Pentachlorophenol Flashcards Preview

Toxicology > Pentachlorophenol > Flashcards

Flashcards in Pentachlorophenol Deck (30)
1

What are fungicides?

Chemicals used to prevent or treat fungal infections in plants

2

T/F: Generally, fungicides have low toxicity to animals if properly used

TRUE

3

Uses of pentachlorophenol (PCP)?

  • Only used by certified applicators as a wood preservative (to protect limber from fungal rot and wood-boring insects)
  • No longer found in wood-preserving solutions or insecticides and herbicides for home/garden use

4

4 sources of PCP toxicosis?

  • Vapors can penetrate intact skin--dermal exposure is the most toxic route of exposure, esp to newborns
  • Inhalation of toxic amounts from treated walls in sheds and barns (even if applied months-years before), esp with poor ventilation
  • Licking wood treated w/ PCP
  • Ingestion of contaminated feeds or water with spills of PCP

5

What is PCP?

Chlorinated hydrocarbon insecticide and fungicide

6

Solubility (salts and solution)?

  • Solution not very soluble in water, but soluble in oils and organic solvents
  • Salts are soluble in water

7

Stability?

PCP is volatile and can give off toxic vapors in toxic conc. esp. in high ambient temp

8

Persistence?

Not persistent in water, sewage, or soil b/c of bac. composition

 

9

Is PCP an irritant?

Yes--to mm, resp tract, and skin

10

What do older preparations contain?

Dioxins--carcinogenic and teratogenic

11

Acute oral (dermal LD50) toxicity?

Chronic toxicity?

  • Acute oral in domestic animals ranges from 100-200 mg/kg
  • Chronic toxicity ranges from 40-70mg/kg

12

Factors increasing toxicity?

  • High ambient temp
  • Oily or organic solvent vehicles
  • Previous exposure
  • Poor condition
  • Newborn
  • Hyperthyroidism

13

Factors decreasing toxicity?

  • Cold temp
  • Antithyroid drugs
  • Presence of body fat

14

Where is PCP readily absorbed from? Where is it distributed?

  • Readily absorbed from GI tract, by inhalation, and from intact skin
  • Distributed throughout the body w/ some accumulation in body fat

15

Half-life?

1.5-2 days in various species

16

What is PCP metabolized by?

Conjugation to glucuronic acid

17

How is PCP excreted?

Excreted as glucuronides or unchanged in urine

18

Residues?

Residues in tissues and fat are depleted from the body w/in 1 week of exposure

19

Mechanism of action?

  • Uncouples oxidative phosphorylation and blocks or decreases ATP
  • Increases oxygen demand in an effort to produce ATP
  • Oxygen demand > oxygen supply
  • Resulting in overheating, metabolic acidosis, and dehydration

20

Effects on the body?

  • Irritation of eye, GI mucosa, resp, and intact skin
  • Decreased cellular energy may cause neurotoxic and other effects (wt. loss, dec. milk prod., repro problems)
  • High exposures may lead to signs of CNS stimulation or seizures

21

Clinical signs of acute toxicosis?

  • Onset and duration may be so fast that no signs are seen
  • Hyperthermia, tachycardia, dyspnea, cyanosis, seizures, collapse, death
  • Newborn pigs show hyperthermia, skin irritation, and rapid death

22

Clinical signs of chronic toxicosis?

  • Wt. loss, dec. milk production, anemia, fetal malformations, and poss. abortions
  • Fever and resp distress may be absent

23

What are the lesions of PCP toxicosis?

  • Rapid rigor mortis
  • Local irritation of skin and mm
  • Pulmonary congestion and edema
  • Degenerative changes in liver, kidney, and brain
  • Dark blood (oxygen deprivation)
  • Hyperkeratosis of skin and villous like hyperplasia of urinary bladder mucosa in chronic cases

24

Laboratory diagnosis: live vs. dead animal?

  • Live animal--chemical analysis in blood and urine
  • Dead animal--chemical analysis of kidney and skin

25

Diagnosis

  • History of exposure
  • Signs of rapid overheating and resp distress
  • Lesions of rapid rigor mortis and dark blood
  • Chemical analysis

26

DDx

  • Heat stroke (history)
  • Toxicants causing resp insufficiency
    • Nitrate (brown blood, no fever)
    • CO (bright red blood, no fever)
    • Pesticides (marked neuromuscular signs, autonomic signs)
  • Peracute infectious diseases

27

Is there a specific antidote?

Of course not

28

Detoxification?

  • Emetics or gastric levage w/ 5% sodium bicarbonate
  • Activated charcoal or mineral oil
  • Soap and water bath (use gloves)

29

Supportive/symptomatic therapy?

  • Oxygen therapy
  • Lower body temp--apply cold water to skin, ethanol
  • IV fluids (no glucose) and electrolytes for dehydration and metabolic acidosis
  • Prophylactic use of antibiotics and mult vitamins may be used to prevent secondary bac. infections (due to liver, kidney, and intestinal damage)

30

Prognosis?

If animal survives for 24hrs, chances for complete recovery are fair