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|Drug Toxicity - clinical assessment
|Metabolic acidosis
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|Ethylene glycol toxicity
|Ethanol toxicity
|Methanol toxicity
|Ricin toxicity
|Carbon Tetrachloride Toxicity
|Renal Tubular Acidosis
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|Drug Toxicity with Specific Antidotes
Ricin 🧪 is a type 2 ribosome-inactivating protein with a heterodimeric structure (A-chain + B-chain).
The B-chain facilitates cell entry, while the A-chain halts protein synthesis, leading to cell death.
A dose of only ~500 micrograms can be lethal.
ℹ️ About
- Extracted from the castor bean plant (Ricinus communis) 🌱.
- Highly toxic – considered a potential bioterrorism agent (CDC Category B).
- Routes of exposure: inhalation 🫁, ingestion 🍽️, or injection 💉.
- Historically associated with deliberate poisonings (e.g. the "umbrella assassination" in London, 1978).
Aetiology & Pathophysiology
- Type 2 ribosome-inactivating protein (RIP):
- A-chain: Irreversibly inactivates ribosomes → blocks protein synthesis → apoptosis.
- B-chain: Binds cell membranes and internalises the toxin.
- Damages endothelial cells → vascular leak syndrome → oedema, hypovolaemia, multi-organ failure.
- Target organs depend on exposure route (lungs 🫁, gut 🍽️, kidneys/heart 🫀).
🩺 Clinical Features
- Inhalation: 🫁
- 4–8h: fever, cough, chest tightness, dyspnoea.
- Progresses → pulmonary oedema, hypoxia, ARDS → death 36–72h.
- Ingestion: 🍽️
- Within 6h: nausea, vomiting, diarrhoea, abdominal pain.
- Severe dehydration, renal/hepatic failure, shock → death in 3–5 days.
- Injection: 💉
- Pain, swelling at site → rapid systemic collapse, multi-organ failure.
- General: Weakness, hypotension, multi-organ dysfunction.
Differential Diagnoses
- Other causes of ARDS 🫁 (toxic inhalants, chemical burns).
- Acute gastroenteritis or poisoning (if ingested).
- Septic shock or severe systemic infection.
🔎 Investigations
- Bloods: FBC, U&E, LFTs – monitor renal/hepatic injury.
- CXR / CT: Pulmonary oedema, lung injury (if inhaled).
- Urinalysis: Renal impairment.
- Specialised labs: ELISA or PCR for ricin (rare, reference labs only).
- Postmortem: Organ haemorrhage, necrosis, and oedema.
💊 Management
- No antidote available ⚠️.
- Supportive care:
- Airway/ventilatory support for ARDS.
- IV fluids for dehydration/shock.
- Renal replacement if AKI.
- Vasopressors if hypotensive.
- Decontamination:
- Skin/eyes: wash thoroughly with soap/saline 🚿.
- GI: activated charcoal if recent ingestion.
- Experimental: monoclonal antibodies & vaccines are under study, but not yet standard.
Prognosis
- Mortality depends on dose and route.
- Injection & inhalation → very poor prognosis (death in 2–3 days).
- Ingestion → slightly better odds with aggressive support.
References
