Bladder and Urethral Calculi

　　Firstly, etiology

　　1. In addition to malnutrition, factors such as lower urinary tract obstruction, infection, bladder foreign bodies, and metabolic diseases can lead to secondary bladder calculi. Lower urinary tract obstruction, such as benign prostatic hyperplasia, urethral stricture, bladder neck tumor, etc., are prone to induce the formation of bladder calculi due to urine stasis. Bladder foreign bodies such as catheters, sutures, etc., can act as cores and lead to the formation of secondary bladder calculi. In addition, in areas where Schistosomiasis haematobium is prevalent, bladder calculi with egg cores can be seen.

　　2. Urethral calculi are divided into primary and secondary types, and their etiologies are as follows:

　　(1) Primary urethral calculi: Refers to calculi that form within the urethra from the beginning. Causes include urethral stricture, infection, obstructive cysts, mucosal injury, diverticula, and foreign bodies, etc.

　　(2) Secondary urethral calculi: Refers to calculi that first form in the urinary system above the urethra, then drain into the urethra and remain there, mostly remaining in the proximal parts of the physiological dilated and narrow parts of the urethra. Therefore, urethral calculi are more common in the prostate part, bulb, penile part, navicular fossa, and external orifice of the urethra.

　　Secondly, pathogenesis

　　The formation mechanisms of upper urinary tract and lower urinary tract calculi have certain differences but also some commonalities. The basic theories of calculus formation include several types, such as local lesions of the kidney; the theory of excessive excretion of urinary stone components; the theory of lack of inhibitory factors; the theory of free particles and fixed particles forming stones; the theory of the components and functions of the calculus matrix; the theory of orientation attachment and immune mechanisms, etc. Most upper urinary tract calculi are calcium oxalate calculi. Magnesium ammonium phosphate calculi are more common in bladder calculi than in the upper urinary tract. Infectious calculi are caused by bacteria that produce urease, which decomposes urea in urine to produce ammonia, alkalinizing the urine and causing relative supersaturation of phosphates and uric acid ammonium, leading to precipitation. Bacteria, infectious products, and necrotic tissue are also the core of calculus formation. In summary, urine supersaturation is the energy source for the formation of urinary stones, and its chemical kinetics generally includes several stages such as nucleation, growth, aggregation, and solid-state transformation. Secondary urethral calculi are formed first in the urinary system above the urethra and then drained into the urethra, remaining in the physiological dilated parts and narrow parts of the urethra, and causing a series of clinical symptoms of obstructive changes.

　　1. The accumulation of infected urine is prone to infection. Calculi as foreign bodies promote the occurrence of infection, invasion, and reproduction of bacteria. If it causes infection in the kidneys, it can lead to pyelonephritis, renal parenchymal abscess, pyonephrosis, and perinephritis. Obstruction and infection can both cause calculi to increase rapidly. Therefore, calculi, obstruction, and infection are interrelated, exacerbating urinary system damage.

　　2. Polyps or malignant tumors embedded in the urinary tract for a long time can cause damage to the local mucosa and chronic mechanical stimulation, leading to localized inflammatory hyperplasia in the urinary tract. Some patients may form benign polyps, including inflammatory polyps and fibrous polyps. Some polyps have tumor-like structural characteristics and are called polypoid tumors. Long-term presence of calculi in the bladder may occasionally lead to malignant transformation.

　　I. Clinical manifestations of bladder calculi

　　1. Sudden interruption of urination:It is a typical symptom, caused by the sudden interruption of the urine stream when the stone moves and blocks the bladder outlet, which can be resumed after changing the body position.

　　2. Dysuria:It is caused by the stimulation and injury of the stone to the local bladder during urination, which can radiate to the glans penis and distal urethra, and sometimes accompanied by symptoms of urinary urgency and frequency.

　　3. Difficulty in urination:The stone is located in the trigone area of the bladder, close to the bladder neck, which increases the resistance of urination. When the stone is embedded in the bladder neck orifice, it can cause significant difficulty in urination.

　　4. Hematuria:It can cause gross hematuria due to friction of the bladder mucosa by the stone or associated with urinary tract infection.

　　5. Urinary tract infection:It can manifest as frequent urination, urgency, dysuria, and pyuria.

　　II. Clinical manifestations of urethral calculi

　　The main symptoms are difficulty in urination, effort, dropwise urination, and pain. Acute urinary retention occurs when the urethra is completely blocked by the stone.

　　The formation of stones is related to diet. It is caused by excessive intake of components that can form stones in the diet. To prevent the occurrence of stone disease, attention must be paid to the matching of foods, eating various foods in moderate amounts, and even when a deficiency of a certain nutrient is found and a certain food needs to be supplemented, it is not advisable to eat a large amount of food at one time, because the digestive and absorptive functions of the human body are limited. Nutrients that cannot be digested or absorbed need to be excreted through the excretory organs, which will also increase the burden on the urinary system. Even if kidney stone disease is not present, it is not good for health. Especially when the urinary system stone disease is confirmed, during the illness, patients should be restricted from eating foods that are prone to cause stone formation. The specific method is:

　　1. Increase water intake and urine volume to dilute urine. The urine volume of adults should be greater than 2000ml per 24 hours.

　　2. According to the composition of the stones, adjust the diet. Patients with oxalate stones should eat less spinach, potatoes, strong tea, etc., and taking vitamin B6 can reduce the excretion of oxalates. For those with calcium stones, milk, refined wheat flour, chocolate, and other foods should be limited. For those with uric acid stones, it is not advisable to consume foods high in purines (such as animal internal organs), and alkaline drugs can be taken to maintain the urine pH at 7 to 7.5.

　　3. Timely relief of urinary tract obstruction and control of urinary tract infection. Promptly remove or replace catheters left in the urinary tract, remove foreign bodies from the urinary tract, and encourage long-term bedridden individuals to perform functional exercises.

　　1. Fresh urine should be centrifuged immediately after urinalysis, and crystals should be found in the sediment. Do not store urine using refrigeration methods, as cooling itself can cause normal urine to form crystals, which can be observed under a microscope, such as red blood cells, crystals, and in case of infection, a large number of white blood cells or pus cells. The comparison of urinalysis before and after exercise has diagnostic significance.

　　2. Continuous 24h urine calcium, phosphorus, chlorine, sodium, potassium, magnesium, citrate, oxalate, pH, uric acid, urine creatinine, urine volume, leave 24h urine to observe whether stones are excreted, and analyze their composition.

　　3. Low calcium, low sodium diet (calcium: 400mg, sodium: 100mmol) for 1 week, after finishing, leave fasting urine to measure calcium to detect renal calcium leakage, after taking 1g calcium, leave urine to detect the amount of calcium absorbed by the intestines, measure cystine, xanthine, aminopterin, adenosine.

　　4. Urine bacterial culture and drug sensitivity test Leave the middle urine for bacterial culture to help identify the infecting bacteria and select effective antibiotics.

　　5. Determine blood calcium, phosphorus, chlorine, sodium, potassium, alkaline phosphatase, parathyroid hormone levels, uric acid, creatinine and protein, combined with 24h urine calcium, uric acid, creatinine, and oxalic acid content analysis to understand the metabolic state, determine whether there is endocrine disorder.

　　6. Renal function determination Measure blood creatinine and urea nitrogen to understand the state of renal function.

　　7. Ultrasound examination can show the shadow of stones, and can also detect prostatic hyperplasia at the same time.

　　8. X-ray examination The vast majority of stones can be visualized on the abdominal flat film, and at the same time, attention should be paid to whether there are renal and ureteral stones, and urinary tract imaging can be performed if necessary to understand the urinary tract condition.

　　9. Cystoscopy can be used for diagnosis when the above methods cannot confirm the diagnosis.

　　10. CT examination has diagnostic value for the localization of stones in bladder diverticula.

　　Food therapy recipe:

　　1. Home remedy one: Stone reed winter melon seed tea: 30 grams of stone reed, 30 grams of winter melon seed, 30 grams of herba lysimachiae, decoct with water, can expel stones.

　　2. Home remedy two: Corn silk tea: 50 grams of corn silk, 20 grams of plantago seed, 10 grams of dried licorice root, decoct 500 milliliters of water to 400 milliliters, remove the residue and take 3 times a day warm.

　　3. Home remedy three: Sunflower heart tea: 100 cm of sunflower stem, cut into 3 cm long pieces, decoct with water, take 1 dose a day, for 1 month. Treats stones with hematuria.

　　4. Home remedy four: Lotus node winter melon soup: 500 grams of fresh lotus node, 1000 grams of winter melon, wash and slice, add appropriate amount of water to boil into soup. Take it all in one day.

　　What foods are good for urinary tract stones

　　1. Drink plenty of water: The most important way to prevent urinary tract stones is to increase water intake. Water can dilute urine and prevent the accumulation of high concentrations of salts and minerals into stones. The appropriate amount of water is to produce 2 liters of urine a day, which is sufficient. 2. Eat foods rich in vitamin A: Vitamin A is necessary to maintain the health of the urinary tract mucosa and also helps prevent the recurrence of stones. Healthy adults need to consume 5,000 units (Iu) of vitamin A a day. A cup of carrots can provide 10,055 Iu of vitamin A. Other foods rich in vitamin A include broccoli, apricots, melon, pumpkin, and beef liver.

　　It is best not to eat certain foods for urinary tract stones

　　1. Salt: Patients with urinary tract stones should reduce the intake of salt. The daily salt intake should be reduced to 2-3 grams. Adding fiber and rice bran can prevent the occurrence of stones.

　　2. Foods rich in oxalates: About 60% of stones are calcium oxalate stones. Therefore, the intake of foods rich in oxalates should be limited, including beans, beets, celery, chocolate, grapes, green peppers, coriander, spinach, strawberries, and vegetables of the brassica family. Also avoid alcohol, caffeine, tea, chocolate, dried figs, lamb, nuts, green peppers, black tea, opium poppy, etc.

　　3. Limit the intake of high-protein foods: There is a direct relationship between kidney stones and the intake of protein. Protein is easy to cause uric acid, calcium, and phosphorus in urine, leading to the formation of stones. If you have ever had calcium stones, you should pay special attention to whether you have consumed an excessive amount of protein, especially if you have a history of hyperuricemia or cystine stones. Limit the intake of high-protein foods to 180 grams per day, which includes meat, cheese, chicken, and fish.

　　I. Treatment

　　1. Treatment of Bladder Calculi

　　The main treatment is surgery, and etiological treatment, anti-infection, and symptomatic treatment are also carried out at the same time.

　　(1) Cystolithotomy Clamp: Suitable for diameters

　　(2) Ultrasonic, Electrolithotripsy, or Laser Lithotripsy: This surgical treatment is performed under epidural anesthesia or local anesthesia through the urethra. It is divided into 4 types:

　　① Ultrasonic Lithotripsy.

　　② Electrolithotripsy.

　　③ Microexplosion Lithotripsy.

　　④ Urethral Mechanical Lithotripsy (Direct Vision Cystolithotomy and Blind Lithotripsy).

　　(3) Suprapubic Cystolithotomy: Suitable for large, hard calculi or calculi caused by obstruction factors, and symptomatic treatment should be given at the same time. If the course of the disease is long, attention should be paid to whether there are lesions in the bladder during surgery, and biopsies should be performed in time to exclude the possibility of malignancy.

　　2. Treatment of Ureteral Calculi

　　(1) Pre-urethral calculus: After injecting liquid paraffin under anesthesia, gently push, hook, clamp out, or crush and remove it from the proximal end, and try not to perform urethrotomy to remove the stone. If the stone is embedded in the navicular fossa and cannot be removed, then a urethral orifice incision is needed to remove the stone.

　　(2) Post-urethral calculus: First, push the calculus into the bladder with a urethral probe, and then treat it as a bladder calculus.

　　II. Prognosis

　　Early diagnosis and medication treatment for urinary stone patients, the stones can be excreted spontaneously, and if necessary, the operation to remove the stones can be performed. After the stones are excreted, the clinical symptoms are immediately relieved, and the prognosis is generally good if the obstruction time is not long and there are no complications.