Glucocorticoids (steroids) are first-line treatment for acute graft-vs-host disease. Acute graft-vs-host disease is the pro-cess of donor T cells attacking host recipient tissues (includ-ing skin), despite ongoing immunosuppressive therapy such as tacrolimus. Adding a steroid (eg, prednisone) can amelio-rate the T-cell response of graft-vs-host disease in most cases of grade II disease. See section in this chapter on Clinical Uses of Immunosuppressive Drugs.
Introduction to Toxicology: Occupational & Environmental
Daniel T. Teitelbaum, MD*
A 6-year-old girl is brought to the emergency department by her parents. She is comatose, tachypneic (25 breaths per minute), and tachycardic (150 bpm), but she appears flushed, and fingertip pulse oximetry is normal (97%) breathing room air. Questioning of her parents reveals that they are homeless and have been living in their car (a small van). The nights have been cold, and they have used a small char-coal burner to keep warm inside the vehicle. What is the most likely diagnosis? What treatment should be instituted immediately? If her mother is pregnant, what additional measures should be taken?
Humans live in a chemical world. They inhale, ingest, and absorb through the skin many of these chemicals. The occupational-environmental toxicologist is primarily concerned with adverse effects in humans resulting from exposure to chemicals encountered at work or in the general environment. In clinical practice, the occupational-environmental toxicologist must identify and treat the adverse health effects of these * The author thanks the late Gabriel L. Plaa, PhD, previous author of this chapter, for his enduring contributions.
exposures. In addition, the trained occupational-environmental toxicologist will be called upon to assess and identify hazards associated with chemicals used in the workplace or introduced into the human environment.
Occupational and environmental toxicology cases present unusually complex problems. Occupational and environmental exposure is rarely limited to a single type of molecule. Most workplace or environmental materials are compounds or mixtures, and the ingredients are often poorly described in the documentation that is available for physician review. Moreover, although regulatory agencies in many countries have requirements for disclosure of hazardous materials and their health impacts, proprietary information exclusions often make it difficult for those who treat occupationally and environmentally poisoned patients to understand the nature and scope of the presenting illness. Because many of these illnesses have long latency periods before they become manifest, it is often a matter of detective work, when patients finally present with disease, to ascertain past exposure and relate it to present clinical effect. Monitoring of exposure concentrations both in the workplace and in the general environment has become more common, but it is far from widespread, and so it is often very difficult to establish the extent of exposure, its duration, and its dose rate when this information is critical to the identification of the toxic disorder and its management.
Occupational toxicology deals with the chemicals found in the workplace. The major emphasis of occupational toxicology is to identify the agents of concern, identify the acute and chronic diseases that they cause, define the conditions under which they may be used safely, and prevent absorption of harmful amounts of these chemicals. The occupational toxicologist will also be called upon to treat the diseases caused by these chemicals if he or she is a physician. Occupational toxicologists may also define and carry out programs for the surveillance of exposed workers and the environment in which they work. They frequently work hand in hand with occupational hygienists, certified safety professionals, and occupational health nurses in their activities.