Chronic Interstitial Nephritis - Types, Causes, Symptoms, Diagnosis, and Treatment

What Is Interstitial Nephritis?

Interstitial nephritis is a condition of the kidney. The kidneys' primary function is to eliminate waste from the body and filter the blood. The interstitial inflammation leads to chronic changes with the subsequent development of chronic kidney disease. The kidney tubules reabsorb the important organic substances and water from the filtered blood and secrete substances that are not needed in the urine for removal from the body. Swelling of these tubules causes several kidney symptoms ranging from mild to severe. Environmental factors and genetic factors can cause the development of tubulointerstitial nephritis (TIN).

What Are the Types of Interstitial Nephritis?

There are two types of interstitial nephritis, they are:

• Acute Interstitial Nephritis: This type of interstitial nephritis develops quickly. The affected person urinates too often, especially at night. Bacterial infections cause acute interstitial nephritis. The symptoms include back pain, fever, and pain while urinating.

• Chronic Interstitial Nephritis: This type of interstitial nephritis develops with time. The symptoms of chronic interstitial nephritis include nausea, vomiting, fatigue, itchiness, breathing issues, appetite changes, excessive urine, and fatigue.

What Are the Symptoms of Chronic Interstitial Nephritis?

The typical symptom of interstitial nephritis is decreased amount of urination. But in some cases, the urine output can increase. Some people may not have any symptoms. Other symptoms of chronic interstitial nephritis include:

• Nausea.

• Fever.

• Blood in the urine.

• Exhaustion.

• Vomiting.

• Swelling.

• Fatigue.

• Rash.

• Confusion.

• Water retention.

• Weight gain.

• Feeling bloated.

• Increased blood pressure.

What Causes Chronic Interstitial Nephritis?

Chronic interstitial nephritis is a result of an allergic reaction. They can have bad reactions to drugs. Different factors may trigger interstitial nephritis. It can also be because of other medications they include:

• Antibiotics.

• NSAIDs - Nonsteroidal anti-inflammatory drugs that are known as painkillers.

• Proton pump inhibitors are used to treat stomach acid.

• Allergic reactions are common in older people.

• Drug reactions.

• Immune disorders.

• Unbalanced levels of nutrients in the blood.

• Infections - Bacterial infections like viral infections, Escherichia coli, herpes, syphilis, fungal infections, etc.

The causes of nonallergic interstitial nephritis include:

• High blood calcium levels.

• A low blood potassium level.

• Certain infections.

• Autoimmune disorders.

Non-allergic interstitial nephritis can be acute and chronic. Chronic non-allergic interstitial nephritis may last several months or years, and chronic underlying conditions cause them.

How Is Chronic Interstitial Nephritis Classified?

• Drug-Induced: Calcineurin inhibitors, analgesics, 6-aminosalicylic acid, nonsteroidal anti-inflammatory drugs, caffeine, and a combination of acetylsalicylic acid.

• Toxic: Mercury, lead, and cadmium.

• Metabolic Diseases: Hypercalcemia, hypokalemia, and gout.

• Immune-Mediated: Systemic lupus erythematosus, Sjogren syndrome, anti-glomerular basement membrane disease, and chronic rejection of kidney transplant.

• Vascular Disease: Ischemic nephropathy.

• Hereditary: Dent disease, primary hyperoxaluria, polycystic kidney disease.

• Other: Radiation nephropathy, aristolochic acid nephropathy, and Balkan endemic nephropathy.

• Structural Abnormalities of Urinary Tract: Reflux nephropathy, obstructive nephropathy.

• Hematologic Diseases: Multiple myeloma, sickle cell disease, light-chain disease, and lymphoproliferative disorders.

Who Is at Risk for Chronic Interstitial Nephritis?

Older people are at greater risk for interstitial nephritis as they take multiple medications. Other groups are at high risk for chronic interstitial nephritis, which includes:

• People that have autoimmune diseases.

• People have sarcoidosis, which is an inflammatory disease of the lung.

• People who chronically use over-the-counter painkillers.

How Is Chronic Interstitial Nephritis Diagnosed?

If the kidneys are not functioning well, the healthcare provider may take a detailed medical history and complete a family history of medical problems. In addition, healthcare providers may ask a few questions:

• History of medications.

• Duration of those medications.

• Complete physical examination.

Make sure to tell the healthcare provider about the drug use and history of medications, including OTC pain relievers and dietary supplements, as these supplements and drugs impact the kidneys. The following tests are used to evaluate kidney function they include:

• A complete blood count.

• A blood creatinine test.

• A blood urea nitrogen test.

• A blood gas test is used to evaluate the levels of oxygen, carbon dioxide, and acid-base imbalance in the blood.

Other tests that are used to detect kidney problems include:

• Kidney Function Tests: The kidney biopsy test can detect the signs of kidney failure. The test can detect metabolic acidosis, waste products, uric acid, phosphate, and acidosis.

• Kidney Biopsy: In a kidney biopsy test, tissue from the kidney tissue is removed and examined under a microscope.

• Abdominal ultrasound.

• Urinalysis.

How Is Chronic Interstitial Nephritis Treated?

The treatment of chronic interstitial nephritis depends upon the cause and duration of the condition. For example, when a drug allergy causes interstitial nephritis, in such cases, the only treatment needed is the removal of the drug. Other cases can be treated with anti-inflammatory medications. In some cases, interstitial nephritis causes permanent damage to the kidneys. The damage to the kidneys requires treatment. Specific methods can be useful in treating chronic interstitial nephritis, including:

• Eliminate salt from the diet as it can improve water retention and high blood pressure.

• Intake of a low-protein diet can be beneficial.

• In more severe cases, dialysis can be needed for support.

• Kidney transplantation can be needed.

What Is the Prognosis of Chronic Interstitial Nephritis?

The prognosis of chronic interstitial nephritis depends upon the cause and the degree of renal dysfunction at the time of diagnosis and other treatment options for the underlying conditions. However, early identification can often lead to improved renal outcomes.

What Are the Complications of Chronic Interstitial Nephritis?

The possible complications of chronic interstitial nephritis are metabolic acidosis, chronic kidney failure, and end-stage kidney disease.

Conclusion

Chronic interstitial nephritis is characterized by chronic inflammation originating in the renal interstitium. It is associated with loss of glomerular filtration rate with time. So it is important to remove the potentially offending agent and to treat the associated systemic disease to help recover and preserve renal function.