Pediatric Nephrolithiasis

　　One, related factors of stone formation

　　1. High concentration of substances forming stones in urine: Commonly seen in increased excretion of calcium, oxalate, or uric acid in urine, less urine volume, and urine concentration, which can lead to increased concentration of all solutes in urine.

　　2. Change in urine pH value.

　　3. Decreased inhibition of crystal precipitation in urine: Such as decreased citrate, pyrophosphate, acidic mucopolysaccharides, magnesium, etc.

　　4. Bacteria, necrotic tissue, and pus in the urine can all become the core of stones.

　　Second, local factors of the urinary system

　　1. Urinary stasis: Such as urinary tract stenosis, obstruction, diverticula can cause urine stasis, and stone-forming substances to precipitate.

　　2. Urinary tract foreign bodies: Such as long-term indwelling catheters, non-absorbable sutures, fragments, plastic tubes, hairpins, etc., which can become adhesions for stones.

　　Three, systemic factors

　　1. Abnormal metabolism: Hyperparathyroidism, abnormal calcium and phosphorus metabolism can lead to hypercalciuria; increased uric acid excretion during gout; familial hereditary cystine metabolism abnormalities can lead to cystine stones.

　　2. Dietary structure: Children with a lack of animal protein are prone to bladder stones. Excessive intake of animal protein, vitamin D, and insufficient fiber can easily induce upper urinary tract stones. Insufficient water intake, urine concentration, and crystal formation are more likely.

　　Kidney stones often occur with obstruction and infection, with symptoms such as urinary reflux, urinary retention, and renal pelvis hydrops. Urolithiasis can directly damage kidney and urethral tissues, causing bleeding, or can lead to tissue cell damage due to infection, causing bleeding. The characteristic is hematuria accompanied by renal colic, or symptoms such as interrupted urination, difficulty in urination, and dysuria.

　　Pediatric urinary stone disease is mainly bladder and urethral stones, which are more common in children under 4 years old. There is no significant age difference in kidney and ureteral stones. Kidney stones can be solitary, but multiple occurrences are not uncommon, especially in cases secondary to obstruction at the renal pelvis-ureteral junction, with bilateral kidney stones accounting for about 20%.

　　1. Kidney Stones:Hematuria is the main symptom of kidney stones, which often appears after strenuous exercise, sometimes with mild hematuria, only visible under a microscope with a large number of red blood cells. Back or inguinal pain is an important manifestation of kidney stones. In infants and young children who cannot complain, they may cry and even vomit, with pale complexion and cold sweat. Some cases present with systemic symptoms, such as low fever, loss of appetite, weight loss, and delayed growth and development. Urinalysis may show a large number of white blood cells, indicating symptoms of urinary tract infection. Occasionally, kidney stones may present with acute anuria as the initial symptom, which is due to the renal-renal reflex.

　　2. Ureteral calculus:The symptoms are basically the same as those of renal calculi, with the main symptoms being dysuria and pain during urination. The degree of dysuria and pain varies, with severe pain causing children to be extremely uncomfortable. They may pull or rub the penis and perineum with their hands, and sometimes have a phenomenon of urine interruption, which can only be continued after changing the position. Children may have chronic urinary retention, dribbling, and extremely difficult urination to the extent of anal prolapse. Due to the frequent pulling of the penis, they are often larger than children of the same age, but only renal calculus in the ureterovesical segment can cause urinary frequency, urgency, and pain, which are symptoms of bladder irritation.

　　3. Bladder calculus:All bladder calculi are accompanied by infection, and therefore they all have pyuria.

　　4. Urethral calculus:It is usually solitary, such as impaction in the anterior urethra, where stones can be felt in the penile area, and it is common to have terminal hematuria. There is often acute urinary retention. If urinary tract stones are considered, an abdominal X-ray film can detect radio-opaque calcium stones, cystine and infectious stones can appear as faintly radio-opaque, and radio-opaque stones can be detected by B-ultrasound, intravenous urography, or CT as positive filling defects. If diagnosis of stones is made, a complete urinary tract function and radiological examination should be performed to detect the presence of urinary tract retention, obstruction, and infection. About 1/4 of children with urinary tract stones have vesicoureteral reflux, and as part of the etiological investigation, the physicochemical properties of stones removed surgically, endoscopically, or spontaneously should be examined, and crystal morphology analysis should also be performed. It is also necessary to pay attention to factors of metabolic abnormalities.

　　Dietary adjustments based on stone composition: Patients with oxalate stones should eat less spinach, potatoes, strong tea, etc., and taking vitamin B6 can reduce the excretion of oxalates. Those with calcium stones should limit the intake of milk, refined wheat flour, chocolate, etc. Those with uric acid stones should avoid high-purine foods (such as animal organs) and can take alkaline drugs to maintain urine pH at 7 to 7.5.

　　Nursing
　　1. It is advisable to drink more water, increase urine volume, and dilute urine. The urine volume of adults should be greater than 2000ml per 24 hours.
　　2. Timely relief of urinary tract obstruction, control of urinary tract infection, timely removal or replacement of catheters left in the urinary tract, removal of urinary tract foreign bodies, and encouragement of long-term bedridden individuals to perform functional exercises.

　　1. Urine examination:There may be microscopic hematuria, with increased leukocytes and pus cells during concurrent infection, and crystals. The 24-hour urine calcium, uric acid, creatinine, and oxalate content should be measured to understand the metabolic state and the presence of endocrine disorders; urine bacterial culture should also be performed. Children with recurrent gross hematuria should have their urine calcium levels checked. The normal upper limit is 4mg/(kg·24h) or a urine calcium/creatinine ratio greater than 0.25.

　　2. Blood examination:There may be anemia, with increased blood leukocytes during infection, bilateral hydrops leading to renal dysfunction, and the appearance of uremia with increased serum creatinine. Blood calcium, phosphorus, alkaline phosphatase, and drug sensitivity tests should be determined.

　　3. Urological Plain Film (KUB):More than 95% of kidney and ureteral stones can be visualized on X-ray films. Additional lateral films can be taken to exclude other calcified shadows in the abdomen, such as gallbladder stones, mesenteric lymph node calcification, venous stones, fecal stones, etc., which are all located in front of the anterior edge of the vertebral body, while upper urinary tract stones are generally located behind the anterior edge of the vertebral body. Stones that are too small or insufficiently calcified often cause difficulties in diagnosis.

　　4. Excretory urography (IVU):It can understand the stone, urinary tract lumen shape, and kidney function, and whether there are local factors causing stone formation. The radiolucent uric acid stones are shown as filling defects in the kidney that are visible in the image.

　　5. Cystoscopy and retrograde ureteropelvic nephrourogram:Bladderoscopy may be performed if necessary. Bladderoscopy can see the stones trapped in the ureteral orifice. Retrograde ureteropelvic nephrourogram is suitable for cases that remain undiagnosed after IVU, to understand the location, degree, and nature of the obstruction.

　　6. B-ultrasound examination:The typical ultrasonic manifestation of kidney stones is strong echo foci in the kidney, followed by acoustic shadows. But due to the differences in size, composition, and shape of the stones, their ultrasonic manifestations can also be different. It can detect small stones and negative stones that cannot be shown on X-ray films, and understand the shape and hydronephrosis of the kidney. For some cases that are not suitable for IVU, such as pregnant women, those allergic to contrast agents, those with anuria or chronic kidney failure, etc., it can be used as a means of diagnosis and treatment method selection.

　　7. Ureteroscope examination:When there is no evidence of stones on abdominal plain films, IVU shows filling defects but cannot be diagnosed, this examination can make a definite diagnosis and can also perform stone removal or lithotripsy.

　　8. CT examination:Can detect stones that do not show up on plain films.

　　Patients with urinary stones should eat some foods according to the doctor's advice and cannot eat arbitrarily. It is better to discover and treat them in time. After treatment, the diet should be light and rich in nutrition.

　　Patients with urinary stones can choose acupuncture and Chinese medicine treatment for ureteral stones. Both acupuncture and Chinese medicine have good effects. For smaller bladder stones, it can be tried with Chinese medicine for litholysis and anti-infection treatment.