dr. lau fei-lung director h.k. poison information centre · heat stable saxitoxin in...
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Hong Kong Poison Information Centre
Chemical Food Poisoning
Dr. LAU Fei-lungDirector
H.K. Poison Information Centre
Hong Kong Poison Information Centre
Food Poisoning
Acute illness with gastrointestinal or neurological manifestations affecting two ormore persons who have shared a meal duringprevious 72 hours
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Food Borne Illness
Hepatits AMad cow disease DEHP related liver cancer?
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Etiology of food poisoning
Infective
Chemical (food borne toxin)– Simple chemical– Biotoxin
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Acute toxic effects Food poisoning Mainly on G.I.T , neurological system
Chronic toxic effects Long term /cumulative effectsBlood, kidney, nerve, skeletal systemCarcinogenicity/teratogenicity
Dioxins, Aflatoxin, Mercury
Food borne toxins
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Food borne toxins
1) Natural occuringCiguatoxin Amatoxin
2) Natural contaminationMercuryDioxin in seafood
3) Artificially addedClenbuterol (pork)TetramineMelamine
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Man-make chemical food poisoning
Criminal poisoning – Rat poison : tetramine
Adulteration – Melamine milk product poisoning
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Tetramine Rodenticide Poisoning
Tetramine (Tetramethylene disulfotetramine) Known as 毒鼠强, 四二四, 三步倒, 聞到死
Extremely toxic rodenticideCause non-stop convulsion
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Tetramine Rodenticide Poisoning
> >100 deaths in hundreds of poisoning outbreaksBanned in China since 1990sPopular : potent and cheap
>3 cases in HK
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Largest food poisoning outbreak In China >47,000 hospitalised >4 death as at Oct 2008High melamine content renal stone Sanlu Milk Product
Melamine Milk Product Poisoning
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Melamine milk product poisoning
Hong Kong:Mass panic in parentsNeed to set up screening clinic & Special assessment centre >50,000 screened 15 stones detected
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Causative Agents of food poisoning Hong Kong (1)
% among all food poisoning outbreaks notified to DH*
Causative Agent2004
(n=821)2005
(n=972)2006
(n=1095)Vibrio parahaemolyticus 45.9% 40.8% 39.5%Staphylococcus aureus 17.2% 13.2% 16.3%Salmonella spp. 11.1% 13.5% 11.4%Norovirus 7.8% 10.5% 16.7%Ciguatoxin 7.8% 4.2% 2.5%
*Source : Department of Health
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Causative Agents of food poisoning Hong Kong (2)
Less common but important causes :No. of notifications*
Causative Agents2004 2005 2006
Paralytic shellfish 2 42 3Mushroom 22 9 11Tetrodotoxin 0 3 2Pesticide 0 2 0Clenbuterol 0 0 0
*Source : Department of Health+ confirmed cases only
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Hong Kong Poison Information Centre
Food Poisoning 2009~2010Total 95 cases
Calcium oxalate
29%
Shellfish
24%
Mushroom
16%
Ciguatera
24%
Puffer fish
2%
Scombroid
5%
Calcium oxalate
Ciguatera
Mushroom
Puffer fish
Scombroid
Shellfish
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Case 1
7 workers 8 hrs after sharing a mealSevere G.E. requiring admissionNotice Jaundice on D3SGOT & bilirubin raised
What can cause such poisoning?
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Clues to causative agents
Symptoms– G.I. Only– also neurological
• Neuropathic • Paralytic
Incubation period– Short – preformed biotoxin/chemical– Long - infection
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Infective food poisoning
Longer incubation periodKilled by adequate cooking
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Chemical (Biotoxin)
Short/No incubation periodMostly heat resistant
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Clues to causative agents (continue)
Type of food– Undercooked seafood (Vibrio parahaemolyticus)– Pig lung (Clenbuterol)– Vegetable (Pesticide)– Coral fish (Ciguatoxin)– Canned food (Botulism)
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GI symptoms beyond 6 hours
Mostly gut infection
Amatoxin mushroom poisoning
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Diagnosis :Amanita vernapoisoning
23/3/05 廣州
七人食用於華南植物園內採摘的“白毒傘“,三人病情嚴重須換血
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GI symptoms beyond 6 hours Mushrooms poisoning
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Amanita Phalloides鵝膏菌又名毒蘑菇、绿帽菌、毒伞
• 記載香港曾有此菌生長,但至今未發現
Delay G.E. &Hepatotoxic mushroom
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白毒鹅膏菌Amanita
verna
Hepatotoxic mushrooms
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Severe GE 6-24 hrs, remission of symptom Fulminant liver & renal damage 2-3daysVigorous fluid replacement Activated charcoal High dose Pen G or silibinin May need liver transplant10-50 % mortality
Amatoxins poisoning
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Toxic mushroom Syndromes
Protoplasmic toxinsDelayed G.E. & liver failureDelayed G.E. & CNS impairmentDelayed G.E. & renal failure
NeurotoxinsCholinergicHallucinationGABAnergic effects
OthersDisulfiram–like reactionG.I. Irritants
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Irritant Mushrooms poisoning
14 patients in 4 yearsAll G.I. SymptomsIn half to 5 hours+/- numbness,sweating, weaknessMushrooms picked in parkSome brought from market
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Mushrooms poisoning
Mushrooms picked in parkMacrolepiota neomastoidea & Lepiota cristata
「冠狀環柄菇」(Lepiota cristata)
「大環柄菇」(Macrolepiota neomastoidea)
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綠褶菌Chlorophyllum molybdites
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Some brought from marketInedible Clitocybe sp. (漏斗菇)confused with edible (豬肚菇)
Mushrooms poisoning
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Case II
20/6/9618 firemen had oral numbness and rasping, burning sensation in throat Immediately after taking some vegetables for lunch in canteen
What is the causative agent?
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G.I. Symptoms within 6 hours
Biotoxin/chemicalPlant irritantBacterial preformed toxinUndercooked green beanGreen potatoIrritant mushroom
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Diagnosis
Oxalate crystal in Alacasia plant
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Irritant Plant :Araceae天南星科
半夏Pinellia spp
萬年青 Dieffenbachia spp海芋 Alocasia macrorrhiza
芋頭Colocasta esculenta (L.) Schott
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Irritant Plant
Contain insoluble Calcium Oxalate CrystalIngestion: irritate oral mucosa , burning pain +/- swellingContact: skin rash & itchiness
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Irritant Plant
Occur in canteen & restaurant during typhoon seasonsContamination withChinese Water Spinach(通菜)
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Bacterial Preformed Toxin
Cooked food contaminated with organismsProduce heat resistant toxinEarly abdominal pain, vomiting & diarrhoea within 6 hrsBacillus cereus: fried rice
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Green Beans四季豆
Under-cooked beanscause many outbreaksin China Haemagglutin destroyed by soaking & cookingOnset 1-3 hoursNausea, vomiting & diarrhoea
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Spouting/green Potatoes
Contain glycoalkaloid – solanine (龍葵碱)Usually low level & non-toxicGreen, sprouting, toxin
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Spouting/green Potatoes
Bitter tasteNot destroyed by cookingOral burning sensation Severe abdominal pain, vomiting+/-Respiratory depressioncerebral edema & haemolysis
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Case III
7 friends share some food in dinner2 hours later 1 die1 developed ventilatory failure requiring intubation5 had weakness
Diagnosis?
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1) Puffer fish2) Ciguatoxin3) Vegetable-borne pesticide4) Shellfishes5) Clenbuterol6) Scombroid
Food poisoning with neurological symptoms
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Diagnosis
Puffer fish poisoning
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Puffer Fish Poisoning
Poisoning common in Japan (fugu)Tetrodotoxin in puffer fishHeat stable potent neurotoxin blocking Na Channel
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Puffer Fish Poisoning
G.I. symptom +/-hypotension ,arrhythmia, Numbness, incoordinationDysphagia, paralysis, resp. failureOnset 10 min. to 4 hrs.
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Ciguatera Poisoning
Heat stable ciguatoxin from Dinoflagellete Big coral fish (snapper, grouper) Increase sodium channel permeability Last for days to monthsG.I. Symptoms 1-6 hrs Numbness of mouth
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Ciguatera Poisoning
Pruritis, muscle and joint painCharacteristic shooting pains in legs & teethdysesthesia (burning pain to cold) Severe cases:
Cranial nerve palsyRespiratory & cardiovascular failure
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Vegetable-borne Pesticide
Methamidophos (organophosphate) in flowering vegetable (choi sum)G.I. symptomsLacrimation/small pupil/ sweating weaknessDose small, none develop paralysisIncubation half to 4 hrs.
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Paralytic Shellfish Poisoning
Heat stable Saxitoxin in dinoflagellates Common in red tide seasonSodium channel blocker in nerve & muscleNumbness + G.I. SymptomsDyspnoea/dysphagia/resp failureIncubation 5 min. to 4 hrs.Duration hours to days
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Clenbuterol
Long acting beta-agonist (half life ~ 30 hours)Induce muscle hypertrophy & reduce fat depositionUsed as animal feedOutbreaks fromtaking Pig lung & pork
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Clenbuterol
Incubation 15 min. to 8 hrs.Most have palpitation, headache, tremor Some dizziness ,weakness, G.I. Symptom, flushing, numbness & weaknessInvestigation: hypokalaemia and hyperglycemiaDiagnosis: food sample or patient’s urineTreatment: β-blocker
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Scombroid
Ingestion of preformed histamine on fish skinEnzymatic decarb of fish fresh histadine by marine bacteriaBurning of mouth/flushing/headache/dizziness+ G.I.Symptoms+ Urticaria, bronchospasmIncubation period 5 min. to 1 hr.Duration few hours
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Management of Chemical food Poisoning
High index of suspicion Diagnosis of specific food poisoning –poison/agent/sourceReporting to CENO( CHP) & FEHD Save sample (residue food/vomitus/stool) for Ix.Epidemiological assessment
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Management of Chemical Food Poisoning
Supportive treatment for most illness– fluid replacement for dehydration– symptomatic treatment for G.l. symptoms– beware in children, fatality cases
monitor respiratory function (PFR) in paralytic type - may need ventilatory support
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Management of Chemical Food Poisoning
Paralytic shellfish,ciguatera, puffer fish, botulism– Consider activated charcoal /gastric lavage if
present early (1-2 hours)Anti-toxin for botulismAntihistamine for scombroidCiguatera: consider mannitol
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Thank you