Curiosity may not kill the cat, but common lilies may prove to be fatal*
Acute renal failure in cats caused by ingestion of parts of the family Lilaceae was first described in 1989 in the USA. Since then an increasing number of reports have emerged that underline the severity and commonness of this intoxication.
It is advisable to consider all Lilium and Hemerocallis species as potentially toxic to cats. Lilium species may be found both outdoors and as houseplants, but cut flowers kept indoors generally pose the greatest risk to cats, perhaps because indoor cats have few other plant choices to munch on!
All vegetative parts of the plant have the potential to cause toxicity in cats, including the pollen, which can fall into the coat and be ingested after grooming.
Although it is well recognised that lily toxicity results in acute renal failure, the chemical moiety responsible and the precise mechanism of toxicity is currently unknown. Pathologically, the principal feature is acute tubular necrosis, which is especially prominent within the proximal tubules of the kidney. Casts, cellular debris and oxalate crystals have all been documented within the tubules. Although the mortality rate is high, there is evidence of the potential for functional recovery of affected renal tubules if supportive care can be provided for sufficient time.
Clinical signs and diagnosis
Initial signs of intoxication develop shortly after ingestion and predominantly reflect gastrointestinal irritation, with vomiting, loss of appetite and depression often observed within a few hours of ingestion. In some affected cats, the severity of vomiting decreases after 12 hours and owners may feel the animal is improving.
More typically, lack of appetite and depression progress. Within 1-3 days of ingestion, acute renal failure develops and the cat displays dehydration, uraemic breath (and sometimes oral ulceration) and enlarged painful kidneys. Urine production is variable at this stage.
Treatment and care of the patient
As the toxic agent and mechanism of toxicity is unknown, no specific antidote is available. If a patient is presented with a known history of lily ingestion, gastrointestinal and/or dermal decontamination is warranted. Once renal failure has developed, treatment is symptomatic and supportive.
Early treatment is the best medicine
The prognosis can be good if the cat is presented immediately following ingestion, and if decontamination can be carried out successfully. However, the prognosis is generally guarded to grave once renal failure has developed, although cases presented earlier in the course of events tend to have a better prognosis.
*The most dangerous lilies are the ones with the loveliest fragrance i.e the Day Lily, Tiger Lily and all Lilum species.
Information taken from the Centre for Veterinary Education