulism can be severe and may lead to death.
3. Wound botulism (rare form): Caused by bacteria (often in soil or gravel) entering the body through a wound or IV drug use. Symptoms can occur up to two weeks after the wound.

Epidemiolgy

Botulism outbreaks are rare, however thay are public health emergencies requiring rapid recognition to identify the disease source, distinguish outbreak types (between natural, accidental or potentially deliberate), prevent more cases and successfully manage treatment to affected patients.

• In 2014, 123 cases of botulism were reported by 16 EU/EEA countries, including 91 cases reported as confirmed. Thirteen countries notified zero cases.
• In Australia, there is typically only one case of botulism reported per year.
• In the United states, 5 years from 2011 through 2015, an average of 162 annual cases of botulism was reported. 

'Botox'

C. botulinum is the bacterium used to produce Botox, a product predominantly injected for clinical and cosmetic use (a purified and heavily diluted botulinum neurotoxin type A).      

Characteristics/Clinical Presentation

Symptoms in adults may include:

• blurred or double vision
• difficulty in speaking, swallowing and breathing
• nausea and vomiting
• dry mouth
• increasing weakness, fatigue and ultimately paralysis

File:Infant botulism2.JPG

Infant with extreme floppiness/weakness

Symptoms in infants may include:

• constipation
• weak, feeble cry
• loss of head control
• loss of appetite (poor sucking and feeding)
• breathing difficulties, choking and gagging
• reduced movement of limbs and increased weakness and floppiness, paralysis

Paralysis of breathing muscles may cause loss of respiratory failure and death unless mechanical ventilation is provided.

Diagnosis

Usually based on clinical history and clinical examination followed by laboratory confirmation including demonstrating the presence of botulinum toxin in serum, stool or food, or a culture of C. botulinum from stool, wound or food.

Misdiagnosis includes: Stroke, Guillain-Barré syndrome, or myasthenia gravis.

Treatment

Administered of antitoxin as soon as possible after a clinical diagnosis, if given early reduces death rates. Severe botulism cases need supportive treatment, especially mechanical ventilation (may be required for weeks or even months). Antibiotics are not required (excepting wound botulism). A botulism vaccine exists but it effectiveness has not been fully evaluated and it has harmful side effects.

Systemic Involvement

Cadiovascular:

• Most cases are accompanied by normal vital signs and blood pressure.
• The normal blood pressure is a result of a vagal blockade as well as extensive peripheral vasodilation which are both caused by the toxin.
• In some cases the individuals will present with hypotension.

Neuromuscular:

• Cranial nerve palsies
• Paralysis starting from proximal to distal
• Progressive disappearance of deep tendon reflexes
• Loss of muscle tone

Gastrointestinal: Constipation almost always occurs in individuals with botulism

Urinary: Individual may have the inability to urinate

Respiratory: Paralysis of diaphragm and accessory breathing muscles possibly leading to respiratory arrest.

Central Nervous System: Infants occassionaly have seizures

Physical Therapy Management

Physical therapists will be a part of the supportive care team that is required for individuals with botulism. Their recovery will be dependent on the administering of the antitoxin as well as the help of the supporting staff to get the individual back to their normal selves. Some interventions are listed below, but the physical therapy management of a patient with botulism could be handled many different ways. 

Breathing Exercises

• Since respiratory failure is the primary cause for death in individuals with botulism it is very important to try to maintain controlled breathing as long as possible.
• Diaphragmatic controlled breathing will be important to try to maintain quality control of the respiratory cycle.
• Pursed lip breathing will be beneficial as well. The goal of this exercise will be to improve gas mixing at rest, decrease the mechanical disadvantage the individual might develop during the progression of botulism, and finally pursed lip breathing can reduce premature collapse of airways.

ROM Exercises: important for the patient to keep their joints moving as much as possible during their time in the hospital. ROM will begin as active until the patient loses function. The exercises will need to be continued passively if the individual has developed paralysis of the extremities.

Strengthening Exercises: Immobilization can do a lot of damage to the muscles of the body and it is the job of the physical therapist to keep the individual working on strengthening those muscles. In a patient with botulism it will be important to try to maintain the function as long as possible. While this is a progressive disease when the antitoxin is not administered, having the patient perform isometric exercises in their hospital bed can only help maintain that control and activation of the muscles.