Diagnosis of Toxicosis in Animals

Diagnosis of a toxicosis, as with any disease, is based on history, clinical signs, lesions, laboratory examinations, and in some cases, analytical procedures. Circumstantial evidence is valuable and should be noted; however, it does not replace a thorough clinical and postmortem examination, when applicable.

Histories from animal owners can stress obvious factors and omit subtle, important details. Reports of “sudden death” in animals may not truly denote peracute death; they may reflect simply that animals were found dead (ie, tardy observation).

Sample submission to a diagnostic laboratory is valuable in many cases of toxicosis in food-producing animals. Sample submission is less common with small animals because, typically, treatment is initiated and the patient recovers before results from a diagnostic laboratory are complete.

Laboratory results are helpful if litigation is being considered or if there is concern for unexpected product contamination or continued exposure to other animals. A complete history is necessary to develop a plan for further investigation and to formulate differential diagnoses.

Pertinent information to consider when assessing an exposure or diagnostic laboratory submissions includes the following:

1. For production animals:

   • number of animals exposed, sick, or dead

   • age, weight, and a chronology of morbidity and mortality rates, when applicable

   • clinical signs and course of the disease

   • prior disease conditions

   • lesions observed at necropsy, with careful examination of ingesta

   • response to treatment (medications should be listed to avoid analytic confusion)

   • related events (pesticide application, feed change, or introduction of medications, feed additives, new water sources, etc)

   • description of facilities (a drawing or photograph can be helpful), access to refuse, machinery, etc

   • recent previous locations and when moved

1. For companion animals:

   • specific substance, strength, form, and amount of the toxic agent

   • route of exposure

   • species and breed of the animal

   • amount of time since the exposure

   • current medical concerns and medications

   • current clinical signs

The diagnostic laboratory should be consulted on questions about the appropriate sample, amount, or container. (Also see Collection and Submission of Laboratory Samples.)