The kidneys are workhorses. When all is working well, the bean-shaped organs that are around the size of a fist may be given little thought, yet they play an important role removing waste and extra…
The kidneys are workhorses. When all is working well, the bean-shaped organs that are around the size of a fist may be given little thought, yet they play an important role removing waste and extra fluid from the body. This is done using about a million filtering units per kidney — or nephrons, which each include a filter, or glomerulus, and a tiny tubule that collects urine from the glomerulus, the National Institute of Diabetes and Digestive and Kidney Diseases notes.
But in some people the kidneys become damaged and aren’t able to filter blood properly. A sustained decline in function, or chronic kidney disease, can cause a wide range of complications from fluid retention to decreased immune response and a spike in potassium levels in the blood called hyperkalemia that can affect heart function. CKD and kidney failure can be life-threatening.
Among the most common causes of kidney disease are diabetes and high blood pressure, followed by inflammation of the kidneys, or what’s called nephritis — most frequently glomerulonephritis — says Dr. Tarek Alhamad, an assistant professor of renal medicine at Washington University School of Medicine and medical director of the kidney transplant program at Barnes-Jewish Hospital in St. Louis.
— Glomerulonephritis, which involves damage to the filters in the kidney, is the most common. “When the glomerulus gets inflamed, there’s glomerulonephritis,” explains Dr. Anupam Agarwal, a nephrologist and the director of the division of nephrology at the University of Alabama at Birmingham.
— Interstitial nephritis affects the space between tubules in kidneys, and commonly accompanies inflammation of tubules themselves, or tubulointerstitial nephritis. “The tubules comprise about 80 percent of the volume of the kidney — so it’s hard to get interstitial nephritis without the tubules being involved as well,” Agarwal says.
Causes of Nephritis
The list of things that can cause nephritis is long — and it can be difficult to predict who will develop inflammation of the kidneys. But the nature of the cause can affect, for example, whether glomerulonephritis comes on suddenly and is acute, or if it develops over time and is chronic, or whether a person develops acute interstitial nephritis or chronic interstitial nephritis.
For acute glomerulonephritis, causes may include:
— Infections like strep throat
— The autoimmune disease lupus. Lupus can also cause interstitial nephritis.
— Goodpasture’s syndrome, or pulmonary renal syndrome, where there’s destruction of glomeruli.
— ANCA- (Anti-Neutrophil Cytoplasmic Autoantibody) associated vasculitis, an autoimmune disease that can attack organs including the kidney.
Genetics may also play a role in a person’s developing nephritis, like for chronic glomerulonephritis. “Sometimes the disease runs in the family. This kind often shows up in young men who may also have hearing loss and vision loss,” the National Kidney Foundation notes. “Some forms are caused by changes in the immune system. However, in many cases, the cause is not known. Sometimes, you will have one acute attack of the disease and develop the chronic form years later.” Along with other conditions like lupus that are known to cause inflammation of the kidneys, hepatitis C and HIV are also associated with glomerulonephritis.
While it’s not known precisely how glomerulonephritis can be prevented, NKF notes that “good hygiene, practicing ‘safe sex’ and avoiding IV drugs are helpful in preventing viral infections such as HIV and hepatitis, which could lead to this illness.” In addition, early detection can also make all the difference to treat those conditions and reduce a person’s risk of developing nephritis. “Now we have good treatments for both HIV and hepatitis C luckily,” says Dr. Joseph Vassalotti, chief medical officer of the National Kidney Foundation. “So even if unfortunately you develop those infections, early treatment can help prevent the disease.”
For interstitial nephritis, the causes also vary. But acute interstitial nephritis is often caused by the side effects of certain drugs.
Drugs linked with interstitial nephritis include NSAIDs (non-steroidal anti-inflammatory drugs) — like ibuprofen and naproxen (Aleve) — which are available over the counter; and antibiotics — namely, penicillins or cephalosporins. That’s in addition to proton-pump inhibitors — medications taken for gastroesophageal reflux disease, or GERD — for which research has increasingly raised concerns about the potential side effects of long-term use. “If you don’t need these medications, you should not take them; and if you need them, you need to take them for a short period of time,” Alhamad says.
— An allergic reaction to a drug — called acute interstitial allergic nephritis.
— Autoimmune disorders, such as antitubular basement membrane disease, Kawasaki disease and Sjögren syndrome
— Long-term use of medications like acetaminophen (Tylenol), aspirin and NSAIDs. This is referred to as analgesic nephropathy
— Too little potassium in the blood
— Too little calcium or uric acid in the blood
As with kidney disease in general, it can be difficult to detect nephritis, especially in the early going. “Kidney disease overall is a silent disease,” Alhamad says. Generally speaking, there aren’t any major symptoms until the disease is advanced, he says.
While routinely there are no outward signs that a person has nephritis, sometimes a person may notice blood in the urine or a significant change in urine color, so that it’s more pinkish or more sometimes even java- or cola-like in color — “dark, dark urine,” Alhamad says. “This might be one of the symptoms that can lead to early detection.”
As kidney function declines, a person can also get swelling — including in the feet, and around the legs and eyes — Agarwal says, and nephritis is also often associated with high blood pressure. “One of the big jobs of the kidney is to excrete water and other waste products,” he explains. “So when the kidney is not able to function, it tries to protect itself, and the body, and tries to hang onto salt, or sodium; and whenever you retain sodium, you also retain water.”
Especially for those who may be at higher risk, routine bloodwork, in addition to urine testing, can be done to look at levels of a compound called creatinine that will reflect kidney function.
Where damage is suspected, clinicians may also recommend imaging, like an X-ray, MRI or a CT scan to take a closer look at the kidney. But a kidney biopsy is usually needed to make a definitive diagnosis.
Some patients with nephritis may recover fully and regain normal kidney function. Along with going off a drug, patients who have an allergic reaction to a drug that causes interstitial nephritis may be given low-dose steroids to reduce the inflammation and help the kidney recover, Alhamad says. But, he adds, in the majority of cases, those who develop nephritis will continue to have some kidney disease. “They may not end up on dialysis … but they will have some kidney damage,” he says.
That said, experts say treating or managing underlying conditions or addressing other causes — in addition to being aware of family history and other risk factors — can help limit kidney damage and retain function. “Some of the medications that are used to treat lupus can help prevent the development of kidney disease or slow the development with it, if the patient does develop lupus nephritis,” Vassalotti says.
Limiting Kidney Damage
The challenges of early detection with nephritis can make preventing serious complications and even kidney failure, in some instances, difficult. That makes it all the more important to monitor kidney function, particularly in those who have risk factors for developing nephritis. That includes people with lupus — about half of whom, according to research, develop lupus nephritis — for whom clinicians say careful management of the disease is critical to limit damage to the kidneys.
Experts also advise routinely reviewing medications you take. Talk with your doctor, too, about any supplements you might be taking. Alhamad says certain herbal supplements used for weight loss, which aren’t regulated by the Food and Drug Administration, have also been linked to nephritis.
While it’s hard to know who might develop nephritis from taking medications that may cause inflammation in the kidneys, it’s best to proceed with caution. “We don’t want patients to stop their medications indiscriminately.” Vassalotti says. “But we want them to be careful about what they take, and know what they take, and talk to their doctors about whether everything’s really necessary.”