Alcoholic nephropathy is a chronic kidney injury of an inflammatory nature, which is based on autoimmune mechanisms induced by exposure to ethyl alcohol and its metabolites on the body. The severity of symptoms depends on the type of pathology, the asymptomatic course prevails until the development of signs of chronic renal failure, in some forms progressive hematuria and hypertension are observed. The diagnosis of alcoholic nephropathy is based on the data of physical examination, laboratory and functional studies. Treatment includes a ban on taking alcoholic beverages and symptomatic therapy.
ICD 10
N14.4 Toxic nephropathy, not classified elsewhere
General information
Alcoholic nephropathy is also known as hepatic glomerulopathy, alcoholic chronic glomerulonephritis (AHGN) or alcoholic IgA nephritis. Synonymous names reflect the main stages of the pathogenesis of the disease, including the involvement of other organs (the liver) and the autoimmune mechanism of kidney damage involving class A immunoglobulins. The spread of AHGN is directly correlated with the level of alcohol-containing products consumption in various regions of the planet. Exact statistics are unknown due to the relatively small number of people who go to the doctor (the reason for this is a long asymptomatic course). Complicating the accounting of such patients is the fact that alcoholic nephropathy is often part of a symptom complex called “alcoholic disease”.
Causes of alcoholic nephropathy
There are several basic theories of the development of alcoholic nephropathy, there are no reliable and unambiguous data in favor of any of them yet. The reasons for the lack of consensus are a variety of clinical and morphological manifestations of alcoholic nephropathy, which suggests the presence of several mechanisms of damage to the urinary system. The range of opinions regarding the nature of the disease is quite wide – from statements that nephropathy is part of an alcoholic disease to proposals to divide AN into several pathologies similar in course with different etiologies. The most recognized theories of the development of this condition in modern urology are the following:
- Immunological reasons. There are a number of immunological mechanisms of kidney tissue damage that may be associated with alcohol intoxication. First of all, it is sensitization to the antigens of alcoholic hyaline with the release of immunoglobulins A, capable of damaging the membranes of nephrons. A similar mechanism is the direct cytotoxic effect of ethanol and its metabolic products by stimulating the release of cytokines.
- Infectious causes. Some researchers believe that alcohol reduces the body’s defense against infections, including the hepatitis C virus and some bacteria (E. coli). As a result, along with the direct effect of infectious agents on various target organs, indirect kidney damage occurs.
- Systemic reasons. Ethanol is a systemic poison, with prolonged use it provokes an increase in blood pressure, damage to the liver, gastrointestinal tract, pancreas, metabolic disorders (abnormalities of purine metabolism). It is believed that these factors play a decisive role in the pathogenesis of alcoholic nephropathy.
Modern researchers tend to believe that the development of AHGN has a multifactorial nature, all of the above processes are more or less involved in the pathogenesis. The role of genetic predisposition is unknown, although the presence of a wide range of individual characteristics of the disease indicates its presence. Risk factors may be previously transferred kidney pathologies, diabetes mellitus, hypertension, but in such cases it is extremely difficult to differentiate alcoholic glomerulonephritis from forms of secondary nephropathy of another type.
Pathogenesis
The mechanism of development of alcoholic nephropathy is very complex due to the multiplicity of pathogenetic factors, the influence of each of which varies greatly in different patients. This is what gives some researchers reason to believe that AHGN is only an integral part of the symptom complex of alcoholic illness. Almost all patients have IgA antibodies against nephron components, which indicates an autoimmune mechanism of pathogenesis. When taking large doses of ethanol, the latter can directly stimulate the release of cytokines in the kidneys, which leads to the destruction of nephrons.
With the systematic use of alcohol, ethanol metabolites cause damage to the liver, nervous system, pancreas, and vessels of the microcirculatory bed. This indirectly increases the damage to the organs of the urinary system. An increase in blood pressure, typical of chronic alcoholism, in itself can lead to secondary nephropathy. Metabolic failures, especially purine metabolism, increase the load on the excretory organs and also lead to a violation of their functions up to chronic insufficiency. The severity and speed of the development of AHGN manifestations depends on the amount of alcohol consumed – a critical dosage is considered to be a figure over 35 ml per day.
Classification of alcoholic nephropathy
There are several forms of alcoholic nephropathy, the difference between them lies in the clinical course, the presence or absence of concomitant diseases. Some types of the condition are quite easily confused with other types of secondary nephropathy due to similar manifestations and pathogenesis mechanisms. A distinctive feature of AHGN is the fact that the root cause of all pathological changes in the body, directly or indirectly impairing kidney function, is alcohol abuse. The existence of the following types of disease is generally recognized:
- Latent form. It is the most common and difficult to diagnose due to the almost complete absence of subjective symptoms. It occurs not only in people who constantly consume alcoholic beverages, but also in those who do it with a certain frequency (1-2 times a week). Exacerbations are characteristic shortly after the last alcohol intake, manifested by a decrease in the functional activity of the kidneys, which is confirmed by laboratory studies. The pathogenesis is dominated by the role of direct nephrotoxic effects of ethanol.
- Hypertensive form. A rarer type of pathology, mainly occurring in people suffering from alcoholism, obesity and hypertension. The latter circumstance makes it difficult to distinguish between this type of AHGN and secondary hypertensive nephropathy. Damage to nephrons occurs with the development of hemodynamic and metabolic disorders, tubular acidosis.
- Nephrotic form. Extremely rare and the most severe form of chronic alcoholic nephropathy. It is accompanied by progressive diffuse glomerulonephritis, which quickly leads to CRF. The main link of pathogenesis is a sharp sensitization of the body and autoimmune tissue damage by immunoglobulins A.
Some authors classify acute conditions as alcoholic nephropathy, for example, acute renal failure with alcohol poisoning. Despite the fact that the direct nephrotoxic activity of ethanol is most clearly manifested in this case, acute renal failure with alcohol intoxication differs in its mechanism of development from other kidney damage on the background of AHGN. Therefore, most specialists do not consider such a condition as classical nephropathy.
Symptoms of alcoholic nephropathy
In most cases, the disease is almost asymptomatic, manifestations of pathology are registered accidentally when performing laboratory tests for a different reason. This is especially characteristic of the latent form – often the asymptomatic course can last for many years. Exacerbations that occur on 1-3 days after the use of ethanol can manifest themselves only with complaints of a decrease in urine volume (oliguria) and extremely rarely with weak pulling pains in the lower back. With a prolonged course, manifestations of alcoholic illness come to the fore: erythema of the palms, gynecomastia in men, symptoms of pancreatic and liver damage (pain in the hypochondrium and abdomen, jaundice).
The hypertensive variant of alcoholic nephropathy at the initial stages of development is also characterized by a weak severity of the actual nephrogenic symptoms. The patient complains of headaches, flushes of blood to the face, unpleasant sensations in the heart area and other consequences of increased blood pressure. Often this type of disease is accompanied by obesity. For the nephrotic form of AHGN, a fairly rapid course is typical – usually after an excess, oliguria, visible hematuria, deterioration of the general condition occurs. Extrarenal manifestations of chronic ethanol intoxication are necessarily present.
In the absence of therapeutic measures and the continued intake of ethyl alcohol into the body, alcoholic nephropathy invariably reduces to the occurrence of CRF. Its signs are fatigue, a broken state, headache, which worsen after taking ethyl alcohol. Then there is an ammonia smell from the mouth, intense thirst, vomiting, dry skin, inflammation of the mucous membranes. The amount of urine excreted decreases sharply, a whitish plaque forms on the surface of the skin from the urea secreted by the sweat glands.
Complications
It is not always possible to strictly differentiate the complications of alcoholic nephropathy proper and intoxication with ethyl alcohol. With AHGN, alcohol poisoning occurs much more easily, accompanied by acute renal failure with anuria, headache, vomiting, edema and other signs of uremia. Given the progressive nature of the condition, previously habitual dosages of alcohol can lead to acute poisoning, which increases the risk of complications. A formidable and unfavorable complication can be a uremic coma caused by intoxication with metabolic products not excreted through the kidneys.
Diagnostics
Methods of physical examination, a number of laboratory tests and instrumental studies are used to diagnose alcoholic nephropathy. It is necessary to consult a nephrologist, sometimes a narcologist may be involved in determining the condition. Usually , the AHGN diagnostic algorithm includes the following steps:
- Questioning and anamnesis collection. The degree of dependence of the patient on alcohol is determined (which directly correlates with the severity of kidney damage), the duration of abuse and its nature (constant or periodic “binge” consumption). It is important to clarify the prescription of the last excess and the approximate amount of ethyl alcohol consumed.
- Physical examination. Especially pay attention to the extrarenal signs of alcoholism: erythema of the palms, darkening of the skin, an increase in the size of the liver, gynecomastia in men. In some cases, high blood pressure and obesity are detected. The detection of ammonia odor from the mouth, an unpleasant “urinary” smell of sweat, dry skin, white plaque on it indicate the development of CRF and uremia.
- Laboratory research methods. Often it is a general urine test performed on another occasion that reveals the presence of alcoholic nephropathy. Its results in AHGN are microhematuria and moderate proteinuria, the indicators of which increase after drinking alcohol. In addition to OAM, biochemical blood tests, functional renal tests (Rehberg, Zimnitsky test) are used to diagnose the condition, indicating a decrease in the level of glomerular filtration (a decrease in creatinine clearance to 30 ml / min or less, oliguria).
- Ultrasound diagnostics. To determine the condition, ultrasound of the kidneys and dopplerography (UZDG) of the renal vessels are prescribed. A simple ultrasound examination reveals a decrease in the size of the kidneys, a decrease in the thickness of the parenchyma. Dopplerography confirms a decrease in renal blood flow correlated with the severity of nephropathy. Additionally, ultrasound of other organs (pancreas, ureters, liver) can be performed to assess their condition.
In rare and controversial cases, liver and kidney biopsies are performed for histological examination of these organs. With alcoholic nephropathy, signs of hyaline-drip dystrophy will be determined in the liver, and in the kidneys – mesangioproliferative nephritis of a diffuse or focal nature. Radiopaque methods of examination (for example, urography) are prescribed with caution due to the nephrotoxicity of most contrast agents. Differential diagnosis is carried out with other types of primary and secondary nephropathies, the determining factor is often the fact of long-term alcohol abuse.
Treatment of alcoholic nephropathy
The main and fundamental purpose is a complete ban on the consumption of alcoholic beverages. Only with the refusal of alcohol, more than half of patients with latent form of alcoholic nephropathy have a persistent improvement in laboratory urine parameters and almost complete remission. Failure to comply with this prescription, even when implementing other recommendations and therapeutic measures, only slightly slows down the progression of the condition. In advanced cases of AHGN and the presence of concomitant pathologies, in addition to refusing alcoholic beverages, a number of auxiliary therapeutic measures are prescribed:
- Antihypertensive therapy. Lowering blood pressure has a beneficial effect on the prognosis due to the elimination of hemodynamic disorders in the kidneys. This component of treatment is especially important in hypertensive forms of nephropathy. In case of disorders of the excretory system, ACE inhibitors, calcium channel blockers and angiotensin 2 receptors are used to reduce pressure.
- Normalization of metabolism. The consequence of alcohol intoxication is often metabolic disorders: purines, carbohydrates, fats. Through special diets, it is necessary to normalize metabolism and reduce the load on the excretory system. Especially detrimental to the kidneys is the violation of purine excretion, therefore, with insufficient effectiveness of dietary nutrition, antipodagric drugs (allopurinol) may be prescribed.
- Anti-inflammatory drugs. With rapid progression of the condition (nephrotic form), corticosteroid and cytostatic drugs are used. The purpose of their use is to reduce the activity of inflammatory processes to reduce the degree of kidney damage. To date, their effectiveness has been criticized by a number of researchers.
When diagnosing CRF, hemodialysis is recommended, the frequency of which depends on the degree of damage to the excretory system. An auxiliary role in the treatment of alcoholic nephropathy can be played by a narcologist – with his help, it is easier for the patient to get rid of addiction. The use of pharmacological agents in the fight against alcoholism should be carried out taking into account the reduced glomerular filtration rate.
Prognosis and prevention
In the case of strict compliance with the prohibition on alcohol intake and early detection of a pathological condition, the prognosis of alcoholic nephropathy is almost always favorable – the functions of the excretory system are restored almost in full. In the presence of concomitant disorders caused by the abuse of alcohol-containing products, the outcome of pathology depends on their quality treatment. With CRF, the restoration of normal kidney function is almost always impossible, but supportive treatment is able to maintain an acceptable quality of life for the patient for many more years. The most unfavorable prognosis is a combination of AHGN and severe manifestations of alcoholic illness: cirrhosis of the liver, alcoholic pancreatitis, cardiomyopathy. But even in this case, long-term complex treatment can significantly improve the patient’s condition.
