Page 940 - Veterinary Toxicology, Basic and Clinical Principles, 3rd Edition

892 SECTION | XIV Poisonous Plants

VetBooks.ir can act synergistically. The toxic dosage varies with the TABLE 62.1 Diagnosis of Plant Poisoning
species of the plant, the stage of plant growth, the part of
the plant consumed (i.e., leaves, roots, etc.), the type of
soil, and other environmental factors. General approach
History: After stabilization of vital signs, the questions addressed
Plants can be roughly classified depending on which
to the animal owner should be accurate
body system they affect. The pharmacology and toxicol-
ogy of commonly found plants are known. However, even Animal species, breed, sex, age, pregnancy, number of animals/
current size of groups (for herds), weight (loss, gain, stable),
if a plant is suspected of causing an adverse outcome,
condition, vaccination status, mineral supplements, feeding or
without information about similar cases, toxicological pasture changes, and other treatments
analysis of biofluids, or pharmacological or toxicological
Plant identification: Accurate identification of the plant is
effects of the plant, further investigation might prove dif-
needed (genus and species) as well as recognition of the
ficult or impossible. scientific name, common name and the plant parts
Relevant circumstances: breed, sex, age, number, condition,
Plant Identification vaccination status, mineral supplements, feeding or pasture
changes, and other treatment
Plant toxicity occurs consistently at the genus level,
Clinical signs: Number of affected animals, signs, clinical course
although species variation may alter toxicity. and progression of signs (sudden death; acute onset moving to
Consequently, accurate identification of the plant and its less severe; gradual onset becoming more severe), lesions,
toxic compounds, is necessary (genus and species), which mortality, and suspicious odors
often requires recognition of the scientific name and the Postmortem examination: Animal condition and lesions
plant parts by a qualified person. Usually, a family mem-
Laboratory tests: Toxicant isolation, search for toxic plants (in
ber knows the common names of household and garden
the meadow or forage) and search of toxicant in animals (rumen
plants, but the problem is that the same common names and stomach; gastrointestinal tissues and contents). Blood tests
are used for many different plants (e.g., milk plant and to evaluate inflammation, organ function, and evaluate
milk-weed). Some are hazardous to livestock, and other immunological response to infectious agents (complete blood
ornamentals may be hazardous to small animals. Still cell counts and serum element, metabolites and clinical
chemistry analysis, and serological tests). Hay, silage, or
others are edible or innocuous (Fowler, 1981). For this
concentrated feed samples; water, salt, and mineral supplements
reason, therapeutic decisions are sometimes based on (location and use) (samples frozen for analysis)
imprecise common names. Currently, plant toxicology is
Treatment
changing; knowledge of poisonous plant names is impor-
tant to ensure that the same name is universally applied. Decontamination, especially gastrointestinal: emesis, gastric
lavage, activated charcoal, enemas, laxatives/cathartics
Both common names and scientific names are needed for
communication with the public and for scientific Elimination enhancement: Diuresis, urine acidification, urine
exchange. alkalinization
Ornamental plants are not easily identified botani- Antidotes
cally and standard botanical keys are not very helpful. If
the species of an ornamental plant is in question, it
should be taken to a qualified person for identification.
Botany or horticultural herbaria in museums, colleges, or
universities are helpful resources for plant identification
(Forsyth, 1968). environment in which animals are living. However,
many times owners are not aware of potential toxic
plants that are present. Field information can also help in
Diagnosis of Plant Poisoning
the diagnosis, particularly: (1) general conditions of
The following information is usually required for diag- affected animals, unusual behaviors, clinical signs, and
nosis: region, location, time and amount of exposure, lesions; (2) forage availability, plant species composi-
type of plant, part of plant ingested, onset and progres- tion, and evidence of grazing patterns; collection of
sion of symptoms, type of symptoms, and the presence potential problem plants or unidentified plants (dried
of insecticides or herbicides. A formal diagnosis of poi- samples for identification, frozen samples for chemical
soning must be made using a thorough history of the poi- analysis); and (3) physical location, weather conditions
soning incident, clinical signs and laboratory analysis of at the time of the poisoning and their effect on forage
samples (Table 62.1). Clinical signs are of primary and forage availability (Welch et al., 2012).
importance to the clinician. The owner may be able to Many infectious, degenerative, and immunological
provide data on what toxicants may be in the diseases produce clinical signs, biochemical changes, and