eosinofiluria

Eosinofiluria refers to the presence of eosinophils, a type of white blood cell, in the urine. Eosinophils are primarily involved in the immune response, particularly against parasites and in allergic reactions. Their presence in urine is generally considered abnormal and suggests an underlying inflammatory process affecting the urinary tract.

The most common cause of eosinofiluria in developed countries is drug-induced interstitial nephritis. This condition occurs as an adverse reaction to certain medications, such as antibiotics (like penicillins and cephalosporins), nonsteroidal anti-inflammatory drugs (NSAIDs), and proton pump inhibitors. The inflammation and damage to the kidney tubules can lead to the infiltration of eosinophils.

Other potential causes of eosinofiluria include urinary tract infections (UTIs), particularly those caused by certain bacteria or fungi, and parasitic infections affecting the kidneys or bladder. In some cases, eosinofiluria can be seen in individuals with kidney diseases like IgA nephropathy or minimal change disease, though it is not always a prominent feature.

Diagnosing the cause of eosinofiluria typically involves a urinalysis to confirm the presence of eosinophils, often identified using special stains. Further investigations may include a detailed medical history focusing on medication use and recent exposures, blood tests to assess kidney function, and sometimes a kidney biopsy to determine the specific type and extent of kidney damage. Treatment is directed at the underlying cause, which may involve discontinuing offending medications, treating infections, or managing kidney disease.