Pentachlorophenol (PCP)

Question 1

What are PCPs used for?

Answer 1

wood preservatives - protection from fungal rot and insects

Question 2

How are animals exposed to PCPs?

Answer 2

licking treated wood, inhalation of toxic amounts from treated walls in sheds or barns
Vapors can also penetrate the skin
Ingestion of contaminated feeds or water

Question 3

Are PCPs water soluble?

Answer 3

not very much - but they are soluble in oils and organic solvents

**the SALT forms are soluble in water

Question 4

What temperatures promote increased vapors from PCPs?

Answer 4

high ambient temp - can increase the concentration of toxic vapors

Question 5

What do older PCP preparations include that is a carcinogenic and teratogenic?

Answer 5

Dioxins

Question 6

What is the acute oral or dermal LD50 of PCPs for domestic animals? What category of toxicity do they belong to?

Answer 6

ranges from 100 - 200mg/kg

Moderately toxic

**Chronic toxicity ranges from 40-70 mg/kg

Question 7

What factors will increase the toxicity of PCPs?

Answer 7

High ambient temperature, oily or organic solvent vehicles, previous exposure, poor condition of animal, newborn, hyperthyroidsim (increased metabolism =increased body temp)

Question 8

Where can/do PCPs get stored in the body?

Answer 8

Adipose tissue

***lipophilic

Question 9

What factors will decrease the toxicity of PCPs?

Answer 9

Cold temp, antithyroid drugs, and the presence of body fat (since it will go to the fat for storage - where it is inactive)

Question 10

How are PCPs absorbed?

Answer 10

Lipophilic = readily absorbed from the GIT, inhalation, thru intact skin

Question 11

Where are PCPs distributed throughout the body

Answer 11

All over - with some accumulation in fat

Question 12

What is the average half life of PCPs in the body?

Answer 12

a day and a half to two days

Question 13

How are PCPs metabolized and excreted?

Answer 13

Conjucation to glucuronic acid –> Glucuronides are excreted in the urine

Cats are deficient

Question 14

Residues of PCPs in tissues and fat are depleted from the body within ____ days of exposure

Answer 14

7 days / 1 week

Question 15

What is the MOA of PCPs?

Answer 15

irritant to resp. tract, mm, and skin

uncouples oxidated phosphorylation and blocks or decreased ATP –> lack of energy = increased oxygen demand in efforts to produce ATP –>

• overheating
• metabolic acidosis
• dehydration

decreased cellular energy = neuro toxic, wt loss, decreased milk production, repro problems

Question 16

What clinical signs are associated with acute PCP toxicosis?

Answer 16

“animal cooks in it’s own heat”

fever, tachycardia, dyspnea, cyanosis, sz, collapse, death

***newborn pigs = hyperthermia, skin irritation, rapid death

Question 17

What clinical signs are associated with chronic PCP toxicosis?

Answer 17

Wt. loss, decreased milk production, anemia, fetal malformations/abortions

Fever and resp. distress may be ABSENT

Question 18

T/F: PCP toxicosis will increase the onset of rigor mortis

Answer 18

TRUE

hyperthermia will increase the onset of rigormortis and that is one of the main clinical signs

Question 19

What lesions will be noted with PCP toxicosis?

Answer 19

Fast onset of rigor mortis
local irritation to MM and skin
degenerative lesions in the liver and kidney
Dark blood = oxygen deprived
Hyperkeratosis of the skin and villous like hyperplasia of urinary bladder in chronic cases (this is pathopneumonic but RARELY seen)

Question 20

What samples can be used for PCP chemical analysis?

Answer 20

blood and urine from a live animal

kidney and skin of a dead animal

Question 21

How is a PCP toxicosis diagnosis made?

Answer 21

History of exposure + signs of rapid overheating and respiratory distress, rapid rigor mortis, dark blood, and chemical analysis

Question 22

What are ddx for PCP poisoning?

Answer 22

Heat stroke (differentiated via hx)

Toxicants causing resp distress:
Nitrate (should have brown blood + no fever)
CO (bright red blood + no fever)
Pesticides (Neuromuscular signs/autonomic signs)
Peracute infections

Question 23

What is the course of tx for PCP poisoning?

Answer 23

General and symptomatic

emetics or G.L. with sodium bicarb
ACTIVATED CHARCOAL or mineral oil
Soap/water detox bath

O2 therapy, IVF, decrease body temp, prophylactic ABs

Question 24

What is the prognosis for animals with PCP toxicosis?

Answer 24

If the animal survives the first 24 hours - chances for a complete recovery are fair