N20-N23: Urolithiasis

N21: Calculus of lower urinary tract

The N21 grouping in the ICD-10 classification pertains to conditions related to the calculus of the lower urinary tract. These conditions involve the formation of stone-like deposits known as calculi or urinary stones in the lower urinary tract, which includes the bladder and the urethra. These calculi are primarily composed of minerals and acid salts which have crystallized together and, depending upon their size and location, may cause significant discomfort and complications. While the exact cause of stone formation can vary, common contributing factors include dehydration, certain dietary habits, and genetic predisposition. Common symptoms associated with these conditions include pain during urination, blood in the urine, and lower abdominal discomfort. If the stones obstruct the urinary flow, it can lead to more severe problems, such as urinary tract infections or acute urinary retention.