What are Pus Cells (Urine)?

Also Know as: Pyuria

Pyuria is a urinary condition that is characterized by an elevated number of white blood cells in the urine.
Doctors define a high number as at least 10 white blood cells per cubic millimeter (mm3) of centrifuged urine. Pyuria can cause the urine to look cloudy or as if it contains pus.

The presence of pyuria often occurs in a urinary tract infection (UTI). In rare cases, it can be a sign of a complicated UTI or sepsis. A sterile pyuria is a form of pyuria that occurs without a detected presence of bacteria. In these cases, it may be related to non-detected bacteria, a virus or other germ type, or some other underlying medical condition.

Causes

Pyuria can occur as a result of many different conditions. It is most commonly caused by a UTI, which is an infection in any area of the urinary system, including the kidneys, ureters, urethra, or bladder.
Sterile pyuria is most often caused by sexually transmitted infections (STIs), such as gonorrhea or viral infections.

Other causes of sterile pyuria include:

• interstitial cystitis
• bacteremia with sepsis
• tuberculosis
• urinary tract stones
• kidney disease
• prostatitis
• pneumonia
• autoimmune diseases, such as SLE or Kawasaki’s disease
• parasites
• tumors in the urinary tract
• polycystic kidney disease

Pyuria can also be a reaction to taking certain types of medications, including:

• nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen and aspirin
• diuretics
• penicillin antibiotics
• proton pump inhibitors, such as omeprazole

Symptoms

Pyuria can cause cloudy urine and urine with pus that may not be accompanied by any other symptoms. The change in color or texture is due to the increased number of white blood cells.
If a UTI is present, symptoms may also include:

• frequent urges to urinate
• a burning sensation when urinating
• blood in urine
• foul-smelling urine
• pelvic pain
• fever

Other symptoms that may occur if another underlying condition causes pyuria:

• fever
• abdominal pain
• abnormal discharge
• shortness of breath
• nausea or vomiting

Diagnosis

A doctor will do a urinalysis to diagnose pyuria. This involves taking a urine sample, which is then analyzed based on its appearance, concentration, and content.

Cloudy urine with an abnormal white blood cell count may indicate pyuria.
The urinalysis might also highlight other abnormalities. For example, the presence of nitrite or leukocyte esterase can indicate a UTI, while elevated protein levels might indicate kidney disease.