Table of Contents
Defnition of Nephritis
Nephritis – INFLAMMATION of the kidney.
Nephritis can be acute (come on suddenly), chronic (long-term), or recurrent (repeated episodes of acute nephritis). Chronic nephritis can lead to NEPHROPATHY.
When infection involves the glomeruli, it is infectious GLOMERULONEPHRITIS. Infectious glomerulonephritis develops as a complication of untreated or undertreated STREP THROAT or other streptococcal infection elsewhere in the body. Occasionally another bacterial strain such as staphylococcus is responsible.
Infection that travels up the ureters from the BLADDER as a complication of untreated or undertreated URINARY TRACT INFECTION (UTI) is pyelonephritis. In pyelonephritis the infection involves the pelvis of the kidney where URINE drains from the kidney into the ureters. VESICOURETERAL REFLUX, in which urine backflows from the bladder through the ureters to the kidneys, is a common cause of pyelonephritis.
In interstitial nephritis the inflammation affects the spaces between the tubules in the nephrons. Such inflammation is nearly always a consequence of acute toxic nephropathy. Medications such as penicillin and penicillin-derived antibiotics, the diuretic medication furosemide and thiazide diuretics, and NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) are commonly responsible for acute interstitial nephritis. The nephritis generally resolves without lingering complications within a few weeks of stopping the medication.
The autoimmune disorder SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) affects the KIDNEYS in about 40 percent of people who have SLE. In some people, lupus nephritis may be the only manifestation of SLE. Lupus nephritis can progress rapidly to RENAL FAILURE and END-STAGE RENAL DISEASE (ESRD). Because women who have SLE outnumber men who have SLE nearly nine to one, lupus nephritis far more commonly affects women.
Hereditary nephritis is a genetic disorder that results from GENE mutations. The symptoms of hereditary nephritis are apparent at or shortly after birth, and the inflammation tends to be progressive. The most frequent presentation of hereditary nephritis is ALPORT’S SYNDROME, a disorder of protein encoding.
Symptoms and Diagnostic Path
The symptoms of nephritis may include
- HEMATURIA (bloody urine)
- OLIGURIA (diminished urine volume)
- edema (fluid retention that causes swelling in the tissues), notably of the face, hands and arms, and legs and feet
- loss of APPETITE, NAUSEA, and VOMITING
- FEVER (bacterial nephritis)
The diagnostic path begins with urinalysis and BLOOD tests that assess kidney function. Urinalysis may show the presence of BACTERIA, indicating the cause of the nephritis is infection. Other diagnostic procedures the nephrologist may choose to conduct include further blood and urine tests, ULTRASOUND, COMPUTED TOMOGRAPHY (CT) SCAN, and kidney biopsy. The biopsy shows the presence of inflammation and any damage that has occurred to the tubules or glomeruli.
Treatment Options and Outlook
Treatment depends on the underlying cause. Bacterial nephritis requires antibiotic therapy, often long term (up to six months). Severe infection requires hospitalization for intravenous ANTIBIOTIC MEDICATIONS. Most people recover fully and without residual damage from bacterial nephritis. Because the kidneys play key roles in regulating BLOOD PRESSURE kidney disease that interferes with such functions can result in HYPERTENSION (high blood pressure), which requires treatment. The doctor may recommend dietary changes to limit sodium, protein, and water intake. Treatment for lupus nephritis often includes IMMUNOSUPPRESSIVE THERAPY.
Risk Factors and Preventive Measures
The primary risk factors for nephritis are the conditions that can cause it. Nephrotoxins are generally avoidable once the doctor identifies them as responsible for the nephritis. Bacterial infections nearly always migrate to the kidneys from elsewhere in the body. Early and appropriate treatment for the primary infection, particularly strep throat, helps prevent the infection from spreading to the kidneys.