Analgesic nephropathy results from years of use of certain pain medications. In the worst cases, chronic interstitial nephritis results in complete kidney failure.
What is analgesic nephropathy?
Analgesic anphropathy results from years of use of certain pain medications. Analgesic anphropathy also goes by the name phenacetin kidney in medicine. This refers to a chronic tubolo-interstitial nephropathy that results from prolonged abuse of various analgesics. The most important component here is the active ingredient phenacetin. In addition, non-steroidal anti-inflammatory drugs such as acetylsalicylic acid (ASA) and paracetamol are also considered possible triggers. The proportion of analgesic anphropathy in terminal renal failure is between one and three percent. In the female sex, the disease manifests itself significantly more frequently than in the male sex. Thus, women resort to analgesics more often than men. People who take phenacetin or mixed analgesics at regular intervals are twenty times more likely to develop analgesic anphropathy than other people. In 1986, phenacetin was banned in Germany. Since then, the disease has almost completely disappeared in the Federal Republic.
Causes
In earlier years, the cause of analgesic anphropathy was the constant use of drugs containing the active ingredient phenacetin. These were not infrequently offered as mixed preparations. Thus, in addition to phenacetin, they also contained caffeine or codeine. The use of mixed preparations with paracetamol resulted in a two to three times higher risk of developing analgesic anphropathy. Analgesic anphropathy was particularly prevalent in the GDR, Australia, the USA, Switzerland, Belgium, Sweden, and Eastern Europe. In West Germany, the proportion of people with analgesic anephropathy was between four and nine percent among patients requiring dialysis. Despite the continued use of acetaminophen mixed analgesics, analgesic anphropathy almost disappeared after phenacetin was banned. Phenacetin as well as its metabolite paracetamol have the property of causing inhibition of prostaglandin synthesis. Prostaglandins are tissue hormones that induce pain and inflammation. In this process, prostaglandin E2 is inhibited, which is responsible, for example, for dilation and increased blood flow to the renal medulla. The constant drug-induced inhibition causes the vasodilatation to cease, which in turn results in a permanent reduction in blood flow to the renal medulla. This results in the development of ischemia as well as papillary necrosis.
Symptoms, complaints, and signs
In the initial stage of analgesic anphropathy, no symptoms can be perceived at first. As the disease progresses, symptoms such as fatigue and headache develop. The skin of the affected individuals shows a brown-grey coloration. Furthermore, the signs of anemia become noticeable. They are caused by gastrointestinal hemorrhage, hemolysis, and the formation of sulf- and methemoglobin. If necrotic papillae spontaneously detach, there is a risk of ureteral colic. Other signs of analgesic anephropathy may include hypokalemia, hyponatremia, recurrent urinary tract infections, and distal renal tubular acidosis. Due to a decreased urinary concentrating ability, tubular dysfunction is also in the realm of possibility. In the worst case, terminal chronic renal failure is seen. A possible late complication of phenacetin abuse is an increased risk of urothelial carcinoma.
Diagnosis and course
If analgesic anphropathy is suspected, the physician first considers the patient’s history (medical history) in detail. In doing so, it may be necessary to determine possible abuse of analgesics. A total consumption of more than 1000 grams of phenacetin is considered groundbreaking. If abuse of the drug is suspected, the degradation product N-acetyl-paraminophenol (NAPAP) can be determined within the urine. A daily intake of one gram of phenacetin per day over a period of one to three years has been established as the lower limit for the development of analgesic anephropathy.The same applies to a total amount of one kilogram of phenacetin together with other analgesics. The diagnosis of analgesic anphropathy involves various methods of investigation. These include 24-hour collection urine, detection of normochromic anemia, detection of hematuria, an excretion program, and measurement of blood pressure. In advanced stages, an ultrasound examination (sonography) or a computed tomography (CT) scan can diagnose reduced size of the kidneys, calcifications on the papillae, and papillary necrosis. Leukocyturia may be present in the findings of the urine sample. Also of importance is the differential diagnosis of other chronic tubolo-interstitial renal inflammation. The same applies to diabetic nephropathy, sickle cell disease, or genitourinary tuberculosis. If the harmful agent is discontinued before terminal renal failure occurs, analgesic nephropathy usually takes a positive course. Thus, in this case, the disease is stopped in time.
Complications
Analgesic anphropathy results from the abuse of analgesics, which has a wide variety of complications. In general, analgesics can lead to addiction development, the affected person can become dependent on the painkillers and shows withdrawal symptoms after stopping the drug, causing both physical and psychological symptoms. Certain analgesics can also cause the blood to become hyperacidic. In addition, the risk of ulcers (ulcers) in the gastrointestinal tract is increased. Nephropathy can lead to kidney failure. This leads to a severe impairment of quality of life. Initially, there is an increased flow (polyuria), which quickly dries up again (oliguria). In addition, there is an increase in the concentration of urinary substances in the blood, such as creatinine, but also toxins such as ammonia. Ammonia can lead to blood poisoning (uremia). In addition, ammonia can enter the central nervous system and cause encephalopathy. In the worst cases, dialysis must be intervened. Furthermore, renal failure is associated with decreased excretion of potassium (hyperkalemia)which can lead to cardiac arrhythmias. Disruption of the acid-base balance due to reduced excretion of acids by the kidney again favors hyperkalemia. In addition, there is an increase in the risk of edema due to decreased excretion of fluids.
When should you see a doctor?
Analgesic anphropathy should always be examined and also treated by a physician. The doctor should be consulted especially if the affected person has been taking painkillers for a long period of time. As a rule, patients suffer from severe headaches, fatigue and exhaustion. If the skin of the affected person continues to turn brown or gray, a doctor must be consulted in any case. Immediate treatment is also necessary for symptoms of anemia. The affected person may suffer from renal insufficiency in the further course. If complaints of the kidneys or urinary tract occur, a doctor must be consulted just as urgently. Bleeding in the stomach and intestines can also be symptoms of analgesic anphropathy and should be investigated. As a rule, the affected person can initially consult a general practitioner. If the symptoms are acute, an emergency physician may also be called.
Treatment and therapy
Analgesic anphropathy always requires treatment. Discontinuation of the triggering medications represents the most important therapeutic step. In addition, anemia and existing urinary tract infections such as renal pelvic inflammation must be treated consistently. This can include, for example, the administration of antibiotics and the elimination of risk factors. Sufficient fluid intake is also important. If renal insufficiency is already present, this must also be treated. If the functional impairment is only mild or moderate, further deterioration should be counteracted. This includes, among other things, a reduction in table salt and a protein-reduced diet. In the case of chronic kidney failure, only dialysis (blood washing) or even a kidney transplant can help at an advanced stage. In the latter case, a suitable donor organ is required.
Outlook and prognosis
In the worst case, analgesic anphropathy leads to complete renal failure in the patient. The affected individual is then usually dependent on dialysis and on a kidney transplant to continue to survive. As the disease progresses, it is not uncommon for infections to occur in the urinary tract, resulting in relatively severe and, above all, burning pain during urination. The pain in general can have a negative effect on the psyche of the affected person, possibly leading to depression or other psychological upsets. Likewise, analgesic anphropathy causes bleeding in the stomach and intestines, resulting in relatively severe pain. The affected persons suffer from headaches and also from a strong lassitude. Due to the anemia, the ability of the affected person to cope with stress also decreases significantly, resulting in various restrictions in the patient’s everyday life. As a rule, analgesic anphropathy must be treated with the help of medication to limit various inflammations. Those affected must also continue to take care of themselves and must not perform any strenuous activities. Whether this will result in a reduction in life expectancy due to analgesic anphropathy cannot generally be predicted.
Prevention
Avoidance of analgesic abuse is considered the best preventive measure against analgesic anphropathy. However, ingestion of phenacetin cannot occur in modern times because the drug has been banned since 1986.
Follow-up
One of the purposes of follow-up is to prevent recurrence of disease. This can best be achieved in analgesic anphropathy by avoiding the triggering agents. Phenacetin has been banned since 1986. As a result, the disease is almost non-existent in Germany. Doctors are aware of the negative consequences and no longer prescribe corresponding preparations. Basically, patients always suffer from the typical symptoms after taking the triggering substances. Immunity does not build up. If therapy is started before renal insufficiency, there is a good chance of recovery. Possible complications concern the kidney. The kidney regularly fails if there is no acute treatment and the causative substances remain in the bloodstream for a long time. Patients then have to undergo regular dialysis. Transplantation is usually recommended to improve quality of life. Scheduled follow-up visits include a medical history, urine samples, blood measurements and sonography. As time progresses, affected individuals must take medications to prevent inflammation. In everyday life, it is recommended that a number of precautionary measures be taken. These include high fluid intake, muscle relaxation techniques and at least light physical activity. These and other measures have a pain-relieving effect. A physician may prescribe therapy on a transitional basis.
Here’s what you can do yourself
Patients with analgesic nephropathy can play a significant role in improving their condition themselves. This is especially true if the renal insufficiency was diagnosed at a stage that is still reversible. First and foremost is behavioral change. The use of painkillers should be completely discontinued. Alternative treatment of the underlying disease that does not require the use of painkillers is conceivable. In addition, behavioral patterns can be practiced with which chronic pain can also be controlled without having to take analgesics. Autogenic training and progressive muscle relaxation can help relieve pain. It is also advisable to integrate exercise and sport into everyday life. This prevents secondary diseases caused by lack of exercise. Physical activity and sports also have a pain-relieving effect themselves through the release of happiness hormones. Sport in a group with people of similar physical ability is ideal. In addition, an appropriate diet is important. For example, a high fluid intake helps the kidneys to regenerate. Water, bladder and kidney teas or very diluted juices are good drinks. Foods rich in potassium and table salt should be avoided. Vitamins, however, should be substituted if they cannot be sufficiently absorbed with food. Due to unfavorable nutrient composition and high density of salts, consumption of convenience foods is not indicated.Reducing protein also supports therapy.
