Kidney stones are stones that occur in the renal calyces, renal pelvis, and the junction of the renal pelvis and ureter. Kidney stones occupy an important place among urinary stones. This is because stones in any part of the urinary tract can originate in the kidney, especially ureteral stones which almost always come from the kidney, and they are more likely to damage the kidney directly than stones in any other part of the body. The disease is more common in young adults, more in men than in women. Most of the stones are located in the renal pelvis and, to a lesser extent, in the infrarenal calyces. Unilateral kidney stones are the most common, with a similar incidence on the left and right side and l0% on both sides.
The mechanism of urolithiasis formation is not fully understood. Many factors are thought to be involved in stone formation. The etiology of stones is not a single factor, but the result of a combination of many factors.
I. The following are some of the most common causes.
1, hyperparathyroidism: adenoma and hyperplasia can cause increased secretion of parathyroid hormone, which increases blood calcium, urinary calcium and urinary phosphorus excretion, and increases the concentration of calcium crystals in the urine, making it very easy to form stones. The concentration of calcium crystals in the urine increases, making it easy to form stones. 60% of people with this disease are combined with kidney stones.
2, metabolic diseases: some patients can cause high blood calcium and high urinary calcium disease are easy to produce urinary stones, such as vitamin D poisoning, bone marrow metastasis cancer, pediatric congenital vitamin D metabolic disorders and multiple myeloma. In addition to disorders of calcium metabolism, abnormalities in the metabolism of uric acid, cystine and xanthine can lead to the formation of corresponding stones. Long-term bed-ridden patients are prone to decalcification and stone formation.
3, climate and geographical conditions: tropical, dry areas or areas with high calcium content in the water, due to the concentration of urine and increased calcium content, easy to form stones.
4, diet and nutrition: such as vitamin A deficiency, so that the urinary epithelium deformation, “core” increase; urinary magnesium ions and citrate deficiency is easy to make calcium precipitation to form stones.
5, urinary tract obstruction: urethral stricture, prostate hypertrophy, renal pelvic ureteral stricture and other reasons can cause retention and concentration of urine, crystal precipitation precipitation.
6, urinary tract infection: bacteria, pus and shedding epithelium increase the “core” part of the urine. Infection also alkalizes the urine, which facilitates phosphate precipitation and disrupts the relative balance of crystals and colloids in the urine, resulting in stone formation.
7, foreign body: thread, broken catheter can become the “core” of stones.
The main pathological changes of the kidney caused by kidney stones are as follows.
1, the direct damage to the kidney caused by stones.
① Causes mucosal congestion and edema in the renal pelvis and calyces, epithelial exfoliation, erosion and necrosis to form ulcers.
② Damage to small blood vessels of mucosa causing bleeding.
(2) Chronic local stimulation by stones can cause cellular chemosis and tissue hyperplasia to form papillary-like changes, and some of them can become cancerous.
2.Stones cause urinary flow obstruction.
The extent of obstruction and water retention varies depending on the location of the stone, and if the stone is confined to the neck of the calyx, water retention may occur. If the stone is located in the junction of the glenoid and duct, or if the stone falls into the ureter, it may cause total hydronephrosis, resulting in decreased renal function. In severe cases, the kidney parenchyma may be shrunken into a cystic bag, resulting in complete loss of kidney function.
3.Secondary infection.
Stone obstruction causes urine stagnation leading to intrarenal infection. Infection accelerates stone formation and renal parenchymal damage. Finally, the obstruction is aggravated and the infection is more difficult to control, making the inflammation in the kidney aggravated to form kidney abscess. Bacteria enter the blood circulation and urogenic sepsis occurs, i.e. negative bacillary sepsis and death.
4.Stone dislodgement and downward migration.
to ureter, bladder, urethra, causing corresponding damage.
III. Diagnostic points
1, clinical manifestations of kidney stones symptoms.
It mainly depends on the size of the stone, its location, whether the stone is active or not, the presence or absence of urinary flow obstruction and the presence or absence of infection. If the kidney stone does not cause obstruction or has only mild obstruction without secondary infection, there may be no significant conscious symptoms for a long time.
In some cases, the kidney stones are so large that they may cause kidney damage, but they are not detected at the time of physical examination. On the contrary, smaller stones, because of their large range of activity, often cause acute obstruction with serious symptoms and are detected early. The main symptoms and signs of kidney stones are as follows.
(1) Pain: The pain caused by kidney stones is mainly caused by the increase in pressure in the renal pelvis due to obstruction of urinary flow caused by stones. About 40% to 50% of patients have a history of intermittent pain attacks. Large stones in the kidney, because of the small activity, often feel soreness and discomfort, dull pain or vague pain at the corner of the spine, while small stones in the kidney, because of the large activity, easy to cause obstruction of the glenoid connection and colic, pain radiating to the lower abdomen or groin, accompanied by nausea, vomiting, pale and sweaty. The pain often comes on during or after strenuous activity.
(2) Hematuria: Hematuria is another major symptom of kidney stones, often followed by painful visual hematuria or microscopic hematuria, the latter being more common. Hematuria is aggravated by activity or colic. Patients with kidney stones occasionally seek medical attention for painless hematuria.
(3) Pus urine: Pus urine can be seen in cases of kidney stones complicated by infection or infected stones, accompanied by symptoms such as urinary urgency, frequency, painful urination and fever.
(4) Lithotripsy symptoms: After acute colic attack, small stones or urinary sand may be excreted in the urine.
(5) Anuria: Bilateral kidney stones or solitary kidney stones causing urinary tract obstruction may present symptoms of anuria.
(6) Signs: Tenderness in the spinal rib angle or percussion pain in the kidney area at the onset. In a few patients, a mass may be found in the upper abdomen or abdomen due to chronic obstruction by kidney stones, resulting in hydronephrosis. During the acute attack of colic, hypertension may occur; chronic atrophic kidney also has the possibility of producing renal hypertension.
Second, auxiliary examination.
1, urine: routinely visible red blood cells, especially after the appearance of colic, is helpful for diagnosis. When combined with infection, there are pus cells. Urine biochemical determination of urinary calcium, phosphorus, uric acid, oxalic acid, cystine quantification and urinary pH are helpful to detect the etiology of stones. Urine culture, if simple kidney stones should be free of bacterial growth. If the stone is combined with infection or infection secondary to stone, the culture should be positive for bacteria.
Blood: changes in blood calcium, phosphorus, alkaline phosphatase, uric acid and pH vary with each type of stone and its primary cause; parathyroid hormone level should be measured if hyperparathyroidism is suspected.
3.Stone composition analysis: When obtaining stones that the patient expelled by himself or removed by previous surgery, stone composition analysis should be done to clarify the type of stones, which is important for both diagnosis and prevention of urolithiasis. Visual observation, calcium oxalate or calcium oxalate calcium phosphate mixed stones surface mulberry-like, or stellate protrusion, more blood stained brown, hard; magnesium phosphate amine calcium phosphate mixed stones are white, rough surface, often antler-shaped, brittle; uric acid stones smooth surface or rent brown, yellow or brown; cystine stones smooth surface yellow wax-like, hard texture.
4.Imaging examination
(1) Urological imaging: 95% of kidney stones can be seen on X-ray, which is an important means to diagnose kidney stones. The location, number, size and shape of the stone can be initially determined. If the right kidney stone should be distinguished from the bile duct stone, a lateral film should be added.
(2) Intravenous urography (IVU) can clarify the location of stones and the function of both kidneys.
(3) Retrograde urography should not be used as a routine test, but only for patients whose diagnosis by IVU is still unclear, who have X-ray negative stones, who are allergic to iodine, who have very poor renal function, and who do not show IVU. Retrograde urography can show the location of kidney stones and the degree of obstruction; gas injection angiography can show negative stones.
(4) Ultrasound examination can detect stones as well as hydronephrosis.
(5) Radionuclide scan and nephrogram: radionuclide scan can not only show the stones but also determine the degree of renal impairment; nephrogram indicates the presence of obstruction.
(6) CT is not generally used as the first choice for stone examination, but has important diagnostic value in cases with negative X-ray stones or suspected combined renal tumors.
(7) Renal arteriogram: Only individual patients need to have renal arteriogram. For example, if a congenital hoof-shaped kidney or fused kidney is complicated by stone extraction, renal arteriogram can show the malformed artery, which can help to develop a surgical plan.
(8) If hyperparathyroidism is suspected, radiographs of the hands, ribs, spine, pelvis and femoral head should be taken.
5. Ureterorenoscopy.
When the abdominal plain film does not show stones and the IVU has filling defects, this examination can clarify the diagnosis and treatment.
Differential diagnosis
Based on the clinical manifestations and the above mentioned examinations, we can generally determine the location, size, number, morphology, the effect of the stone on the kidney and the possible causes of the stone. Sometimes it must be distinguished from the following diseases.
1. Acute biliary colic: sudden onset of right upper abdominal pain, easily confused with right-sided renal colic. However, there is limited pressure pain, rebound pain and abdominal muscle tension in the right upper abdomen, the enlarged gallbladder can be palpated and Murphy’s sign is positive; no abnormal findings in routine urine examination.
2, acute appendicitis: right lower abdominal pain, may be accompanied by fever, limited pressure pain, pressure pain, rebound pain and muscle tension in the right lower abdomen, no kidney area buckling pain; urinalysis generally no abnormal findings; imaging examination no stone signs.
3, pyelonephritis: can show back pain and hematuria symptoms. However, it is mostly seen in women, and there is no history of episodic pain or worsening of pain after activity. No stone image on X-ray; no strong echogenic light spot and sound shadow on ultrasound.
4, renal tuberculosis: can show hematuria and calcified foci of diseased kidney. However, there are obvious symptoms of bladder irritation, mostly terminal hematuria; calcified images are distributed in the kidney parenchyma in regular plaques with uneven density on the plain radiograph of urinary tract, and sometimes tuberculosis bacilli can be found in the urine.
5.Kidney and ureteral cancer: manifesting as lumbar pain and hematuria, calcified images can also appear on plain radiographs of urinary tract, which are sometimes confused with this disease. However, it is painless carnal hematuria, often mixed with blood clots. IVU shows compression, deformation, displacement or absence of the renal pelvis and calyces or ureter, or the kidney is not visible.
6. spongy kidney: calcified images may appear on plain radiographs of the urinary tract, but they are multiple small stones located in the conical cystic dilatation of the papillary ducts and collecting ducts, arranged in clusters or radially. ivu shows multiple small pyknotic cysts around the renal calyces, arranged in a grape bunch pattern, and the lesions are mostly bilateral.
The calcification of intra-abdominal lymph nodes: calcification – generally multiple, scattered, rarely confined to the renal area, its density is not uniformly speckled. ivu pelvic calyces with normal morphology, lateral slices are located outside the shadow of the renal area.
IV. Treatment
1.Conservative treatment
(1) General treatment: Drinking a lot of water can reduce the concentration of inorganic salts in the urine to form stones, reduce the chance of precipitation into stones, and also facilitate the drainage of infection. According to the composition of stones, adjust the diet reasonably. If the stone is accompanied by infection, antibacterial drugs should be selected according to the bacterial culture and drug sensitivity test. In case of renal colic attack, the pain should be relieved first.
(2) Etiological treatment: If the cause of upper urinary tract stones is not removed, the recurrence rate is directly proportional to the follow-up period, regardless of the way to remove or discharge the stones. For example, in patients with primary hyperparathyroidism, parathyroid lesions should be treated first; in patients with uric acid stones, hyperuricuria and possible hyperuricemia should be controlled; in infected stones, antibiotics sensitive to urinary culture growth bacteria should be used for a long time to control the spread of infection, whether after surgery or extra-restrictive shock wave lithotripsy treatment.
(3) Pharmacological treatment: For some types of stones even the purpose of stone elimination can be achieved. For example, for calcium-containing stones caused by primary high urinary calcium, the efficiency of taking dihydrocoumaric acid to prevent stone recurrence is 90%; for uric acid stones, patients can take oral potassium citrate and other drugs to alkalize urine and allopurinol to reduce uric acid content; for cystine stones, in addition to alkalizing urine, taking D penicillamine can reduce urinary cystine levels; and for infected stones, ammonium chloride should be taken to acidify urine.
(4) Chinese herbal medicine treatment: the principle of Chinese herbal medicine for stone removal is to clear heat and dampness and to pass lymphatic and eliminate stones, generally stones below 6 mm can be discharged, the main effect of the drug is diuretic, anti-inflammatory, enhance ureteral peristalsis, reduce ureteral smooth muscle tension (antispasmodic), which is conducive to the discharge of stones.
2.Lithotripsy: extracorporeal shock wave lithotripsy is an important means of kidney stone treatment, which is generally suitable for kidney stones below 2cm, and requires the ureter on the stone side to be open, with good kidney function and no complication of infection.
3.Surgical treatment: percutaneous nephrolithotomy, percutaneous nephrolithotomy is suitable for stones in the renal pelvis, renal calyces, upper ureteral stones and even stones in the diverticulum of renal calyces. It is especially suitable for re-operation, residual stones and active metabolic diseases.
4.Open surgery.
(1) Renal pelvic dissection and stone extraction.
(2) Intra-sinus pyelotomy for stone extraction.
(3) Renal parenchymal dissection for stone extraction.
(4) Nephrectomy: If the stone causes serious damage to the kidney, loss of function, or combined with pus in the kidney, and the kidney on the opposite side is functioning well, the affected kidney can be removed.
At present, with the improvement of doctors’ technical level and medical equipment, percutaneous nephrolithotomy has gradually replaced open surgery.