Cholecalciferol Rodenticide Flashcards Preview

Toxicology Fall17 > Cholecalciferol Rodenticide > Flashcards

Flashcards in Cholecalciferol Rodenticide Deck (27)
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1
Q

What is the most common source of exposure to this type of rodenticide?

A

Accidental exposure

**relay or secondary toxicosis is possible, but not really common with this rodenticide

2
Q

What are other sources of vitamin D that can cause a toxicosis similar to cholecalciferol?

A

Feed additives, multivitamins, poisonous plants, human psoriasis medications

3
Q

What is cholecalciferol?

A

Vitamin D3

it is insoluble in water, soluble in most organic solvents/oil

has no bait shyness

4
Q

What animals are susceptible to cholecalciferol?

A

all animals: Cats>dogs

young animals are more sensitive than adults

nursing animals can be exposed through milk

5
Q

T/F: Cholecalciferol rodenticides cause just a chronic toxicosis

A

FALSE

can be acute or chronic depending on the preparation and dose

6
Q

What is the cholecalciferol toxic dose for canines?

A

0.5 - 20mg/kg

highly toxic

FYI: a 30g pack contains approximately 23mg

7
Q

Where and how is cholecalciferol absorbed?

A

absorbed very well in the GI tract bc it is lipid soluble. Can also have storage in adipose tissue

8
Q

T/F: Cholecalciferol will undergo hepatic recycling

A

TRUE

that means that patients will need to receive multiple doses of toxiban (activated charcoal) to continue adsorbing

9
Q

How is Cholecalciferol transported to the liver? What type of metabolism occurs?

A

Transported via binding to plasma proteins

Metabolized in the liver to 25-hydroxycholecalciferol (CALCIDIOL)

Calcidiol is transported to the kidney and metabolized to 1,25-dihydroxycholecalciferol (CALCITRIOL)

calcitriol is very potent

10
Q

What metabolite of Cholecalciferol has the highest presence in circulation?

A

CalciDiol (metabolized in the liver)

11
Q

Where are the highest concentrations of Cholecalciferol after absorption?

A

plasma, liver, kidneys, and fat

12
Q

How is Cholecalciferol excreted?

A

in bile/feces
can be excreted in milk
can undergo enterohepatic recirculation

13
Q

What factors can increase the toxicity of Cholecalciferol ?

A

renal dz, hyperparathyroidism, high calcium/phos in the diet

14
Q

What is the MOA of Cholecalciferol ?

A

It causes hypercalcemia and hyperphosphatemia

The body will be “tricked” into thinking there is low Ca - and it will increased absorption and decrease excretion

leads to mineralization throughout the body - ***kidneys, lung, cardiac, vascular walls and stomach –> tissue damage, increased renal loss of sodium and potassium

15
Q

What hormone will assist in the transformation of calcidiol to calcitriol?

A

PTH

Calcitriol = active form

16
Q

What will the PTH levels be like in a patient with Cholecalciferol toxicosis?

A

Low

17
Q

When do you see clinical signs associated with Cholecalciferol toxicosis?

A

within 24-36 hours

takes time for hypercalcemia and hyperphosphatemia to cause mineralization

18
Q

If you have a patient with Cholecalciferol toxicosis and they have melena and hematemesis, what is their prognosis?

A

POOR

these are bad prognostic indicators

19
Q

What clinical signs are associated with Cholecalciferol toxicosis?

A

GI: anorexia, vomiting (+/- with blood) abdominal pain, constipation, +/- melena

Renal: PU/PD, hyposthenuria

Cardio: arrhythmias, hypertension

Neur: depression, weakness, muscle twitching, sz, coma and death (within days)

20
Q

What lesions are associated with Cholecalciferol toxicosis?

A

HGE, mineralization of kidney, myocardium, lungs, stomach, major vessels

*can measure 25-hydroxyvitamin D (calcidiol) or calcium levels in kidney and bile

21
Q

What abnormalities will you see on the lab work of a patient with Cholecalciferol toxicosis?

A

Hypercalcemia, hyperphos, elevated calcidiol and calcitriol, decreased PTH

azotemia, proteniuria, glucosuria

22
Q

Is a chemical analysis often done if you suspect Cholecalciferol poisoning?

A

No - it’s very expensive and has a long turn around time

but it is good to have for legal purposed etc

23
Q

Is there a treatment that can correct the mineralization that occurs from Cholecalciferol toxicosis?

A

NO

need to decrease Ca and Phos to prevent further mineralization - but the damage that has been done is not reversible

24
Q

What is the decontamination protocol for Cholecalciferol toxicosis?

A

Emesis (exposure less than 2-6 hrs ago)

Activated charcoal - repeated doses will be necessary

25
Q

What treatments can be done for a patient with Cholecalciferol toxicosis?

A

supportive care - IVF, antiemetics, GI protectants, Oral phosphate binders, furosemide, glucocorticoids, sodium bicarb

Salmon calcitonin?
Bisphosphatonates?

Avoid sunlight and decrease Ca/phos in the diet

26
Q

What is the prognosis of Cholecalciferol toxicosis?

A

Depends on the severity of the dz at presentation

Better if tx is started before hypercalcemia

Severe hypercalcemia with melena and hem. vomit = poor/grave prognosis

27
Q

What are your DDX for Cholecalciferol toxicosis?

A

Things that cause hypercalcemia: Dragon shit

Things that cause PU/PD: diabetes, Cushing’s, Addison’s, renal dz