Some accidents may result in high levels of exposure. Should this occur, the physician should be prepared for the resulting biologic effects. In general, the most radiation sensitive cells of the body are those that rapidly turnover. The lymphocyte, a long-lived, but radiosensitive cell responds rapidly to radiation exposure. Within hours of exposure, the lymphocyte count can be seen to decrease in proportion to the level of exposure. This biological dosimeter can be useful in estimating the amount of total body exposure that the patient received. To make use of this fact, a baseline CBC with differential is necessary. Obtaining blood samples every 12 hours for the first three days following exposure will allow for the estimation of exposure. Selecting one of the choices below will display a graph of the hematologic response at that level of exposure and a paragraph of discussion.
Neutrophils and platelets also respond to significant levels of exposure. These cells however take a longer time to respond and generally demonstrate their nadir at about 30 days post exposure. It is at this time when the patient is at higher risk for infection and bleeding. The hematopoeitic syndrome which consists of an increased incidence of bleeding and infection occurs at doses between 150 and 600 Rads.
The gastrointestinal syndrome occurs when the exposure is approximately 500 Rads. Symptoms include nausea, vomiting, diarrhea and fluid loss. There may be significant GI bleeding as well.
The neurological syndrome occurs with levels of exposure at or above 1,500 Rads. The patient presents with early confusion, disorientation, obtundation, coma and eventual death.
Many of the early symptoms of high level exposure such as malaise, nausea and vomiting are also symptoms of the common cold. Indeed, these symptoms can also be induced just by telling the patient that they may experience them. Caution should be observed when obtaining a history from a patient or discussing the incident so as not to inadvertently produce these symptoms.