Cholinergic toxidrome
Formal Definition
A clinical toxidrome resulting from exposure to acetylcholinesterase inhibitors or direct cholinergic agonists, causing accumulation of acetylcholine at muscarinic and nicotinic receptors — common causes include organophosphate and carbamate insecticides (intentional or unintentional exposure, including "nerve agents" like sarin, VX in chemical warfare), therapeutic cholinesterase inhibitors (donepezil in Alzheimer's overdose, pyridostigmine), and certain mushrooms (Inocybe species); characterized by the DUMBELS mnemonic (Diarrhea, Urination, Miosis, Bronchorrhea/Bronchospasm/Bradycardia, Emesis, Lacrimation, Salivation/Sweating) for muscarinic effects PLUS nicotinic effects (muscle fasciculations, weakness, paralysis, tachycardia possible from sympathetic outflow), seizures, and altered mental status.
How It's Used on the Ward
"Cholinergic toxidrome" or "SLUDGE syndrome" — the patient is wet from every mucus membrane (tears, salivation, sweating, urination, GI secretions), their pupils are pinpoint (miosis), they're bradycardic and bronchospastic, and they have fasciculations; classic after organophosphate poisoning (pesticide exposure, suicide attempts with insecticides); the antidote is atropine + pralidoxime.
Example
""35-year-old farmer brought to ED after accidental skin exposure to parathion (organophosphate pesticide) while spraying fields. Family reports he suddenly developed drooling, tears, profuse sweating, vomiting, diarrhea, and respiratory distress. Exam: pinpoint pupils, copious secretions, wheezes throughout, bradycardic to 48, BP 88/56 with tonic-clonic seizures. Fasciculations visible in face and extremities. Diagnosis: cholinergic toxidrome from organophosphate. Treatment: atropine 2-4 mg IV bolus repeated q5-15min until secretions dry + pralidoxime 1-2g IV for nicotinic symptoms and to reactivate acetylcholinesterase. Benzodiazepines for seizures. Skin decontamination. ICU admission.""
Clinical Context
Two mnemonic tools: SLUDGE (Salivation, Lacrimation, Urination, Defecation, GI distress, Emesis) — emphasizes visible secretions; DUMBELS (Diarrhea, Urination, Miosis, Bronchorrhea/Bronchospasm/Bradycardia, Emesis, Lacrimation, Salivation/Sweating) — emphasizes clinical effects. Both describe muscarinic effects. Nicotinic effects (often coexist or follow): muscle weakness, fasciculations, paralysis, seizures, tachycardia possible from ganglionic sympathetic outflow. Organophosphates phosphorylate and irreversibly inhibit acetylcholinesterase; aging — the enzyme cannot be reactivated after an hour of binding; pralidoxime (2-PAM) must be given within 24-48 hours and ideally much earlier (before aging complete). Carbamates bind reversibly (aging minimal). Nerve agents (sarin, VX, Novichok): massive exposures, often military/terrorism context; same principles. Treatment hierarchy: (1) Decontamination — remove clothing, wash skin (essential to prevent ongoing exposure to providers), (2) Atropine — blocks muscarinic effects, titrate to drying secretions (often requires huge cumulative doses — tens of milligrams), (3) Pralidoxime — regenerates acetylcholinesterase before aging (works for nicotinic symptoms and limits long-term neuropathy), (4) Benzodiazepines — for seizures, (5) Supportive — intubation for respiratory failure, IV fluids for hypotension.