Internal contamination protective equipment such as respirators are used to prevent internal deposition as a result of inhalation and ingestion of radioactive material. Dermal protective equipment, which protects against external contamination, provides shielding to prevent radioactive material from being deposited on external structures. While these protective measures do provide a barrier from radioactive material deposition, they do not shield from externally penetrating gamma radiation. This leaves anyone exposed to penetrating gamma rays at high risk of ARS. Naturally, shielding the entire body from high energy gamma radiation is optimal, but the required mass to provide adequate attenuation makes functional movement nearly impossible. In the event of a radiation catastrophe, medical and security personnel need mobile protection equipment in order to safely assist in containment, evacuation, and many other necessary public safety objectives. Research has been done exploring the feasibility of partial body shielding, a radiation protection strategy that provides adequate attenuation to only the most radio-sensitive organs and tissues inside the body. Irreversible stem cell damage in the bone marrow is the first life-threatening effect of intense radiation exposure and therefore one of the most important bodily elements to protect. Due to the regenerative property of hematopoietic stem cells, it is only necessary to protect enough bone marrow to repopulate the exposed areas of the body with the shielded supply. This concept allows for the development of lightweight mobile radiation protection equipment, which provides adequate protection, deferring the onset of ARS to much higher exposure doses.
The build up of fluid in the lungs increases the pressure in the lungs leading to vasoconstriction. The coupled vasoconstriction and pulmonary hypertension causes the right side of the heart to fail which in turn, increases the venous hydrostatic pressure in the body. The summation of these effects ultimately leads to peripheral edema and ascites. All in all, the left side failure of the heart will lead to pulmonary edema whereas right side failure will lead to peripheral edema and ascites. The non-immune form of hydrops fetalis has many causes including:
Iron deficiency anemia
Paroxysmal supraventricular tachycardia resulting in heart failure
Deficiency of the enzyme beta-glucuronidase. This enzyme deficiency is the cause of the lysosomal storage disease called mucopolysaccharidosis type VII. Congenital disorders of glycosylation
Parvovirus B19 (fifth disease) infection of the pregnant woman (most common cause)
Cytomegalovirus in mother
Congenital pulmonary airway malformation (formerly called congenital cystic adenomatoid malformation)
Maternal syphilis and maternal diabetes mellitus
Alpha-thalassemia can also cause hydrops fetalis when all four of the genetic loci for α globin are deleted or affected by mutation. This is termed Hb Barts (consists of y-4 tetramers). Uncommonly, Niemann-Pick disease Type C (NPC) and Gaucher disease type 2 can present with hydrops fetalis. Turner syndrome
Tumors, the most common type of fetal tumor being teratoma, particularly a sacrococcygeal teratoma.