Brief overview
- Symptoms:Depending on the form of kidney inflammation, glomerulonephritis: often asymptomatic for a long time, nonspecific complaints such as fever and/or joint pain in interstitial nephritis, pain typical in renal pelvic inflammation.
- Diagnosis: doctor-patient interview (medical history), physical examination, blood and urine tests, in some cases imaging procedures and removal of a tissue sample.
- Causes and risk factors: In glomerulonephritis, usually immune system involved; triggers of interstitial nephritis often drugs, other underlying diseases; renal pelvic inflammation usually due to bacterial infection
- Prevention: causal prevention difficult, general healthy lifestyle with sufficient fluid intake and balanced diet as well as physical activity beneficial for (kidney) health
What is kidney inflammation?
Accordingly, kidney inflammation sometimes has serious consequences if the kidney only works to a limited extent or no longer at all. In some cases, there is even a danger to life.
It is urgently advisable to always have a kidney inflammation clarified by a doctor.
Types of kidney inflammation
Doctors distinguish between three forms of kidney inflammation, depending on the type of inflamed tissue:
- Inflammation of the renal corpuscles (glomerulonephritis)
- Interstitial nephritis
- Renal pelvic inflammation (pyelonephritis)
In glomerulonephritis, the so-called renal corpuscles (Malpighi corpuscles) are inflamed. These consist of a capsule and a vascular tangle, the so-called glomerulus. The name of this form of kidney inflammation is derived from the latter.
Interstitial nephritis
In interstitial nephritis, the so-called interstitium of the kidney is inflamed. This is the interstitial tissue – mainly connective and supporting tissue – of the kidneys, which encloses the renal corpuscles and the connected system of minute urinary tubules. If the urinary tubules (renal tubules) are also affected, the patient has tubulointerstitial nephritis.
Renal pelvic inflammation (pyelonephritis)
You can read all the important information about risk factors, symptoms, treatment and prevention of pyelonephritis in the article Renal Pelvic Inflammatory Disease.
What are the symptoms?
Whether symptoms occur with kidney inflammation and what exactly they look like depends on the form of the disease, its causes and the course of the disease. In some cases, affected individuals show no symptoms for a long time. The kidney inflammation and resulting kidney damage then remain untreated for (too) long.
Symptoms of glomerulonephritis
In contrast to renal pelvic inflammation, inflammation of the renal corpuscles (glomerulonephritis) usually progresses without pain. Doctors often discover the disease only by chance during routine examinations. Sometimes the disease is only noticed when the kidneys are already severely damaged and blood washing (dialysis) or transplantation are unavoidable.
The following signs, among others, indicate inflammation of the renal corpuscles:
- Reddish or brown-colored urine (blood in the urine)
- Water retention in the tissues (edema) especially in the face and eyelids
- High blood pressure (hypertension)
- Tiredness and fatigue
Kidney inflammation sometimes leads to acute deterioration of kidney function (acute renal failure). In contrast, in some affected patients, the kidney loses its function slowly and over several years, culminating in chronic kidney failure requiring dialysis.
The symptoms of interstitial nephritis manifest themselves in different forms. Sometimes there are no symptoms at all (asymptomatic course). In other cases, symptoms include:
- Fever
- Joint pain
- Skin rash
- Nodular changes under the skin (nodular erythema, erythema nodosum)
- Bloody or cloudy, foamy urine
In the long term, people with interstitial nephritis experience symptoms such as a yellow-brownish skin color, headaches and an overall dehydrated appearance. It is possible that chronic kidney failure will then occur.
A typical symptom of pyelonephritis is flank pain, which is pain on the side of the lower back.
For more signs of pyelonephritis, see the article Kidney Pelvic Inflammation.
How is kidney inflammation treated?
Effective treatment involves eliminating or treating the cause of the nephritis if possible. If, for example, the immune system is involved in the development of nephritis, the doctor sometimes prescribes drugs to suppress the immune response. Such immunosuppressants include glucocorticoids (cortisone).
If existing underlying diseases such as systemic lupus erythematosus or the human immunodeficiency virus (HIV) are the cause of kidney inflammation, doctors try to intensify treatment of these.
In addition, physicians often recommend general therapeutic measures for kidney inflammation. These include, for example:
- Physical rest
- Low-protein diet
- Low-salt diet in case of water retention in the tissues (possibly also dehydrating medication)
If glomerulonephritis does not cause any symptoms, no or hardly any protein and blood are detectable in the urine, and kidney function and blood pressure are normal, it is usually sufficient for patients to have regular check-ups by their doctor (including blood and urine tests).
Home remedies and kidney inflammation? Many people treat inflammations of the lower urinary tract, such as cystitis, often with home remedies themselves, at least in the initial stages. This is expressly not recommended in the case of kidney inflammation. Early medical examination and treatment are strongly recommended.
How is kidney inflammation diagnosed?
First, the doctor will have a conversation with you. Here he takes your medical history (anamnesis). Important questions are:
- Are there any complaints and if so, what are they?
- Do you have any previous or underlying diseases?
- Have you taken any medications or do you do so regularly? And if so, what are they?
This information helps the physician to narrow down the possible causes of the complaints and to assess the course of the disease.
Blood and urine tests are important for further diagnosis of kidney inflammation. In the blood test, the creatinine value is particularly important: if it is elevated, this indicates impaired kidney function. The doctor also has the urine examined in the laboratory for proteins and blood, among other things.
The increased excretion of proteins via the urine in glomerulonephritis causes the protein concentration in the blood to fall over time. In parallel, blood lipid levels rise (hyperlipoproteinemia). If water retention also occurs, physicians speak of nephrotic syndrome. For a doctor, a combination of these symptoms is a clear sign of kidney inflammation or damage to the renal corpuscles.
What causes kidney inflammation?
The different forms of kidney inflammation (glomerulonephritis, interstitial nephritis and pyelonephritis (inflammation of the renal pelvis)) have different underlying causes.
Causes of glomerulonephritis
- Primary glomerulonephritis: This occurs when no existing underlying disease is the cause of the inflammation of the kidneys or renal corpuscles, but the disease exists in the kidney itself. An example of this is the so-called IgA nephritis or IgA nephropathy, also known as Berger’s disease. This is the most common cause of glomerulonephritis worldwide.
Causes of secondary glomerulonephritis include:
- Human immunodeficiency virus (HIV)
- Certain connective tissue diseases (autoimmune diseases) such as systemic lupus erythematosus (SLE)
- Inflammation of the inner lining of the heart (endocarditis lenta) caused by certain bacteria (streptococci)
- inflammation of the liver (hepatitis)
- Cancer
- Medications
- Genetic defects
Causes of interstitial nephritis
Acute interstitial nephritis usually develops as an allergic reaction to drugs. Sometimes toxic effects of certain chemical substances are also behind it. Doctors refer to this as “abacterial interstitial nephritis”, i.e. interstitial kidney inflammation not caused by bacteria. More rarely, infections with bacteria or viruses or genetic causes are the trigger.
If interstitial nephritis results in infection not only of the surrounding tissue of the kidney, but also of the renal tubules, doctors refer to this as tubulointerstitial nephritis. Causes of this form of kidney inflammation are:
- Infections
- Reactions to medications
- Other diseases, such as glomerulonephritis, that spread to the interstitial tissue of the kidney
What is the course of a kidney inflammation?
The prognosis of a kidney inflammation is highly variable depending on the type, severity and course (acute or chronic). The duration of the disease is also not predictable across the board.
Acute nephritis heals in many cases if diagnosed and treated in time. If left untreated, it can lead to complete kidney failure in severe cases.
Early diagnosis and treatment are particularly important in the case of rapidly progressive glomerulonephritis (RPGN). This sometimes takes a severe course and leads quite quickly (within weeks or months) to kidney failure. If the kidneys still have residual function at the start of treatment, kidney function improves in more than 60 percent of those affected.
Chronic courses of kidney inflammation are possible, for example when people take high-dose painkillers for a long time (analgesic anphropathy).
How do I maintain kidney health?
As diverse as kidney inflammation is as a disease, so are the causes. Nevertheless, there are certain measures that generally help to maintain the health of your body and, in particular, your kidneys. These include:
- Give up smoking. This will protect your blood vessels, not just those in your kidneys.
- Ensure daily physical activity, which contributes to normal blood pressure and prevents diabetes mellitus.
- Eat a healthy, balanced diet to regulate your body weight and keep deposits in the blood vessels to a minimum.
