Ver el código de «Depleted uranium toxicity»

==Background==
* Uranium is an alpha-emitting, radioactive heavy metal that occurs naturally in nearly all rocks and soil. Natural uranium is made up of the three naturally occurring isotopes of uranium namely <sup>234</sup>U, <sup>235</sup>U, and <sup>238</sup>U. Naturally occurring uranium deposits are over 99% <sup>238</sup>U. You eat, drink, and breather natural uranium on a daily basis.
* Health hazards of natural uranium have been studied extensively since 1940s. Health impact of Depleted Uranium (DU) has been studied since the early 1970s.
* Enrichment is the industrial process by which natural uranium is separated into enriched uranium which has an increased percentage of <sup>235</sup>U and depleted uranium which has a decreased percentage of <sup>235</sup>U.
** DU is a byproduct of the enrichment process.
** DU has 40% less radioactivity than natural uranium. It has a specific activity of 0.33 microCi/g.
** DU has the same chemical properties as naturally occurring uranium, it simply has different ratio of isotopes of <sup>234</sup>U, <sup>235</sup>U, and <sup>238</sup>U.
** DU health effects will be the same as for natural uranium because the toxicity is primarily due to the chemical toxicity rather than radiotoxicity.
* United States Armed Forces have used depleted uranium in the manufacture of ammunition, armor, and aircraft.
** DU's high density, self-sharpening quality and pyrophoricity make it a good choice for projectile munitions. 
** DU's density makes it a good armor choice.
** DU's density also makes it a good choice for counterbalance weights used in aircraft and on helicopter rotors.
{| {{table}}
| align="center" style="background:#f0f0f0;"|''''''
| align="center" style="background:#f0f0f0;"|'''Natural Uranium'''
| align="center" style="background:#f0f0f0;"|'''Depleted Uranium'''
|-
| Isotope||Concentration of isotope||Concentration of isotope
|-
| <sup>234</sup>U||0.0058%||0.0010%
|-
| <sup>235</sup>U||0.72%||0.20%
|-
| <sup>238</sup>U||99.28%||99.80%
|-
| Relative Radioactivity||1.0||0.6
|-
| 
|}

===Routes of exposure===
* Inhalation - minor route of exposure for general population. Major route for occupational population. On average in US individual daily intake of uranium is 0.007 micrograms by inhalation.
* Oral - predominant route of exposure for general population through ingestion of food and drinking water. Average daily intake of uranium in US is 1.9 micrograms by ingestion.
* Dermal - unlikely route of exposure for general population. Potential route of exposure for military service members.

===Toxicokinetics===
* DU is poorly absorbed following inhalation, oral, or dermal exposure route.
** Amount absorbed heavily dependent on the solubility of the compound.
** <0.1-6% of uranium is absorbed following oral exposure.
* 67% of uranium in blood is filtered in the kidneys and leaves body in urine within 24 hours. Remainder is distributed to tissues primarily bone, liver, and kidney.
* Retention half-time for uranium in bone is 70-200 days.
* Retention in body skeleton (66%), liver (16%), kidneys (8%), other tissues (10%)

====Radiation Toxicity====
* Alpha emitter thus not serious external radiation hazard. Alpha radiation has poor penetrating ability. Direct contact with bare DU for 250 hours is necessary to exceed annual occupational exposure limits.
* Internal exposure via inhalation, ingestion, wound contamination or retained fragments warrants some concern.
* Chronic exposure by inhalation is potential radiologic hazard to the lung and thoracic lymph nodes.
* Genotoxicity, mutagenicity and reproductive effects are being studied.

====Chemical Toxicity====
* Kidney dysfunction main chemically-induced effect of uranium
* Can develop tubulopathy or renal tubular acidosis

==Clinical Features==
* Exposure normally does ''not'' cause symptoms, as small amounts are quickly passed
* If significantly large exposure, can cause [[AKI|renal damage]] due to [[heavy metal]] properties

==Differential Diagnosis==
*Alpha [[radiation exposure]]
*[[Heavy metal toxicity]]

==Evaluation==
* Patients who feel they have been exposed to high levels of DU should be evaluated
===History===
* Circumstances : date, time, route of exposure, amount
* Evidence of wound or embedded fragments?
* Prolonged skin contact i.e. through keeping of a souvenir?
===Exam===
===Workup===
*[[UA]]
*CBC
*BMP for renal function
*[[CXR]] if significant inhalation exposure
*Tests for uranium exposure if close proximity/large exposure or any abnormalities:
**Beta-2 microglobulin 24h urine to evaluate for tubulopathy
**Urine uranium level; if elevated, check 24h excreted DU level to include isotope-specific ratios


==Management==
* Remove patient from exposure
* Externally decontaminate if residue present on patient
* Base further treatment on symptoms observed
* Renal tubulopathy treatment:
**Needs to be initiated early, prior to fixation of uranium in the skeleton
** [[Sodium bicarbonate]] to alkalinize urine
** Consider heavy metal chelation therapy
** Monitor renal function

==Disposition==
* Most cases of exposure have no permanent effect
* Likelihood to develop any health effects is low
* If exposure is via inhalation and significant amounts of insoluble uranium compounds deposited in lungs than patient will need long-term surveillance/follow-up

==See Also==

==References==
<references/>
# Agency for Toxic Substances and Disease Registry (ATSDR), Toxicological Profile for Uranium (Update), February 2013.
# McDiarmid, M.A. (2001). ''Depleted uranium and public health''. BMJ, 322(7279), 123-124.
# U.S. Army Environmental Policy Institute (AEPI). (June 1995). Health and Environmental Consequences of Depleted Uranium Use in the U.S. Army: Technical Report.
# Department of Defense. (August 4, 1998). Health Effects of Depleted Uranium - Fact Sheet.
# U.S. Army Environmental Policy Institute, (AEPI). (June 1994). Health and Environmental Consequences of Depleted Uranium Use by the U.S. Army, Summary Report to Congress.
# World Health Organization (WHO), Guidance On Exposure to DU- For Medical Officers and Programme Administrators, 2001.
#  World Health Organization (WHO), Depleted Uranium: Sources, Exposure and Health Effects, 2001.
#  World Health Organization (WHO), Depleted Uranium Fact Sheet, revised January 2003.

[[Category:Military]]
[[Category:Toxicology]]