Q.What is uremia?

Several disorders arise from failures at different points of the excretory system. Kidney stones (renal calculi) form anywhere along the urinary tract and are classified by composition — calcium stones (oxalate or phosphate; a reason kidney-stone patients are advised to limit oxalate-rich foods like tomatoes), struvite stones (from urea-splitting bacterial infection), uric acid stones (linked to low water intake or high-protein diets), and cystine stones (a genetic disorder); symptoms include flank pain, discoloured urine, frequent urination and pain on micturition. Uremia is a rise in blood urea above about 0.05% (from a normal 0.01-0.03%), which can progress to kidney failure. Nephritis is kidney inflammation with proteinuria, caused by increased permeability of the glomerular-capsular membrane, which lowers blood colloidal osmotic pressure and drives fluid into tiss …