toxi 6.1

What causes Ciguatera poisoning?

Toxins produced by dinoflagellates that accumulate in reef fish.

Other dinoflagellates associated with Ciguatera poisoning?

A:

Ostreopsis

Amphidinium

Prorocentrum

Common fish vectors for Ciguatera poisoning.

Barracuda

Grouper

Mackerel

Parrotfish

Goatfish

Snapper

Triggerfish

Wrasse

Jacks and scads

Surgeonfish

Squirrelfish

Needlefish

Moray eel

Mullet fish

What type of fish are most commonly associated with Ciguatera poisoning?

Large reef fish (>2 kg).

Most potent toxin in Ciguatera poisoning.

Ciguatoxin

Mechanism of action of ciguatoxin.

Keeps voltage-gated sodium channels open in nerve endings and voluntary muscles.

Effects of ciguatoxin on muscles.

Muscle weakness

Myalgia

Toxin causing increased intracellular calcium leading to hypotension and shock.

Maitotoxin

Toxin associated with delayed disequilibrium and ataxia (5–10 days).

Scaritoxin

Toxin whose effects are additive with ciguatoxin.

Okadaic Toxin

Toxin causing severe tonic-clonic muscle contractions.

Polytoxin

Characteristics of Ciguatera toxins.

Odorless

Colorless

Tasteless

Heat stable

Acid stable

Which toxin is water-soluble and may be removed by washing?

Maitotoxin

Incubation period of Ciguatera poisoning.

2–12 hours

Classic neurologic symptom of Ciguatera poisoning.

Hot–cold sensory reversal

Gastrointestinal symptoms of Ciguatera poisoning.

Diarrhea

Abdominal cramps

Gastroenteritis

Neurologic symptoms of Ciguatera poisoning.

Paresthesia

Dysphagia

Odontalgia

Athetosis

Ataxia

Cholinergic symptoms seen in Ciguatera poisoning.

Hypersalivation

Diaphoresis

Lacrimation

Tremors

Seizures

Cardiovascular effects of Ciguatera poisoning

Bradycardia

Hypotension

Is there a specific laboratory test for Ciguatera toxin in humans?

No

Where should suspected fish samples be sent for toxin analysis in the Philippines?

A:

University of the Philippines Marine Science Institute

Bureau of Fisheries and Aquatic Resources

Drug used to treat neurologic symptoms in Ciguatera poisoning.

20% Mannitol

Mannitol dose for Ciguatera poisoning.

1 g/kg IV over 30 minutes

Drug used to treat seizures in Ciguatera poisoning.

Diazepam

Drug used for cholinergic excess.

Atropine

Drug used for persistent paresthesias.

Amitriptyline 25 mg BID

Treatment for deranged prothrombin time in Ciguatera poisoning.

Vitamin K

Substances to avoid after Ciguatera poisoning

Alcohol

Nuts

Shellfish

Fish

Mayonnaise

Barbiturates

Opiates

Solvents

Herbicides

Insecticides

Chronic symptoms of Ciguatera poisoning.

Pruritus

Weakness

Hiccups

Hypertension

Paresthesia

Main toxin responsible for pufferfish poisoning.

A: Tetrodotoxin

Mechanism of tetrodotoxin.

Blocks sodium channels → prevents nerve conduction

Minimum lethal dose of tetrodotoxin.

8 mcg/kg

Liver

Gonads

Skin

Tetrodotoxin mostly present in:

Cause of death in tetrodotoxin poisoning.

Respiratory paralysis

GI symptoms of tetrodotoxin poisoning.

Nausea

Vomiting

Diarrhea

Abdominal pain

Neurologic symptoms of tetrodotoxin poisoning.

Paresthesia

Dysphagia

Dysphonia

Ascending paralysis

Severe neurologic syndrome in tetrodotoxin poisoning.

Locked-in syndrome

Drug for bradycardia in tetrodotoxin poisoning

Atropine

Drugs for muscle weakness in tetrodotoxin poisoning.

Edrophonium 10 mg IV

Neostigmine 0.5 mg IV

Treatment for respiratory paralysis in tetrodotoxin poisoning.

Mechanical ventilation

Another name for histamine fish poisoning.

Scombroid poisoning

Cause of histamine fish poisoning.

Bacterial breakdown of histidine → histamine.

Bacteria responsible for histamine formation in fish.

E. coli

Proteus

Klebsiella

Enzyme responsible for converting histidine to histamine.

Histidine decarboxylase

Histamine fish poisoning incubation period.

Minutes after ingestion

Dermatologic symptoms of histamine fish poisoning.

Diffuse erythema

Pruritus

Urticaria

Angioedema

Cardiovascular symptoms of histamine fish poisoning.

Palpitations

Weak pulse

Supraventricular arrhythmias

First-line drugs for histamine fish poisoning.

H1 and H2 antihistamines

Additional treatments for histamine fish poisoning.

Bronchodilators

IV fluids

Vasopressors

Mushroom responsible for deadly hepatotoxic poisoning.

A: Amanita phalloides

Syndrome caused by Amanita phalloides.

Delayed gastroenteritis → hepatorenal syndrome

Mushroom toxin causing hyperactivity and delirium.

Amanita Muscaria:

ibotenic acid and muscimol

Hallucinogenic mushroom toxins.

A:

Psilocybin

Psilocin

Does boiling detoxify poisonous mushrooms?

HELL NAH

Does a silver spoon turning black indicate mushroom toxicity?

OH HELL NAH

Toxic compounds in Jatropha seeds.

Ricin

Curcin

Tannic acid

Symptoms of Jatropha poisoning.

Abdominal pain

Vomiting

Hepatic injury

Muscle twitching

Treatment for Jatropha poisoning.

Stabilization

Gut decontamination

Fluid replacement

Toxic compound in dumbcane.

Calcium oxalate crystals (raphides)

Symptoms of dumbcane poisoning

Salivation

Tongue swelling

Mouth irritation

Treatment for dumbcane poisoning.

Demulcents

Cold packs

Analgesics

Scientific name of cassava.

A: Manihot esculenta

Main toxin in cassava.

Linamarin (cyanogenic glycoside)

Antidotes for cyanide poisoning from cassava.

Nitrites

Sodium thiosulfate

Hydroxocobalamin

100% oxygen

Scientific name of Jimsonweed.

Datura stramonium

Active alkaloids in Datura poisoning.

Atropine

Hyoscyamine

Scopolamine

Classic mnemonic for anticholinergic toxicity.

Dry as a bone, blind as a bat, hot as a hare, red as a beet, mad as a hatter.

Treatment for severe anticholinergic poisoning.

Physostigmine

Cyclopentides

Pale Yellow-green to green

Amanita Phaloides

Delayed gastroenteritis

Gyromitrin

Tan, Chocolate brown, red brown

Delayed Gastroenteritis with CNS Abnormalities

Psilocybin and Psilocyn

Whitish to pale yellow

Hallucinations

Muscarine

Found in:

Clitocybe (white to lilac)

Gymnophilus (buff yellow to yellow orange)

Inocybe (brown to dark brown)

Coprine

Disulfam-like reaction

Light gray-brown

Chlorophyllum molybdites

Gastrointestinal irritants

White to buff scales

Tx. Cyclopeptides

• Activated chaecoal

• Fluid Electrolytes

• High dose pen G

Gyromitrin tx.

• Pyridoxine

Muscinol tx.

• Benzodiazepines

Muscarine tx.

• Atropine

Coprine tx.

• IV fluids

• Electrolytes

Psilocybin tx.

Benzodiazepines

Belladonna Alkaloids

• Charcoal, Physostigmine

Datura tx.

• Activated charcoal

• IV Benzodiazepines

• Physostigmine