Renal vein thrombosis in children

Introduction to renal vein thrombosis in children Renal vein thrombosis (renalveinthrombosis) refers to the formation of thrombus in the trunk and/or branch of the renal vein, resulting in partial or total blockage of the renal vein causing a series of pathological changes and clinical manifestations. Renal venous thrombosis can occur on one or both sides, occurring in the trunk, a single branch or multiple branches, and can coexist with thrombosis of other organs. Acute renal vein thrombosis may be complicated by acute renal failure. The clinical manifestations of chronic renal vein thrombosis are not obvious. Because there is sufficient time to form collateral circulation to improve renal venous return, most renal insufficiency is reversible. Most of the diseases are autopsy diagnosis. With the progress of X-ray angiography and selective vascular catheterization, prenatal diagnosis is increased. basic knowledge The proportion of illness: 0.002% Susceptible people: children Mode of infection: non-infectious Complications: Hypertension Renal glucosuria Renal failure

Causes of renal vein thrombosis in children

Cause:

1. Primary: Most neonates are dehydrated due to infection or gastrointestinal disorders. Others such as low volume, septic shock, asphyxia and sickle cell anemia are also common in children with congenital renal or cardiac abnormalities. After angiography, it may be related to hyperosmolar state, which is more likely to occur in children with pregnancy poisoning, dystocia, prenatal hypoxia and diabetic mothers. It can also be seen in small age groups without obvious incentives.

2. Secondary

(1) Secondary to kidney disease: Children are more common in patients with refractory disease after recurrence of simple nephropathy.

(2) secondary to inferior vena cava thrombosis: secondary to inferior vena cava thrombosis or renal vein, the inferior vena cava caused by external tumor compression, such as abdominal aortic aneurysm, renal cell carcinoma and lymphatic reticulum tumor.

Pathogenesis:

Neonatal and infant extracellular fluids are relatively more, and the renal concentrating function is poor, the kidney has double capillary circulation, and the blood transport is slow, so in the blood concentration, dehydration, hypercoagulability and hyperosmotic state, venous thrombosis is easy to form. Especially in the perinatal period, in children with large children and adults with nephrotic syndrome, often associated with hypercoagulable state, due to some small molecular weight in plasma (similar to the molecular weight of albumin) anticoagulant factors, such as Antithrombin III (68,000), 1-antitrypsin (5.4 million) and fibrinolytic plasminogen (81,000) are lost from the urine, while some procoagulant coagulation factors such as V, VII, VIII, fibrinogen (molecular weight > 200,000) and antifibrinolytic 2-macroglobulin (840,000) have large molecular weights, are not easily lost from the urine, and can increase with the compensatory protein synthesis of the liver, thus In a state of hypercoagulation.

On the other hand, the number of platelets is mostly moderately increased, aggregation and adhesion are enhanced, and -thromboglobulin, platelet factor 4 and factor 3 are released. The former two can activate factor X and increase thrombin activity. The latter is involved in the formation of thromboplastin, as well as an increase in platelet activating factor (PAF), which also promotes platelet aggregation. In addition, due to renal plasma hypoproteinemia, plasma volume is reduced, plus furosemide and accompanying Hyperlipidemia increases blood viscosity. The application of hormones stimulates platelet production and VIII is more severely hypercoagulable. Renal venous thrombosis usually begins in small renal veins such as interlobular veins, ascending straight vessels and arch veins, and even inferior vena cava and adrenal veins, either unilaterally or doublely. Side involvement, the main renal vein to the branch extension is rare, the kidney can be seen with hemorrhagic infarction, necrosis, late visible scars, lobulation and contracture, sometimes can be mistaken for renal hypoplasia and chronic pyelonephritis, and some can be seen diffuse kidney Small ball sclerosis, tubular atrophy and extensive medullary destruction with hemosiderin deposition, prenatal morbidity often accompanied by renal calcification or necrosis, neonatal may have focally organized thrombosis.

Pediatric renal vein thrombosis prevention

Infection or gastrointestinal disorders caused by dehydration can often occur in this disease, should be actively preventive treatment, timely correction of dehydration, do a good job in perinatal care, active prevention and treatment of pregnancy poisoning, dystocia and diabetes, because the mother of the above-mentioned children are prone to this disease, For children with high risk of kidney disease, preventive anticoagulant therapy should be taken to actively prevent the occurrence of this disease.

Pediatric renal vein thrombosis complications Complications, hypertensive renal hypoglycemia, renal failure

Patients with prolonged disease may have hypertension, renal glucosuria, complicated renal failure, hyperosmolar syndrome and so on.

Symptoms of renal vein thrombosis in children Common symptoms Face pale kidney area snoring venous thrombosis facial hemisphere blue black nodule abdominal pain metabolic acidosis proteinuria renal glucosuria azotemia dehydration

The main characteristics of newborns and babies are a smooth shape on the waist, a hard surface with gross hematuria, fever, vomiting and diarrhea, dehydration and metabolic acidosis. It is characterized by rapid breathing, pale complexion, shock, and before and after the appearance of the tumor. Increased white blood cell count, often leading to progressive renal failure, hyperosmolar state and death, the primary disease symptoms are more obvious, mostly hyperosmolar syndrome, generally only after the swelling of the waist to consider the disease, the larger children and Adults with secondary nephropathy may be due to the rapid formation of thrombosis and the size of the blocked blood vessels. The acute main renal vein thrombosis often presents typical symptoms; while the chronic renal vein thrombosis, especially the collateral circulation is better. Asymptomatic, most of the patients diagnosed by renal venography at home and abroad are asymptomatic. Typical symptoms are:

1. Severe abdominal pain or lumbar hypotension, may be associated with pain in the kidney area.

2. There are often gross hematuria, almost all under the microscope hematuria.

3. Children with simple kidney disease may suddenly have a large amount of proteinuria.

4. Sudden deterioration of renal function, decreased GFR, acute renal failure, elevated BUN and serum creatinine, and no urinary or oliguria and azotemia were bilaterally affected.

5. Some sick children may have fever and infection symptoms.

6. Children with longer course of disease may have renal tubular dysfunction such as hypertension, renal glucosuria and distal renal tubular acidosis. Dehydrated and hypertonic infants can touch the kidneys, accompanied by microscopic and gross hematuria. The characteristics of this disease, sudden hyperalgesia or low back pain in children with nephrotic syndrome, hematuria, proteinuria, renal function deterioration should be thought of this disease, in the above circumstances, such as microvascular hemolytic anemia, platelet count Increase or progressive reduction, serum or urinary fibrin degradation products increase or progressively decrease, plasma D-dimer is positive, should be highly suspected, and further confirm the diagnosis, abdominal plain film, B-mode ultrasound can be used as Routine examination, such as renal vein pyelography or renal scan showed that the kidney can be roughly diagnosed. If there is condition, DSA or selective renal venography should be confirmed. DSA can be filled with defects on the side of the main vessel lumen; If the internal thrombus causes the lumen to be completely obstructed, the distal branch of the branch is not developed; in the acute case, except for the lesion, the other veins are thickened and the kidney shape Large, those who have chronic collateral circulation.

Examination of renal vein thrombosis in children

One third of children have obvious anemia, and the clotting time is prolonged. 90% of the children have progressive thrombocytopenia. The latter is the most helpful and simple and reliable laboratory finding for the disease. Anemia is microvascular hemolytic anemia, peripheral blood Red blood cell debris (heterologous red blood cells) can be seen, combined with microvascular coagulation and hemolytic uremic syndrome, thrombocytopenia and clotting factor reduction, reflecting its consumption in the venous system of other parts (such as brain and liver) in the renal vein and severe cases. , AT-III decreased, serum fibrin degradation products (FDP) increased by >10mg / L (10g / ml), plasma D-dimer positive and plasma fibrin decreased <2g / L (200mg / dl), However, most of the above are acute cases. There is no definite index to predict the tendency of renal disease with renal vein thrombosis. It is more common to increase plasma fibrinogen, which can increase plasma viscosity and directly affect the incidence of thrombosis. At the same time, increased platelet count, decreased plasma plasminogen and decreased antithrombin III predict the risk of thrombosis, but if there is consumptive intravascular coagulation, fibrinogen and The number of platelets can be progressively reduced, non-invasive computed tomography (CT).

B-mode ultrasound and Doppler ultrasound blood flow map positive for diagnosis, but less sensitive, can be used for the diagnosis of large renal thrombus, abdominal plain film can show enlarged kidney and advanced calcification; B-mode ultrasound can show kidney The size of the blood vessels can still be seen in the large blood vessels; renal vein pyelography or renal scan showed that the kidney can be roughly diagnosed, intravenous pyelography (IVP) is helpful in older children, more than 90% of the acute can show kidney The entire kidney or some segments of the infarcted area have no function, and some of the affected kidneys are enlarged, the development is delayed, most of the asymptomatic adults are normal, and some of the proximal collateral circulation of the ureter can be seen, but in neonatal development Poor and a certain degree of risk and the use of renal scan instead, retrograde pyelography may be normal, or due to edema, renal pelvis is incomplete, necrotic kidney tissue is easily penetrated by the ureteral catheter, contrast agent injected into the renal pelvis can penetrate and spread to the liquefied renal parenchyma Inferior vena cava angiography and venous phase of renal angiography.

Due to lack of sensitivity and specificity, it is gradually eliminated. The diagnosis requires the use of percutaneous femoral vein puncture selective venography. It can be found that the filling defect or the vein branch is not developed. For example, the drainage delay may be a small thrombus. The collateral circulation is still visible. Digital subtraction angiography (DSA) has good digital subtraction angiography in recent years. It has a small dose, low contrast agent concentration, and can be used for renal dysfunction. For traumatic examination, complications are more serious, such as vascular perforation, acute renal failure, endovascular injury can induce thrombosis (kidney vein and lower extremity vein) and pulmonary embolism, so do not routinely use, should choose the indications carefully.

Diagnosis and diagnosis of renal vein thrombosis in children

RVT can be diagnosed by imaging examination and clinical manifestations and hypercoagulopathy and hyperviscosity. The differential diagnosis of the cause depends on the medical history, clinical features and laboratory tests to determine the extent to which the kidney can be touched, with or without hematuria. Should pay attention to the identification of nephroblastoma, hydronephrosis, multiple renal cysts and retroperitoneal hemorrhage.

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