The presence of blood in the urine is called hematuria. The haematuria is also described as macroscopic when the urine is red in color due to the presence of a substantial amount of blood. If the amount of blood loss in the urine is scanty, its color may appear normal, though red cells are seen in urine when viewed under a microscope. This condition is called microscopic hematuria. Whatever be the amount, the presence of blood in urine is always abnormal and is associated with some disorder.
The urinary tract
The urinary tract in men includes both kidneys, ureters, urinary bladder, prostate, and urethra. Haematuria may be related to urinary tract disease or be part of a generalized bleeding disorder.
Causes of blood in the urine
Generalized bleeding disorders
Purpura: In this condition, bleeding occurs spontaneously due to multiple factors. Some patients lack platelets that form plugs to stop bleeding after an injury normally. In this condition called thrombocytopenia, patients may pass blood-stained urine. Some patients have inflammation of blood vessels called vasculitis and develop haematuria. A deficiency of vitamin C which causes scurvy may also be associated with bleeding into the urinary system. In some patients with cocaine abuse, where the preparation also contains levamisole to prolong the high, can cause the presence of blood in the urine.
Anticoagulants: Anticoagulants are drugs that prevent coagulation of blood. They are given to patients who are prone to develop deep vein thrombosis (DVT) and are also given to prevent DVT during major surgery. An overdosage of these drugs may result in abnormal bleeding including haematuria. Hence these drugs are given under monitoring of clotting parameters. These drugs include warfarin and heparin.
Sickle cell trait: This is a less severe form of sickle cell disease and is associated with haematuria.
Kidney disorders
Tumours: Renal tumours are richly supplied with blood. These often lead to spontaneous bleeding and lead to a suspicion of malignancy. These may be hypernephroma or transitional cell carcinoma.
Renal tuberculosis: Tuberculosis of the kidney is a chronic granulomatous inflammatory disease. It gradually destroys the kidneys and causes renal failure. In tropical countries, this is an important cause of haematuria. These patients may present with a past history of tuberculosis of the lungs.
Injury: Though kidneys are located in the rearmost part of the abdomen in a well-protected position, a forceful blow may cause injury. There may be bleeding and the presence of blood clots in the urine.
Stone disease: The presence of kidney stones is a major risk factor for the development of haematuria. The stones have a rough surface, especially the oxalate stones, and large staghorn stones can damage the urinary epithelium and cause severe pain associated with haematuria.
Glomerulonephritis: Inflammatory conditions leading to swelling and congestion in the kidneys are an important and treatable cause of haematuria.
Ureters
Small stones formed in the kidneys may pass into the ureter along with urine. They usually get impacted in the ureters and cause severe pain associated with bleeding in the urinary passage. Tumours involving the ureter may bleed into the lumen.
Urinary bladder
The urinary bladder is affected by a multitude of disorders. Cystitis is inflammation of the bladder and is part of the urinary tract infection (UTI). This may be associated with haematuria. Tuberculosis and urinary stones are important causes. Schistosomiasis is a parasitic disease seen in the developing world and affects the urinary bladder. This is also a risk factor for bladder cancer which presents with painless haematuria.
Prostate
Benign or malignant enlargement of the prostate gland causes urinary obstruction. It is commonly associated with bleeding.
Urethra
Urinary catheter-induced trauma, the passage of a small stone or a tumour of the lining of the urethra may cause bleeding in the urine.
Jogger’s haematuria
This is also called exercise-induced haematuria. It occurs after strenuous exercise and is not related to any disease. It subsides on its own after rest.
Passage of red urine always raises an alarm. Though in many situations the urine is red due to intake of beetroot, drugs like rifampicin, and does not contain blood. It always calls for an investigation to confirm the presence of red cells in urine. If found positive, a complete assessment to rule out the disorder of the urinary tract is done.
