Importance of initial management of persons internally contaminated with radionuclides

Pharmacy Preparedness for Incidents Involving Nuclear, Biological, or Chemical Weapons

Recent worldwide terrorist attacks and hoaxes have heightened awareness that more incidents involving weapons of mass destruction (WMD) may occur in the United States. With federal funding assistance, local domestic preparedness programs have been initiated to train and equip emergency services and emergency department personnel in the management of large numbers of casualties exposed to nuclear, biological, or chemical (NBC) agents. Hospital pharmacies will be required to provide antidotes, antibiotics, antitoxins, and other pharmaceuticals in large amounts and/or have the capability for prompt procurement. Pharmacists should become knowledgeable in drug therapy of NBC threats with respect to nerve agents, cyanide, pulmonary irritants, radio-nucleotides, anthrax, botulism, and other possible WMD.

Management of Persons Internally Contaminated with Radionuclides

Aspects of internal contamination with radionuclides are reviewed. The possible association of this kind of accident with radiation and conventional accidents is addressed. The most important mishaps in the initial diagnosis, the need for prompt treatment, and a well-prepared plan to cope with radioisotopes at the workplace are discussed. The metabolic behavior and specific treatment for radionuclide contamination is reported.

Diagnosis and treatment of polonium poisoning

OBJECTIVES

Interest in the clinical toxicology of (210)polonium ((210)Po) has been stimulated by the poisoning of Alexander Litvinenko in 2006. This article reviews the clinical features, diagnosis, and treatment of acute radiation syndrome (ARS) resulting from the ingestion of (210)Po. PHYSICAL CHARACTERISTICS: (210)Po is a high-energy alpha-emitter (radioactive half-life 138 days) that presents a radiation hazard only if taken into the body, for example, by ingestion, because of the low range of alpha particles in biological tissues. As a result, external contamination does not cause radiation sickness.

TOXICOKINETICS

Ingested (210)Po is concentrated initially in red blood cells and then the liver, kidneys, spleen, bone marrow, gastrointestinal (GI) tract, and gonads. (210)Po is excreted in urine, bile, sweat, and (possibly) breath and is also deposited in hair. After ingestion, unabsorbed (210)Po is present in the faeces. The elimination half-life in man is approximately 30-50 days. In the absence of medical treatment, the fatal oral amount is probably in the order of 10-30 microg.

CLINICAL PRESENTATION

If the absorbed dose is sufficiently large (e.g., >0.7 Gy), (210)Po can cause ARS. This is characterized by a prodromal phase, in which nausea, vomiting, anorexia, lymphopenia, and sometimes diarrhea develop after exposure. Higher radiation doses cause a more rapid onset of symptoms and a more rapid reduction in lymphocyte count. The prodromal phase may be followed by a latent phase during which there is some clinical improvement. Subsequently, the characteristic bone marrow (0.7-10 Gy), GI (8-10 Gy), or cardiovascular/central nervous system syndromes (>20 Gy) develop, with the timing and pattern of features dependent on the systemic dose. The triad of early emesis followed by hair loss and bone marrow failure is typical of ARS. Those patients who do not recover die within weeks to months, whereas in those who survive, full recovery can take many months.

INVESTIGATION AND DIAGNOSIS

Serial blood counts are important for assessing the rate of reduction in lymphocyte counts. Chromosome analysis, especially the dicentric count, may establish radiation effects and provides an estimation of dose. The diagnosis of (210)Po poisoning is established by the presence of (210)Po in urine and faeces and the exclusion of other possible causes. In the absence of a history of exposure, diagnosis is very difficult as clinical features are similar to those of much more common conditions, such as GI infections and bone marrow failure caused, for example, by drugs, other toxins, or infections.

MANAGEMENT

Good supportive care is essential and should be directed at controlling symptoms, preventing infections but treating those that do arise, and transfusion of blood and platelets as appropriate. Gastric aspiration or lavage may be useful if performed soon after ingestion. Chelation therapy is also likely to be beneficial, with research in animals suggesting reduced retention in the body and improvements in survival, although increased activity in some radiosensitive organs has also been reported with some chelating agents. Dimercaprol (British Anti-Lewisite) (with penicillamine as an alternative) is currently recommended for (210)Po poisoning, but animal models also indicate efficacy for 2,3,-dimercapto-1-propanesulfonic acid, meso-dimercaptosuccinic acid, or N,N -dihydroxyethylethelene-diamine-N,N -bis-dithiocarbamate.

CONCLUSIONS

Internal contamination with (210)Po can cause ARS, which should be considered in patients presenting initially with unexplained emesis, followed later by bone marrow failure and hair loss.

Pharmacy Preparedness for Incidents Involving Weapons of Mass Destruction

Recent worldwide terrorist acts and hoaxes have heightened awareness that incidents involving weapons of mass destruction (WMD) may occur in the United States. With federal funding assistance, local domestic preparedness programs have been initiated to train and equip emergency services and emergency department personnel in the management of large numbers of casualties exposed to nuclear, biological, or chemical (NBC) agents. Hospital pharmacies will be required to provide antidotes, antibiotics, antitoxins, and other pharmaceuticals in large amounts and/or have the capability for prompt procurement. Pharmacists should become knowledgeable in drug therapy of NBC threats with respect to nerve agents, cyanide, pulmonary irritants, radionucleotides, anthrax, botulism, and other possible WMD.

The effect of composite oral treatment for internal contamination with several radionuclides on 131I thyroid uptake in humans

The efficiency of a composite oral treatment on 131I thyroid uptake was investigated in three adult volunteers. The treatment consisted of 10 g of calcium alginate, 3 g ferrihexacyanoferrate(II), 130 mg of potassium iodide and 5 g of Zn-DTPA. This mixture when administered 30 min before 131I almost completely blocked the 131I thyroid uptake. This indicates that simultaneous administration of other antidotal agents do not cancel or decrease the effect of potassium iodide on 131I thyroid uptake. The finding deserves attention since composite oral treatment is the recommended therapy in cases of accidental environmental exposure to several radionuclides.

Emergency management of radiation accidents

The Joint Committee on Accreditation of Hospitals requires that hospitals have a written procedure to cope with radiation accidents. Emergency personnel, specifically, should be prepared to manage radiation accident victims initially. Guidelines currently in use in over 15 hospitals in the United States include 1) advance notification to the hospital of arrival of such patients; 2) designated treatment area; 3) operating room attire; 4) perform life-saving functions first; 5) cover open wounds and remove clothing; 6) search for contamination with radiation detector, or 7) flush all wounds if no radiation detector is available; 8) wash patient; 9) evaluate internal and external radiation exposure, and 10) obtain medical consultation. For community hospitals, a less elaborate procedure will suffice for adequate handling of radiation accident victims and accreditation.