Interstitial nephritis is an inflammation of the kidneys that can present in acute or chronic form. In addition to viral and bacterial causes, possible triggers include autoimmune diseases and drug noxious agents. Treatment consists of eliminating the causative noxious agent and serves to preserve kidney function.
What is interstitial nephritis?
The kidneys are sometimes the most important detoxification organs in the human body. They filter the blood free of harmful substances and remove these substances from the body in the form of urine. Damage to the kidney tissue can result in functional impairment of the filtering system. Lesions in kidney tissue have different causes. For example, inflammation leaves scars in the tissue, which can cause permanent impairment of kidney function, especially in the renal tubule system. Like pyelonephritis or renal pelvic inflammation, interstitial nephritis or tubulointerstitial nephritis is an inflammatory disease. While renal pelvic inflammation is usually associated with bacterial infections, tubulo-interstitial nephritis is not necessarily a bacterial inflammation. The disease shows low incidence, so it is rare. The inflammation was first described in 1878. Jean-Martin Charcot is considered to be the first describer. He already documented at that time that the disease in the late stage dilates the tubular epithelium and can lead to death by renal failure. In addition to an acute form of the disease, he pointed out a chronic form that extends over time and causes gradual renal failure to occur.
Causes
The causes of interstitial nephritis vary with the form. For example, the acute form may correspond to an allergic hypersensitive reaction to drugs, most notably antibiotics such as ampicillin, methicillin, cimetidine, NSAIDs, diuretics, or proton pump inhibitors. Herbal toxins are also possible triggers. In addition, the acute variant may be viral in nature and thus be due, for example, to hantavirus. In addition, acute parainfectious forms can occur in the context of bacterial infections with streptococci, legionella or similar pathogens. The cause of the acute autoimmune form is again autoimmune diseases such as Goodpasture’s syndrome. Chronic interstitial nephritis, as an allergic-toxic event, again presents to different drugs than the acute form, so especially to analgesics. In addition, this form is often associated with substances such as lead and cadmium or has metabolic causes, for example, in the context of hyperuricemia in gout. Hypercalcemia, hyperoxaluria, hypokalemia, and cystinosis may also be causative. The chronic form in ADPKD is hereditary. It is autoimmunological in SLE, Sjögren’s syndrome and sarcoidosis. In addition, infectious and obstructive diseases such as chronic bacterial phyelonephritis exist. Apart from these, the chronic form may develop in response to physical agents, including radiation nephritis.
Symptoms, complaints, and signs
Tubulointerstitial nephritis is characterized by a clinically multifaceted picture. All changes in the renal parenchyma may remain asymptomatic during the course of the disease. However, the lesions may just as well lead to partial failure of tubular functions or even induce acute renal failure. In acutely manifest tubulointerstitial nephritis, renal symptoms are sometimes joined by hypersensitivity reactions. In at least 15 percent of all cases, patients suffer from fever, exanthema of the skin or arthralgia. Some patients complain of flank pain. In the chronic form, the patients’ condition deteriorates insidiously. Pathology differs depending on the form. In acute interstitial nephritis, the interstitium is odematous altered. Mononuclear infiltrates of plasma cells, lymphocytes, and eosinophilic granulocytes can be detected. Chronic interstitial nephritis additionally leads to tubular atrophy and glomerulopathy. The symptoms and pathology of the renal tissue provide detailed information about the cause of the inflammation. In allergic reactions, for example, skin symptoms are common, while increased eosinophilic granulocytes are seen in the tissue.
Diagnosis and course of the disease
Laboratory tests for suspected interstitial nephritis include determination of urea and creatinine. Urine sediment and 24-h collected urine are indicated. Tubular dysfunction may cause hematuria or proteinuria, hyperphosphaturia, and aminoaciduria or glucosuria. In addition, increased urine pH or salt loss indicates the disease. Suspicion of the acute form can be corroborated with evidence of eosinophilia or IgE elevation. Sonography again shows an echo-rich and widened parenchyma in the acute form. The prognosis of patients depends on the unform of the disease and the time of diagnosis. The acute form has a relatively favorable prognosis.
Complications
In this disease, the patient may die in the worst case. Death can occur when the kidneys fail and proper treatment is not initiated. Similarly, the affected person is then dependent on dialysis or organ transplantation to continue to survive. The quality of life is significantly reduced by this disease. It is not uncommon for those affected to suffer from a severe fever and also discomfort on the skin. Likewise, flank pain also occurs, which leads to movement restrictions. Everyday life is made significantly more difficult for the patient by the symptoms. Due to the permanent pain and discomfort, it is furthermore not uncommon for mental illness or even depression to occur. Treatment is carried out with the help of medication. No particular complications occur. However, renal insufficiency must be avoided at all costs to prevent a life-threatening condition for the patient. If necessary, the life expectancy of the affected person is reduced by the disease. If necessary, psychological treatment of the patient may also take place to avoid depression or other discomfort.
When should you see a doctor?
Individuals who notice typical warning signs, such as fever or exanthema of the skin, should see a doctor promptly. Interstitial nephritis must be diagnosed and treated with medication to rule out subsequent health problems. In addition, the disease significantly restricts the quality of life. That is why medical advice is needed at the first sign of kidney inflammation. People who regularly take antibiotics or have recently contracted a bacterial infection are particularly susceptible to developing interstitial nephritis. People with gout, hypercalcemia or sarcoidosis also belong to the risk groups and should definitely have the above symptoms examined. The appropriate physician is the general practitioner or a nephrologist. If underlying diseases are present, the physician in charge is optimally informed. Children should be taken to the pediatrician if they have kidney disease. If psychological complaints have already developed, therapeutic help is also recommended. The sufferer should seek comprehensive treatment of physical and psychological complaints at an early stage in order to avoid negative health consequences.
Treatment and therapy
Treatment of tubulointerstitial nephritis focuses on eliminating the primary cause or treating the underlying disease. For drug-related causes, the drugs are discontinued to eliminate the causative noxious agent. If acute renal failure occurs, hemodialysis takes place. Drug therapy is indicated especially in autoimmune diseases. Prednisone is often administered for immunosuppression. Progress has also been observed in some cases in connection with therapies of intravenous or oral corticosteroid administration. In addition, mycophenolate mofetil has recently been used for treatment. If the triggering noxious agent can be eliminated, more than half of all cases heal without developing chronic renal failure. In the chronic form, the glomeruli of the kidneys are often affected as well. For this reason, additional supportive measures are often used in the treatment. This supportive therapy is used to prevent chronic renal failure and to prevent further deterioration of function. Evidence-based treatments are not available.
Outlook and prognosis
The prognosis of interstitial nephritis depends on the disease trigger present. Without treatment or therapy, the symptoms experienced can be expected to increase.The general well-being continuously decreases and the symptoms increase. In severe cases, kidney failure may occur. This poses a potential threat to the life of the affected person. Dialysis is necessary to ensure survival. In the long term, the patient needs a donor kidney. Organ transplantation is the only way to improve the quality of life as well as the life expectancy of the affected person. The surgical procedure is associated with various complications and side effects. The healing process is long and limitations in coping with everyday life are to be expected. If medical treatment is used at an early stage, a drug treatment is applied after the cause has been clarified. This pursues the goal of killing the pathogens as well as germs. Subsequently, they are removed from the body by the organism. At the same time there is an improvement of health. Existing complaints are alleviated and, in the best case, recovery occurs. In case of interstitial nephritis, there is a risk of permanent pain and irregularity. In addition, psychological sequelae may occur due to the severe mental stress. These worsen the overall prognosis of the patient.
Prevention
Because interstitial nephritis can have quite a few causes, all-inclusive prophylaxis is not possible.
Follow-up care
What follow-up care for interstitial nephritis looks like depends on the cause of the disease. Because there may be different triggers, there are no clear recommendations for follow-up and prophylaxis. However, patients can perform certain measures as directed by the physician to promote therapy. If discomfort occurs from an inappropriate medication, patients should consider an alternative with the physician. After discontinuing the medication, patients may experience interactions and side effects. Feedback from the physician can be used to tailor an improved medication regimen. If kidney failure underlies the condition, patients need to take it easy and stay in bed. Diet also helps reduce complications and relieve pain. Kidney failure can be counteracted by a healthy lifestyle with sufficient but moderate exercise. Avoiding stress is also important, not only during the recovery phase but also as a preventive measure. In addition, sufferers should have regular medical checkups so that they can act quickly if problems arise. In the case of a chronic disease, a permanent change in diet is recommended. If necessary, psychotherapeutic counseling is advisable. This helps those affected to have a better self-image and a better quality of life. Patients can also find a self-help group through their doctor or therapist.
What you can do yourself
Interstitial nephritis first requires a diagnosis by a doctor. The patient can take some steps to help medical treatment. If the symptoms are due to a poorly adjusted medication, this must first be discontinued. The patient should then make a note of any side effects and interactions of the prescribed medication and inform the doctor of these so that optimal medication can be achieved quickly. If the cause is kidney failure, the first thing to do is rest and bed rest. In addition, the patient should change his diet to avoid pain, dysfunction and other complications. In acute kidney failure, the most important self-help measure is to lead a healthy lifestyle with moderate exercise, a balanced diet and avoidance of stress. Chronic interstitial nephritis requires close monitoring by the appropriate medical professional. In addition, the affected person should adapt his or her lifestyle to the respective symptoms. Since a chronic disease represents a considerable impact on quality of life and well-being, therapeutic counseling is often useful. The doctor can also put the patient in touch with other sufferers or a self-help group. In the long term, the symptoms of kidney inflammation can be alleviated by dietary measures, rest and drug treatment.
