Early Radiation Effects on Organ Systems Flashcards
Definition of somatic effects
Biologic damage experienced by living organisms (such as humans) as a result of exposure to ionizing radiation.
Depending on the length of time from the moment of irradiation to the first appearance of symptoms of radiation damage, the effects are classified as either:
Late somatic effect or early somatic effects.
Effects of ionizing radiation that appear within minutes, hours, days, or weeks of high doses; also called acute effects.
Early somatic effects
Data concerning early somatic effects of ionizing radiation derived from:
laboratory animal studies and irradiated human populations.
Non-genetic effects that appear months or years following exposure to ionizing radiation:
Late somatic effects
Somatic and genetic damage factors:
The quantity of ionizing radiation to which the subject is exposed.
The ability of the ionizing radiation to cause ionization of human tissue.
The amount of body area exposed.
The specific body parts exposed.
Ionizing radiation produces the greatest amount of biologic damage in the human body when:
a large dose of densely ionizing radiation (high-LET) is delivered to a large or radiosensitive area of the body.
If the consequences of irradiation include cell killing and are directly related to the dose received, they are termed:
deterministic somatic effects.
These effects have a threshold, a point at which they begin to appear and below which are absent.
deterministic somatic effects.
The amount of deterministic somatic effects depends on:
the absorbed dose.
Depending on the exposure, early deterministic somatic effects appear within:
minutes, hours, days or weeks.
Severity of early deterministic somatic effects is:
dose-related.
High dose early deterministic somatic effects include:
nausea fatigue erythema epilation (loss of hair) blood disorders intestinal disorders fever dry and moist desquamation depressed sperm count temporary or permanent sterility in male and females injury to CNS (extremely high doses)
When the whole body is exposed to a dose of _____, many of the manifestations of early deterministic somatic effects occur in succession and may be related to the cellular effects discussed in previous chapter.
6 Gy(t) (600 rad)
Occurs in humans after whole body reception of large doses of ionizing radiation delivered over a short period of time.
Acute Radiation Syndrome (ARS). (This is a result from something as large as a nuclear disaster…not medical imaging.)
Data about ARS has been obtained from epidemiological studies of:
Atomic bomb survivors of Hiroshima and Nagasaki
Marshall Islands
Nuclear radiation accident victims (‘86 Cherynobyl disaster)
Radiation therapy patients
The clinical signs and symptoms of ARS present themselves in four stages:
The prodromal stage
The latent period
The manifest illness (or acute stage)
Death
The three possibilities of manifest illnesses of ARS include:
Hematologic syndrome
Gastrointestinal syndrome
CNS syndrome
Also called “initial stage.”
Immediate response of ARS.
Means “running before” and refers to the initial stage of the disease.
May last from a few hours to a couple of days.
Severity of symptoms is dose related.
Immediate response of radiation sickness.
Prodromal Stage
Individuals who are exposed to radiation levels greater than ____ usually show prodromal symptoms which include varying degrees of nausea, vomiting and diarrhea and a reduction in the white blood cells of the circulating blood (leukopenia)
1 Gy(t) (100 rad)
The time between the exposure and the onset of prodromal symptoms is an indication of the:
magnitude of the exposure. At higher doses, the duration of the prodromal stage becomes shorter until it may be difficult to separate it from the manifest illness.
The onset of prodromal symptoms shortly after exposure indicates:
a major radiation exposure to the whole body.
Some references refer to the prodromal stage as:
the NVD syndrome (Nausea, Vomiting, Diarrhea)
The latent period is also called:
The period of “well being.”
During the “latent period,” the exposed individual has no:
clinical symptoms or illness from the radiation exposure and appears to have recovered with no ill effects (not so…)
The latent period can extend from a few hours or less (at doses in excess of 50 Gy(t)) to:
weeks (at doses from 1 to 5 Gy(t)). Higher doses result in shorter latent periods.
Manifest illness is also referred to as:
The acute stage.
During the acute stage, what is evident?
the full clinical effects.
The acute stage is a dose related period characterized by what?
Three separate syndromes: Hematologic (hematopoetic) syndrome, Gastrointestinal Syndrome, and CNS Syndrome.
Hematopoietic syndrome occurs when humans receive whole body doses of ionizing radiation ranging from:
1 to 10 Gy(t) (100-1000 rad)
Gastrointestinal syndrome occurs when humans receive whole body doses of ionizing radiation ranging from:
6 to 10 Gy(t) (600-1000 rad)
CNS syndrome occurs when humans receive whole body doses of ionizing radiation of:
over 50 Gy(t) (over 5000 rad)
Prodromal stage of Hematopoietic syndrome starts at ____, lasts ____, and consists mainly of:
2 hours, 2 days, nausea and vomiting.
Describe the latent period of Hematopoietic syndrome:
follows the prodromal stage, can extend as long as 4 weeks and is characterized by a general feeling of wellness. There are no signs of illness, although the number of cells in the circulating blood are declining during this time. Stem cells die during the prodromal and latent periods.
Manifest illness of the hematopoietic syndrome is characterized by:
the reduction of all blood cell counts (pancytopenia). This results in anemia and hemorrhage (due to depression of RBC’s) and serious infections (due to depression of white cells-leukopenia.)
Hematopoietic syndrome: Manifest illness: at the lower limits of the dose range (which is_____), bone marrow cells will:
1 - 2 Gy(t) or 100 - 200 rad, repopulate the marrow to an extent great enough to support life in the majority of individuals.
Many people who suffer from the manifest illness of hematopoietic syndrome will recover how long after irradiation?
3 weeks to 6 months.
A few sensitive individuals may die how long after a whole body exposure to 200 rad? (2Gy(t))
6-8 weeks. As whole body dose increases from 2 to 10 Gy(t) irradiated individuals die sooner.
The primary cause of death in the hematopoietic syndrome is:
destruction of bone marrow, resulting in infection and hemorrhage.
Victims who received doses in excess of 5 Gy(t) at Chernobyl benefited from:
bone marrow transplants.
In humans, the gastrointestinal form of ARS appears at a threshold dose of about _____ and peaks after a dose of ____
6 Gy(t), 10 Gy(t)
Without medical support, persons receiving doses of 6 - 10 Gy(t) may die ______ days following exposure. Even with medical support, the exposed person will live only a few days longer.
3- 10
Prodromal stage of Gastrointestinal syndrome occurs within:
a few hours of post exposure.
Prodromal stage of gastrointestinal syndrome characterized by:
severe nausea and vomiting, which may be accompanied by severe cramps and diarrhea.
The latent period of the gastrointestinal syndrome can last as long as:
5 days.
The manifest illness stage of the gastrointestinal syndrome signs and symptoms
fever fatigue loss of appetite lethargy anemia leukopenia hemorrhage infection electrolyte imbalance emaciation
Death occurs from manifest illness stage of GI syndrome primarily because of:
damage to epithelial cells lining the GI tract.