What exactly is trench nephritis?

Obsolete. "Trench Nephritis" is an obsolete term for glomerulonephritis..It goes back to World War I when a lot of soldiers developed it. There are different types of nephritis (inflammation of microscopic anatomical portions of the kidney called the glomeruli). There are different types of nephritis but hen the term is used without specifying,they usually are referring to glomerulonephritis.Hope this answe.
Trench Nephritis. An epidemic of nephritis occurred among soldiers in world war i, predominantly those in the trenches. Characterized by the sudden onset of albuminuria, hypertension, edema, and dyspnea, atypical features such as bronchitis, an evanescent course, low early mortality, and frequent relapses distinguished it from poststreptococcal glomerulonephritis.