Uremia is a severe clinical manifestation of progressive renal insufficiency caused by autointoxication with nitrogenous and other toxic metabolites. It is manifested by increasing asthenia, pallor and subictericity of the skin, painful itching, petechial rash, arterial hypertension, ammonia odor from the mouth, dyspeptic disorders, respiratory disorders. It is diagnosed using a biochemical blood test, a Rehberg test, kidney ultrasound, excretory urography, nephroscintigraphy. Treatment involves complex therapy of the underlying disease, correction of metabolic disorders and individual symptoms, RRT, kidney transplantation.
ICD 10
R39.2 N17-N19
Meaning
Uremia (urolithiasis) is a leading clinical and biochemical syndrome that develops in stages 2-3 of acute renal failure and in terminal CRF. The disorder is caused by the accumulation of toxic metabolic products in the blood of patients, which are normally excreted by the kidneys. The term “uremia” to define the intoxication syndrome that occurs in patients suffering from renal insufficiency was proposed in 1840 by French doctors P.A. Piorri and D. L’ritje.
Traditionally, uremic syndrome is considered as an independent pathological condition due to the polysystemic nature of lesions, the severity of symptoms, and an unfavorable vital prognosis, which go beyond the direct signs of renal pathology. Like kidney failure, urolithiasis can be acute and chronic.
Causes
Autointoxication in urolithiasis is associated with the progression of acute or chronic renal failure. Accordingly, the causes of uremic syndrome are the same renal and extrarenal factors that disrupted the functioning of the kidneys. Specialists in the field of urology and nephrology distinguish the following groups of causes that cause the state of uremia:
- Kidney diseases. A decrease in the number of active nephrons with a decrease in renal functionality becomes a consequence of purulent, autoimmune, ischemic destruction of renal tissues. The development of uremia is possible with pyelonephritis, glomerulonephritis, hereditary nephritis, lupus nephropathy, pionephrosis, renal transplant rejection, renal vein thrombosis.
- Oncopathology. Nitrogen intoxication is observed when the renal parenchyma is destroyed by the cancer process, the hemato-uremic barrier is damaged in patients with renal adenocarcinoma and other malignant neoplasms of the organ. Uremia also occurs due to renal dysfunction in paraneoplastic nephropathy, which complicated extrarenal tumors.
- Obstruction of the urinary tract. Violation of the outflow of urine leads to increased pressure in the tubules and glomeruli. The penetration of toxins into the blood contributes to the destruction of glomerular membranes. The obstructive mechanism of uremia is noted in urolithiasis, uretero-vaginal fistulas, shrunken bladder, prostate adenoma, etc.
- Kidney damage caused by poisoning and intoxication. Renal failure with uremic syndrome is a stage in the development or outcome of a number of toxic nephropathies. Uremia due to acute and chronic kidney destruction is diagnosed with Balkan endemic nephropathy, drug-induced kidney damage, contrast-induced dysfunctions.
- Extrarenal reasons. Kidney failure is complicated by acute conditions (cardiogenic shock, DIC syndrome, bleeding). Kidney damage is detected in diabetes mellitus, hypertension, tuberculosis, gestosis, other somatic, endocrine, infectious diseases. Dysmetabolic nephropathies with an outcome in uremia occur with metabolic disorders.
Pathogenesis
The mechanism of development of uremic syndrome in acute renal failure, CRF is based on the complex damaging effect of metabolites, the excretion of which is disrupted by renal dysfunction. A key role in the pathogenesis of uremia is played by the accumulation of protein metabolism products, primarily urea, which undergoes transformation in the intestine, is excreted through the skin, mucous membranes, respiratory organs, irritating their tissues. Ammonia, aromatic acid metabolites (phenols, indoles, skatols), medium-molecular peptides, acetone, proteases, and a number of other compounds have a toxic effect on cells of various organs and systems.
Damage to cell membranes and disruption of enzyme systems in uremia exacerbates intoxication syndrome and provokes multiple organ failure. Low excretion of substances with acid reaction, inhibition of the processes of ammonio- and acidogenesis, violation of tubular reabsorption results in the development of acidosis, electrolyte imbalance, the occurrence of severe cerebral, cardiovascular, respiratory, hormonal disorders.
Symptoms of uremia
The clinical picture of uremic syndrome is usually formed gradually. The first signs of uremia are changes in the general condition: weakness, fatigue, cognitive impairment, loss of appetite, daytime drowsiness followed by night insomnia, severe thirst, a decrease in body temperature to 35.0-35.5 ° C. The skin becomes dry, pale with a yellowish tinge, with prolonged renal failure — gray. There is severe itching, petechial rash, scratching.
The tongue is covered with a grayish coating, the smell of ammonia can be heard from the patient’s mouth. Many patients have an increase in blood pressure. At the late stage of uremia, toxic metabolites are released through the mucous membranes of the gastrointestinal tract and respiratory system, which is manifested by symptoms of gastroenteritis (nausea, vomiting, diarrhea), sore throat, dry cough. In severe cases, noisy deep breathing is observed, indicating a lesion of the respiratory center.
Complications
Prolonged decompensated course of uremia leads to the development of acute encephalopathy, in which there is confusion, the presence of delusions and hallucinations, myoclonia, convulsions. Against the background of an ionic imbalance, arrhythmia and heart failure are detected. Suppression of immunity increases the risk of occurrence and severity of the course of infectious processes. Uremia is characterized by the formation of pleurisy and pericarditis due to the release of urea crystals through serous membranes.
The disorder can be complicated by gastrointestinal, pulmonary, nasal, uterine bleeding, caused by ulceration of the mucous membranes, a decrease in the number of platelets and proteins of the blood coagulation system. With a significant decrease in calcium levels, uremia is aggravated by osteoporosis, osteomalacia, hyperplasia of the parathyroid glands. The most dangerous complication of the disease is uremic coma, which develops with a high concentration of ammonia in the blood, severe metabolic acidosis and often ends in death.
Diagnostics
The diagnosis of uremia is not difficult in the presence of characteristic clinical signs and changes in the biochemical composition of the blood. A violation of the filtration and excretory function of nephrons should be suspected in patients who have a history of diseases of the urinary system. A number of laboratory and instrumental research methods are used for diagnosis:
- Blood test. In all patients, there is a multiple increase in the level of urea. The concentration of creatinine increases, its amount correlates with the severity of the condition. Uremia is characterized by a decrease in albumin levels, dysproteinemia, changes in electrolyte metabolism — a decrease in sodium and calcium, an increase in potassium concentration.
- The Rehberg test. The filtration capacity of the kidneys is determined using a formula method based on data on the level of creatinine in urine and plasma. With a glomerular filtration rate from 60 ml/min to 15 ml/ min, the patient is diagnosed with a compensated stage of uremia. An indicator below 15.0 ml/min is considered prognostically unfavorable and indicates decompensation of the condition.
- Ultrasound of the kidneys. Ultrasound examination allows you to quickly assess the condition of the cortical and medulla of the organ, identify kidney abscess, kidney stone disease, malignant neoplasms, sclerotic changes that can serve as a direct cause of uremia. Sonography is usually supplemented with ultrasound of the renal vessels to assess renal blood flow.
- Radiography. Radiologically, it is possible to visualize the shape and contours of the calyx-pelvic system, ureters, bladder, and the dynamics of filling the urinary tract with contrast. Due to the load on the kidneys when contrast agents are administered in patients with severe uremia, urography is used only to a limited extent. Excretory urography is combined with nephroscintigraphy.
Changes in the clinical blood test for uremia are nonspecific, normochromic anemia is usually observed, increased ESR, thrombocytopenia is possible, relative lymphopenia. In the general analysis of urine, hypoisostenuria, cylindruria, erythrocyturia are noted, with decompensated conditions, the pH of urine decreases to 4.5-5. CT and MRI can be used as additional methods of examination of the urinary system.
Differential diagnosis of uremia is performed with hypochloremic azotemia, hepatorenal and pancreorenal syndromes, hepatic encephalopathy, eclampsia, atypical hemolytic-anemic syndrome, in terminal stages — with diabetic coma and other comatose conditions. In addition to a nephrologist and a urologist, a hematologist, a toxicologist, a rheumatologist, an oncologist, an infectious disease specialist, an endocrinologist, an anesthesiologist-resuscitator can consult a patient.
Treatment
The choice of medical tactics is determined by the form and causes of the development of renal insufficiency, the features of the clinical picture, the severity of the patient’s condition. The main therapeutic tasks are the maximum preservation of the functional ability of the kidneys, prevention and reduction of intoxication disorders, correction of disorders that have arisen.
Medicinal and surgical methods of management of patients with uremia are supplemented by a change in diet with a reduction in calories, restriction of protein products, salt, the introduction of fresh vegetables and fruits into the diet, which have an alkalizing effect. To eliminate the manifestations of urolithiasis, in addition to the therapy of the underlying disease, against which kidney failure has developed, can be used:
- Infusion therapy. The introduction of colloidal, crystalloid solutions is aimed at correcting the water-electrolyte and acid-base imbalance, reducing intoxication. Competent detoxification and rehydration therapy can reduce the manifestations of multiple organ failure, normalize the work of the heart and brain. Infusions of special formulations, if necessary, are used for parenteral nutrition of patients.
- Drug correction of individual symptoms. Most often, patients with uremia are prescribed antianemic therapy (erythropoietins, iron preparations, folic acid, vitamin B12, transfusion of whole blood, erythrocyte mass), hypotensive agents. With painful itching, enterosorbents and osmotic laxatives are recommended to enhance the detoxification effect of infusions. Glycosides are used to treat heart failure.
- Renal replacement therapy. With insufficient efficacy of pharmacotherapy, severe acute renal failure and progressive CRF with significant multiple organ disorders, the threat of developing uremic coma is indicated by hardware detoxification. Depending on the capabilities of the medical institution and the patient’s condition, peritoneal dialysis, hemodialysis, hemofiltration, hemodiafiltration are performed once or periodically to remove toxic metabolites.
Surgical treatment of uremia is effective in acute intoxication conditions caused by obstruction of the urinary tract. Ureterolithotomy, ureterolithoextraction, contact and remote ureterolithotripsy are performed to ensure a natural passage of urine during obturation with a ureter stone. If it is impossible to restore the renal parenchyma in patients suffering from chronic nephrological diseases, the only radical method of treatment is kidney transplantation.
Prognosis and prevention
The outcome of the disease depends on the degree of renal dysfunction and the presence of concomitant pathologies. The prognosis for acute uremia is relatively favorable if the glomerular filtration rate exceeds 30 ml/min. Thanks to the use of RRT in 65-95% of such patients, it is possible to achieve a positive therapeutic result. In chronic cases, patients require lifelong dialysis or kidney transplantation. There is no specific prevention. To prevent the development of uremia, timely diagnosis and complex therapy of conditions that can cause irreversible deterioration of the excretory function of the kidneys is necessary.