Pyuria is the condition of

urine Urine is a liquid by-product of metabolism in humans and in many other animals. Urine flows from the kidneys through the ureters to the urinary bladder. Urination results in urine being excreted from the body through the urethra. Cellul ...

containing white blood cells or pus. Defined as the presence of 6-10 or more

neutrophils Neutrophils (also known as neutrocytes or heterophils) are the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. They form an essential part of the innate immune system, with their functions varying ...

per high power field of unspun, voided mid-stream urine, it can be a sign of a bacterial

urinary tract infection A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidne ...

. Pyuria may be present in people with

sepsis Sepsis, formerly known as septicemia (septicaemia in British English) or blood poisoning, is a life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. This initial stage is follo ...

, or in older people with

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severit ...

. Others additionally require discoloration, clouding or change in the smell of urine for a pyuria to be present. Without these additional features, there is said to be leukocyturia. Sterile pyuria is urine which contains

white blood cells White blood cells, also called leukocytes or leucocytes, are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders. All white blood cells are produced and derived from mult ...

while appearing sterile by standard culturing techniques. It is often caused by sexually transmitted infections, such as gonorrhea, or viruses which will not grow in bacterial cultures. Sterile pyuria is listed as a side effect from some medications such as paracetamol (acetaminophen). Its occurrence is also associated with certain disease processes, such as

Kawasaki disease Kawasaki disease is a syndrome of unknown cause that results in a fever and mainly affects children under 5 years of age. It is a form of vasculitis, where blood vessels become inflamed throughout the body. The fever typically lasts for more th ...

and genitourinary

tuberculosis Tuberculosis (TB) is an infectious disease usually caused by '' Mycobacterium tuberculosis'' (MTB) bacteria. Tuberculosis generally affects the lungs, but it can also affect other parts of the body. Most infections show no symptoms, ...

. However, there are many known causes, including

systemic Systemic fundamental to a predominant social, economic, or political practice. This refers to: In medicine In medicine, ''systemic'' means affecting the whole body, or at least multiple organ systems. It is in contrast with ''topical'' or ''loc ...

or infectious disease, structural and physiological reasons, intrinsic kidney pathology, or drugs.

Leukocyturia

Under normal conditions, fewer than two million leukocytes are expelled in urine per day. A number greater than two million is called leucocyturia and can be determined when determining the

Addis count The Addis count is a urine test measuring urinary casts over time. It is named for Thomas Addis Thomas Addis Jr. (July 27, 1881 – June 4, 1949) was a Scottish physician-scientist from Edinburgh who made important contributions to the underst ...

. However, this method requires a 24-hour urine collection, so it is not practical. Currently, the number of leukocytes is estimated under the microscope for which morning urine is taken. It has been arbitrarily assumed that a number of over 4-5 leukocytes in the field of vision of the microscope indicates leukocyturia. At the moment, there are also quick test strips available, allowing after wetting a special diagnostic bar, the detection of granulocytes in the urine, as evidenced by the color change of the test strip. The principle of their operation is based on the detection of

granulocyte Granulocytes are cells in the innate immune system characterized by the presence of specific granules in their cytoplasm. Such granules distinguish them from the various agranulocytes. All myeloblastic granulocytes are polymorphonuclear. They ha ...

s esterases, including leukocytes. This method, however, is burdened with a large number of false positive results (use of

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention ...

s, such as imipenem,

meropenem Meropenem, sold under the brand name Merrem among others, is an intravenous β-lactam antibiotic used to treat a variety of bacterial infections. Some of these include meningitis, intra-abdominal infection, pneumonia, sepsis, and anthrax. C ...

, clavulanic acid, which is sometimes combined with

penicillin Penicillins (P, PCN or PEN) are a group of β-lactam antibiotics originally obtained from '' Penicillium'' moulds, principally '' P. chrysogenum'' and '' P. rubens''. Most penicillins in clinical use are synthesised by P. chrysogenum usin ...

derivatives) or false negative (

gentamicin Gentamicin is an antibiotic used to treat several types of bacterial infections. This may include bone infections, endocarditis, pelvic inflammatory disease, meningitis, pneumonia, urinary tract infections, and sepsis among others. It is not ...

cefalexin Cefalexin, also spelled cephalexin, is an antibiotic that can treat a number of bacterial infections. It kills gram-positive and some gram-negative bacteria by disrupting the growth of the bacterial cell wall. Cefalexin is a beta-lactam antibi ...

, glycosuria, proteinuria). Leukocyturia is a laboratory symptom of many diseases like

glomerulonephritis Glomerulonephritis (GN) is a term used to refer to several kidney diseases (usually affecting both kidneys). Many of the diseases are characterised by inflammation either of the glomeruli or of the small blood vessels in the kidneys, hence the ...

pyelonephritis Pyelonephritis is inflammation of the kidney, typically due to a bacterial infection. Symptoms most often include fever and flank tenderness. Other symptoms may include nausea, burning with urination, and frequent urination. Complications ...

. It may occur in the case of diseases of the urinary tract, reproductive system and diseases of the abdominal organs. Leukocyturia is mostly a sign of

, especially if significant bacteriuria is found (for most people, the number of bacteria in a culture is > 10^5) and other symptoms associated with passing urine. The presence of leukocyturia does not indicate the need for antimicrobial therapy yet.

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Medical signs Symptoms and signs: Urinary system {{med-sign-stub

Leukocyturia

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