Environmental Medicine Integrating a Missing Element into Medical Education (1995) / Chapter Skim
Currently Skimming:
Case Study 29: Pentachlorophenol Toxicity
Case Study 29: Pentachlorophenol Toxicity
Pages 542-557
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 542... ...
This monograph is one in a series of self-instructional publications designed to increase the primary care provider's knowledge of hazardous substances in the environment and to aid in the evaluation of potentially exposed patients. See page 16 for more information about continuing medical education credits and continuing education units.
|
From page 543... ...
The patient lives in a log cabin that has only natural ventilation and is heated by a wood stove. Physical examination reveals a well-nourished male, sweating profusely and mildly tachypneic.
|
From page 544... ...
To control fungal growth and sap stain, a typical sawmill will apply a solution of the sodium salt to the lumber in a spray box immediately before grading and stacking. Pressure-treating wood to thoroughly impregnate it with PCP results in "penta" wood, a product commonly used to build outdoor structures such as residential fences, decks, and equipment for children's playgrounds.
|
From page 545... ...
Dermal exposure occurs primarily to those in trades or professions that handle wood, such as carpenters, electric utility-line workers, lumber-mill workers, and dock loaders. Sawmill workers are at potential risk due to inhalation- of contaminated wood dust and volatilized PCP when penta wood is cut, especially freshly treated wood.
|
From page 546... ...
Aspirin, which can also uncouple oxidative phosphorylation when absorbed in large amounts, may enhance the risk of toxicity for PCP-exposed persons. Because PCP is highly proteinbound, persons taking medications on a long-term basis that have a high affinity for plasma proteins may be at increased risk of PCPinduced toxicity.
|
From page 547... ...
It is believed that PCP's high degree of binding to proteins may induce conformational changes in enzymes involved in oxidative phosphorylation. Oxidative phosphorylation is the process whereby electrons generated from various sources such as the tricarboxylic acid cycle are transported down the cytochrome system.
|
From page 548... ...
Persons acutely exposed to PCP may experience lethargy, tachypnea, tachycardia, intermittent delirium, seizures, cerebral edema, focal swelling of the myelin sheath, and respiratory distress. Signs indicative of central nervous system toxicity in a 3-year-old girl exposed to PCP via the domestic water supply included intermittent delirium, fever, and convulsions.
|
From page 549... ...
Lowlevel chronic exposures to airborne PCP can cause irritation of the eyes, nose, throat, and lungs. Case reports have been published of hemolytic anemia and aplastic anemia with subsequent acute leukemia or Hodgkin's disease.
|
From page 550... ...
Clinical Evaluation History and Physical Examination O A thorough environmental and occupational history may reveal a possible PCP exposure in cases in which hyperthermia occurs. The history of a person who has possible PCP exposure should include information about other precipitating factors for hyperthermia such as age; clothing; environmental temperature and humidity; medications with anticholinergic effects, such as phenothiazines, antihistamines, and antidepressants; medications that predispose to dehydration, such as diuretics; medications or chemicals that uncouple oxidative phosphorylation, such as salicylates or dinitrophenols; and medications that interfere competitively with protein binding, such as warfarin, phenytoin, furosemide, and ibuprofen.
|
From page 551... ...
Chronic Exposure In addition to nonspecific signs and symptoms, such as fever and malaise, chronic occupational exposure to high levels of PCP vapor, as well as to aerosols, has been associated with conjunctivitis, chronic sinusitis, bronchitis, and reduced glomerular filtration and tubular function. There is evidence of elevated SGOT and SGPT levels in workers after chronic, predominantly dermal, exposure to PCP.
|
From page 552... ...
guideline for PCP in the workplace be 1,000 ,ug/g creatinine. Indirect Biologic Indicators In PCP poisoning, laboratory evaluation should include tests for hepatic and renal dysfunction, electrolyte imbalance, hemolytic anemia, and metabolic acidosis.
|
From page 553... ...
Activated charcoal has been shown to bind most phenolic compounds; repeated dosing may be useful in preventing absorption and in interrupting enterohepatic recirculation. Cholestyramine resin was also used for this purpose in primates, but its effectiveness in humans is unknown.
|
From page 554... ...
In addition, EPA set restrictions on the dioxin levels allowed in pentachlorophenol products. The EPA maximum contaminant level (MCL)
|
From page 555... ...
Pentachlorophenol measurements in bodyfluids of people in log homes end workplaces. Arch Environ Contam Toxicol 1989;18:475-81.
|
From page 556... ...
· Mildly altered mental status · History of depression, currently under treatment · History of hypertension, currently under treatment · Electrolyte abnormalities · Azotemia · Erythematous rash (b) The differential diagnosis for a patient who has high fever, tachypnea, and mildly altered mental status must include acute overwhelming infections such as pneumonia, meningitis, or urinary tract infection.
|
From page 557... ...
However, the action of phenol and PCP in the body is quite different. PCP primarily acts to uncouple oxidative phosphorylation with resultant hyperthermia.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.