Radiation exposure can cause a wide range of diseases, primarily due to the damage ionizing radiation inflicts on cells and tissues. The diseases most commonly linked to radiation exposure include acute radiation syndrome, various cancers, cardiovascular diseases, and specific organ damage such as to the skin and nervous system.
**Acute Radiation Syndrome (ARS)** is one of the most immediate and severe conditions caused by high doses of radiation over a short period. It manifests in several forms depending on the dose and affected tissues:
– **Hematopoietic syndrome** occurs at moderate doses (around 0.7 to 10 Gy). It damages rapidly dividing cells in the bone marrow, leading to a drop in blood cell counts. This results in symptoms like infection, bleeding, and anemia due to the loss of white blood cells, platelets, and red blood cells.
– **Gastrointestinal syndrome** arises at higher doses (6 to 30 Gy). It destroys the intestinal crypt stem cells, causing severe nausea, vomiting, diarrhea, abdominal pain, and dehydration. This syndrome can be fatal due to the breakdown of the intestinal lining and subsequent infections.
– **Neurovascular syndrome** happens at extremely high doses (above 30 Gy). It involves damage to the brain and blood vessels, causing neurological symptoms such as confusion, seizures, loss of consciousness, and rapid death within days due to cerebral edema and circulatory collapse.
In addition to these systemic effects, **cutaneous radiation injury (CRI)** can occur even at lower doses (starting around 2 Gy). This injury affects the skin in stages: initial redness and itching, followed by a latent period, then manifest illness with erythema, swelling, pigmentation changes, and potentially ulceration or necrosis. Long-term effects include skin atrophy, fibrosis, chronic ulcers, and an increased risk of skin cancer.
Beyond acute effects, **radiation exposure significantly increases the risk of various cancers**. The most commonly linked cancers include:
– **Leukemia**, particularly acute myeloid leukemia, due to radiation’s impact on bone marrow cells.
– **Thyroid cancer**, often linked to radioactive iodine exposure, especially in children.
– **Breast cancer**, with increased risk observed in populations exposed to radiation during childhood or adolescence.
– **Lung cancer**, especially in those exposed to radioactive particles or radon gas.
These cancers may develop years or decades after exposure, reflecting the long latency period of radiation-induced carcinogenesis.
Radiation also contributes to **cardiovascular diseases**, particularly when the heart or major blood vessels are exposed during radiation therapy or accidental exposure. Ionizing radiation causes damage to the endothelial cells lining blood vessels, leading to inflammation, fibrosis, and accelerated atherosclerosis. This can result in conditions such as:
– **Radiation-induced carotid artery stenosis**, which narrows the carotid arteries and increases the risk of stroke.
– **Baroreflex failure**, where damage to nerves and vessel walls impairs blood pressure regulation, causing symptoms like labile hypertension, syncope, and headaches.
These vascular complications often appear years after exposure and may remain underdiagnosed.
Other organ-specific diseases linked to radiation include:
– **Pulmonary fibrosis** from radiation to the lungs, causing chronic breathing difficulties.
– **Radiation-induced cataracts** due to damage to the lens of the eye.
– **Thyroid dysfunction**, including hypothyroidism, from radiation exposure to the neck.
– **Neurological damage**, including cognitive decline and neuropathies, especially after high-dose exposure to the central nervous system.
In summary, radiation exposure can cause a spectrum of diseases ranging from acute, life-threatening syndromes affecting the bone marrow, gastrointestinal tract, and nervous system, to long-term risks of cancer and cardiovascular disease. The severity and type of disease depend on the dose, duration, and area of exposure, as well a