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

Lily toxicity in cats

Lilies, that is, species of Lilium (Liliaceae) (true lily) andHemerocallis (Hemerocallidaceae) (day lily), cause renaldamage in cats. All parts of the plant are toxic and asmall amount of plant material can have seriousconsequences if ingested. The mechanism of toxicityremains unknown. Signs develop rapidly withgastrointestinal irritation, followed by polyuria,dehydration and then acute kidney injury. Seizures canoccur in severe cases. Treatment is aimed at reducingabsorption with emesis and/or activated charcoal andenhancing renal perfusion with intravenous fluiddiuresis for at least 48 h. Once acute kidney injury hasoccurred treatment options are limited and referralshould be considered. Prognosis is good in cats wheredecontamination is prompt and treatment has beenstarted before the onset of renal impairment. Cats withacute kidney injury have a more guarded prognosis.

Lilies, that is, species of Lilium (true lily) andHemerocallis (day lily), cause renal failure

in cats. Cats are the only species known todevelop renal damage from lilies and this wasfirst reported in 1992.1 Studies and clinical datahave shown that these plants do not causerenal toxicity in dogs, rats or rabbits.2

It is important to be aware that many plantshave lily in their name, such as lily of the valley(Convallaria majalis), peace lily (Spathiphyllum

species) and calla or arum lily(Zantedeschia aethiopica). Thesehave different toxic effects; onlyLilium (Figure 1) and Hemerocallisspecies (Figure 2) are discussedhere (Table 1).

ExposureMost cases of feline lily exposureoccur in the home, usually fromflowers in a bouquet or a pot plant(although these species are grownoutside as well). Consequently,house cats are more at risk oftoxicity. In a review of cases of lilyexposure in 57 cats in 48households, almost half of the lilieswere a gift to the cat’s owner.3

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Key pointMost cases of lily exposure occurin the home, from flowers ina bouquet or a pot plantand owners are oftenunaware of the danger suchpretty flowers pose to theircats.

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Mechanisms of actionThe toxic principle(s) andmechanism of lily toxicity areunknown,4 but renal damage is dueto necrosis of renal tubular epithelialcells. The basement membraneremains intact,5,6 and prompt,aggressive treatment can result inregeneration of tubular epithelialcells.5 The mechanism of toxicityinvolves two processes; initially thereis damage to renal tubularepithelium resulting in polyuric renalfailure (acute kidney injury) which inturn results in severe dehydration.7

Whatever the toxic agent, eithersomething in the plant or a feline-specific metabolite, it appears to beeliminated within 48 h; thiscontention is supported by theobservation that fluid diuresis for 48h can prevent lethal acute kidneyinjury.8

In a small number of cases

pancreatic degeneration has beenreported and this may be due to adifferent mechanism.9

Toxic doseAll parts of the plant, the pollen,flowers, stem and leaves are toxic.Ingestion of less than one leaf,5 orpart of a flower,7 could cause severepoisoning. There are also reports ofcats developing renal failure afterexposure to only pollen (VeterinaryPoisons Information Service data).

In an experimental study in cats the

Key pointIngestion of less than oneleaf, part of a flower orjust brushing against theplant resulting in pollenexposure can be fatal.

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Scientific name Common name

Hemerocallis species Day lily

Lilium x asiatica Asiatic lily

Lilium x asiatica americana

Lilium candidum Madonna lily

Lilium hydridum Japanese showy lily

Lilium lancifolium(Lilium tigrinum)

Tiger lily

Lilium longiforum Easter lily

Lilium orientalis Stargazer lily; orientallily

Lilium regale Royal lily

Lilium speciosum

Lilium rubrum Rubrum lily

Lilium umbellatum Western or wood lily

Table 1: Lilies that are toxic to cats

Figure 2: Hemerocallis species

Figure 1: Lilium species

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toxic component was found to bewater-soluble, and the aqueousflower extract was more toxic thanthe aqueous leaf extract. A cat givena dose of 3.84 g of extract(equivalent to eight flowers) diedwithin 4 h.9

Clinical signsInitial signs after ingestion of liliesare due to gastrointestinal irritationand usually start within 1–6 h,whereas the later effects are due touraemia.

Clinical signs first observed mayinclude hypersalivation, vomiting,anorexia, weakness, lethargy anddepression. The vomiting usuallyresolves within 12 h, but recurs againat 36–48 h due to uraemia.2

There is polyuria from around 12–30h, followed by dehydration at 18–30h. As acute kidney injury developsowners may note depression,weakness, anorexia and vomiting.10

Physical examination will show signstypical of acute kidney injury such asdehydration, oral ulceration, uraemicbreath, enlarged, painful kidneys andreduced urine production (anuria).10

Seizures can occur in cats withsevere acute kidney injury.9

Laboratory findings The main finding in cats with lilyexposure is severe azotaemia.Biochemical changes with risingurea, creatinine, potassium andphosphorus concentrationsgenerally occur from 18–24 h.8 Thecreatinine may be disproportionablyelevated compared to the urea.10,11

There is tubular necrosis withhaematuria, proteinuria, glycosuria,isosthenuria, squamous andepithelial cells in the urine andnumerous urine casts.

A mild elevation in liver enzymesmay be noted but may be due tosevere anorexia and hepatic stress.7

Pancreatitis has been reported in afew cases.9,12

Prognosis Prognosis is good in cats wheredecontamination is prompt andtreatment has been started beforethe onset of renal impairment. It isgenerally stated that treatmentstarted more than 18 h afteringestion is associated with a pooroutcome,5 however, a recent analysisof 25 cases found that outcome wasgood in cats treated withgastrointestinal decontamination,intravenous fluid diuresis or bothwithin 48 h of ingestion. It is worthnoting however, that in this studymost cats (68%) presented within 6 h and only eight (32%) presentedafter more than 6 h. Of these, five

TipPrompt treatment with gastricdecontamination and fluiddiuresis is associated with agood outcome so any catwith suspected or confirmedexposure should be seen andtreated immediately. Cats treated later andcats with acute kidney injury have a guardedprognosis.

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Acute renal failure should now be termed‘acute kidney injury (AKI)’ to bringveterinary medicine in line with humanmedicine, and to reflect more accuratelythe spectrum of pathology occurring in thekidneys, with only a subset of patients withsevere disease suffering renal failure. TheInternational Renal Interest Society hasuseful information on AKI and chronickidney disease (CKD), the term now usedin place of chronic renal failure. Seehttp://www.iris-kidney.com/ for moreinformation.

Acute kidney injury

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had vomited at home and in twocases it was likely to have occurredwithin 6 h of ingestion.4

In a review of 55 cases of feline lilyexposure with known outcome, 48cats (87%) had either brief clinicalsigns or remained asymptomatic.Three cats (5.5%) had continuingabnormalities in renal parameters, one(1.8%) had aspiration pneumonia andthree cats (5.5%) were euthanasedwith renal failure. In this group of 55cats, six (11%) developed renal signs.3

Cats with acute kidney injury have aguarded prognosis and those withanuria have a grave prognosis.10 Incats given no treatment death canoccur 3–7 days after ingestion oflilies.2,8 In cats that survive chronickidney disease may occur as a long-term consequence of lilynephrotoxicity.10

TreatmentThe aim of treatment is to reduceabsorption and support renalfunction. If exposure to lilies issuspected advice should be soughtfrom the VPIS and a veterinaryspecialist, with prompt referral to aspecialist centre considered.

Decontamination An emetic and/or activated charcoalcan be given if ingestion was recent.If vomiting has already occurred anantiemetic and activated charcoalshould be given. It is important towash the cat thoroughly to removeany residual pollen on the coat, faceor feet.

Monitoring Monitoring of renal function isessential. The hydration statusshould also be monitored bycalculating fluid in and fluid out,which allows appropriateadjustment of the fluid rate asrequired. Placement of a urinarycatheter is important to allowaccurate monitoring of urineoutput. Urine analysis will showevidence of renal tubular injury (eg,renal casts, isothenuria, glucosuria)before the onset of azotaemia,11 andthese changes can be observed asearly as 12 h after ingestion.7,8

Prevention of renal injuryTreatment in cats with lily exposureis aimed at preventing anuria andenhancing renal perfusion. Fluidrates (Figure 3) should be based onpercentage dehydration atpresentation, ongoing losses (viapolyuria and vomiting for example)and adequate to enhance renalperfusion without volume overload.Monitoring blood pressure,bodyweight and urine output isrecommended, with measurementof central venous pressure ideal butoften unavailable. The fluid shouldbe either isotonic saline or apolyionic solution such asHartmann’s solution.10 In all cats,

TipWash exposed catsthoroughly to remove anyresidual pollen on the coat orfeet but monitor temperatureto avoid hypothermia.

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Figure 3: Prompt fluid therapy is the mainstay ofmanagement of lily toxicity but consult with aspecialist for advice

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particularly those with reduced urineproduction or cardiomyopathy,volume overload should be avoidedwith close monitoring (see Fluidtherapy in cats 1 and 2 Feline Focus2015; 1(1): 7–12 and 2015; 1(2): 41–47).Rehydration and restoration of renalperfusion and urine output usuallycorrects metabolic abnormalities,but severe hyperkalaemia should betreated appropriately (dextrose,insulin).10

Management of acute kidney injuryOnce renal damage has occurredtreatment options are limited.Although haemodialysis andperitoneal dialysis have beensuccessful in some cases,6,7,13

availability may be limited. Otherdrugs commonly used in themanagement of acute kidney injury,such as furosemide or mannitol, arenot very effective in cats with lily-induced renal toxicity.7,10 Asmentioned previously, consulting aveterinary specialist for advice ontreatment, or referral is stronglyrecommended.

ConclusionsCats appear to be uniquely sensitiveto lilies (Figure 4) and develop acuterenal injury following exposure.Successful treatment relies onprompt decontamination and fluiddiuresis to maintain renal function.Once renal failure occurs treatmentoptions are limited and there is a risk

of chronic kidney disease. Raisingawareness and prevention aretherefore key to reducing cases oflily-induced renal failure in cats.

References1 Hall JO. Nephrotoxicity of Easter lily (Lilium

longiflorum) when ingested by the cat[abstract]. J Vet Intern Med 1992; 6: 121.

2 Hall JO. Nephrotoxicity of Easter lily (Liliumlongiflorum). In: Panter KE, Wierenga TL andPfister JA (eds). Poisonous plants: globalresearch and solutions. Wallingford: CABIPublishing, 2007 pp 271–278.

3 Slater MR and Gwaltney-Brant S. Exposurecircumstances and outcomes of 48households with 57 cats exposed to toxic lilyspecies. J Am Anim Hosp Assoc 2011; 47:386–390.

4 Bennett AJ and Reineke EL. Outcomefollowing gastrointestinal tractdecontamination and intravenous fluiddiuresis in cats with known lily ingestion: 25cases (2001–2010). J Am Vet Med Assoc 2013;242: 1110–1116.

5 Volmer PA. Easter lily toxicosis in cats. VetMed 1999; 94: 331.

6 Volmer PA. How dangerous are winter andspring holiday plants to pets? Vet Med 2002;97: 879–884.

7 Hall JO. Lilies. In: Peterson ME and Talcott PA(eds). Small animal toxicology, 3rd ed. St Louis,Missouri: Elsevier, 2013, pp 617–620.

8 Fitzgerald KT. Lily toxicity in the cat. TopicsCompan Anim Med 2010; 25: 214–217.

9 Rumbeiha WK, Francis JA, Fitzgerald SD, et al.A comprehensive study of Easter lilypoisoning in cats. J Vet Diag Invest 2004; 16:527–541.

10 Tefft KM. Lily nephrotoxicity in cats. CompContin Educ Pract Vet 2004; 26: 149–157.

11 Malik R. Lily intoxication. Control and TherapySeries 2011; 263: 26–27.

12 Langston CE. Acute renal failure caused by lilyingestion in six cats. J Am Vet Med Assoc2002; 220: 49–52.

13 Berg RIM, Francey T and Segev G. Resolutionof acute kidney injury in a cat after lily (Liliumlancifolium) intoxication. J Vet Intern Med

2007; 21: 857–859.

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Figure 4: Lilies may look attractive, andfeature in many a bouquet, but ingestion canbe fatal

Educate your clients about the risks oflily toxicity in cats. Are they aware ofthe potential for fatal injury followingcontact with lilies? Create a clienteducation handout and download aposter to display in your practice from:http://icatcare.org/cat-campaigns/lily-toxicity

Do your clients know the dangers of lilies?

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