Accidental mothball ingestion

Case presentationToxicology course 2005

By Dr. CK Chan, UCH

History

F/1, good past health. No G6PD deficiency

Found playing with mothballs in wardrobe

Brought to AED ∵ suspected moth ball ingestion

Asymptomatic

Mothball brought by mother

Packing not available

Investigation? Management plan?

AXR taken No radiopaque sub

stance found Taken mothball?

Progress

Patient observed in “O” room for 4 hours.

Remain asymptomatic ?Really taken a mothball Discharged home with advice

Moth ball / moth repellents

Naphthalene Paradichlorobenzene

Historically, camphor ( 樟腦 ) has been used as moth repellents. Due to its toxicity, it is not used as moth repellent any more.

However camphorated oil ( 樟腦油 ) is still widely available as herbal remedy (cough mixture, local analgesic) & essential oil in aromatic therapy

Camphor

Natural contained in bark/leaves of camphor tree

Hydrocarbon (cyclic ketone) Wet oily crystal with pungent aroma. 1 teaspoon of 20% camphorated oil (1g) has

been reported to cause death in infant 1983 FDA ruling: nonprescription camphor

products should not contain >11% camphor

Clinical manifestations Rapid GI absorption with CNS toxicity

∵ highly lipid soluble Route – mainly GI; dermal & mucosal

absorption, inhalation, transplacental transfer have been reported

Hallmark – generalised tonic-clonic convulsion within minutes to 1-2hrs postingestion

Other toxic effects: CNS depression, GI disturbance, psychiatric effects with hallucination / agitation, liver function derrangement (∵metabolized by liver)

Rarely cause death (4 lethal cases in past 15yrs in USA). Cause of death: status epilepticus & respiratory failure.

Management No specific diagnostic test Gastric lavage – not well-studied,

possibly contraindicated ∵ (1) rapid GI absorption; (2) risk of aspiration (hydrocarbon); (3) early onset convulsion

Activated charcoal – indicated, but efficacy never studied

Supportive care Suspected poisoning – medical

clearance after 4-6 hrs observation.

Naphthalene Most common ingredient of mothball in HK

(all mothballs available in supermarket are naphthalene ball)

Hydrocarbon – rapid GI absorption Hallmark – oxidant stress resulting in napht

halene-induced haemolysis & methaemoglobinemia, especially in susceptible persons (e.g.: G6PD deficiency)

Delayed presentation (>2 days)

Oxidant stress α-Naphthol is the liver metabolite of napht

halene which responsible for naphthalene’s haematogic toxicity

Oxidant stress – oxidizing agents that oxidized the ferrous (Fe2+) iron in haemoglobin to ferric (Fe3+) iron, forming the methaemoglobin

Methaemoglobin has no oxygen carrying capacity, and will preciptate in RBC to cause haemolysis.

Why patients with G6PD deficiency are more susceptible to oxidant stress?

Normal RBC is protected from oxidant stress by the glutathione system

In patient with G6PD deficiency, RBC NADPH production reduced, therefore limiting the efficacy of glutathione system

RBC glucose metabolism

Clinical manifestation In practice, naphthalene-induced haemolysis is mo

re common c/w naphthalene-induced methaemoglobinemia

Development of haemolysis / methaemoglobinaemia takes 1-2d become clinically detectable.

Anaemia secondary to haemolysis takes 3-5 days to develop.

Haemolysis: jaundice (unconjugated hyperbilirubinemia), low serum haptoglobin, direct & indirect Coombs test negative, haemoglobinuria, abnormal peripheral blood smear

Methaemoglobinemia: cyanosis, SaO2 85%, Heinz bodies in RBC in peripheral blood smear

Management GI decontamination: only indicated in multiple mo

thballs ingestion or intentional ingestion Syrup of ipeca: possible useful in children, give within 1 hr

postingestion AC 1g/kg WBI should be considered in massive ingestion, or patient

s with haemolysis /methaemoglobinemia + symptoms suggestive of ongoing delayed GI absorption

Managed as outpatient. Follow up 2/7 later to detect symptoms & signs of haemolysis/ methaemoglobinemia.

Treatment: Supportive, rarely need transfusion. Significant methaemolglobinemia should be treated with methylene blue.

Paradichlorobenzene Replaced naphthalene

as the commonest ingredient of cake / hanger type of moth repellant

Relatively safe – toxicity usually limited to GI disturbance

Unintentional ingestion can be managed as outpatients.

Mothball recognition You got a mothball in

hand. Likely naphthalene ??paradichlorobenzen

e Can it be camphor???

The toxic one float! Camphor mothball flo

at in water (specific gravity <1)

Both naphthalene & paradichlorobenzene sink in water (SG>1)

Naphthalene (SG~1.1) is less dense c/w paradichlorobenzene (SG~1.4). Naphthalene will float up in saturated salt water.

Radiopaque mothball is nontoxic Paradichlorobenzene:

densely radiopaque Naphthalene: faintly ra

diopaque Camphor: radiolucent

*make sure the patient has taken a mothball before ordering a AXR!

Differentiation-floating test - X ray

Float in water

Float in sat. salt solution

X - ray

Camphor yes yes Not opaque

Naphthalene no yes Faintly opaque

Paradichlorobenzene

no no Denselyopaque

Survey of moth repellent in supermarket

1. All mothballs are naphthalene balls 2. All cake type moth repellent contai

n paradichlorobenzene 3. Hanger type can be naphthalene / p

aradichlorobenzene / insecticide with potential toxicity!!

Park’n shop白元高級防蟲餅 (Hanger type, $27.5) Paradichlorobenzene白元箂莉太太防蟲掛裝 (Hanger type with aluminium foil, $27.5)

Empenthrin (pyrethroid ester insecticide)o-phenylphenol (?organic solvent)

拜高防蟲掛裝 (Hanger type, $31.9) Transfluthrin (pyrethroid ester insecticide)

絲莎無味防蟲掛裝 (Hanger type, $45.9) EmpenthrinFreside S (insecticide)

象球牌防蟲防潮劑 (Hanger type, $39.9) Paradichlorobenzene象球牌防蟲片 (Hanger type $23.9) Naphthalene

Park’n Moth repellent (Hanger type, $16.9)

Paradichlorobenzene

Park’n moth ball ($7.9) Naphthalene

Welcome Store

雞仔牌高級防蟲餅 (Hanger type, $26.5)

Naphthalene

蘭香水晶腦 (Hanger type, $12.9)

Paradichlorobenzene

No Frills deodorant hanger ($9.8)

Naphthalene

大利牌高級樟腦餅 (cake, $10.9)

Paradichlorobenzene

No Frills moth ball ($4.9)

Naphthalene