Keeping cats safe

Nicola has worked in human and veterinarytoxicology for 25 years and has been with theVeterinary Poisons Information Service (VPIS)since it started. As well as providingemergency advice via telephone she haswritten extensively on veterinary toxicology.In addition to service provision, she isinvolved in training of VPIS staff andveterinary professionals. She is currently thecongress abstract editor for the EuropeanAssociation of Poisons Centres and ClinicalToxicologists (EAPCCT).

Nicola Bates BSc (Brunel), BSc (Open), MSc, MA

Benzalkonium chloride exposure in cats

Benzalkonium chloride is commonly found in householdproducts, particularly disinfectants and some patiocleaners. Cats are typically exposed to these productsafter use, rather than from chewing or knocking overthe container. The signs most commonly reported afterexposure to benzalkonium chloride in cats arehypersalivation or drooling, tongue ulceration,hyperthermia, oral ulceration, inappetence and lethargy.It is important to note that the onset of signs is typicallydelayed and that owners may not immediately associatethe cat’s clinical condition with the use of the producthours previously. A typical initial clinical picture ofbenzalkonium chloride exposure in cats is hyperthermia,hypersalivation and inflammation or ulceration of thetongue. Treatment is supportive and recovery takes, onaverage, 4 days.

Benzalkonium chloride (BAC,alkyldimethylbenzylammonium chloride)

is a quaternary ammonium compound (QAC)which is classified as a cationic detergent.Anionic and non-ionic detergents arecommonly used in cleaning products, butQACs are used extensively as domestic andindustrial disinfectants and rarely as simplecleaning agents.

Mechanisms of actionDetergents are surfactants (surface activeagents) that reduce the surface tension ofwater; they concentrate at oil and waterinterfaces and possess emulsifying properties.The primary adverse effects frombenzalkonium chloride exposure are due to itsirritancy which results in local tissue damage.It has been shown to interact with proteinsand lipids in biological membranes,1 andstudies on the use of benzalkonium chloride ineye drops have shown that it produces animmuno-inflammatory reaction.2

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The Veterinary Poisons InformationService (VPIS) is a 24-h telephoneemergency service providinginformation on the management ofactual and suspected poisoning inanimals. It provides direct support toveterinary professionals worldwide.

See http://vpisglobal.com/ for moreinformation and how to sign yourpractice up to receive this vitalservice.

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Keeping cats safe

Sources and circumstances ofexposureBenzalkonium chloride is found inhousehold antibacterial cleaners anddisinfectants. Other sources includemould removers, hand cleansers andpatio cleaners. It is also a commonpreservative (at a low concentration)in pharmaceutical preparationsincluding ear and eye drops andnasal sprays.

In cats, exposure to benzalkoniumchloride products typically occursby ingestion and/or dermal exposureafter the product has been used,rather than from chewing orknocking over the container.Walking on or licking surfacestreated with a household antisepticor disinfectant is a particular risk forfeline exposure to benzalkoniumchloride,3 and dermal contaminationusually results in subsequentexposure of the tongue and oralmucosa because of the groomingbehaviour in cats. Automatic handcleanser dispensers are battery-operated devices designed todispense cleanser when triggered bya hand in close proximity to thesensor, but a passing cat can alsoact as a trigger and be accidentallyexposed. Most cases ofbenzalkonium chloride exposure incats involve household antibacterialcleaners and disinfectants.3

In Europe, the typicalconcentration of benzalkoniumchloride in household products isbetween 0.2% and 5% (E Colson,McBride, personal communication2014). In humans, the most severeinjury occurs with exposure tosolutions of 10% or more,4 but thisis not the case with cats whodevelop signs after exposure tomuch lower concentrations.Another potential risk is the use ofa product, such as patio cleaner,that has not been diluted inaccordance with themanufacturer’s instructions.

There are often no immediateclinical signs following exposure tobenzalkonium chloride and as aconsequence no action is taken todecontaminate the cat or limitexposure. Owners may be unawarethat their cat has been exposeduntil they develop signs hours later.

Presentation and treatmentClinical signsBenzalkonium chloride exposure ischaracterised by gastrointestinalirritation and tissue damage with

Figure 1: Hypersalivation and inflammation of the tongue12 h after licking a patio treated with a cleaner containingbenzalkonium chloride. (Picture courtesy of Bates andEdwards 2014)3

Key point

Benzalkonium chloride isfound in householdantibacterial cleaners anddisinfectants, mouldremovers and patiocleaners and cats areoften exposed after theproduct has been usedby licking contaminatedfeet and fur.

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associated signs. The most commonsigns in a review of 245 cases ofexposure in cats reported to theVeterinary Poisons InformationService (VPIS) in the UK cats werehypersalivation or drooling, tongueulceration, hyperthermia, oralulceration, inappetence, lethargy,depression, vomiting and anorexia.3

Signs associated with respiratoryirritation (eg, respiratory distress)and dermal irritation (eg,inflammation, burns or dermatitis)may also occur. The mechanism ofhyperthermia is unclear but may bedue to an inflammatory response,stress or pain.

Apart from the recent case seriesthere are few feline cases ofbenzalkonium chloride exposurereported; these involved exposure inlaboratory facilities to concentratedsolutions rather than clinical casesfrom exposure to householdproducts.5,6 Anorexia,hypersalivation, depression,dehydration, stomatitis with mucosalulceration, nasal and oculardischarge and dermal ulcerationwere reported in cats housed in afacility that was cleaned with aproduct containing 20%benzalkonium chloride that had notbeen diluted as specified by themanufacturer (1:400).6 In anotherreport, chemical burns werereported in cats and dogs after useof an undiluted electrical conductant

containing benzalkonium chloride(17%) during routineelectrocardiographic monitoring. Inthis incident three cats developedsevere oral ulceration after lickingthe affected areas of skin and onedeveloped oesophagitis andoesophageal stricture.5

Signs of irritation and ulceration ofthe gastrointestinal tract beyond themouth and pharynx were notreported in the review of VPIS caseswhich mostly involved exposed todomestic products.3 A typical initialclinical picture of benzalkoniumchloride exposure in cats ishyperthermia, hypersalivation andinflammation or ulceration of thetongue. In such cases owners shouldbe asked about recent use ofdisinfectants, patio cleaners andother household products that cancontain benzalkonium chloride.

Figure 1 shows a cat with a typicalpresentation after exposure tobenzalkonium chloride withhypersalivation and inflammation ofthe tongue. Figure 2 shows another

Key point

Injury due tobenzalkonium chloridemay not be apparentuntil some hours afterexposure so ownersmay not associate use of the cleanerwith the cat’s signs.

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Figure 2: Ulcerated blisters of the tongue 2days after exposure to benzalkoniumchloride. (Picture courtesy of Bates andEdwards 2014)3

Keeping cats safe

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Keeping cats safe

cat with progression of signs anddevelopment of ulcerated blisters onthe tongue 2 days after exposure.

Onset of effectsThere may be no early signs ofbenzalkonium chloride exposure andeffects, when they do develop, arenon-specific. This delay inpresentation may exacerbate theeffects as the cats are notdecontaminated promptly and maygroom and lick exposed skin and fur.

In the review of VPIS cases ofbenzalkonium chloride exposure themean onset of signs was reported as6.4 h (median 4.5 h), although therange was very wide (5 mins to 48h). Telephone contact with the VPISdid not occur until a mean 14 hoursafter exposure.3

The first signs to occur, typicallywithin the first 10 hours afterexposure are generally lethargy,inappetence or anorexia andhypersalivation. The mean onset oftongue and/or oral ulceration hasbeen reported as 8.8 and 16.5 h,respectively. Hyperthermia wasreported in approximately a third ofcases and was generally apparent by24 h.3

TreatmentTreatment of benzalkoniumexposure in cats will depend on howlong has elapsed between exposureand presentation.

In cats that present soon afterexposure prompt decontamination isrecommended. Emesis is notrecommended as the product is apotential aspiration hazard andcould increase the risk of respiratorysigns. Also the amount typicallyingested is very small, particularly ifthe cat has been licking a treatedsurface. Activated charcoal is veryunlikely to be of benefit in thesecases and is not recommended.Irrigation of the oral cavity may behelpful with the use of a short-actinganaesthetic to facilitatedecontamination, if required. It isalso important to wash exposedskin, including the feet.

It is more common for cats topresent late and for these animalstreatment is symptomatic andsupportive. Atropine can be givenfor hypersalivation and analgesia isrecommended if they have evidenceof inflammation of the tongueand/or oral mucosa.

Rehydration is often required as catsmay not have been eating ordrinking because of oral discomfortand pain. In the review of 245 cases,only 5.3% of cats were reported tohave been given syringe ornasogastric feeding, despite the highincidence of oral and tongueulceration.3 Steroids andgastroprotectants have also beenused,3 but the efficacy of theseinterventions in benzalkonium

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Key point

Tip

Signs of exposureinclude hyperthermia,hypersalivation andinflammation orulceration of thetongue.

Treatment issupportive; emesisshould be avoided.Attention should befocused on analgesia,nutrition and correctionof dehydration.

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chloride exposure in cats has notbeen evaluated. Antibiotics havealso been commonly used but it isunclear if their use is justified.3

Routine endoscopy is notrecommended as tissue injurybeyond the mouth is not common.3

Oxygen therapy can be given in catswith respiratory signs.

Duration of effects andoutcomeRecovery in cats with benzalkoniumchloride exposure is typicallyprolonged and the majority of catsrequire several days of supportivetreatment. Most cats recover fully. Inthe review of 245 cases the time tofull recovery was reported in 67cases and ranged from 1 to 360 h (15days) with a mean of 100.4 h (4.2days).3

Deaths have been reported in catsexposed to benzalkonium chloride.In the review of 245 cases, threecats (1.2%) died. Details were limitedin two of these cats but in the third,the cat was exposed to a patiocleaner containing 7.5%benzalkonium chloride (presumablydiluted as directed to produce a 1.9%solution) and developed severetongue and laryngeal oedema whichprogressed to obstructive airwaydisease after she sat on the treatedpatio in the rain. Approximately 45.5h after exposure she had a cardiacarrest and died.3

ConclusionsHousehold products containingbenzalkonium chloride are a serioushazard to cats. Although fatal casesare rare, these products causesignificant damage to the oralmucosa. Presentation is typicallydelayed and recovery can takeseveral days.

AcknowledgementsWith thanks to Kate Russell andJulian Hoad for the images.

References1 Patarca R, Rosenzwei JA, Zuniga AA and

Fletcher MA. Benzalkonium salts: effects on Gprotein-mediated processes and surfacemembranes. Crit Rev Oncog 2000; 11: 255–305.

2 Baudouin C, Labbé A, Liang H, et al.Preservatives in eyedrops: the good, the badand the ugly. Prog Retin Eye Res 2010; 29:312–334.

3 Bates N and Edwards N. Benzalkoniumchloride exposure in cats: a retrospectiveanalysis of 245 cases reported to theVeterinary Poisons Information Service (VPIS).Vet Rec 2014; 176: 229.

4 Spiller HA. A case of fatal ingestion of 10%benzalkonium chloride solution. J ForensicToxicol Pharmacol 2014; 3: 1.

5 Bilbrey SA, Dulisch ML and Stallings B.Chemical burns caused by benzalkoniumchloride in eight surgical cases. J Am AnimHosp Assoc 1989; 25: 31–34.

6 Trapani M, Brooks DL and Tillman PC.Quaternary ammonium toxicosis in cats. LabAnim Sci 1982; 32: 520–522.

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Keeping cats safe

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All nurse members are emailed details of how to register for this webinar. Details also appear

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