Diagnosis of Colchicum Autumnale Poisoning Using Colchicine Detection in Urine

Background: Colchicine is used as an antiphlogistic and analgesic drug for gout treatment in human medicine, among others. For horses, colchicine is marked as banned on the FEI prohibited substance list. Ingestion of roughage contaminated with Colchicum autumnale (autumn crocus) can lead to colic, bloody diarrhoea and circulatory disorders and even death. While colchicine in blood has a short half-life of 12-30 min, it is mainly taken up into the tissues and eliminated retarded through faeces and urine. 
Objectives: To develop a method for colchicine detection from urine to aid in diagnosing Colchicum autumnale poisoning. 
Study design: Assay development. 
Methods: Colchicine analysis was performed in 95 excess urine samples sent to a diagnostic veterinary laboratory from horses with no suspicion of colchicine poisoning. For positive controls, 25 urine samples from a farm where horses showed clinical signs after ingesting Colchicum autumnale-contaminated hay were used. 
Methods: Urine samples were precipitated with methanol. LC-MS/MS analysis was carried out on a Water Xevo TQ-XS equipped with electrospray ionisation and a Waters ACQUITY UPLC I-Class. Chromatography was performed using a Waters UPLC BEH C18 column. For compensation of matrix effects Thiocolchicine was used as internal standard. 
Results: 83 of 95 samples with no suspicion of colchicine poisoning had urine colchicine concentrations below the lower limit of detection of the test. The mean colchicine concentration was 1.21 ± 1.00 ng/mL, with a maximum of 8.80 ng/mL. The horses known to have ingested Colchicum autumnale had urine colchicine concentrations between 1.60 and 152.80 ng/mL and a mean of 13.20 ± 32.12 ng/mL. 
Main limitations: Detection of colchicine in urine is possible, but further studies are needed to determine toxic or lethal limits in urine samples and the elimination rate after Colchicum autumnale ingestion. 
Conclusions: Colchicine detection in urine can help to diagnose Colchicum autumnale poisoning. 
Ethical animal research: Research ethics committee oversight not required by this congress: the study was performed on archived material collected previously during clinical procedures. 
Informed consent: Not stated. 
Competing interests: None declared. 
Sources of funding: None.

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