Microscopic polyangiitis is an ill-defined autoimmune disease characterized by a systemic, pauci-immune, necrotizing, small-vessel vasculitis without clinical or pathological evidence of necrotizing granulomatous inflammation. Signs and symptoms
Clinical features may include constitutional symptoms like fever, loss of appetite, weight loss, fatigue, and kidney failure. A majority of patients may have blood in the urine and protein in the urine. Rapidly progressive glomerulonephritis may occur. Because many different organ systems may be involved, a wide range of symptoms are possible in MPA. Purpura and livedo racemosa may be present. Cause
While the mechanism of disease has yet to be fully elucidated, the leading hypothesis is that the process is begun with an autoimmune process of unknown cause that triggers production of p-ANCA. These antibodies will circulate at low levels until a pro-inflammatory trigger—such as infection, malignancy, or drug therapy. The trigger upregulates production of p-ANCA. Then, the large number of antibodies make it more likely that they will bind a neutrophil. Once bound, the neutrophil degranulates. The degranulation releases toxins that cause endothelial injury. Most recently, two different groups of investigators have demonstrated that anti-MPO antibodies alone can cause necrotizing and crescentic glomerulonephritis. Diagnosis
Laboratory tests may reveal an increased sedimentation rate, elevated CRP, anemia and elevated creatinine due to kidney impairment. An important diagnostic test is the presence of perinuclear antineutrophil cytoplasmic antibodies (p-ANCA) with myeloperoxidase specificity (a constituent of neutrophil granules), and protein and red blood cells in the urine. In patients with neuropathy, electromyography may reveal a sensorimotor peripheral neuropathy.
"The bends" is a colloquialism for decompression sickness. The Bends may also refer to:

The Bends (album), a 1995 studio album by Radiohead
"The Bends" (song), a 1995 song by Radiohead
"The Bends", a song by Mr. Bungle from the 1995 album Disco Volante
"The Bends", a song by Earl Sweatshirt from the 2018 album Some Rap Songs

See also
Bends (film), a 2013 British film
All pages with titles containing The Bends
Bend (disambiguation)
Bending (disambiguation)