Allergic interstitial nephritis

Allergic interstitial nephritis (AIN) is a kidney disease that results from an allergic reaction to certain medications or infections. It is characterized by inflammation of the kidney's interstitial tissue, which can lead to acute or chronic kidney disease if not treated promptly.

Causes

AIN is most commonly caused by an allergic reaction to certain medications, particularly nonsteroidal anti-inflammatory drugs (NSAIDs), antibiotics, and proton pump inhibitors (PPIs). Other potential causes include infections, particularly those caused by Streptococcus bacteria, and autoimmune diseases such as lupus or Sjögren's syndrome.

Symptoms

The symptoms of AIN can vary widely, but often include fever, rash, and fatigue. Some patients may also experience hematuria (blood in the urine), proteinuria (excess protein in the urine), or pyuria (pus in the urine). In severe cases, AIN can lead to acute kidney injury (AKI), which can cause symptoms such as decreased urine output, fluid retention, and shortness of breath.

Diagnosis

AIN is typically diagnosed through a combination of urinalysis, blood tests, and kidney biopsy. Urinalysis can reveal the presence of white blood cells, red blood cells, and eosinophils, which are indicative of inflammation. Blood tests can reveal elevated levels of creatinine, a waste product that is normally filtered out by the kidneys. A kidney biopsy, in which a small sample of kidney tissue is removed and examined under a microscope, can confirm the diagnosis.

Treatment

The primary treatment for AIN is to discontinue the offending medication or treat the underlying infection or autoimmune disease. In some cases, corticosteroids may be used to reduce inflammation. If the patient has developed AKI, they may require dialysis to remove waste products from the blood.

Prognosis

The prognosis for AIN is generally good if the condition is diagnosed and treated promptly. However, if left untreated, AIN can lead to chronic kidney disease or end-stage renal disease, both of which require long-term dialysis or a kidney transplant.

See also

• Interstitial nephritis
• Acute kidney injury
• Chronic kidney disease
• End-stage renal disease