module 15b Snakes, Ticks, Toads Flashcards
snakes
TYPESred bellied black, tiger, eastern/western brown, taipan, death adder.
SIGNS;lmn ,flaccid paralysis, collapse, lack of gag, may have coagulopathy, myoglobunolysis,haemolysis, bite site swelling (red bellied black)
RED-bellied Black Snake (Pseudechis porphyriacus):
* Haemoglobinuria/haemolysed serum +/- anaemia (this occurs later, often 24 - 48hours after envenomation)
* Swelling and pain at bite site
* Often mildly coagulopathic but can occasionally causes severe coagulopathy
* CK elevation +/-
Eastern Brown Snake (Pseudonaja textilis):
* Weakness to flaccid paralysis
* Can cause severe coagulopathy in dogs but less reliably in cats. Depending on the
region, it can cause severe clinical bleeding.
TXAntivenom
* All patients diagnosed with snake bite should receive the appropriate antivenom as
soon as possible. At AES we stock multivalent antivenom (4000IU Brown and
3000IU Tiger (Total 7000IU)) that can be used for both red bellied black snakes and
eastern brown snake envenomation. Our current recommendations are:
○ Eastern brown snake: 2 x vials tiger/multi brown (7000IU)
○ Red bellied black snake: 1-2 x vial tiger/multi brown (7000IU)
**The recommended amount of antivenom varies between region, due to
variability of clinical signs produced by the same species of snake.
Plus supportive care as appropriate. Fresh frozen plasma controversial but must only be given after adequate dose of antivenene.
TICKS
Tick paralysis is one of the most common diseases of cats and dogs in South East
Queensland. Animals can be affected at any time of year, but particularly during the
spring/summer months. The adult female paralysis tick (Ixodes holocyclus) contains a
variety of toxins (holocyclotoxins) within the salivary glands, which are injected into the
bloodstream of the host during feeding. Affected animals suffer from lower motor neuron
paralysis that results in the variety of clinical signs that we see. Common clinical signs
include weakness, dyspnoea, vomiting/gagging/grunting, changes in bark/meow. Early in
the disease, symptoms can be mild and can mimic other diseases.
For this reason tick paralysis should be a differential diagnosis for any patient presenting
with neuromuscular weakness, altered respiratory character, or vomiting/regurgitation. Rule
out tick paralysis, by repeated tick searches by multiple team members. Concentrate efforts
on the head and neck as ~90% of ticks are found here. If a tick or a tick crater is not found
and tick paralysis is considered likely, a diagnostic tick clip should be performed.
Approximately 10% of patients will have additional ticks.
TX* Tick antiserum (TAS) should be administered immediately following diagnosis.
The dose is controversial, with weak evidence to support any given dose.* At AES we now administer 1ml/kg for dogs up to 20kg, and for cats 1 vial
purified or 5ml TAS. We used to administer 20mls or 1ml/kg for dogs (whichever
is higher) and 10mls for cats over one hour. Patients must be closely monitored as
reactions to the TAS are common and can be life threatening (especially in cats).
* Cats and TAS: Cats have a higher rate of anaphylactic reactions than dogs, which
can be fatal.
* Padula Serums now produces a purified serum for cats with virtually all canine
albumen removed. Anaphylactic reactions were not observed during clinical trials
in cats. This is now the preferred antivenom for treating cats, especially if the
patient has previously received TAS
* TAS Reactions are typically recognised as either-
○ Anaphylactic reactions – most common in cats.
Tachycardia, injected mucous membranes, anxiety, pilo-erection, swelling
of the muzzle, vomiting, diarrhoea and dyspnoea. In the event of an
anaphylactic reaction, stop the TAS infusion immediately. Administer
oxygen therapy, give a 10ml/kg crystalloid fluid bolus (if hypotensive).
Give an adrenaline bolus (0.01mg/kg IV) followed by a CRI at 0.05
mcg/kg/min, titrated to effect. Anaphylactic reactions are often fatal despite
treatment.
○ Bezold-Jarisch reflex – most common in dogs.
Bradycardia, hypotension, weakness, depression, reduced heart sounds.
Treatment involves stopping the TAS immediately, followed by atropine
(0.01-0.04mg/kg IV), supportive care (fluid bolus, oxygen therapy).
Adrenaline can be considered in the event of persistent bradycardia. If the
symptoms resolve, the TAS can be restarted at a slower rate. These
reactions are very rarely fatal.
* Aspiration pneumonia is a common sequela to tick paralysis (especially in dogs)
secondary to megaoesophagus or laryngeal dysfunction.
Plus supportive care, oxygen, fluids, ventilation, anti-nausea, eye care, bladder care etc.
Tick clip is controversial and usually requires ga to do.
USE BRAVECTO to kill any unfound ticks asap. (ideally find all ticks and r/o obviously).
TOADS
Toxins are stored in the parotid gland. Toxicosis occurs when the animal approaches or
chews the toad - oral exposure to the glandular excretions. Although it can be life
threatening, the majority of patients survive, but it does depend on the severity of signs and
how quickly the owner can present to a veterinary clinic.
CLIN SIGNS;
* The clinical signs occur quickly, most occurring within 30-60 minutes.
* Profuse ptyalism and hyperaemic mucous membranes
* Vomiting – acutely
* Neurological effects
o Mydriasis, altered mentation, abnormal gait ➔ progress to extensor rigidity,
opisthotonos, seizures, coma
* Hyperthermia, non-cardiogenic pulmonary oedema
* Arrhythmias - bradycardia, sinus tachycardia, first and second-degree AV block,
ventricular tachycardia, ventricular fibrillation
DIFFERENTIAL DIAGNOSIS
* Hyperthermia, heat stroke
* Hypocalcaemia, hypoglycaemia
* Primary seizure disorder (if coming in and out of seizures, unlikely toad)
* Serotonin syndrome
* Organophosphates or carbamate insecticides
* For ptyalism only – exposure to caustic substances, oral and oesophageal foreign
bodies
TX * On way to clinic – advise owner to start wiping mouth out with wet cloth and start
travel to the emergency service.
o There has been some discussion of hosing ensuring facing the nozzle away
from the throat but there is concern of increased risk of aspiration, so a wet
cloth is safer. This also can ensure owners are starting to travel.
* On arrival.
o If in status epilepticus
▪ Diazepam – rectally initially if can’t place IV then place IV ASAP
* 0.5mg/kg IV
▪ Buccal lavage
▪ Fluid therapy
▪ Anti-emetic – maropitant 1mg/kg IV or metoclopramide 0.5mg/kg
IV
▪ Oxygen therapy
o If neurological
▪ Buccal lavage for 20 minutes
▪ Monitor for further signs
o If hypersalivating – no neurological signs
▪ Buccal lavage for 20minutes
▪ Monitor for further signs
o If asymptomatic
▪ Unlikely to progress further – keep them in a consultation room for at
least 20-30 minutes to ensure no further signs.
* In very severe cases some patients have severe respiratory compromise and require
positive pressure ventilation.
* Treat electrolyte abnormalities that arise (usually secondary to seizures).
* Arrhythmias – do not usually require specific treatment otherwise treat the specific
arrhythmia found.
