Acute radiation syndrome hall

1. Acute radiation syndrome

2. • Effect of ionizing radiation on organism
• Hiroshima & Nagasaki
• Chernobyl

3. Early lethal effects
• Considered to be death occurring within a few
weeks
• High intensity exposure to radiation
• Three distinct modes of death
– At very high dose 100Gy
• Cerebrovascular syndrome – death 24-48 hrs
– Intermediate dose 5-12Gy
• Gastrointestinal syndrome – extensive bloody diarrhea
• Death in 9-10days
– Lower dose 2.5 to 5gy
• Hematopoetic syndrome – death weeks to 2 months

5. Early lethal effects
• Stages of ARS
– Prodromal radiation syndrome
– Latent period
– Manifestation of illness
– Recovery or death

6. Prodromal radiation syndrome
• Early symptoms soon after irradiation
• Last for limited period
• May clear up after few days
• Onset of symptoms within 5-10 min of
exposure
• Maximum about 30 min
• Persists for few days

7. • Signs & symptoms
– Gastrointestinal
– Neuromuscular
• GI
– anorexia, nausea, vomiting, diarrhea, intestinal
cramps, salivation, fluid loss, dehydration, weight loss
• NM
– Easy fatiguablity, apathy, sweating, fever, headache,
hypotension

8. • LD 50 symptoms
– Easy fatigability, anorexia, nausea, vomiting
• Supralethal dose
– Diaarhea, fever, hypotension
• Followed by latent period
•

9. • Diagnosis of ARS
– Drop in lymphocyte count after an exposure as
low as 0.5Gy
– Circulating lymphocytes most radiosensitive
– Fall in absolute lymphocyte count
– Chromosomal abberation analysis from
lymphocytes
– Lower limit of dose detected is 0.2Gy

10. Cerebrovascular syndrome
• Total body dose of 100Gy – death in 24-48 hrs
• All systems damaged
• Death occurs before other symptoms have
time to appear
• Severe nausea and vomiting followed by
disorientation, loss of coordination,
respiratory distress diarrhea, seizures, coma,
death

11. • Cause of death is damage to microvasculature
• Increase in fluid content of the brain

12. Gastrointestinal syndrome
• More than 10Gy
• Usually between 3 & 10 days
• Nausea, vomiting, prolonged diarrhea
• Prolonged diarrhea bad sign
• Dehydration, loss of weight, emaciation, death

13. • Depopulation of epithelial lining of GI tract
• GI lining is self renewing tissue
– Stem cell compartment – achilles heel
– Differentiating compartment
– Mature functioning cells
• Radiation of 10Gy sterilizes the dividing cells
• As the surface of villi is sloughed off there are no
replacement
• Villi begin to shorter and shrink
• Completely denuded of villi
• It doesnot occur until about 9-10 days
• Death from denuding of gut occurs

14. Hematopoetic syndrome
• 2.5 Gy to 5 Gy
• Damage to hematopoetic system
• Mitotically active precursor cells are sterilised
• Subsequent supply of RBC, WBC & platelets
diminished
• The time of potential crisis is delayed for some
weeks
– Mature cells begin to die off
– Supply of new cells inadequate to replace

15. • LD50
– Dose that causes mortality rate of 50% population
in a specified period
– The peak incidence of death from hematologic
damage occurs about 30 days after exposure
(upto 60days)
– LD50/60

16. • Symptoms
– Chills, fatigue, petechiae
– Oral ulceration, hairloss
– Infection, fever – granulocyte depression &
impairment in immune mechanism
– Bleeding, Anemia – platelet dysfunction
– Anemia from RBC depression does not occur
– Infection – cause of death

17. • Mean lethal dose
• LD50/60
– 3.25Gy in young healthy individual
– 4Gy in conservative care, modern well equipped
hospital

18. Pulmonary syndrome
• 8 Gy or more
• 130 days after irradiation

19. Cutaneous radiation injury
• Radiation injury to the skin
• Non penetrating β particles & low energy
photons
• Injury becomes apparent in hours
• Threshold local dose of epilation 3Sv & erythema
6Sv
• Itching, tingling, epilation, erythema, edema, dry
desquamation, wet desquamation, ulceration &
necrosis
• Life threatening concomitant infection

20. Symptoms
MILD
(1–2 Gy)
MODERATE
(2–4 Gy)
SEVERE
(4–6 Gy)
SEVERE
(6–8 Gy)
LETHAL
(>8 Gy)
Lymphocytes
(G/L) (days
3–6)
0.8–1.5 0.5–0.8 0.3–0.5 0.1–0.3 0.0–0.1
Granulocytes
(G/L) >2.0 1.5–2.0 1.0–1.5 ≤0.5 ≤0.1
Diarrhea None None Rare
Appears on
days 6–9
Appears on
days 4–5
Epilation None
Moderate,
beginning on
day 15 or later
Moderate or
complete on
days 11–21
Complete
earlier than
day 11
Complete
earlier than
day 10
Latency
period (d)
21–35 18–28 8–18 7 or less None
Medical
response
Hospitalizat
ion
not
necessary
Hospitalization
recommended
Hospitalizati
on
necessary
Hospitalizati
on
Urgently
necessary
Symptomatic
treatment
only

21. Treatment
• Radiation <4-5Gy
– Watch carefully
– Symptomatic treatment
• >5Gy
– p/o death from hematopoetic syndrome
– Isolation & antibiotics to prevent infection
– Control of bleeding

22. • BMT
– To rescue patients exposed to supralethal dose
– Window of dose within which the BMT is useful
– Narrow 8-10Gy
– >10Gy – no use