Healthy organ systems function to keep humans alive and in good physical shape. One very important pair of organs is the kidneys. The kidneys are a pair of bean-shaped organs, placed on either side of the body in the back just below the ribcage. The kidneys' primary function is to filter waste products from the body where they are excreted as urine.

Each kidney consists of millions of small, tiny structures called nephrons. The nephrons assist the filtration process by filtering blood and removing waste products and extra water to form the urine. The nephrons are known as "the filtering unit" of the kidneys. Once the waste products are removed, urine moves from the kidney through the ureters, or tubules, and to the bladder when it is stored until excreted out of the body. Any damage to these nephrons results in ineffective filtering of the waste products and can lead to a condition called interstitial nephritis.

Understanding Interstitial Nephritis

Interstitial nephritis is a condition where there is inflammation within the kidneys. 'Interstitial' means that the inflammation does not affect the blood vessels or filters in the kidney but only the parts in between. Nephritis means, quite simply, kidney disease.

Inflammation in the region between the tubules often cause swelling and scarring inside the kidney; however, typically it does not cause any pain. Unfortunately, the inflammation does inhibit the filtering ability of the kidney. Interstitial nephritis is a serious condition, and should be treated promptly because untreated interstitial nephritis can result in kidney failure. Kidney failure occurs when waste and extra fluid build up in the body and affect the heart, brain, lungs, and other organs.

There are two kinds of interstitial nephritis – acute interstitial nephritis (AIN) is temporary while chronic interstitial nephritis (CIN) is long-lasting and can become worse over time.

The following are causes of interstitial nephritis:

• Infections, such as acute bacterial pyelonephritis, renal tuberculosis, and fungal nephritis, can cause direct injury to the kidneys or can be associated with indirect injury caused by medications used in the treatment of said infections
• Allergic reactions to drugs
• Long-term use of medicines such as acetaminophen, aspirin, and non-steroid anti-inflammatory drugs can result in a condition called analgesic nephropathy
• Side-effects of certain antibiotics like penicillin, ampicillin, and sulfonamide medicines, just to name a few
• Medicines like furosemide and thiazide diuretics that are used to reduce swelling
• Autoimmune disease, a disease where a person’s immune system acts against their kidney and damages it; the exact reason for autoimmunity is not known
• Side-effects of medications often are the cause of acute interstitial nephritis, but they can lead to chronic interstitial nephritis and kidney failure especially in elderly people

Interstitial nephritis is sometimes difficult to detect because it does not cause any pain and the quantity of the urine is typically normal even when the kidneys are not functioning properly.

Some people may notice an excessive or reduced output of urine, or an increase in trips to the bathroom during the night. Urine may be dark-colored and, in some cases, may contain blood. The person may have nausea or vomiting and feel frequently dry and thirsty.

A fever with or without skin rashes may be present. As the toxins accumulate in the body, there may be change in mental status, such as drowsiness or confusion. There may be swelling or sudden weight gain due to retention of excess fluid.

In severe cases, the kidneys may start to fail, where wastes and body fluid build-up resulting in tiredness, sickness, and nausea. In extreme cases coma is a possibility.

Increased blood pressure is a common indication of interstitial nephritis. An arterial blood gas test may be performed to measure the amount of oxygen and carbon dioxide present and to determine the pH of blood. Since the main function of kidneys is to maintain the blood pH, levels being too high or low can indicate a problem. The amount of urea and creatinine in the blood is also analyzed because these elements are normally excreted out through urine.

Any excess fluid in the heart and the lungs is diagnosed by listening to abnormal sounds through a stethoscope.

In more serious instances, a kidney biopsy is performed by removing a small piece of kidney. This test is done in order to determine the exact cause of the kidney malfunction. Urinalysis involves a number of tests, detecting the amount of various compounds excreted in the urine. An ultrasound scanning will demonstrate the size and structure of kidney but is usually performed in conjunction with other tests because an ultrasound cannot conclusively diagnosis interstitial nephritis.

Treatment for interstitial nephritis is aimed at the underlying causes. If caused by medications such as acetaminophen, aspirin, and nonsteroidal anti-inflammatory drugs then stopping the medicines is the first step to reduce the symptoms. If the cause is an infection, then the doctor will focus on treating that infection. In the case of more severe inflammation, corticosteroids or anti-inflammatory drugs may be prescribed.

In addition to medical assistance, simple dietary changes such as limiting the intake of salt and fluid can help reduce swelling and lower high blood pressure. Protein intake should also be limited in order to avoid waste buildup in the body. In serious cases, patients will require a treatment procedure called dialysis. In these cases, a special machine is used to filter waste products from the patient's blood.

Outlook

Many people with interstitial nephritis lead a normal life. Sickness is very common in the early stage of the disease. However, once they symptoms are treated, in many cases, the disease goes away.

Patients with underlying problems like high blood pressure require continued treatment and medication for those causes. Obviously, severe kidney disease and dialysis will affect the patient's lifestyle, but fortunately it is possible to cope with these challenges.