Attachment C

Acute Radiation Syndrome

A.  **Acute Radiation Syndrome: Dose Less Than 2 Gy (200 rad).**

Nausea and vomiting due to radiation are seldom experienced unless the
exposure has been at least 0.75 to 1 Gy (75-100 rads) of penetrating
gamma or X-rays and it has occurred within a matter of a few hours or
less. The prospective patient who has been asymptomatic within the past
24 hours will most certainly have had less than 0.75 Gy of whole-body
exposure. Hospitalization generally will be unnecessary if the dose has
been less than 2 Gy (200 rads).

-   Management of ARS (dose \<2 Gy):

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-   Close observation and frequent CBC with differential.

-   Outpatient management may be appropriate.

-   Provide instructions regarding home care.

B.  **Acute Radiation Syndrome: Dose Greater Than 2 Gy (200 rad).**

Signs and symptoms become increasingly severe with dose.

-   **Hematopoietic Syndrome.**

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-   The prodromal phase − nausea, vomiting and anorexia within a few
    hours at the higher dose levels, or after 6 to 12 hours at the lower
    dose levels. Lasts 24 to 48 hours, after which time the patient is
    asymptomatic and may feel well. The absolute lymphocyte count will
    fall; a stress response of WBC may be present.

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-   The latent phase − lasts a few days to as long as 2 to 3 weeks at
    the lower dose levels. The patient is asymptomatic but CBCs will
    show characteristic changes in the blood elements, with lymphocyte
    depression and gradual decrease in neutrophil and platelet counts.

-   A bone marrow depression phase requires sophisticated treatment.
    Infection and hemorrhage could occur when white cell and platelet
    counts become critically low.

-   The recovery phase − stem cells in the bone marrow are never
    completely eradicated at 2 to 10 Gy (200 to 1000 rads); some may
    replicate and eventually produce sufficient blood elements.
    Supportive therapy is required.

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-   **Gastrointestinal Syndrome.**

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-   Over 10 Gy (1000 rads) − This syndrome is distinguishable from the
    hematopoietic syndrome by the immediate, prompt and profuse onset of
    nausea, vomiting and diarrhea, followed by a short latent period. GI
    symptoms recur and lead to marked

> dehydration, and vascular effects. The GI mucosa becomes increasingly
> atrophic, and massive amounts of plasma are lost to the intestine.
> Massive denuding of the GI tract and accompanying septicemia and
> dehydration can occur. If the patient survives long enough, depression
> of the hematopoietic system occurs and complicates the clinical
> course.

-   **Cardiovascular Syndrome.**

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-   Over 30 Gy (3000 rads), an extremely high dose, to the whole body.
    Always fatal, there is immediate nausea, vomiting, anorexia and
    prostration, and irreversible hypotension; blood pressure will be
    markedly unstable. Within hours after exposure, the victim will be
    listless, drowsy, tremulous, convulsive, and ataxic. Death most
    likely will occur within a matter of days.

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-   **Management of Acute Radiation Syndrome (Dose \>2 Gy).**

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-   **Initial Management:**

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-   Vomiting − use selective blocking of serotonin 5-HT~3~ receptors or
    use 5-HT~3~ receptor antagonists.

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-   Consider initiating viral prophylaxis.

-   Consider tissue, blood typing.

-   Treat trauma.

-   Consider prompt consultation with hematologist and radiation
    experts, re: dosimetry and prognosis, use of colony stimulating
    factors, stem cell transfusion, and other treatment options.

-   Draw blood for chromosome analysis; use heparinized tube.

-   Note areas of erythema and record on body chart. If possible, take
    photographs.

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-   **Begin, as indicated:**

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-   SUPPORTIVE CARE in a CLEAN environment (reverse isolation).

-   Prevention and treatment of infections.

-   Stimulation of hematopoiesis (use of growth factors, i.e., GCSF,
    GMCSF, interleukin 11).

-   Stem cell transfusions: cord blood, peripheral blood, or bone
    marrow. Platelet transfusions if bleeding occurs or if platelet
    count too low. Psychological support. Observe carefully for erythema
    (document locations), hair loss, skin injury, mucositis, parotitis,
    weight loss, and/or FEVER.

-   Consultation with experts in radiation accident management is
    encouraged.

![](media/image1.png)

**Figure 1.** Classical Andrews lymphocyte depletion curves and
accompanying clinical severity ranges. According to the data presented
in this paper, curve 1--4 correspond roughly to the following whole-body
doses:

> curve 1--3 1 Gy
>
> curve 2--4 4 Gy
>
> curve 3--5 6 Gy
>
> curve 4 7.1 Gy

From Goans, Ronald E., Holloway, Elizabeth C., Berger, Mary Ellen, and
Ricks, Robert C. \"Early Dose Assessment Following Severe Radiation
Accidents,\" *Health Physics* 72(4): 1997.