Toxic neuromuscular block caused by the presence of a bacterial neurotoxin, the botulinum toxin (formerly called botulinic toxin) or botulin, produced by different species of Gram-positive anaerobic bacteria of the  Clostridium strain, the most frequently involved being Clostridium botulinum. Clostridium baratii and butyricum are rarely involved. Clostridium botulinum spores are ubiquitous (soils, dust, fruits...) and heat-resistant (they are destroyed when  temperature is greater than 120 ° C). 

Human botulism is essentially associated with the type A, B and E (exceptionally with toxins F and G) toxins. Its mechanism of action is the inhibition of the assembling of the fusion complexes of acetylcholine at the level of the presynaptic vesicles. That process blocks the release of acetylcholine at level of the neuromuscular junctions. Symptoms typically affect the cranial nerves, and the digestive tract.

Depending on the mode of acquisition of the disease, different forms are described:

-         foodborne botulism following the proliferation of Clostridium botulinum in ill-prepared canned food; incubation time is 12 to 36 hours; symptoms: diplopia, dysphagia, dysphonia, dryness of the mouth; muscle weakness following sustained / repeated efforts ; sometimes breathing difficulties and hyporeflexia.

-         infant botulism (toxin A or B): caused by the germination of spores in the gut of an infant under 6 months:  it results in constipation, oculomotor paralysis, dilated pupils, poorly reactive face with diplegia, ptosis, generalized hypotonia and difficulty in swallowing and breathing. Cases of associated IADHS (inappropriate antidiuretic hormone secretion) have been reported. In the United States, where this condition is the most common, these symptoms have given to infant botulism the name of floppy baby syndrome ('flaccid baby'). The origin of the contamination of infants is ingestion of sugar products, such as honey or corn syrup. The spores of C. Botulinum are indeed widespread in the environment and are among the few to survive in honey. 

-         botulism following a traumatic wound (contamination) or illicit intravenous drug abuse 

-         adult infectious enteric botulism: similar to infant botulism

-         botulism inhalation: in the context of bioterrorism

A treatment with IV selective human gammaglobulin exists.

Injection of botulinum toxin A (Botox ®, Dysport ®, Myobloc ®) is also therapeuticallty used by local IM injection to:

-         reduce the contracture of some muscles: spasticity of the handicapped, spasmodic torticollis, strabismus, dysphonia, anal fissure etc

-         pathological sweating: palmar hyperhidrosis

-     eliminate facial wrinkles.

In polyhandicapped spastic children, systemic resorption of the dose injected IM can occur in 1-2% of the cases: it can cause transient urinary incontinence or respiratory symptoms. It is therefore recommended not to exceed 16 UI/kg with a maximum of 400 UI per child and per session.

Anesthetic implications: 

1) infection: sensitivity to non-depolarisant neuromuscular blocking agents; risk of hyperkalemia when using succinylcholine (reappearance of  nicotinic fetal receptors outside the motor plates like in situations of denervation). This situation of temporary denervation can result in muscle atrophy and in a variable response to non-depolarisant neuromuscular blocking agents.

2) in the course of local injection of botulinum toxin A: it is best to monitor the curarization at the level of a muscle that has not been infiltrated (for example at the level of the forehead).

References:

•        Oken A, Barnes S, Rock P, Maxwell L. 
  Upper airway obstruction and infant botulism 
  Anesth Analg 1992; 75: 136-8.
•        Paust JC. 
  Respiratory care in acute botulism: a report of four cases. 
  Anesth Analg 1971; 50: 1003-9.
•        Chakravarty EF, Kirsch CM, Jensen WA, Kagawa FT. 
  Cardiac arrest due to succinylcholine-induced hyperkalemia in a patient with wound botulism. 
  J Clin Anesth 2000; 12: 80-2.
•        Godart V, Dan B, Mascart G, Fikri Y, Dierick K, Lepage P. 
  Botulisme infantile après exposition à du miel. 
  Arch Pédiatr 2014 ; 21 :628-31.
•        Frick CG, Richtsfeld M, Sahani ND, Kaneki M, Blobner M, Martyn JAJ. 
  Long-term effects of botulinum toxin on neuromuscular function. 
  Anesthesiology 2007; 106: 1139-46.
•        O’Flaherty SJ, Janakan V, Morrow AM, Scheinberg AM, Waugh M-CA. 
  Adverse events and health status following botulinum toxin type A injections in children with cerebral palsy. 
  Develop Med & Child Neurol 2011; 53: 125-30.
•        Bernardor J, Neveu J, Haas H, Pitelet G, Popoff M-R et al.
  Infant botulism: two case reports and electroneuromyogram.
  Arch Pédiatr 2018; 25: 340-3.

Updated: July 2018