Final answer:
Blood in urine, or hematuria, can be caused by conditions such as urinary tract infections, trauma, and kidney stones. Infections such as pyelonephritis, and obstructions like kidney stones, can lead to visible blood in urine due to damage or inflammation in the urinary system.
Step-by-step explanation:
Blood found in urine, known medically as hematuria, can be caused by several conditions, some of which include a urinary tract infection (UTI), trauma to the urinary tract or attachment sites, and the presence of kidney stones (urolithiasis). A UTI may involve bacterial infection of the bladder (cystitis) and can lead to visible blood in the urine if the infection is severe. On the other hand, trauma could cause bleeding in the urinary system directly. Kidney stones can cause blood in the urine when they damage the kidneys or when they pass through the urinary tract, scraping the tissues and causing hematuria.
Post-renal uremia can be a consequence of obstructions, such as kidney stones, leading to increased blood urea levels due to impaired urinary outflow. Kidney infections, like pyelonephritis, arise due to bacteria like E. coli and can lead to systemic infection with symptoms like fever, vomiting, and in some cases, hematuria. Lastly, glomerulonephritis, an inflammation of the kidney's filtering units, can cause blood cells to leak into the urine.