Chronic radiation syndrome

Chronic radiation syndrome (CRS), or chronic radiation enteritis,^[1][2] is a constellation of health effects of radiation that occur after months or years of chronic exposure to high amounts of radiation. Chronic radiation syndrome develops with a speed and severity proportional to the radiation dose received (i.e., it is a deterministic effect of exposure to ionizing radiation), unlike radiation-induced cancer. It is distinct from acute radiation syndrome, in that it occurs at dose rates low enough to permit natural repair mechanisms to compete with the radiation damage during the exposure period. Dose rates high enough to cause the acute form (> ~0.1 Gy/h) are fatal long before onset of the chronic form. The lower threshold for chronic radiation syndrome is between 0.7 and 1.5 Gy, at dose rates above 0.1 Gy/yr.^[3] This condition is primarily known from the Kyshtym disaster, where 66 cases were diagnosed. It has received little mention in Western literature;^[3] but see the ICRP’s 2012 Statement.^[4]

In 2013, Alexander V. Akleyev described the chronology of the clinical course of CRS while presenting at ConRad in Munich, Germany. In his presentation, he defined the latent period as being 1–5 years, and the formation coinciding with the period of maximum radiation dose. The recovery period was described as being 3–12 months after exposure ceased. He concluded that "CRS represents a systemic response of the body as a whole to the chronic total body exposure in man."^[5] In 2014, Akleyev's book "Comprehensive analysis of chronic radiation syndrome, covering epidemiology, pathogenesis, pathoanatomy, diagnosis and treatment" was published by Springer.^[6]

Symptoms of chronic radiation syndrome would include, at an early stage, impaired sense of touch and smell and disturbances of the vegetative functions. At a later stage, muscle and skin atrophy and eye cataract follow, with possible fibrous formations on the skin, in case of previous radiation burns. Solid cancer or leukemia due to genetic damage may appear at any time.^[7]

References

1. Theis, V.S.; Sripadam, R.; Ramani, V.; Lal, S. (2010). "Chronic Radiation Enteritis". Clinical Oncology. 22 (1). Elsevier BV: 70–83. doi:10.1016/j.clon.2009.10.003. ISSN 0936-6555. PMID 19897345.
2. "Radiation Enteritis and Proctitis: Practice Essentials, Pathophysiology, Etiology". Medscape Reference. 2019-11-18. Retrieved 2019-12-27.
3. Gusev, Igor A.; Gusʹkova, Angelina Konstantinovna; Mettler, Fred Albert (2001-03-28). Medical Management of Radiation Accidents. CRC Press. pp. 15–29. ISBN 978-0-8493-7004-5. Retrieved 2012-06-11.
4. ICRP (2012). ICRP Statement on Tissue Reactions / Early and Late Effects of Radiation in Normal Tissues and Organs – Threshold Doses for Tissue Reactions in a Radiation Protection Context. Vol. ICRP Publication 118. Ann. ICRP 41(1/2). Compare the published draft (ICRP. "Early and late effects of radiation in normal tissues and organs: threshold doses for tissue reactions and other non-cancer effects of radiation in a radiation protection context" (PDF). Archived from the original (PDF) on 3 November 2014. Retrieved 11 June 2012.) and note dose thresholds.
5. Akleyev, Alexander (2013-05-13). "Chronic Radiation Syndrome (CRS) in residents of the Techa riverside villages" (PDF). Archived from the original (PDF) on 2016-05-31.
6. "Chronic Radiation Syndrome | Alexander V. Akleyev | Springer". www.springer.com. Retrieved 2016-04-30.
7. Grammaticos, Philip; Giannoula, Evantia; Fountos, George P. (2013-02-27). "Acute radiation syndrome and chronic radiation syndrome" (PDF). Hellenic Journal of Nuclear Medicine. 16 (1): 56–9. PMID 23570025. Retrieved 2019-09-09.