Acute radiation syndrome

What it is

From: Orphanet

A rare radiation-induced disorder resulting from whole body exposure to large doses of penetrating radiation (>0.7 Gray) within a very short period of time (usually minutes) and characterized by bone marrow syndrome with pancytopenia (mild symptoms of which may occur already at 0.3 Gray), gastrointestinal syndrome resulting in mostly fatal infection, dehydration, and electrolyte imbalance (occurring at doses >10 Gray), and cardiovascular/central nervous system syndrome with watery diarrhea, convulsions, coma, and death within three days of exposure (occurring at doses >50 Gray). The syndrome develops in four clinical stages (prodromal/latent/manifest illness/recovery or death) of variable duration.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Dermal atrophy · Very frequent (99-80%)

Partial or complete wasting (atrophy) of the skin.

Abnormal bleeding · Frequent (79-30%)

An abnormal susceptibility to bleeding, often referred to as a bleeding diathesis. A bleeding diathesis may be related to vascular, platelet and coagulation defects.

Diarrhea · Frequent (79-30%)

Abnormally increased frequency (usually defined as three or more) loose or watery bowel movements a day.

Fever · Frequent (79-30%)

Body temperature elevated above the normal range.

Headache · Frequent (79-30%)

Cephalgia, or pain sensed in various parts of the head, not confined to the area of distribution of any nerve.

Hyperpigmentation of the skin · Frequent (79-30%)

A darkening of the skin related to an increase in melanin production and deposition.

Hypopigmentation of the skin · Frequent (79-30%)

A reduction of skin color related to a decrease in melanin production and deposition.

Lymphopenia · Frequent (79-30%)

A reduced number of lymphocytes in the blood.

Muscle weakness · Frequent (79-30%)

Reduced strength of muscles.

Scaling skin · Frequent (79-30%)

Refers to the loss of the outer layer of the epidermis in large, scale-like flakes.

Telangiectasia · Frequent (79-30%)

Telangiectasias refer to small dilated blood vessels located near the surface of the skin or mucous membranes, measuring between 0.5 and 1 millimeter in diameter. Telangiectasia are located especially on the tongue, lips, palate, fingers, face, conjunctiva, trunk, nail beds, and fingertips.

Thrombocytopenia · Frequent (79-30%)

A reduction in the number of circulating thrombocytes.

Vomiting · Frequent (79-30%)

Forceful ejection of the contents of the stomach through the mouth by means of a series of involuntary spasmic contractions.

Cataract · Occasional (29-5%)

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

Other findings in the same source

From: Orphanet

Additional reported features include Fatigue (Occasional (29-5%)); Granulocytopenia (Occasional (29-5%)); Hyperkeratosis (Occasional (29-5%)); Hypotension (Occasional (29-5%)); Inflammatory abnormality of the skin (Occasional (29-5%)); Loss of consciousness (Occasional (29-5%)); Seizure (Occasional (29-5%)); Skin ulcer (Occasional (29-5%)); Vertigo (Occasional (29-5%)); Interstitial pneumonitis (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

All ages

Inheritance in the source

From: Orphanet

Not applicable

Frequency and the population described

From: Orphanet

Point prevalence: 1-9 / 1 000 000; Europe; Class only.

Which doctor should you see?

The suggested department for discussing Acute radiation syndrome is Emergency Medicine, with a emergency physician as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• What is the immediate problem that needs stabilisation?
• Which results and discharge instructions should the family keep?
• What follow-up and return precautions are needed after emergency treatment?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Acute radiation syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.