blast crisis A phase of advanced leukemia, usually chronic myelogenous leukemia (CML), in which the number of immature, abnormal white blood cells (blasts) in the bone marrow and blood is extremely high. Also known as the blast phase. See also leukemia.
blast An immature blood cell.
Blalock-Taussig operation A pioneering operation to treat children born with the heart malformation tetralogy of Fallot named for the US surgeon Alfred Blalock and the US pediatric cardiologist Helen B. Taussig.
bladder pain Pain from the urinary bladder. Among the symptoms of bladder infection are feelings of pain, pressure, and tenderness around the bladder, pelvis, and perineum (the area between the anus and vagina or anus and scrotum), which may increase as the bladder fills and decrease as it empties; decreased bladder capacity; an urgent need…
bladder inflammation Inflammation of the urinary bladder. Also called cystitis. Can be due to infection from bacteria that ascend the urethra to the bladder or for unknown reasons, such as with interstitial cystitis. Symptoms include a frequent need to urinate, often accompanied by a burning sensation. As bladder inflammation progresses, blood may be observed in…
bladder infection Infection of the urinary bladder. Some people are at greater risk for bladder infections and other urinary tract infections (UTIs) than others. Women are at greater risk than men; one woman in five develops a UTI during her lifetime. Not everyone with a UTI has symptoms. Common symptoms include a frequent urge to…
bladder cancer A common form of cancer that begins in the lining of the bladder. The most common warning sign is blood in the urine. Symptoms include pain during urination, frequent urination, and feeling the need to urinate without results. A diagnosis of bladder cancer is supported by findings in the medical history, physical examination,…
bladder, overactive A condition in which sudden involuntary contractions of the muscular wall of the bladder cause urinary urgency, immediate and unstoppable needs to urinate. Overactive bladder is a form of urinary incontinence (the unintentional loss of urine) and is relatively common, particularly in older adults. Treatment may include pelvic muscle strengthening, behavioral therapy, and…
bladder A hollow organ in the lower abdomen that stores urine. The kidneys filter waste from the blood and produce urine, which enters the bladder through two tubes, called ureters. Urine leaves the bladder through another tube, the urethra. In women, the urethra is a short tube that opens just in front of the vagina….
blackhead A familiar term for what is medically called an open comedo. A comedo, the primary sign of acne, consists of a widened hair follicle filled with skin debris, bacteria, and oil called sebum. A blackhead has a wide opening to the skin and is capped with a blackened mass of skin debris. In contrast,…
Black Plague See bubonic plague.
black lung disease A disease of the lungs that is caused by inhaling coal dust, which in some patients can lead to progressive massive fibrosis of the lungs and severely impaired lung function. Also known as anthracosis and coal miner’s pneumoconiosis.