This disorder may be caused by diseases, drugs, and toxins that damage the kidneys.
People may have excessive urination, urinate at night, or have fever and/or a rash.
Laboratory tests of blood and urine are done as well as usually imaging tests and sometimes a kidney biopsy.
Stopping exposure to harmful drugs and toxins and treating underlying disorders improve kidney function.
(See also Overview of Kidney Filtering Disorders Overview of Kidney Filtering Disorders Each kidney contains about 1 million filtering units (glomeruli). The glomeruli are made up of many microscopic clusters of tiny blood vessels (capillaries) with small pores. These blood vessels... read more .)
Tubulointerstitial nephritis may be
Tubulointerstitial nephritis often results in kidney failure Overview of Kidney Failure Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney failure has many possible causes. Some lead to a rapid decline in kidney function... read more (loss of most kidney function). It may be caused by various diseases, drugs, toxins, or radiation that damages the kidneys. Damage to the tubules results in changes in the amounts of electrolytes (for example, sodium and potassium) in the blood or in problems with the kidney's ability to concentrate urine, resulting in urine that is too dilute. Problems concentrating urine causes an increase in daily urine volume (polyuria Excessive or Frequent Urination Most people urinate about 4 to 6 times a day, mostly in the daytime. Normally, adults pass between 3 cups (700 milliliters) and 3 quarts (3 liters) of urine a day. Excessive urination can refer... read more ) and difficulty maintaining the proper balance of water and electrolytes in the blood.
The most common cause of acute tubulointerstitial nephritis is an allergic reaction to a drug. Antibiotics such as penicillin and the sulfonamides, diuretics, and nonsteroidal anti-inflammatory drugs (NSAIDs)—including aspirin—may trigger an allergic reaction. The interval between the exposure to the allergen that caused the reaction and the development of acute tubulointerstitial nephritis varies usually from 3 days to 5 weeks.
Drugs can also cause tubulointerstitial nephritis through nonallergic mechanisms. For example, NSAIDs can directly damage the kidney, taking up to 18 months to cause chronic tubulointerstitial nephritis.
Infection of the kidneys Kidney Infection Pyelonephritis is a bacterial infection of one or both kidneys. Infection can spread up the urinary tract to the kidneys, or uncommonly the kidneys may become infected through bacteria in the... read more (pyelonephritis) can also cause acute or chronic tubulointerstitial nephritis. Kidney failure is unlikely unless inflammation causes a blockage in the urinary tract or pyelonephritis occurs in both kidneys.
Tubulointerstitial nephritis may be caused by immunologic disorders that primarily affect the kidney such as anti-tubular basement membrane (anti-TBM) Goodpasture Syndrome Goodpasture syndrome is an uncommon autoimmune disorder in which bleeding into the lungs and progressive kidney failure occur. People usually have difficulty breathing and may cough up blood... read more antibody-associated interstitial nephritis.
Some people have few or no symptoms. When symptoms develop, they are highly variable and may develop suddenly or gradually.
When tubulointerstitial nephritis develops suddenly, the amount of urine produced may be normal or less than normal. Sometimes the amount of urine produced is excessive and people urinate more frequently and waken during the night to urinate (nocturia). If the cause is pyelonephritis, symptoms may include fever, painful urination, and pain in the lower back or side (flank). If the cause is an allergic reaction, symptoms may include fever and a rash.
When tubulointerstitial nephritis develops gradually, the first symptoms to appear are those of kidney failure, Overview of Kidney Failure Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney failure has many possible causes. Some lead to a rapid decline in kidney function... read more such as itchiness, fatigue, decreased appetite, nausea, vomiting, and difficulty breathing. Blood pressure is normal or only slightly above normal in the early stages of the disease. The amount of urine produced may be greater than normal.
Laboratory tests (kidney function tests Kidney Function Tests Doctors can assess kidney function by doing tests on blood and urine samples. Creatinine, a waste product, is increased in the blood when kidney function is decreased by a large amount. Creatinine... read more ) usually detect signs of kidney failure, such as an increase in the level of waste products in the blood, or other characteristic abnormalities, such as metabolic acidosis Metabolic acidosis Acidosis is caused by an overproduction of acid that builds up in the blood or an excessive loss of bicarbonate from the blood (metabolic acidosis) or by a buildup of carbon dioxide in the blood... read more and low levels of potassium, uric acid, or phosphate. A kidney biopsy Tissue and Cell Sampling Site-specific biopsies and cell sampling are also used in the evaluation of people with suspected kidney and urinary tract disorders. (See also Overview of the Urinary Tract.) A kidney biopsy... read more is the only conclusive means of diagnosing tubulointerstitial nephritis, although a biopsy is rarely done except when the cause cannot be found or treatment with corticosteroids is being considered.
When tubulointerstitial nephritis develops suddenly, the urine may be almost normal, with only a trace of protein or pus, but often the abnormalities are striking. The urine may show large numbers of white blood cells, including eosinophils. Eosinophils do not normally appear in the urine, but when they do, a person may have acute tubulointerstitial nephritis caused by an allergic reaction. In such cases, blood tests may show that the number of eosinophils in the blood is increased.
A doctor may order ultrasonography, radionuclide scanning, or both. When an allergic reaction is the cause, the kidneys usually are large because of inflammation caused by the allergic reaction. This enlargement can be seen with radionuclide scanning or ultrasonography, which are imaging studies done to differentiate acute tubulointerstitial nephritis from other sudden kidney disorders.
Kidney function usually improves when an offending drug is stopped or treatment of the underlying disorder is effective, although some kidney scarring is common. The prognosis tends to be worse when the offending drug is a nonsteroidal anti-inflammatory drug Nonsteroidal Anti-Inflammatory Drugs In some cases, treating the underlying disorder eliminates or minimizes the pain. For example, setting a broken bone in a cast or giving antibiotics for an infected joint helps reduce pain.... read more (NSAID).
When the inflammation occurs gradually, kidney damage may develop at different rates in different portions of the kidney. The person may develop abnormalities characteristic of damage to different portions of the kidney at different times. However, kidney damage usually progresses to involve most or all of both kidneys and becomes irreversible.
The first step in treating acute tubulointerstitial nephritis is to stop whatever drug is causing the kidney damage and treat the underlying disorder. Treatment with a corticosteroid may speed the recovery of kidney function when tubulointerstitial nephritis is caused by certain disorders (such as systemic lupus erythematosus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic autoimmune inflammatory connective tissue disorder that can involve joints, kidneys, skin, mucous membranes, and blood vessel walls. Problems in the... read more and Sjögren syndrome Sjögren Syndrome Sjögren syndrome is a common autoimmune rheumatic disorder and is characterized by excessive dryness of the eyes, mouth, and other mucous membranes. White blood cells can infiltrate and damage... read more ) or an allergic reaction. If kidney function worsens and kidney failure develops, dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more is usually needed. In some cases, the damage is irreversible, and kidney failure becomes chronic.
Chronic tubulointerstitial nephritis is treated by stopping the causative drug or treating the underlying disorder. Supportive care such as controlling blood pressure is often used. Drugs may be used to try to slow progression of kidney disease. Irreversible severe kidney damage, whatever the cause, results in the need for dialysis Dialysis Dialysis is an artificial process for removing waste products and excess fluids from the body, a process that is needed when the kidneys are not functioning properly. There are a number of reasons... read more or kidney transplantation. Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more