Pregnancy complicated with urolithiasis

　　1. Etiology

　　The etiology of urolithiasis has not been fully understood. Currently, it is believed that the formation of urolithiasis is mainly due to metabolic disorders in the body, such as hypercalcemia, hypercalciuria, endocrine disorders, etc.; secondly, it may be related to urinary tract infection. Pregnant women may have urinary system smooth muscle relaxation, decreased peristalsis of the ureter, and urinary stasis, difficult urination, and are often accompanied by urinary tract infection. In theory, this should be conducive to the formation of urinary stones, but in fact, urolithiasis during pregnancy is relatively rare. This may be due to the development of the intrauterine fetus during pregnancy, the increased need for calcium, and the increased protective colloids in the urine, effectively preventing the formation of urinary tract stones.

　　2. Pathogenesis

　　The pathological changes of urinary stones are mainly caused by the trauma to the tissue caused by the stones, obstruction of urine flow, and concurrent infection. At the stone location, there may be epithelial shedding, tissue ulceration, and fibrous tissue proliferation. Long-term trauma by stones can thicken the renal pelvis wall, fibrous tissue proliferation in the interstitial tissue, and leukocyte infiltration. Generally, urinary stones cause obstruction of urine flow and cause hydronephrosis of the proximal urinary tract, especially renal pelvis hydronephrosis, but the obstruction is often not complete. When hydronephrosis occurs, the renal calyces become blunt and there is a varying degree of calyceal expansion. With further progression of the disease, renal cortex atrophy and damage may occur, and the expanded calyces can make the renal cortex very thin. If calculous hydronephrosis is complicated with infection, it can become purulent calculous hydronephrosis, accelerating the damage to the renal parenchyma. Infection can also cause perinephritis and perinephric abscess.

　　Urethral obstruction is a rare but extremely serious complication, caused by obstruction of both urinary tracts by stones, or by obstruction of the urinary tract of the only functioning kidney. Pregnancy complicated with urolithiasis almost always leads to secondary infection, thus, the patient may have purulent urine, and the original symptoms may worsen with severe infection. Very few obstructions can cause hydronephrosis of the ureter or pyelonephritis, and even lead to renal function impairment. Bladder irritation symptoms caused by stones, and secondary chronic inflammatory reactions can lead to serious complications such as squamous cell carcinoma of the bladder, and should be treated early and given great attention.

　　First, symptoms

　　The symptoms of urolithiasis depend on the size, shape, location, and whether there is infection, as well as the degree of obstruction of the calculi.

　　1. Asymptomatic:Smooth surface calculi or calculi fixed in the renal pelvis or lower renal pelvis without movement and without infection can cause no symptoms.

　　2. Pain:The movement of renal calculi can cause lumbar pain, which may be persistent or episodic, with a nature of dull pain, sharp pain, distension, or colic. When the calculus moves due to activity and becomes lodged in the ureter, the pain can radiate along the ureter to the bladder, external genitalia, the inner side of the thigh, and other places.

　　3. Hematuria:It is a common symptom of urolithiasis. Due to the movement of the calculus and the injury to the renal pelvis and ureter, hematuria may occur, with most patients having gross or microscopic hematuria, but 20% to 25% of patients have no hematuria.

　　4. Urinary tract infection symptoms:Urolithiasis complicated with infection can cause symptoms such as frequent urination, urgency, dysuria, and pyuria, and in acute infection, symptoms such as fever and chills may occur.

　　Second, signs

　　During the attack of renal colic, deep palpation of the renal area can stimulate and exacerbate the colic, making palpation difficult to perform. On the side of the calculus, there may be muscle spasms and protective muscle tension. Light tapping on the renal area can cause pain and tenderness. Large calculous renal pelvis hydronephrosis may be palpated in the abdomen, but the enlarged pregnant uterus can limit abdominal palpation.

　　The etiology of urolithiasis is not completely understood. It is currently believed that the formation of urolithiasis is mainly due to metabolic disorders in the body, such as hypercalcemia, hypercalciuria, endocrine disorders, and so on; secondly, it may be related to urinary tract infection, so it is necessary to drink plenty of water to avoid urinary retention, which can flush the urinary tract and prevent the formation of calculi. At the same time, it is necessary to eliminate lower urinary tract obstruction and infection. Such as surgical treatment for benign prostatic hyperplasia and urethral stricture, radical treatment of urinary tract infection, especially those urea-decomposing bacteria, avoid bladder foreign bodies, and reduce the occurrence of calculi.

　　1. Urinalysis

　　Red blood cells, pus cells, and epithelial cells can be seen, and midstream urine culture can detect pathogenic bacteria.

　　2. Renal function test

　　Urea nitrogen, creatinine, and uric acid levels are measured to understand the renal function status, and repeated checks are conducted for monitoring and comparison.

　　3. Blood test

　　In addition to the routine blood test for red and white blood cell counts, determining serum calcium and inorganic phosphorus, as well as the ratio of serum protein, albumin, and globulin, can be helpful for diagnosing the etiology of calculi.

　　4. X-ray examination

　　Urological X-ray films have important diagnostic significance, but the shadows in the films must be distinguished from other shadows such as gallbladder stones, mesenteric lymph node calcification, and so on. Therefore, lateral films and supine films with deep inspiration and expiration can be taken. If it is renal calculi, the shadow will change its position up and down with the movement of the kidney, and the relative position to the edge of the kidney remains unchanged. Intravenous pyelography can show the location of the calculi and the entire urinary tract. Since X-rays have a certain impact on the fetus, this examination should be avoided during pregnancy.

　　5. Cystoscopy

　　If the main symptoms are pain in the bladder area, sudden interruption of urine flow, and hematuria, bladder stones should also be considered. The diagnosis of bladder stones can be made based on X-ray examination and cystoscopy.

　　6. Ultrasound Examination

　　When the diameter of the urinary stone reaches 0.5 cm or more, a high-resolution ultrasound diagnostic instrument can see dense bright spots or bright spots in the urinary tract or kidneys, which is the characteristic of the presence of stones. The larger the stone, the clearer the bright spot and acoustic shadow. When the stone is accompanied by hydronephrosis, it can also have the characteristics of hydronephrosis sonograms. Although ultrasound can detect stones, its sensitivity is poor. It is not difficult to make a clinical diagnosis of stones that can be detected by ultrasound. At the same time, X-ray films and various renal pelvis angiographies can obtain more information. Therefore, ultrasound can only assist in diagnosis of stones, but for translucent stones, X-ray films cannot be displayed, and the films cannot be distinguished from blood clots or tumors. Ultrasound examination is still helpful for differential diagnosis of stones.

　　In addition to routine treatment, patients with pregnancy complicated by urinary stones should pay attention to a light diet, drink more water, and eat more foods or fruits rich in water, which can assist in the treatment of this disease.

　　1. Treatment

　　The treatment of urinary tract stones during pregnancy varies according to the gestational period and whether there is infection. If stones are found and urinary tract infection occurs in the first half of pregnancy, surgical treatment should be performed after effective antibacterial treatment. In the late pregnancy, due to the enlarged uterus making surgical procedures difficult, and the blood vessels to the kidneys and ureters are abnormally large, and sometimes it is almost impossible to empty the uterus to expose the distal ureter due to other reasons, surgical treatment is generally not performed. For patients with severe infection, continuous antibacterial treatment should be maintained, and surgery should be performed according to the situation after delivery.

　　2. Prognosis

　　In pregnancy, nephrolithiasis does not have any adverse effects on pregnancy outcomes, except for increasing the incidence of urinary tract infections. Pregnancy does not increase the risk of nephrolithiasis.