Makindo Medical Notes

☠️ Botulinum toxins are among the most toxic substances known—lethal at doses as low as 0.001 µg/kg. They block acetylcholine release from presynaptic terminals → causing flaccid paralysis with autonomic dysfunction.

📖 About

• 🤒 Botulism results from exposure to one of eight neurotoxins (A–H).
• Causes paralysis by preventing acetylcholine release at neuromuscular junctions.
• Affects both skeletal and smooth muscles.

🧬 Aetiology

• Caused by exotoxins of Clostridium botulinum (anaerobic, gram-positive, spore-forming).
• 🌍 Found in soil and environmental reservoirs.
• 🧲 Toxin binds irreversibly to presynaptic nerve terminals.
• ✂️ Blocks ACh release by cleaving SNARE proteins involved in neuroexocytosis.

🔄 Methods of Contracting Botulism

• 🥫 Food-borne: ingestion of improperly canned/preserved food.
• 👶 Infant botulism: spores (e.g. honey) colonise immature gut → “floppy baby.”
• 💉 Wound botulism: spores in wounds (common in IV drug users).
• 👩‍⚕️ Adult intestinal botulism: rare, seen with GI surgery/abnormalities.

🩺 Clinical Features

• ⏱️ Onset 2–36h post-exposure.
• ⬇️ Descending weakness: cranial nerves → respiratory → limbs.
• 👀 Bulbar palsy: diplopia, dysarthria, dysphagia.
• ⚡ Autonomic dysfunction: dilated pupils, constipation, diarrhoea, nausea, hypotension.
• 👶 Infants: constipation, lethargy, weak cry → “floppy baby syndrome.”

🩺 Differential Diagnosis

• 🧠 Myasthenia gravis (pupils spared).
• 🦵 Guillain–Barré (with sensory loss).
• ⚡ Lambert–Eaton, diphtheria, Miller–Fisher, shellfish poisoning.
• ☣️ Organophosphate poisoning.

🔎 Investigations

• 🧪 Baseline labs: FBC, U&E, ABG, toxicology.
• 🧫 Detect toxin in stool, blood, food samples.
• ⚡ Nerve conduction: low CMAP amplitude; incremental response with repetitive stimulation.

⚕️ Management

• 💉 Immediate Botulinum antitoxin → mortality ↓ from ~46% → 10% if early.
• 🫁 Intubation/ventilation for respiratory compromise.
• 🏥 ICU supportive care; gastric lavage if recent ingestion.
• 🚽 Enemas (avoid magnesium-based).
• 💊 Antibiotics for wound botulism (penicillin, metronidazole).

📉 Prognosis

• 💀 Type A toxin → most severe course & highest mortality.
• ⏳ Recovery takes weeks–months as new NMJs regenerate.
• 🙂 Most patients ultimately recover fully with supportive therapy.