Glucarpidase (Voraxaze) is a medication used for the treatment of elevated levels of methotrexate (defined as 1 micromol/L) during treatment of cancer patients who have impaired kidney function (and thus cannot reduce the drug to safe levels sufficiently after the drug has been given). Glucarpidase is an enzyme that inactivates methotrexate rapidly after injection. Because this agent reduces systemic levels of methotrexate and could therefore interfere with efficacy, it is not recommended for use in patients with normal or only slightly impaired kidney function or in whom serum levels are normal. The main antidote for methotrexate overdoses prior to the approval of this drug were high doses of folinic acid. However, this agent was not always sufficient at preventing kidney failure due to methotrexate. Glucarpidase also degrades folinic acid so the two should not be used together (within two hours of one another). Glucarpidase, a recombinant form of the bacterial enzyme carboxypeptidase G2 converts methotrexate into glutamate and 2,4-diamino-N(10)-methylpteroic acid. These are generally much less toxic and are excreted largely by the liver. One case series in children has found that high-dose methotrexate therapy can be resumed after an instance of methotrexate-induced acute kidney injury successfully treated with glucarpidase.Adverse effects include mild and include numbness, tingling, flushing, nausea, vomiting, itching, and headache.
Crush syndrome (also traumatic rhabdomyolysis or Bywaters syndrome) is a medical condition characterized by major shock and kidney failure after a crushing injury to skeletal muscle. Crush injury is compression of the arms, legs, or other parts of the body that causes muscle swelling and/or neurological disturbances in the affected areas of the body, while crush syndrome is localized crush injury with systemic manifestations. Cases occur commonly in catastrophes such as earthquakes, to individuals that have been trapped under fallen or moving masonry. People with crushing damage present some of the greatest challenges in field medicine, and may need a physicians attention on the site of their injury. Appropriate physiological preparation of the injured is mandatory. It may be possible to free the patient without amputation; however, field amputations may be necessary in drastic situations. Pathophysiology
Seigo Minami, a Japanese physician, first reported the crush syndrome in 1923. He studied the pathology of three soldiers who died in World War I due to kidney failure. The renal changes were due to the buildup of excess myoglobin, resulting from the destruction of muscles from lack of oxygen. These changes can also be seen in persons who are buried alive. The progressive acute kidney failure is because of acute tubular necrosis. The syndrome was later described by British physician Eric Bywaters in patients during the 1941 wartime bombing of London (the Blitz). It is a reperfusion injury that appears after the release of the crushing pressure.