Pediatric familial recurrent hematuria syndrome
Introduction
Introduction to familial recurrent hematuria syndrome in children Familial recurrent hematuria syndrome (familialrecurrenthematuriasyndrome) is also known as familial recurrent hematuria, benign familial hematuria, familial hematuria syndrome. Repeated hematuria, normal renal function and positive family history are clinical features, and the pathological features are glomerular basement membrane thinning. basic knowledge Sickness ratio: 0.0001% Susceptible people: children Mode of infection: non-infectious Complications: deafness, hearing impairment
Cause
The cause of familial recurrent hematuria syndrome in children
(1) Causes of the disease
Familial recurrent hematuria syndrome is generally autosomal dominant inheritance, and part of autosomal recessive inheritance.
(two) pathogenesis
The etiology and pathogenesis of benign familial hematuria have not been elucidated. Most scholars believe that the disease is autosomal dominant, and the gene is located in chromosome COL4A3/COL4A4, a gene encoding type IV collagen 3 and 4 chains. Due to the disorder of type IV collagen synthesis, the glomerular basement membrane is incomplete and thin, which may be the direct cause of the disease.
1. Immunofluorescence: usually negative, occasionally IgM and/or C3 are deposited in the mesangial area, but the intensity is generally weak.
2. Light microscopy: There is no clear pathological change with diagnostic significance. In most cases, glomeruli and tubulointerstitial are normal. Some cases have mesangial cells and mild hyperplasia of the cells, and some have sclerosis.
3. Electron microscopy: Electron microscopy is the only important basis for diagnosing the disease. Under the electron microscope, the glomerular basement membrane is diffusely thinned, and the thickness of the normal glomerular basement membrane is different. Adults usually have 310-380 nm. Between children, children can vary from age to age, with an average of 220 nm (100 to 340 nm) at 1 year of age. Later, with age, the average thickness of the glomerular basement membrane reaches 310 nm (180 to 380 nm). Diffuse basement membrane thickness.
Prevention
Prevention of familial recurrent hematuria syndrome in children
Avoid infection and overwork, strengthen control of a small number of children with hypertension, and avoid unnecessary treatment and use of nephrotoxic drugs.
Complication
Complications of familial recurrent hematuria syndrome in children Complications, hearing loss, hearing loss
Very few children can develop renal insufficiency, and 10% of children have been reported to have deafness, which is a high-frequency hearing disorder.
Symptom
Symptoms of familial recurrent hematuria syndrome in children Common symptoms Urinary protein hypertensive hematuria tubule collapse glomerular sclerosis deafness
1. Hematuria: persistent microscopic hematuria, some patients may have paroxysmal gross hematuria. The clinical features of this syndrome are persistent microscopic hematuria with recurrent gross hematuria, which is often induced in upper respiratory tract infection and may be associated with strenuous exercise. Long-term persistent hematuria and renal function is almost normal, or slightly reduced, this non-progressive recurrent hematuria, not only seen in familial, but also sporadic cases, some children in addition to hematuria, may be accompanied by urine protein, high Blood pressure, a very small number of sick children can develop to renal insufficiency.
2. Extrarenal performance: There is no extrarenal manifestation in children with TBMN. It is reported that about 10% of children with TBMN have deafness. Hearing tests show high-frequency hearing impairment, but different from Alport syndrome, TBMN has more deafness. Lighter and less progressive.
Examine
Examination of pediatric familial recurrent hematuria syndrome
Urine examination is mainly hematuria, a small number of urine protein, blood biochemistry, renal function, immunological examination, etc. are normal, often need to do imaging examination, B-ultrasound and other routine examinations, in order to exclude other causes of hematuria.
Diagnosis
Diagnosis and diagnosis of familial recurrent hematuria syndrome in children
diagnosis
1. Family history: Conducting a family survey.
2. Clinical manifestations: a benign process, long-term follow-up and stable condition.
3. Laboratory tests: uroscopy examination to find the type of tube, to help exclude hematuria caused by renal parenchymal lesions, 24h urine protein quantitative or only a small amount of protein, other tests check normal.
4. Renal biopsy: completely normal under the light microscope, but red blood cells can be seen in the renal capsule, immunofluorescence examination without immunoglobulin and complement deposition, which can be differentiated from other glomerulonephritis, local small kidney under electron microscope The basement membrane of the ball can be thin or even broken, and focal glomerular sclerosis and tubular atrophy can be seen. The diagnosis of benign familial hematuria mainly depends on ultrastructural examination of renal tissue electron microscopy, where simple hematuria, especially continuous microscopic hematuria Renal function and normal blood pressure, family history of microscopic hematuria, should be highly suspected, renal biopsy is the only means of diagnosis.
Differential diagnosis
The syndrome must be differentiated from various hematuria, especially recurrent hematuria (IgA mesangial nephropathy), Alport syndrome, surgical hematuria (such as stones, tuberculosis, tumors, etc.) and urinary tract infection.
1.Alport syndrome: often with progressive renal dysfunction, often with neurological deafness and eye abnormalities, if there is renal dysfunction or hearing impairment in the family, then support the diagnosis of Alport syndrome, a reliable differential diagnosis is Pathological examination of renal tissue, Alport syndrome can be seen in a variety of pathological changes, renal interstitial, especially at the junction of cortex and medulla, easy to see foam cells help to diagnose Alport syndrome, glomerular basement membrane can be seen under electron microscope GBM) thickened and multi-layered structure, can form a network, containing dense particles, some Alport syndrome GBM thickness is uneven, thickness inlay, these characteristics can be distinguished from benign familial hematuria, but a few Alport syndrome GBM Diffuse thinning, early renal function is a benign process, especially in such cases, the use of anti-type IV collagen non-collagen region (NCl) monoclonal antibody or anti-renal antibody for immunohistochemistry or immunofluorescence detection, Alport syndrome was found to be negative, while benign familial hematuria was positive.
2. IgA nephropathy: clinically often manifested as "pharyngeal hematuria", may also be associated with proteinuria, and even nephrotic syndrome-like changes, mainly relying on renal biopsy, IgA nephropathy pathology mainly characterized by deposition of IgA mesangial area Mesangial proliferative nephritis changes, and benign familial hematuria immunofluorescence is usually negative, but in recent years there have been reports of thin basement membrane nephropathy (benign familial hematuria) with IgA nephropathy. In general, TBMN is mainly characterized by continuous microscopy. Hematuria, but gross hematuria is rare, and urinary red blood cell casts are rare. IgA nephropathy can be characterized by repeated gross hematuria and red blood cell casts. Therefore, the distinction between TBMN and IgA nephropathy should be considered in both clinical and pathological aspects.
3. Surgical hematuria: differential diagnosis can be made by medical history, physical examination, laboratory tests and urography.
