II. Etiology
- Clostridium botulinum
- Gram Positive rod
- Anaerobic
- Spore forming Bacteria
III. Pathophysiology: Toxin mediated disease
- Botulinum Toxin is heat labile (inactivated at high Temperature)
- Botulinum Toxin has 7 different serotypes
- Botulinum Toxins A, B and E are pathogenic in humans
- Botulinum Toxin is typically cleaved into active heavy chains and light chains
- Heavy chains irreversibly bind Acetylcholine containing Neurons
- Light chains interfere with Acetylcholine exocytosis
- Botulinum Toxin binds to presynaptic nerve terminal
- Neuromuscular terminal
- Cholinergic autonomic site
- Receptor binding is irreversible
- Receptors are replaced however over time
- Affects Neuromuscular Junction only
- Prevents presynaptic Acetylcholine release
- Results in bulbar palsy (CN 9-12), Autonomic Dysfunction and skeletal Muscle Weakness
- Does not cause sensory deficit or pain
- Botulinum Toxin medical uses (Botox)
- Treatment for oculomotor disorders
- Strabismus
- Blepharospasm
- Treatment for Dystonias
- Torticollis
- Hemifacial spasm
- Treatment for oculomotor disorders
IV. Transmission
- Not spread from person to person
- Aerosol spread as warfare Biological Toxin
- Incubation: 1 to 5 days
-
Wound Infection
- Associated with Trauma and IV Drug Abuse (e.g. Heroin use)
- Course differs from Foodborne Illness
- Longer Incubation Period: 4 to 14 days
- Minimal gastrointestinal symptoms
-
Foodborne Illness (ingestion of Bacteria or preformed toxin)
- Incubation: 12-72 hours (median 24 hours)
- Toxin types A and B in the United States
- West of the Mississippi: Type A toxins
- East of the Mississippi: Type B toxins
- Ingested spores (esp. from honey) may also cause Botulism in high risk patients
- Spores germinate in Stomach, grow and produce toxin (incubates over weeks)
- Infants (See Infant Botulism)
- Altered Gastrointestinal Tract (e.g. Gastric Bypass surgery, Proton Pump Inhibitors)
- Improperly preserved pickled or canned foods (e.g. tomatoes)
- In-ground vegetables (potatoes, onions, Garlic)
- Potatoes baked in aluminum foil
- Meat products in Europe (Toxin Type B)
- Vegetable products in China (Toxin Type A)
- Preserved fish (Toxin type E)
- Found in Alaska, Japan, Russia, Scandinavia
V. Symptoms
- Sudden onset symptoms
- Symptoms follow ingestion or exposure by 12-72 hours, or inhalation by 12-80 hours
- No associated fever
- Descending symmetric paralysis
- Early changes: Cranial Nerve palsy occurs first
- Diplopia with Blurred Vision (90%)
- Dysphagia (76%)
- Dysarthria
- Dysphonia (55%)
- Later changes
- Progressive, bilateral descending Flaccid Paralysis
- Generalized Weakness (58%)
- Early changes: Cranial Nerve palsy occurs first
-
Anticholinergic Symptoms
- Dry Mouth
- Decreased tears
- Blurred Vision
- Dizziness
- Urinary Retention
- Abdominal Pain or cramping (ileus)
- Constipation
- Other symptoms
VI. Signs
- Early signs
- Bilateral Cranial Nerve 6 (Abducens Nerve) paralysis
- Ptosis
- Mydriasis with sluggish pupil reaction
- Nystagmus
- Diminished Gag Reflex
- Swollen Tongue
- Later signs
- Symmetrical descending Flaccid Paralysis
- Hyporeflexia
- Incoordination
- Irregular respirations to Respiratory Failure
- Distinguishing features from other causes
- Mentation clear
- Patient is usually afebrile
- Neurologic changes are bilateral, descending and motor (not sensory)
VII. Differential Diagnosis
- See Floppy Infant
- Myasthenia Gravis
- Guillain Barre Syndrome
- Eaton-Lambert Syndrome
- Trichinosis
- Cerebrovascular Accident
- Electrolyte disturbance
- Tick Paralysis or Tick Toxicosis (ascending paralysis)
- Other toxin exposure
- Organophosphate Poisoning
- Atropine Poisoning
- Shellfish Poisoning or puffer fish Poisoning
VIII. Labs
- Precautions
- Labs are sent, but typically delayed, and diagnosis and management is started empirically
- Patient sources
- Test suspected food source for toxin
- Classic testing (historical)
- Lab mice die after ingesting suspected food source
- Illness reversed by type specific antitoxin
- Other testing to consider
- Lumbar Puncture (evaluate differential diagnosis)
IX. Diagnostics
- Negative Inspiratory Force
-
Electromyogram (EMG)
- Protocol
- Initial supramaximal single nerve stimulation
- Repetitive stimulation at 40 to 50 hz
- Differentiates from other neuromuscular conditions
- Single maximal stimulus: Diminished Action Potentials
- Repetitive stimuli: Facilitation of Action Potentials
- Hypermagnesemia may give similar EMG
- Protocol
- Other testing
X. Management: General
- Contact Centers for Disease Control for suspected cases
- Supportive care
-
Ventilator support often required
- Follow Vital Capacity on serial Pulmonary Function Testing
-
Gastric Decontamination if recent ingestion in foodborne Botulism
- Consider even in delayed presentation
- If no ileus, may give Laxatives and enemas
- Surgical Wound Debridement in Wound Botulism
- Indicated even in benign appearing wounds
-
Antibiotic precautions
- Antibiotics are only recommended in Wound Botulism
- First-Line
- Penicillin G 3 million units IV q4 hours
- Alternative (if Penicillin allergic)
- Metronidazole (Flagyl) 500 mg IV every 8 hours
- Avoid Aminoglycosides and Clindamycin
- Antitoxin
- Indicated in both food-borne and Wound Botulism in adults and children over age 1 year
- See below
- Other measures
- Tetanus Toxoid booster
XI. Management: Antitoxin (from CDC)
- May shorten disease course if used early
- Does not reverse paralysis, but stops progression
- Indicated in both food-borne and Wound Botulism in adults and children over age 1 year
- Depreciated Heptavalent equine antitoxin (preferred)
- Available from CDC and from state department
- Covers types A, B, C, D, E, F, G
- Reduced risk of Serum Sickness
- Effective if given prior to or early in symptoms
- Trivalent equine antitoxin (replaced by heptavalent Vaccine)
- Risk of Serum Sickness and Anaphylaxis
- Skin Test for Horse Serum Sensitivity first
- Do not use in Infant Botulism
XII. Prevention
- Avoid honey in infants under 1 year of age
- See Infant Botulism
- DOD Pentavalent toxoid Vaccine
- Covers types A, B, C, D, E
- Dose: 0.5 SC at 0, 2, and 12 weeks, then annually
- Protective Antibody >90% after 1 year
XIII. Prognosis
- Untreated: Mortality 60% from Respiratory Failure
- Treated with intensive support: Mortality <7%
XIV. Resources
- CDC Disease Information
XV. References
- (2019) Sanford Guide, acccessed 6/5/2019
- Bartlett in Goldman (2000) Cecil Medicine, p. 1673-4
- Schechter in Behrman (2000) Nelson Pediatrics, p. 875-8
- Seeyave (2015) Crit Dec Emerg Med 29(5): 13-21
- Shearer in Marx (2002) Rosen's Emergency Med, p. 1525
- Sun and Tomaszewski (2017) Crit Dec Emerg Med 31(6): 24
- Arnon (2001) JAMA 285:1059-70 [PubMed]
- Rathjen (2021) Am Fam Physician 104(4): 376-85 [PubMed]