The accidental or hostile exposure of individuals to ionizing irradiation is of great public and military concern. Radiation sickness (acute radiation syndrome, or ARS) occurs when the body is exposed to a high dose of penetrating radiation within a short period of time. Systemic infection is one of the serious consequences of ARS. There is a direct relation between the magnitude of radiation exposure and the risk of developing infection. The risk of systemic infection is higher whenever there is a combined injury such as burn or trauma. Ionizing radiation enhances infection by allowing translocation of oral and gastrointestinal flora, and reducing the threshold of sepsis due to endogenous and exogenous microorganisms. The potential for concomitant accidental or terrorism-related exposure to bio-terrorism agents such as anthrax and radiation also exists.

This site is made of a home page that presents new developments and updates on the management of acute radiation syndrome including concomitant exposure to radiation and anthrax. Separate pages are dedicated to the treatment modalities.


Wednesday, March 16, 2011

Nuclear crisis in Japan out of control


Japan's nuclear crisis appeared to be spinning out of control on Wednesday according Reuter News after workers withdrew from a damaged  power plant because of increasing radiation levels and a helicopter could not drop water on the most effected reactor.
In a sign of desperation, the police will try to cool spent nuclear fuel at one of the facility's reactors with water cannon, which is normally used to quell riots.
Early another fire broke out at the earthquake-crippled facility, which has sent low levels of radiation that drifted to Tokyo in the past 24 hours, triggering fear in the capital and international alarm.
Japan's government announced that radiation levels outside the plant were stable but, appealed to private companies to help deliver supplies to tens of thousands of people evacuated from around the complex.
About 140,000 people inside the zone have been told to stay indoors.
Workers were trying to clear debris to build a road so fire trucks could reach reactor No. 4 at the Daiichi complex in Fukushima, 240 km (150 miles) north of Tokyo. Flames were no longer seen at the building housing the reactor.



A man is scanned for nuclear exposure close to the damaged Daiichi reactors


High radiation levels prevented a helicopter from flying to the site to drop water into the No. 3 reactor -- whose roof was damaged by an earlier explosion and where steam was seen rising earlier in the day -- to try to cool its fuel rods.
The plant operator described No. 3 as the "priority." No more information was available, but that reactor is the only one at Daiichi which uses plutonium in its fuel mix.
According to U.S. government research, plutonium is very toxic to humans and once absorbed in the bloodstream can linger for years in bone marrow or liver and can lead to cancer
The situation at No. 4 reactor, where the fire broke out, was "not so good," the plant operator added, while water was being poured into reactors No. 5 and 6, indicating the entire six-reactor facility was now at risk of overheating.
Nuclear experts said the solutions being proposed to quell radiation leaks at the complex were last-ditch efforts to stem what could well be remembered as one of the world's worst industrial disasters.
"This is a slow-moving nightmare," said Dr Thomas Neff, a physicist and uranium-industry analyst at the Massachusetts Institute of Technology.

At the Fukushima plant, authorities have spent days desperately trying to prevent water which is designed to cool the radioactive cores of the reactors from evaporating, which would lead to overheating and possibly a dangerous meltdown.

smoke ascends 

S
Smoke comes out of reactor 3 after an explosion on march 14, 2011

Until the heightened alarm about No.3 reactor, concern had centered on damage to a part of the No.4 reactor building where spent rods were being stored in pools of water, and also to part of the No.2 reactor that helps to cool and trap the majority of cesium, iodine and strontium in its water.
Japanese officials said they were talking to the U.S. military about possible help at the plant.
Concern has mounted that the skeleton crews dealing with the crisis might not be big enough or were exhausted after working for days since the earthquake damaged the facility. Authorities withdrew 750 workers on Tuesday, leaving only 50.
All those remaining were pulled out for almost an hour on Wednesday because radiation levels were too high, but they were later allowed to return.
Nuclear radiation is an especially sensitive issue for Japanese following the country's worst human catastrophe -- the U.S. atomic bombs dropped on Hiroshima and Nagasaki in 1945.

Tuesday, March 15, 2011

Principle of antimicrobial management of infections after accidental or hostile exposure to iradiation

Radiation sickness (acute radiation syndrome, or ARS) occurs when the body is exposed to a high dose of penetrating radiation within a short period of time. The first symptoms of ARS typically are fatigue, hair loss, nausea, vomiting and diarrhea, as well as skin changes such as swelling, redness, itching and radiation burns. Symptoms may present within a few minutes to days after the exposure, and may come and go. This seriously ill stage may last from a few hours up to several months. Systemic infection is one of the complications of ARS.


 Treatment of ARS includes both general supportive care and specific actions and medications. ( Reeves GI. Medical implications of enhanced radiation weapons. Mil Med. 2010 ;175:964 ) The administration of proper antimicrobial therapy is essential for the prevention and treatment of systemic infection from endogenous and exogenous organisms that can occur following exposure to ionizing radiation. ( Brook et al. Management of postirradiation infection: lessons learned from animal models. Mil Med 2004;169:194) The management of these patients includes also the use of specific and non-specific biological response modifiers or immunomodulators. Care must be taken of any conventional injuries, and affected organ systems.



 ARS is usually caused by radiation exposure, not internal contamination. Ionizing radiation suppresses the host defenses and increases it’s susceptibility to local and systemic infection caused by endogenous or exogenous organisms. 
Exposure of rodents to ionizing 60Co-gamma radiation caused changes in the number of bacteria within the gut. There is a dose-related decease in the number of both aerobic and anaerobic bacteria from 1010-12 to 104-6 /gram of stool within four days. The number of anaerobic bacteria stays low, but the quantities of Enterobacteriaceae per gram of stool increases significantly up to 109 by the 12th day after exposure to irradiation. This increase is associated with bacterial translocation of these microorganisms and lethal bacteremia. The administration of flouroquinolones to irradiated animals was successful in controlling systemic endogenous Gram-negative infection that develops after irradiation. The supplementation of flouroquinolone therapy with penicillin prevented treatment failures due to infection with Streptococcus spp. and increased the survival of the animals. Flouroquinolones administered for 21 days also were effective in the treatment of systemic exogenous infections due to orally ingested aerobic Gram negative bacilli (i.e. Klebsiella pneumoniae and Pseudomonas aeruginosa). The effectiveness of flouroquinolones may be due to their ability to inhibit the growth of exogenous organisms inside the gut lumen, while preserving the anaerobic gastrointestinal flora as well as their systemic antibacterial efficacy. Based on these findings the antimicrobials recommended for the therapy of infection the emerge after exposure to ionizing irradiation are: ciprofloxacin, levofloxacin, ceftriaxone, cefepime, gentamicin +/- amoxicillin or vancomycin.