The symptoms of radiation injury depend on whether the whole body was exposed to radiation or just a small part of the body.
Whole-body exposure to high doses of radiation causes acute radiation illness, while exposure to only part of the body causes local radiation injury.
Acute Radiation Illness
People usually get acute radiation illness when they get very high doses of radiation all at once or over a short period.
Doctors put people with acute radiation illness into three groups, or syndromes, based on the affected main organ system.
- Hematopoietic syndrome is a condition that affects the tissues that make blood cells.
- Gastrointestinal syndrome is a problem with the digestive system.
- Cerebrovascular syndrome affects the brain and nervous system.
Most cases of acute radiation sickness go through three stages:
- Early signs include nausea, loss of appetite, vomiting, tiredness, and diarrhea when a very high dose of radiation is given (collectively called the prodrome)
- A time without symptoms (latent stage)
- Depending on how much radiation was exposed, there are different patterns of symptoms (syndromes).
The radiation dose determines which illness develops, its severity, and its rate of advancement.
As the dose increases, symptoms appear earlier, proceed more quickly (for example, from prodromal to organ system syndromes), and become more severe.
For a given level of radiation exposure, the severity and time course of the early symptoms are very constant from person to person.
Thus, doctors can often estimate a person’s radiation exposure depending on the time, nature, and severity of the early symptoms.
However, injuries, burns, or significant anxiety can make this estimation more difficult.
The effects of radiation on the bone marrow, spleen, and lymph nodes—the key sources of blood cell production—cause the hematopoietic syndrome (hematopoiesis). Loss of appetite (anorexia), lethargy, nausea, and vomiting may occur 1 to 6 hours after radiation exposure of 1 to 6 Gy.
These symptoms usually go away after 24 to 48 hours of exposure, and many feel well for a week or longer.
During this symptom-free interval, blood-producing cells in the bone marrow, spleen, and lymph nodes begin to waste away.
They are not replenished, resulting in a significant shortage of white blood cells, followed by platelets and ultimately red blood cells.
A lack of white blood cells might result in serious infections. Platelet deficiency may result in uncontrollable bleeding.
A lack of red blood cells (anemia) produces weariness, weakness, paleness, and difficulty breathing during physical effort.
If people survive, blood cells begin to be made again after 4 to 5 weeks, but they feel weak and exhausted for months and are at a greater risk of cancer.
The gastrointestinal condition is caused by radiation’s effects on the cells lining the digestive tract.
Severe nausea, vomiting, and diarrhea may occur within 1 hour after exposure to 6 Gy or more radiation.
The symptoms might cause severe dehydration, although they usually go away within two days.
People feel OK for the next 4 or 5 days (latent stage), but the cells lining the digestive tract, which ordinarily act as a protective barrier, die and are removed.
After this period, severe diarrhea—often bloody—recurs, resulting in dehydration. Bacteria from the digestive tract can enter the body and cause serious diseases.
People exposed to this level of radiation also develop hematological syndrome, which causes bleeding and infection and raises the chance of mortality.
Death is common after radiation exposure of 6 Gy or higher. However, with sophisticated medical care, approximately half of the victims may live.
When the overall dosage of radiation exceeds 20 to 30 Gy, the cerebrovascular condition develops.
Confusion, nausea, vomiting, bloody diarrhea, tremors, and shock can occur quickly.
The latent phase is either brief or non-existent—blood pressure drops within hours, followed by convulsions and coma.
The cerebrovascular condition is always lethal in a matter of hours to a few days.
Local Radiation Injury
Cancer radiation therapy is one of the most common causes of local radiation damage.
The amount of radiation received, the rate at which it is administered, and the area of the body treated all influence the symptoms.
Nausea, vomiting, and loss of appetite may occur during or shortly after brain or abdomen irradiation.
Large levels of radiation delivered to a specific location of the body frequently cause skin damage.
Hair loss, redness, peeling, sores, and potentially eventual thinning of the skin and dilated blood vessels beneath the skin’s surface are all symptoms of skin changes (spider veins).
Radiation to the mouth and jaw can induce persistent dry mouth, leading to increased dental caries and jawbone deterioration.
Lung inflammation can be caused by radiation exposure (radiation pneumonitis).
Extremely high doses can induce severe scarring (fibrosis) of lung tissue, resulting in debilitating shortness of breath and death.
After intense radiation to the chest, the heart and its protective sac (pericardium) can become inflamed, resulting in symptoms such as chest pain and shortness of breath.
High accumulated doses of radiation to the spinal cord can result in paralysis, incontinence, and loss of sensation.
Extensive radiation to the abdomen (for lymph node, testicular, or ovarian cancer) can cause persistent ulcers, scarring, and intestinal narrowing or perforation, resulting in stomach pain, vomiting, vomiting blood, and dark, tarry stools.
Severe damage can occur even after radiation therapy has been completed.
Kidney function may diminish six months to a year after exceptionally high doses of radiation are administered, resulting in anemia and high blood pressure.
High cumulative doses of radiation to muscles can result in a painful syndrome characterized by muscle wastage (atrophy) and calcium deposits in the irradiated muscle.
Radiation therapy can occasionally result in the formation of a new cancerous (malignant) tumor.
These radiation-induced tumors often develop ten years or more after exposure.
