Inflammation of the kidneys, known as nephritis, is a potentially dangerous condition that usually develops as a consequence of an infection elsewhere in the body. One type of kidney inflammation, known as pyelonephritis, is most often a result of direct bacterial invasion of the kidney via the lower urinary tract. Another type, known as glomerulonephritis, is often an indirect result of infection elsewhere in the body, although certain inherited disorders and immune system diseases also can trigger it.
All types of nephritis potentially can cause kidney failure, a breakdown in the kidneys' ability to filter blood and regulate the normal balance of fluids. Instead of absorbing adequate amounts of proteins and other essential nutrients back into the body, failing kidneys lose these substances into the urine. Although most children recover from nephritis with no kidney damage, those who suffer kidney failure may require dialysis and transplantation.
HOW DOES NEPHRITIS DEVELOP?
In the course of a urinary tract infection, bacteria may travel up the ureters (the two tubes that connect the kidneys to the bladder) and multiply in the kidney, causing inflammation (pyelonephritis). Also, an infection or other disease process elsewhere in the body can result in the accumulation of antibodies and other proteins in the glomeruli (the kidney's filtering units). These substances lead to glomerular injury and inflammation (glomerulonephritis).
The most common form or glomerulonephritis develops after a strep infection and, in 90 percent of cases, resolves on its own. Other types of glomerulonephritis have a long, chronic and often progressive course. On the other hand, pyelonephritis, which is caused by a bacterial infection, is usually treated with antibiotics.
WHEN SHOULD I SUSPECT THAT MY CHILD HAS NEPHRITIS?
Bloody urine, which may appear pink, cola-colored or cloudy, is the hallmark of nephritis, although the blood is not always visible to the naked eye. Most children with nephritis also feel quite ill. Their symptoms may include fever, poor appetite, nausea, weakness and pain in the side.
IS MEDICAL ATTENTION NECESSARY?
Yes. Since nephritis can lead to kidney failure and permanent kidney damage, a doctor's attention is essential. Possible complications requiring medical care include high blood pressure and fluid buildup. If these complications develop, hospitalization is usually necessary.
HOW CAN THE PEDIATRICIAN TELL IF MY CHILD HAS NEPHRITIS?
The pediatrician diagnoses nephritis on the basis of a physical examination and careful analysis of the urine. Blood tests are frequently performed as well to determine whether antibodies to certain bacteria (particularly one type of stretococcal bacteria) are elevated, indicating that the problem is a secondary effect of infection. In a few cases, the doctor may need to remove a small sample of kidney tissue (a biopsy) for laboratory examination.
WHAT TREATMENTS ARE AVAILABLE?
Unless the child has an active infection, in which case antibiotics are administered, treatment usually consists of watching for complication and administering drugs to keep the body functioning smoothly until the kidney inflammation subsides. To decrease the swelling, the child's intake of fluids may have to be limited.
POSSIBLE CAUSES OF NEPHRITIS
• Bacterial infection spread from the bladder.
• Antibody deposits resulting from a bacterial infection (or, more rarely, a viral infection) elsewhere in the body. Most cases of this type follow streptococcal throat or skin infections.
• Genetic disorders, particularly various types of hereditary nephritis. In one of the most common of these disorders (Alport's syndrome), hearing impairment usually accompanies chronic nephritis.
• Toxic reactions to certain drugs, such as probenecid, which is given to boost the effect of antibiotics.
• Disorders, such as lupus, that are caused by a malfunction of the immune system in which antibodies attack the body's own tissues.
PREVENTING NEPHRITIS
• Tell your pediatrician about any history of drug allergies in your family.
• Get prompt treatment for urinary tract infections and streptococcal throat and skin infections.
GETTING HELP
Call your doctor if:
• Your child begins to urinate more or less frequently than usual.
• Your child's urine has a strange color or odor.
• Your child's face seems puffy, particularly around the eyes.
