The clinical diagnosis of pediatric hematuria follows certain steps and ways of thinking.
1. The diagnosis of true hematuria and pseudohematuria hematuria begins with the exclusion of the following conditions that can produce pseudohematuria.
① ingestion of food (such as honey) or drugs (such as rhubarb, rifampin, sodium phenytoin) containing large amounts of artificial colors (such as aniline) can cause red urine.
② hemoglobinuria or myoglobinuria.
(iii) porphyrituria.
④ uric acid salts in the urine of newborn infants can make the diapers red. However, the above urinalysis can be differentiated by the absence of red blood cells.
⑤ Goose or menstrual blood contamination.
2, determine the glomerular and non-glomerular hematuria hematuria, first determine the source of hematuria, and then determine the primary cause. The following methods are commonly used.
(1) urine sediment erythrocyte morphological examination: if the predominantly heterogeneous red blood cells (> 60%) suggest glomerular hematuria; some people believe that the number of red blood cells in the urine in the form of ink-stone circles (G1 cells) reaches 5%, that is, there is diagnostic significance. If the hematuria is predominantly homogeneous, it indicates non-glomerular hematuria, which originates from the renal pelvis, calyces, ureter, bladder or urethra, mostly due to urinary tract infection, stones, tuberculosis, tumor, trauma, etc.
②Measure the average volume of red blood cells in urine: if MCV<72fl and small cell distribution, it means that the hematuria originates from glomerulus, the sensitivity of this method is 95%, the specificity is 96%, and the subjective error of the detector can be overcome.
③ Urine sedimentation examination sees red blood cell tubular type and renal tubular epithelial cells, which indicates that the hematuria is renal substantial. If the urine protein quantification is >500mg/24h in microscopic hematuria; or >990mg/24h in carnal hematuria, or >660mg/L, it is mostly suggestive of glomerular disease.
④Urine red blood cell electrophoresis: 20, 64±1, 72 seconds for glomerularity and 27, 27±1, 66 seconds for non-glomerularity.
(⑤) The particle tube type of immunoglobulin in urine; if the tube type containing IgG and T-H protein can be found in urine, it is mostly renal parenchymal hemorrhage, mainly glomerulonephritis, and partly interstitial nephritis.
3.Diagnostic steps of glomerular hematuria
(1) Analysis of clinical data: The differential diagnosis of glomerular hematuria should pay attention to especially detailed inquiries about the concomitant symptoms and signs of hematuria.
(1) With edema, hypertension, tubular and proteinuria found in the urine, primary or secondary glomerular disease should be considered.
(ii) With a new skin infection and hematuria after pharyngitis, glomerulonephritis after acute streptococcal infection should be considered first, followed by IgA nephropathy.
(iii) Chronic glomerulonephritis should be considered when accompanied by nocturia and significant anemia.
(iv) Alport syndrome should be considered when accompanied by hearing abnormalities.
(⑤ with a family history of hematuria, thin basement membrane disease should be considered.
(6) With sensory abnormalities, Fabry disease should be considered.
(vii) With pulmonary hemorrhage, pulmonary hemorrhage-nephritis syndrome should be thought of.
(viii) With purpura, purpura nephritis should be considered.
(9) Nephrotic syndrome should be considered with high edema and large amount of proteinuria.
(2) Blood and urine biochemical analysis.
(i) Elevated blood ASO with Q drop should be considered post-acute streptococcal infection nephritis.
(ii) With HBsAg (+) and or HBeAg (+) and hepatitis B virus antigen deposition in the renal tissue, hepatitis B virus-associated nephritis can be diagnosed.
(iii) Persistent decrease in serum complement, considering primary membranoproliferative nephritis, lupus nephritis, hepatitis B virus-associated nephritis, and chronic glomerulonephritis.
(iv) Positive ANA, Anti-dsDNA and ANCA should be considered lupus nephritis.
⑤ Increased serum IgA suggests the possibility of IgA nephropathy; IgG, IgM and IgA are increased, lupus nephritis and chronic nephritis should be considered.
(6) The analysis of urine protein composition is dominated by macromolecular proteinuria, which is mostly seen in acute and chronic glomerulonephritis and nephrotic syndrome; small molecule proteinuria is dominant, suggesting interstitial nephritis.
(3) Kidney biopsy analysis: pathological examination of kidney biopsy is of great value for the etiological diagnosis of hematuria, most commonly IgA nephropathy, thin basement membrane disease, mild lesional nephropathy and focal segmental glomerulosclerosis in children, and some uncommon glomerular diseases such as Alport syndrome, lipoprotein glomerulopathy, fibronectin glomerulopathy and collagen III glomerulopathy can also be diagnosed. Immunopathology is of great value in the diagnosis of anti-glomerular basement membrane glomerulonephritis, IgA nephropathy, IgM nephropathy, lupus nephritis, hepatitis virus-associated nephritis, Alport syndrome, and light chain deposition disease.
4.Diagnostic steps for non-glomerular hematuria
(1) Urine three-cup test: the first cup with increased red blood cells is bleeding from the anterior urethra; the third cup with increased red blood cells is bleeding from the base of the bladder, prostate, posterior urethra or seminal vesicles; all three cups with bleeding are bleeding from above the bladder neck. Upper urinary tract bleeding mostly appears as dark brown urine without signs of bladder irritation, and sometimes blood clots are seen. The presence of blood clots in the urine is usually a non-glomerular disease.
(2) Analysis of clinical data.
(i) With urinary frequency, urinary urgency and painful urination, urinary tract infection should be considered, followed by renal tuberculosis.
(ii) With hypothermia, night sweats and wasting should be considered renal tuberculosis.
③ with skin and mucous membrane bleeding should be considered as bleeding disorders.
(iv) with hemorrhage, hemolysis, circulatory disorders and thrombotic symptoms, DIC or hemolytic-uremic syndrome should be considered.
(⑤ with renal colic or back pain after activity should be considered kidney stone.
(6) Urological trauma should be considered with a history of trauma.
(vii) renal tumor or renal vein embolism should be considered in the presence of a renal mass.
(viii) Acute interstitial nephritis should be considered for recent use of nephrotoxic drugs.
If there are no obvious accompanying symptoms, consider left renal vein compression syndrome, idiopathic hypercalciuria, renal microstones, calyx papillitis, renal small vessel disease and renal pelvis and urinary tract polyps and diverticula.
(3) Analysis of ancillary tests.
(i) two positive urine cultures with urine colony counts >105/ml can diagnose urinary tract infection.
(2) urine culture detection of Mycobacterium tuberculosis, the diagnosis of renal tuberculosis has important value, and can be found through more than 3 morning urine sediment antacid bacilli, its positive rate of 80% to 90%, 24-hour urine sediment to find antacid bacilli, the positive rate of 70%;
③The whole urinary tract X-ray is very important in the diagnosis of the etiology of non-glomerular hematuria, and can detect urinary stones in time. For uric acid stones, ultrasound examination can be used for those with negative X-ray examination.
④ For suspected upper urinary tract pathology, intravenous pyelogram (IVP) is feasible. For negative IVP with persistent hematuria, ultrasound or CT examination should be performed to exclude small renal tumors, small stones, renal cysts, and renal vein thrombosis. If still negative, renal biopsy is feasible.
⑤ Left renal vein compression syndrome is a common cause of non-glomerular hematuria, and color Doppler examination can confirm the diagnosis.
(6) Idiopathic hypercalciuria in children is also a common cause of non-glomerular hematuria and can be diagnosed with a 24-hour urine calcium measurement >4 mg/kg or urine calcium/urine creatinine >0,2.
The clinical diagnosis of hematuria is sometimes difficult, and it is essential to follow certain examination steps. For those who cannot clearly identify the cause, more rest and regular follow-up are very important, and drug treatment is not recommended before the diagnosis is clear.