ID - Botulism

Question 1

Causative organism

Answer 1

C. botulinum
Spore forming, gram positive anaeorobic rod shapred bacillus
Found in soil, marine sediments, mammal guts
Produces neurotoxins A-H or which A B and E are important
Rare life threatening neuroparalytic syndrome by a neurotoxin

Question 2

How does it cause effect

Answer 2

Botulinum forms spores, develop toxin producing bacilli.
Toxins target synaptic vesicle receptors in pre-synapse on NMJ
Leads to irreversible failure to release ACh.
Disrupts transmision at NMJ, autnonomic ganglia.
Cranial nerves preferentially affect –> binds to sites of rapid depolarisation

Question 3

Risk factors for bolutism

Answer 3

ivDU
Crush injury
Consumption of contaminated food stuff (honey, fermented)
Abdo bowel injury –> distribution of flora
Cosmetic bolutinum toxin
Soil ingestion
Reptile exposure

Question 4

Types of botulism syndromes

Answer 4

Wound - most common. Toxin in wound or abcess from spores. IVDU and skin pop.
Infant - toxin absorbed from intestines of babies colonised to c.bot
Food bourne - ingestion of contaminated food.
Adult intestinal - rare, adult bowel absorbs toxin
Iatrogenic - therapeutic botulism
Inhalational - biological weapons.

Question 5

Clinical features

Answer 5

Prodrome: n/v/dry mouth abdo distention
Symmetrical descending flaccid paralysis –> neck, shoulders, upper limb, cant hold head
Deep tendon reflexes lost
Sensation INTACT
Cranial nerve palsies –> oculobulbar weakenss. Cornal and gag spared
Autonomic –> urinary retnetion constipation etc
Resp failure

Question 6

DD of botulism

Answer 6

Motor neuropathy:
GBS
MG
Lambert Eaton

Infection
Polio, Diptheria, Paralytic Rabies

Poison
Organophosphate
Tetrodotoxin
Shellfish poisoning

Question 7

Investigation

Answer 7

Cranial nerve abnormalities plus symmetrical descending weakness
Culture - food samples, gastric aspirate, stool (if food bourn/infant)
Mouse bioassay identifies toxin in serum, secretion, stool
Neurophysiology –> normal velocity but redices amplitude
ELISA for botulism in specialist centres

Question 8

Treatment - specific

Answer 8

Specific:Trivalent ABE equine anti-toxin EARLY
Neutralises free toxin
Skin testing before as anaphylaxis is common
Infants/allergy - Human derive botulinum Ig.

Question 9

Treatmetn - supportive

Answer 9

Resp failure - monitor FVC, ETT is <15/kg
Sats, ABGs, Observe bulbar function
Would debridement and send for culture
Ben pen or metronidazole for wound infection
AMINOGLYCOSIDES POTENTITATE THE EFFECTS
food - gastric lavage, enemas and laxative to remove toxin

Question 10

Prognosis and long term outcomes

Answer 10

Mortality 3-5%
Increased over 60
Lethargy, weakness, SOB, MH issues
Prognosis poor: need MV, severe weakness, the elderly