AKI (acute renal damage) is a pathological condition provoked by a sudden loss of the ability to function in the urinary system. AKI is diagnosed if the pathology forms in a short time (no more than a few weeks). The main manifestation of AKI is the accumulation of decay products in the body with the inclusion of nitrogenous components. This phenomenon is called azotemia.
Nuances and categories
An injury can be caused by trauma, surgery, or pathology. There are cases when the functioning of an organ is weakened due to genetic prerequisites transmitted by inheritance of diseases. A classification has been developed that combines all known cases of acute renal damage. The main symptom for dividing cases into groups is the mechanism for the formation of a pathological condition.
If the condition is due to impaired blood flow in the kidneys, prerenal AKI is diagnosed. For problems of urine outflow due to pathology, postrenal AKI is established. Finally, renal is a type of pathology that is due to damage to the kidney tissue. Foci of inflammation or other aggressive factors can provoke them. In medicine, renal damage is known under the alternative term “parenchymal”. This name reflects the essence of the phenomenon - the renal parenchyma suffers, its structure is violated under the influence of external phenomena.
What triggers the pathology?
There are several reasons that can lead to AKI. When determining the specific, peculiar to the case, they must be recorded in the patient’s personal card, in the medical history. Acute renal damage of the prerenal type, as doctors have established, is usually formed when there is insufficient blood flow in the kidneys. Various pathological conditions can lead to this, including a decrease in the volume of blood located simultaneously in the vascular system. This is likely against the background of acute blood loss or with severe vomiting, infectious bowel disease with diarrhea - these conditions can lead to the loss of liquid blood fractions. Certain risks are associated with the use of diuretics. If the patient does not use the drugs correctly, a certain amount of blood may be lost through the kidneys. Inadequate work of the adrenal cortex or peritonitis, trauma, severe burns, acute pancreatitis can provoke such a problem - against the background of such conditions, the outflow of fluids is disturbed.
The acute renal damage encoded by code N17 in ICD-10 can be observed if the functioning of the heart muscle is impaired. With a sharp inhibition of its ability to contract, the circulatory system suffers, which can cause prerenal AKI. Pathology is accompanied by a decrease in the volume of blood released during one contractile act. Often this is observed against a background of a heart attack, valvular disease, myocarditis. Severe arrhythmia or pulmonary thromboembolism can provoke AKI.
Factors and reasons: continuing the topic
Perhaps acute renal damage due to a decrease in vascular tone in this organ. Blood poisoning, anesthesia or excessive use of drugs to reduce blood pressure can provoke the phenomenon. In a number of cases, AKI is explained by pathological arterial contractions, due to the excess content of calcium in the body. There is a risk of AKI due to the use of drugs from the cyclosporin group, as well as drugs containing norepinephrine, Tacrolimus, Amphotericin B drugs.
Cases are known when acute renal damage developed due to hepatic cirrhosis, which led to hepatorenal syndrome. In some cases, the cause of the condition is impaired patency in the vascular system of the kidneys. This can be triggered by venous, arterial occlusion. Such risks are inherent in patients with atherosclerosis, vasculitis in a systemic form. An increased risk of AKI against embolism, thrombosis, and vascular aneurysm. When identifying the root cause of the condition, consider the possibility of external pressure on the vessel.
There are known cases when the cause of AKI was a too high level of fluid viscosity in the circulatory system. This is possible with blood pathologies: myeloma, Waldenstrom disease, polycythemia.
Etiology: renal form
This type of acute renal damage in children and adults can form due to the pathological condition of the glomeruli of the kidneys and small arteries located in the organ. Of the syndromes that can provoke AKI, vasculitis, glomerulonephritis, and preeclampsia are worth mentioning. Increased risks in people with lupus erythematosus. In a certain percentage of cases, AKI can be associated with scleroderma. The renal parenchyma can suffer from disseminated coagulation of blood inside the vessels, with an increase in cholesterol concentration, accompanied by the formation of crystals. These elements damage the structures of the kidneys.
Prerenal acute renal damage can lead to renal over time. For example, this is often observed with prolonged interruptions in blood flow in the kidneys that are not corrected by medical methods. This leads to perfusion. A similar phenomenon can cause toxic effects of various compounds: cyclosporine, substances used for x-ray studies, antibiotics. There is an increased risk of AKI when using chemotherapy drugs to treat malignant neoplasms. In some cases, a toxic effect is observed on the part of compounds that form in the human body during normal reactions: protein structures, myoglobin, and some others. Hazards are associated with cases where metabolic processes or the removal of hazardous substances from the body are disrupted, which leads to an increase in concentration.
Infections and pathologies
A CT scan of the kidneys with suspected AKI will certainly help confirm this diagnosis or refute it, as well as clarify why the disorder has formed. It is known that in some cases foci of inflammation lead to it. The risk of AKI with pyelonephritis in acute form, infection with fungi from the genus Candida, as well as with infection with cytomegalovirus, is increased. The influence of the allergic response of the body is possible. This is most often observed when the patient is taking antimicrobial beta-lactam-type drugs, diuretics, Captopril, Rifampicin. The dangers are associated with the therapeutic course of non-steroidal anti-inflammatory drugs, Trimethoprim, and sulfanilamide drugs.
If you suspect an AKI, you should immediately consult a doctor. The first measure is to call a urologist at home. The specialist will collect a medical history and determine if hospitalization is necessary. It can be assumed that the symptoms indicate AKI, if the patient has previously had sarcoidosis - it can cause the formation of granulomas in the renal parenchyma, which provokes AKI. Another possible prerequisite is infiltration with atypical structures of the kidney tissue in lymphoma, leukemia.
Rare cases: the nuances of OPP
There are known situations where the cause of acute renal damage could not be identified. Moreover, the idiopathic form of the pathological condition is indicated on the patient’s map. Even CT of the kidneys carried out using the most modern kidney CT devices does not give an accurate idea of the phenomena that provoked parenchymal AKI. In this case, the nuances of adjusting the condition are determined based on the characteristics of the development of pathology.
There are cases when a urologist was required to call a house because of kidney failure due to the use of Methotrexate, Indinavir. Hospitalization and examination of the patient's condition can confirm AKI caused by the formation of crystals in the tubules of the kidneys. Compounds supplied with the aforementioned drugs can occasionally become solid. Such risks are also associated with the use of sulfonamide antimicrobial agents, oxalic acid. To some extent, the parenteral use of Acyclovir is dangerous.
Also, rare factors include necrotic cortical processes, nephropathy due to the use of low-quality medications and food additives. Occasionally, acute renal damage is observed against a background of nephropathy caused by drugs with warfarin and phosphates. OPP is possible:
- if the patient has removed a single kidney;
- with rejection of the transplanted organ.
Etiology: postrenal AKI
This reason may be indicated by nephrotic edema, as well as other pathological conditions that make it possible to suspect abnormal outflow of urine. Renal pathologies, in particular, the formation of stones in the ureter, can provoke AKI. The reason for the phenomenon, the composition of stones from case to case vary quite strongly. In addition to stones, a blood clot, external pressure from the tumor or fibrous tissue degeneration can slow down the progress of urine and block the outflow of fluid. Certain risks are associated with incorrect actions of the surgeon, if during the operation the ureter is bandaged or crossed without the need for this.
In some cases, AKI is due to a neurogenic bladder. In this condition, failures are observed in the work of the nervous system, which is responsible for contractions, relaxation of the walls of the bladder. It is necessary to know which doctor to contact with the kidneys (to the urologist) if a prostate disease is established - it can provoke an AKI with a certain degree of probability, requiring urgent qualified help. Most often, a benign growth of the organ leads to such an outcome, although in some cases the pathology is associated with a malignant tumor.
Manifestations and nuances
Despite such a wide variety of reasons, the clinical picture in most cases is similar. Signs and symptoms of kidney disease in women and men, of course, differ, which to some extent affects the manifestations of AKI. In the general case, the patient feels weak, he is sick and vomits, his appetite is weakened, his performance is deteriorating. There is a state of general poisoning of the body. In some cases, consciousness is confused. The amount of urine released is reduced to the complete absence of fluid. Oliguria is largely dependent on the pathogenesis of the case. So, from statistics it is known that in the prerenal form, oliguria is observed in every second case.
The main sign, a symptom of kidney disease in women, men, provoking postrenal AKI is anuria. This is most typical of cases where a violation of urinary movement occurred in the lower part of the urine excretion system from the body. Diuresis is completely absent. In the renal form with a similar underlying cause, urine volumes remain at the same level or increase.
Step by step
It is customary to talk about the four stages of acute renal damage. The first is the initial period. Its duration is from the moment the influence of the aggressive factor begins to the manifestation of the primary symptoms of the pathology. As a rule, the duration of the stage is within 24 hours.
The second step is lowering urine output. It is not observed with any form of the disease (depends on the causes of the AKI). The duration of the period is up to 14 days.
The third stage is polyuria. It starts at the moment when the aggressive factor is eliminated, lasts until the kidneys are restored. During this period, volumes of urine excreted from the body become larger. The duration of the stage depends on the duration of the first two steps. Polyuria in most patients is fixed within a few weeks. The activity of diuresis is indicated by the restoration of furnace functionality, but at the same time signals a high risk of dehydration. It is necessary to control the amount of fluid consumed by the patient in food.
Finally, the last step is recovery. Its duration reaches several months. The period ends when the functionality of the organ is fully restored.
The nuances of the stages
In rare cases, only the first two stages of the disease are diagnosed. This is characteristic of a situation where the patient does not receive qualified medical assistance. AKI with this development leads to chronic kidney failure.
Status Update
First of all, the doctor will examine the patient and interview for symptoms, as well as evaluate information from the medical history. Next comes the stage of laboratory, instrumental research. First, take blood samples for biochemical studies, urine. AKI can be suspected with an increase in creatinine level and urea concentration. Possible manifestations of acidosis or high potassium content. Take into account that the filtration rate through the renal glomeruli does not give an accurate idea of the severity of the pathological condition. To determine the dynamics of the condition, it is necessary to regularly check the creatinine level and diuresis.
A decrease in diuresis in OOP leads to an increase in potassium concentration to 6.5 mmol / L or more. When this parameter is exceeded, an excess of potassium becomes dangerous to human life. Along with this, there is a higher phosphate content with reduced calcium levels. This indicates rhabdomyolysis, that is, impaired functioning of muscle tissue. If the analysis allows you to clarify the growth of myoglobin, CPK, we can confidently talk about disruption of muscle tissue. Such indicators indicate prolonged compression of the kidneys.
In chronic renal failure, anemia is possible. If with AKI, tests confirm this syndrome, acute blood loss can be suggested.
Urine study
The criteria for acute renal damage include a high specific gravity of urine: the parameter exceeds 1.025 g / ml in the case of the prerenal form. With renal, isostenuria is often diagnosed. In urine, protein fractions can be identified due to inflammatory processes. This is especially typical of glomerulonephritis. In urine sediment, abnormal elements can be detected. Their specificity often helps to establish what exactly caused the AKI in a particular case.
In the recommendations on the diagnosis of acute renal damage, you can see information about the rules for interpreting the presence of tubular cells in urine: this suggests a renal type of pathology. The presence of red blood cells, cell cylinders indicates glomerulonephritis. The content of white blood cells makes it possible to suspect acute pyelonephritis. Fresh red blood cells in the discharge indicate a postrenal pathological condition.
What to do?
The main objective of the therapeutic course is the most rapid exclusion of the factor that provoked AKI. In an impressive percentage of cases, only getting rid of an aggressive phenomenon is already becoming a sufficient measure for recovery. This is characteristic, in particular, of AKI with nephrotoxic drugs.
In acute renal injury, clinical recommendations include monitoring of water balance. It is important to monitor fluid intake and weight. Creatinine level and other significant blood parameters are detected at least once a day. In severe cases, replacement therapy is required: it is necessary to cleanse the circulatory system of metabolic reaction products.
The main task of the doctor is to provide the patient with all the conditions for the normalization of renal function. If the patient follows the doctor’s instructions, the probability of a complete cure is estimated at 95%. At the same time, it is important to remember the risk of death. This is more typical of the case when the AKI is formed against a background of a serious illness, as well as in a person in old age. For children above average, the likelihood of complications is estimated.
AKI warning
The first and main measure to prevent AKI is to identify and adequately correct any renal pathology that could cause acute renal damage. It is necessary to pay attention to all conditions, diseases, due to which the volume of blood in the circulatory system may decrease.
With an increased likelihood of developing AKI, it is important to control diuresis, to take indicators every 24 hours or more often. Blood quality should be checked for concentration of metabolic products. If necessary, use drugs toxic to the kidneys, they are prescribed especially carefully, only in conditions where you can constantly monitor the patient's condition. If there is a safer alternative, you must resort to it.
Status Nuances
One of the main features of AKI is the duration of the therapeutic course. Only substitution therapy is often an insufficient approach to stabilize and improve treatment outcomes. When AKI, it is important to pay attention to adjusting the balance of electrolytes, maintaining immunity, as well as proper nutrition of the patient during recovery. From medical statistics it is known that AKI is especially common among intensive care patients, as well as those who have come to intensive care. For this category, the probability of death is especially high. According to some estimates, for these groups the mortality rate in AKI reaches 60%. To minimize such an outcome, it is important to choose the right time to start treatment, the dosage of drugs, the choice of method for controlling blood coagulation.
According to scientists, recently there have been no significant breakthroughs in the study of AKI and the development of methods to combat this condition. Blood purification, maintaining the patient’s condition with nutritional components, adjusting the balance of electrolytes, the pathophysiology of the syndrome and the use of dopplerometry require a more detailed and in-depth study. Presumably, it is the development of these aspects that will allow in the future to achieve significant progress in the treatment of AKI.
AKI: blood purification as a guarantee of successful therapy
The development of a new concept of blood purification, experts suggest, will help to achieve significant progress in the treatment of AKI. Theories that have proven their truth explain that it is through an effective approach to blood purification that the expression of inflammatory mediators can be reduced. At the same time, the development of effective methods for restoring homeostasis guarantees the best outcomes for the case. Inflammatory processes unite a huge number of mediators, and modulation through work with individual components does not currently show the desired outcome. Substitution therapy with the exception of inflammatory mediators, including microbial toxins, is considered the most promising treatment for AKI.
Important steps in the study of this topic have been made over the past decade and a half. Work in this direction does not stop, which allows us to hope for the formation of fundamentally new and effective approaches to adjusting the RPF. It is worth noting: research in this direction is simultaneously conducted by several large medical institutes in different countries of the world, which allows us to hope for the early achievement of results.