Page 473 - Clinical Small Animal Internal Medicine

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question. Patients exhibiting symptoms consistent with Decontamination
VetBooks.ir toxicity from the substance should be treated as if they Topical Decontamination
have been poisoned, even if exposure cannot be com-
pletely confirmed. If symptoms of toxicity are not pre-
sent and the possible toxicity is not life‐threatening, then Topical exposure to a toxin most often involves parasiti-
a “wait and see” approach of close monitoring may be all cides such as permethrins or pyrethrins. Patients with
that is needed. If signs of toxicity are not present, but the topical poison exposure should be bathed thoroughly
toxin to which the patient was possibly exposed carries in a mild soap (such as Dawn® liquid dishsoap) as soon
some risk of significant morbidity, then decontamination as safely possible. Minimum protective equipment for
(see “Decontamination” later in this chapter) should be veterinary personnel should include rubber gloves. Eye
considered if appropriate, and close monitoring should protection and a rubber apron may be needed, depending
be recommended. If the possible exposure involves a on the nature of the toxin involved.
toxin conferring serious risk of organ failure and/or
death, then aggressive testing to confirm or rule out Ocular Decontamination
exposure is recommended. Decontamination and treat-
ment should also be instituted, even if toxic exposure Eye injury may occur when ocular surfaces contact a
cannot be definitively confirmed. caustic irritant. The resultant corneal damage can be
minor (only resulting in discomfort) or severe enough to
cause melting corneal ulceration. The pH of the ocular
Certain Exposure to an Unknown Substance irritant strongly influences the severity of corneal injury.

Frequently, small animal veterinarians are presented with Acid compounds injure the corneal epithelium, but alka-
a patient who was observed to lick, ingest or otherwise line compounds are associated with more severe damage
contact an unknown substance. This situation typically and a higher likelihood of anterior chamber changes and
involves ingestion of a plant while outdoors. A good permanent vision impairment. The pH of an ocular
familiarity with the local flora will prove useful to the irritant can be checked by applying litmus paper to the
clinician in this instance. Even if the client has obtained a conjunctival fornix. This may help the clinician prepare
sample of the ingested plant, it may be difficult or impos- the client for the likelihood of severe damage.
sible for the clinician to identify whether or not the plant Regardless of the specific chemical toxin, the degree of
is dangerous. If clinical symptoms are present and con- damage is also related to the duration of exposure, so the
sistent with a poison known to be present in the local eye must be flushed as soon as possible. Continuous
environment, then treatment should proceed as if the flushing of the cornea should continue for at least
poisonous compound in question caused the symptoms. 15 minutes following ocular surface exposure to a toxin;
One commonly encountered situation utilizing this many resources recommend a full 20–30 minutes of
approach is the young, otherwise healthy dog presented flushing. The eye can be flushed using a balanced fluid
for muscle tremors after being exposed to rotten food or such as 0.9% NaCl or lactated Ringer’s solution (LRS). Tap
compost. In this situation, the clinician cannot be com- water is an acceptable flushing solution, but the hypoos-
pletely certain that there has been toxin ingestion, and molality of tap water may contribute to corneal edema
even if ingestion is strongly suspected, the exact toxic formation following toxic injury. Bottles of eye wash solu-
compound is unclear. The patient in this scenario is typi- tion are typically too small (i.e., contain too little volume)
cally assumed to have ingested a tremorgenic mycotoxin. to effectively flush the surface of the eye for 15 minutes
Diagnostic testing of the patient should aim to rule out or longer. The damage caused by severe chemical burns
other causes of muscle tremors (hypocalcemia, hypogly- of the cornea can be reduced by using buffered eye wash
cemia, etc.). Once these other common causes have been solutions such as Diphoterine®, but these solutions are
ruled out, treatment of this patient should involve cen- not available in most veterinary hospitals.
trally acting muscle relaxants such as methocarbamol
and supportive measures such as IV fluids to prevent Gastrointestinal Decontamination
dehydration resulting from increased muscle activity in a
patient who is unable to drink properly. The client should Emesis
be informed that tremorgenic mycotoxin toxicity is Induction of emesis may be indicated whenever a toxin
suspected but cannot be confirmed. If initial diagnostic has been ingested and may still be in the stomach. If
testing reveals no obvious cause of the symptoms, and if ingestion has occurred within the previous 4–6 hours, it
symptoms do not improve over 24–48 hours despite is reasonable to consider inducing emesis. While usually
appropriate treatment for tremorgenic mycotoxin toxicity, a safe procedure, there are potential risks associated
then further diagnostic testing is recommended to search with inducing emesis, including aspiration pneumonia
for a separate cause of the muscle tremors. and esophageal or oropharyngeal injury. In general,