HBV-related nephritis in children
Introduction
Brief introduction of hepatitis B virus related nephritis in children Hepatitis B virus associated glomerulonephritis (HBV-GN) refers to glomerulonephritis secondary to hepatitis B virus infection. The disease is one of the common secondary glomerular diseases in childhood. It is characterized by nephrotic syndrome or proteinuria, hematuria, and pathologically the most common membranous nephropathy. In the past, the name of this disease was not uniform, such as hepatitis B-associated nephritis, hepatitis B immune complex nephritis, hepatitis B virus antigen-associated nephritis, etc. Since the 1989 "Chinese Journal of Internal Medicine" held the Hepatitis B Nephritis Symposium, it was uniformly named "B. Hepatitis virus-associated nephritis." basic knowledge The proportion of illness: 0.003% Susceptible people: children Mode of transmission: mother-to-child transmission Complications: chronic hepatitis ascites renal insufficiency hypertension
Cause
Pediatric hepatitis B virus related nephritis etiology
(1) Causes of the disease
HBV is a spherical particle (dane particle) with a diameter of 42-45 nm. It is a DNA virus composed of a double-layered shell and a core. It contains double-stranded DNA and DNA polymerase. One of the negative strands is a long chain, about 3.2 kb, and the other is The positive strand is a short chain, about 2.8 kb, and there are HBsAg, HBcAg, HBeAg, DNA polymerase and X protein on long-chain DNA. In hepatitis B virus-associated nephritis, mainly deposited in the glomerular capillary wall are HBsAg and HBeAg. Ozawa and Hattor have separately eluted from the renal tissues of HBV-GN patients and found anti-HBsAg antibodies and anti-HBeAg antibodies; immunoelectron microscopy showed that the above HBV antigens and immunoglobulins were deposited at the same site of the glomerulus. Both support HBV-GN is an immune complex nephritis caused by the HBV antigen component.
(two) pathogenesis
Membranous nephropathy is the most common pathological type of HBV-GN in children. It is believed that the glomerular basement membrane subcutaneous subcutaneous immune complex is formed in situ, and animal experiments suggest that the antigen can be localized under the glomerular basement membrane. The molecular weight of the polypeptide is generally less than 300-500kd, the molecular weight of HBeAg is small, even if the IgG is not more than 300kd, and it has a positive charge (PI 4.3-4.8), which is consistent with the condition of causing membranous nephropathy, HBsAg is above 3.7Md, and PI is about 4.0. , HbcAg 8Md or more, PI 3.7 ~ 4.0, not only the molecular weight is too large, and has a negative charge, so it is unlikely to penetrate the basement membrane to form an in situ complex under the epithelium, and may deposit in the mesangial area and cause disease, although Thus, it is still clinically seen that most HBV-GN children have HBsAg deposition under the glomerular epithelium. Therefore, it is believed that the HBsAg deposited under the epithelium at this time is not a complete molecule, but an antigenic determinant produced after metabolism. The polypeptide subunit, which has a small molecular weight, can also pass through the basement membrane and be implanted in situ, eventually leading to the occurrence of membranous nephropathy. In addition, it is believed that HBV-GN is induced by HBV infection after HBV infection, due to HBV It is also possible to directly infect the kidney, but the two pathogenesis mechanisms are still controversial. Further research is needed to confirm that the pathology study, Asian Study of Renal Disease in Children (ASRSCC), reports on children's HBV-GN. 66.1% were membranous nephropathy, 16.1% were mild lesions, and 8.1% were membrane proliferative nephritis. Histological changes were different from typical membranous nephropathy:
1. Mesangial cell hyperplasia: often accompanied by mild to moderate mesangial cell proliferation and hyperplastic mesangial insertion, but mostly limited to the collateral area, rarely extended to the distal capillary endothelium.
2. Immunoglobulin deposition: more immunoglobulins are deposited in the basement membrane and mesangial area, resulting in coarse particles or even clumps under immunofluorescence, rather than the fine-grained appearance of primary membranous nephropathy. HBsAg and HBeAg antibodies are immunofluorescent or enzymatically labeled to detect the deposition of HBeAg and/or HBsAg in the glomerulus, which is also a prerequisite for the diagnosis of HBV-GN.
Prevention
Pediatric hepatitis B virus related nephritis prevention
The key to the prevention of this disease lies in the active prevention and treatment of hepatitis B, especially the vertical infection of mother and baby. In recent years, research on hepatitis B vaccine has made great progress, and has been widely used as a planned immunization program to create favorable conditions for prevention and treatment of hepatitis B. Key measures for hepatitis:
1. Inoculation of hepatitis B vaccine.
2. Screen the donor for a disposable syringe.
3. Injecting vaccine before exposure to hepatitis B patients, the effect is significant. Intramuscular injection of hepatitis B immunoglobulin is also effective within 7 days after exposure to hepatitis B patients. Hiroshi Hiroshi receives hepatitis B from newborns born from HBe antigen-positive pregnant women to prevent vertical infection of mother and baby. Long-term follow-up observation of vaccinators, 47 (89%) of 53 patients were HBs antibody positive after 5 years old, no HBs antigen positive, and received good results, I believe that in the near future, with the control of hepatitis B The incidence of this disease is bound to decline.
Complication
Pediatric hepatitis B virus associated nephritis complications Complications chronic hepatitis ascites renal insufficiency hypertension
Chronic hepatitis, individual liver failure, ascites, renal insufficiency, hypertension, hypoproteinemia.
Symptom
Pediatric hepatitis B virus-associated symptoms of nephritis Common symptoms Ascites hypertension jaundice edema nephrotic syndrome proteinuria hematuria hepatitis B surface antibody (... single ALT elevation
Onset
Most of the onset of preschool and school age, boys are significantly more than girls, more insidious onset, often found abnormal when the urine is found.
2. Edema
Most of them were not obvious, and there was no obvious oliguria, but there were also a few children with obvious edema and ascites.
3. Hematuria
Almost all of the microscopic hematuria persists, and often the hematuria after microalbuminuria is still a period of time. Some patients have episodes of hematuria on the basis of this.
4. Proteinuria
There were different degrees of proteinuria, proteinuria showed greater volatility, when it was light and heavy, ASRSC reported that about 61.3% showed nephrotic syndrome, but generally did not respond to adrenal cortical hormone therapy.
5. Hypertension
Most not obvious, mainly seen in patients with membrane proliferative nephritis.
6. Renal insufficiency
Rare.
7. Liver symptoms
Mostly, it is not obvious that about half of the children have abnormal liver or liver function, which is characterized by elevated transaminase, but jaundice is rare.
Examine
Pediatric hepatitis B virus related nephritis examination
Urine
Hematuria and proteinuria, tubular urine, and urine protein are mainly albumin.
2. Blood biochemistry
There are often albumin decline, cholesterol increase, alanine aminotransferase and aspartate aminotransferase can be elevated or normal, plasma protein electrophoresis 2 and beta globulin increase, gamma globulin is often normal.
3. Hepatitis B serological markers and HBV-DNA
Most patients were hepatitis B big three positive (HBsAg, HBeAg and HBcAb positive), a small number of patients were small Sanyang (HBsAg, HBeAb and HBcAb positive), HBsAg-positive patients were rare, blood HBV-DNA was generally positive.
4. Immunological examination
Some people think that blood IgG, IgA increased, but it is also reported that more than 50 cases of HBV-GN membranous nephropathy have no increase in IgG and IgA, on the contrary, about 1/3 showed a decrease in blood IgG, and a slight decrease in complement C3 or normal value. Lower limit, renal biopsy is the final means to determine HBV-GN, is a necessary condition for the diagnosis of HBV-GN, other should be routinely done B-ultrasound, electrocardiogram and other tests.
Diagnosis
Diagnosis and diagnosis of hepatitis B virus related nephritis in children
The diagnosis refers to the opinion on the diagnosis of this disease at the special symposium on hepatitis B (hepatitis B)-associated nephritis held in Beijing in October 1989.
1. Diagnostic conditions
(1) Serum hepatitis B virus markers are positive.
(2) suffering from glomerulonephritis and can exclude secondary glomerular diseases such as lupus nephritis.
(3) Hepatitis B virus (HBV) antigen or HBV-DNA was found in kidney tissue sections.
(4) Pathological changes in renal tissue are membranous nephritis.
2. The description is worth explaining:
(1) The first 3 of the diagnostic conditions can be diagnosed regardless of the pathological changes of the renal tissue.
(2) When the first two of the diagnostic conditions are met and the renal tissue pathology is confirmed as membranous nephritis, although no HBV antigen or HBV-DNA is found in the renal tissue section, it can be used as a diagnosis.
(3) China is a high incidence area of HBV infection, such as glomerular disease patients with HBV antigenemia, is not enough to be the basis for HBV-GN related nephritis.
Hepatitis B-associated nephritis needs to be differentiated from nephritis caused by other causes, such as systemic lupus erythematosus nephritis, glomerulonephritis after streptococcal infection.
