Occult nephritis

Introduction to occult nephritis Latentglomerulonephritis, also known as asymptomatic proteinuria and/or hematuria, refers to mild to moderate proteinuria and/or hematuria, clinically characterized by repeated persistent hematuria, with or without mild proteinuria, or One of them is outstanding. basic knowledge The proportion of illness: 0.001% Susceptible people: no special people Mode of infection: non-infectious Complications: hematuria, proteinuria, hypertension

Cause of occult nephritis

Simple hematuria is the main cause of the manifestations (25%):

1IgA nephropathy, especially early, non-IgA mesangial proliferative glomerulonephritis;

2 focal glomerulonephritis and thin basement membrane nephropathy can also be early manifestations of renal damage caused by allergic purpuric nephritis, lupus nephritis, infective endocarditis, and thin basement membrane nephropathy.

Mild, moderate asymptomatic proteinuria is a common cause of major manifestations (20%):

For minimal pathological nephritis, mesangial proliferative nephritis, membranous nephropathy, focal segmental glomerulosclerosis and early stage of some IgA nephropathy, amyloidosis nephropathy, diabetic nephropathy (DN), systemic lupus erythematosus (SLE) ), lupus nephritis (LN) and finger-bone osteosynthesis syndrome.

Asymptomatic hematuria with proteinuria is a common cause of major manifestations (25%):

It is an early manifestation of a certain stage of various glomerular diseases (such as mild glomerular lesions, mesangial proliferative nephritis, focal proliferative nephritis and IgA nephropathy).

Pathogenesis

The pathogenesis of this disease is still unclear. It is believed that it is related to infection and immune response. Because of different etiology, the pathogenesis is different. There are many types of pathological forms, and many are early stages of various pathological changes.

1. Simple proteinuria: It can be a small pathological nephropathy, mesangial proliferative nephritis, membranous nephropathy, focal segmental glomerulosclerosis and early stage of IgA nephropathy.

2. Simple hematuria: It can be early stage of IgA nephropathy, mesangial proliferative nephritis, focal nephritis, purpuric nephritis, LN and thin basement membrane nephropathy.

3. Asymptomatic hematuria with proteinuria: can also be mild glomerular lesions, mild mesangial proliferative nephritis, focal proliferative nephritis, IgA nephropathy or early membranous nephropathy.

Occult nephritis prevention

Usually should pay attention to rest to avoid fatigue, disable nephrotoxic drugs, those who have repeated infections should be removed, such as tonsil repeated acute inflammation, you can consider tonsillectomy, acute infection should be controlled in time to avoid hematuria and proteinuria.

Concealed nephritis complications Complications, hematuria, proteinuria, hypertension

There is no obvious complication of this disease. If the clinical manifestation is hematuria with proteinuria, it is often a typical manifestation of glomerular disease, also common in non-stationary (progressive) glomerular disease, because it is not accompanied by hypertension, edema And renal dysfunction, the general clinical symptoms are mild, so there is no obvious complications. In addition, asymptomatic hematuria and proteinuria can remain unchanged for a long time. If it is an early manifestation of a disease, it will develop its primary disease as the disease progresses. Clinical manifestations, at this time should not be diagnosed as occult glomerulonephritis, but should be diagnosed as corresponding diseases, such as mild glomerular lesions, mild mesangial proliferative nephritis, focal proliferative nephritis, IgA nephropathy and early Membranous nephropathy and the like.

Occult nephritis symptoms common symptoms back acid protein urine hematuria

Occult glomerulonephritis mostly insidious onset, or sudden appearance of gross hematuria, no other urinary system symptoms, most of the normal renal function, the main clinical manifestations of urinary abnormalities, clinical can be divided into three forms:

1. Asymptomatic hematuria: Most of the patients are young, no clinical symptoms and signs, sometimes found microscopic hematopoietic urinary tract in the physical examination, persistent or recurrent, some patients in strenuous exercise, high fever, infection In the case of drinking, etc., there is a transient gross hematuria, which disappears rapidly in a short period of time. There may be a sore waist during hematuria, so it is called recurrent recurrent hematuria. This type is more common in IgA nephropathy. Found in non-IgA mesangial proliferative glomerulonephritis, focal segmental glomerulonephritis, thin basement membrane nephropathy.

2. Asymptomatic hematuria and proteinuria: This type of patients with hematuria is episode, proteinuria can persist, during the hematuria, proteinuria is also aggravated, after the disappearance of hematuria, proteinuria is reduced, the condition is more serious than simple hematuria Because it does not have high blood pressure, edema, renal dysfunction, patients often can not see a doctor in time, easy to cause early missed diagnosis, this type is more common in mesangial proliferative nephritis, focal glomerulosclerosis and IgA nephropathy.

3. Asymptomatic proteinuria (asymptomatic proteinuria): occurs in young males, with persistent proteinuria (every urinary protein test is fluctuating, but always positive), urine protein is usually less than 2g / d, to Albumin-based, normal urine sediment, edema, hypertension, clinical manifestations, normal renal function, no abnormal blood biochemical tests, the disease can last for many years, the prognosis is good, histologically no clear lesions; may be different Types of glomerular diseases such as membranous nephropathy, mesangial proliferative nephritis, minimally pathological nephropathy, focal segmental glomerulosclerosis, and even early manifestations of certain IgA nephropathy.

Occult nephritis

Urine check

(1) Asymptomatic hematuria: continuous glomerular hematuria and/or repeated gross hematuria can be seen under the microscope. 0.5ml of blood or red blood cells per 100ml of urine is more than 5×109/L. Some patients have transient gross hematuria after fever or strenuous exercise, and disappear quickly in a short time. Sometimes urine routine, blood routine, renal function, blood uric acid, blood sugar, etc. are normal, glomerular urinary red blood cell morphology Abnormal changes often occur, and a variety of deformed red blood cells (such as strawberry, lotus leaf, etc.) can be seen under the phase contrast microscope.

(2) Asymptomatic proteinuria: urine routine protein is positive, urinary white blood cells, red blood cells are negative, 24h urine protein is usually less than 2g, mainly albumin, normal urine sediment, normal renal function, blood biochemical examination No abnormal findings, blood routine, erythrocyte sedimentation rate, platelet, clotting time no abnormality, urinary bacterial culture negative, urinary tuberculosis and cytology negative, liver and kidney function (including creatinine clearance, urine specific gravity and concentration test) normal, blood Anti-chain "O", rheumatoid factor, anti-nuclear antibody, cryoglobulin negative, normal complement, some IgA nephropathy patients with elevated blood IgA levels, other immunoglobulins are normal.

Radionuclide kidney map, kidney B-ultrasound, cystoscopy, intravenous pyelography and other examinations were normal.

Diagnosis and diagnosis of occult nephritis

diagnosis

The diagnosis of occult nephritis is difficult, and it is necessary to exclude other diseases by various tests in order to confirm the diagnosis.

1. Simple hematuria: The incidence of simple hematuria is higher, which is more common in young people. This type is characterized by continuous microscopic hematuria and/or repeated gross hematuria. Symptomatic hematuria or "simple hematuria", patients often find red blood cells in physical examination or accidental urine test, this hematuria is sustainable or recurrent, a small number of patients may have transient gross hematuria after infection or intense exercise, this type Patients with edema, high blood pressure, a variety of routine examinations are normal (such as blood routine, renal function, blood uric acid, blood sugar, etc.), B-ultrasound shows normal kidney size, kidney, ureter, bladder without abnormal findings, ECT, computer There are no abnormalities in tomography (CT), and even 5% to 15% of patients with renal biopsy can be difficult to conclude because the renal tissue is basically normal. Phase contrast microscopy is used to observe the morphology of urinary red blood cells, such as deformed red blood cells. Multi-line glomerular origin; if the red blood cell morphology is normal, it should be further examined for urinary tract, such as: renal pelvic venography (IVP), retrograde pyelography, cystoscopy, prostate examination, etc. In order to exclude other diseases, if still uncertain, renal angiography, CT or magnetic resonance imaging (MRI) may be performed when necessary, and follow-up observation for half a year. Older patients should first do the above examinations and observe for several years or more. Exclude hematuria caused by urological diseases.

2. Light, moderate proteinuria: Asymptomatic mild, moderate proteinuria as the main manifestation, more common in young men, urine routine protein is often positive, while urine white blood cells, red blood cells are negative, 24h urine protein quantification Often less than 2g, mainly albumin, but often fluctuating, clinical edema, hypertension and renal dysfunction, blood sugar, blood uric acid, etc. are normal, even for many years of renal biopsy is difficult to find clear lesions, this situation It can also be an early change for various pathological types.

Asymptomatic proteinuria should be used to detect urinary protein multiple times to determine whether persistent proteinuria, and to exclude transient proteinuria caused by fever, strenuous exercise, and orthostatic proteinuria in children and adolescents, persistent proteinuria For urinary protein quantification and component analysis, large, medium and small molecular proteins can be distinguished by SDS-PAGE gel electrophoresis. Radioimmunoassay can detect various specific urine proteins, and proteinuria caused by glomerular diseases Albumin-based, selective protein, containing immunoglobulin IgA component; renal tubular proteinuria is mainly composed of small molecule protein, 2-microglobulin, lysozyme content, and normal blood levels, early diabetic nephropathy Long-term manifestations of microalbuminuria, lupus nephritis and other secondary glomerular disorders, can be manifested as asymptomatic hematuria and proteinuria, according to their respective underlying disease performance to be checked, one by one.

3. Hematuria with proteinuria: patients with hematuria with proteinuria as the main manifestation, there are hematuria and proteinuria, but without edema, hypertension and renal dysfunction, compared with simple hematuria or simple proteinuria patients, prognosis Relatively poor, often because of no obvious symptoms and not easy to be found, such patients with other clinical manifestations of glomerular disease, it is not occult nephritis, should be diagnosed accordingly.

Differential diagnosis

1. Diseases differentiated from simple hematuria

(1) glomerular diseases: such as hematuria with abdominal pain, blood in the stool, joint pain and skin purpura, should consider allergic purpuric nephritis; such as hematuria with thrombocytopenia or red blood cells, thrombocytopenia, such as young and middle-aged women, in addition to consider thrombocytopenia In addition to sexual purpura, you should be alert to the possibility of SLE, LN, for the corresponding immunological examination (such as ANA, anti-dsD-NA, anti-SM antibody, etc.) and renal biopsy, such as renal tissue immunofluorescence as "full hall bright", then prompt LN Such as simple hematuria, renal biopsy immunofluorescence found that IgA deposition in the glomerular mesangial area, suggesting IgA nephropathy, such as renal biopsy light microscopy normal or basically normal, glomerular basement membrane diffuse thinning under electron microscope, It suggests thin basement membrane nephropathy; if patients with asymptomatic hematuria are middle and old, they should routinely identify urinary tumors, especially urinary tumors, and can do morning urine pathological cytology and B-ultrasound, CT or cystoscopy. If the patient is a child, attention should be paid to the exclusion of idiopathic hypercalciuria. If there is a high degree of suspicion of idiopathic hypercalciuria, it can be used as a calcium load test. For women of childbearing age, the question should be asked whether or not to take estrogen contraception. Be alert to low back pain and hematuria syndrome.

(2) urinary tract infection: hematuria with frequent urination, urgency, urinary incontinence or nocturia, should pay attention to urinary tract infections, such as hematuria with fever, low back pain, mostly pyelonephritis, urine routine see white blood cells>5/HP, check pus Cells, such as with nocturia, should consider whether there is chronic pyelonephritis, such as hematuria with suprapubic tenderness, dysuria, frequent urination, mostly cystitis; if there is a history of tuberculosis, renal calcification or obstructive degeneration, morning urine can be tested for acid resistance Bacillus and urinary tuberculosis culture.

2. Diseases differentiated from simple proteinuria

(1) If it occurs after fever or strenuous exercise and right heart failure, it should be repeated several times. If it is still transient, it is caused by hemodynamic changes.

(2) If the young person has a long-term standing or severe activity after proteinuria (small amount), especially those who are thin and long, should consider orthostatic proteinuria.

(3) If SDS-PAGE gel electrophoresis is based on small molecule protein (2-MG microglobulin, lysozyme), and the corresponding components in the blood are normal, it should be considered as proximal tubular damage (2-MG lysozyme). Glomerular filtration, renal tubular absorption).

(4) If the patient's proteinuria is accompanied by pain in the kidney area, urine protein electrophoresis is a light chain protein, ie, the peri-protein (Bence Jones protein) should consider the possibility of multiple myeloma.

(5) If urinary protein electrophoresis is a medium-sized molecule and albumin-based (selective urinary protein), glomerular disease should be considered.

(6) If accompanied by elevated blood sugar, people with a history of diabetes should consider diabetic nephropathy.

(7) Other diseases such as amyloidosis may also manifest as simple proteinuria in the early stage.

If urinary protein is increased or nephrotic syndrome, as well as edema, hypertension, renal dysfunction, etc., renal biopsy should be performed in time to help confirm the diagnosis.

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