Acute cystitis during pregnancy

　　1. Etiology

　　Cystitis and urethritis are collectively referred to as lower urinary tract infections, which can be divided into bacterial and non-bacterial infections. Escherichia coli is the most common pathogen, followed by Staphylococcus species. The main routes of infection include:

　　Upstream infection, such as prostatitis in males, paraurethral glanditis in females, and various examinations and treatments through the urethra;

　　Downstream infection, such as secondary infections following kidney infections;

　　Through lymphatic spread and direct extension, such as infections of adjacent organs like vaginitis and cervicitis.

　　2. Pathogenesis

　　In lower urinary tract infections, ascending infection by bacteria is most common. Not all bacteria entering the bladder can cause urinary tract infection, as the body has a series of defense mechanisms against bacterial invasion. Urination can clear bacteria from the bladder, and as long as the urinary tract is unobstructed and the bladder emptying ability is normal, bacteria are difficult to stay in the bladder; urine contains urinary mucoprotein, which has the function of blocking bacteria from adhering to the bladder wall; the Tamm-Horsfall protein secreted by renal tubules contains mannose residues, which can wrap around the flagella of Escherichia coli, preventing the flagella from contacting the urinary tract mucosal epithelium, thereby losing the opportunity to adhere and be excreted with urine; during acute cystitis, bladder epithelial cells can be shed more quickly to accelerate the elimination of bacteria adhering to the bladder mucosa.

　　The occurrence of urinary tract infection is determined by the number and virulence of the invasive bacteria, as well as the extent of damage to the body's normal defense function. For example, the pathogenicity of Escherichia coli entering the urinary tract is related to the antigenic characteristics of the strain. Strains containing K antigen have the effect of resisting macrophages and the ability to resist complement destruction, which are more common in patients with acute pyelonephritis and partial cystitis, accounting for 38% of asymptomatic bacteriuria; while O antigen can cause the shedding of bladder epithelial cells, reduce the normal peristalsis of the ureter, accelerate granulocyte inflammatory infiltration, leading to tissue damage, and cause urinary tract infection. Among the Escherichia coli causing urinary tract infection, 80% contain O antigen, and most are kidney infections; while the H antigen of Escherichia coli has no effect.

　　Bacteria must first adhere to the urinary tract mucosa to invade the urinary tract. The surface of the urinary tract epithelium has mannose residues, which may be the receptor for bacterial flagella. Research has shown that Escherichia coli has 10 to 200 flagella, composed of fine proteins on the bacterial surface, which can secrete adhesins with hemagglutinin-like protein activity, recognize receptors on the surface of epithelial cells, bind to mannose residues, adhere to the surface of epithelial cells. The more flagella bacteria have, the greater their adhesion force. Among them, type I flagella, known as mannose-sensitive type, are closely related to lower urinary tract infections.

　　A normal bladder has the function of eliminating bacteria, but when urine retention is caused by any reason, a series of self-defense capabilities disappear. Therefore, patients with poor urine flow are more prone to urinary tract infections. However, to date, there is no evidence to show that the body's own immune system participates in the pathogenesis of lower urinary tract infections.

　　The pathological changes of acute cystitis are mainly hyperemia, redness, swelling of epithelial cells, hyperemia and edema of submucosal tissue, and leukocyte infiltration. These can completely regress with the disappearance of bacteriuria in a short period of time. Only a few severe cases may have punctate or patchy hemorrhage on the bladder mucosa, and mucosal ulcers may also occur.

　　Although acute cystitis does not cause complications, it can quickly involve the upper urinary tract through ascending infection. Among patients with acute pyelonephritis during pregnancy, 40% have symptoms of lower urinary tract infection before onset.

　　Cystitis is often caused by ascending infection, accompanied by acute urethritis. The typical clinical manifestations of cystitis in adult women are frequent urination, urgency, dysuria, and cloudy urine. Frequent urination refers to a significant increase in the number of voiding times, 1 to 2 times per hour, even more frequent; urgency refers to the inability to hold urine immediately upon the urge to urinate, but the amount of urine is not much, each time 10 to 100 ml. The more obvious the frequency and urgency, the less the amount of urine each time. Frequent urination, urgency, and dysuria are collectively referred to as urinary tract irritation syndrome, which is caused by inflammation stimulation of the bladder trigone and posterior urethra. Sometimes, there may be discomfort in the bladder area, and there are generally no obvious systemic infection symptoms, only a few patients have low fever. Urinalysis often shows leukocytes, and there may also be hematuria, even gross hematuria (if urine red blood cell differential microscopy is performed, this hematuria is uniform red blood cell hematuria). The occurrence of cystitis is closely related to sexual life. After sexual intercourse, female patients should undergo bladder puncture and urine culture. Most can grow the same bacterial strain as that at the urethral orifice. Therefore, many patients with urinary tract irritation symptoms often occur after sexual intercourse. If cystitis is not treated with antibacterial drugs, 30% of patients can recover spontaneously within 7 to 10 days.

　　Strengthen prenatal health care, improve health level; pay attention to vulvar cleanliness, after defecation, the toilet paper should be wiped from the front to the back, to reduce the opportunity of intestinal bacteria contamination of the anterior fornix and the urethral orifice, wash the vulva every night; treat asymptomatic bacteriuria, doing the above points helps prevent acute cystitis.

        The diagnosis of pregnancy and acute cystitis needs to rely not only on clinical manifestations, but also on relevant examinations, which are indispensable. The examination methods are as follows:

        1. Urinalysis;

2. Urine sediment;

3. Cystoscopy.

     In addition to routine treatment, attention should also be paid to diet during pregnancy with acute cystitis: patients should pay attention to light diet, try to stay away from spicy and stimulating foods, and at the same time, attention should be paid to balanced diet to ensure nutrition.

　　1. Treatment

　　The treatment principle is the same as that of asymptomatic bacteriuria. Amoxicillin (ampicillin) is used for treatment, 2g/d, for 10 days, with a cure rate of 97%. Although a single dose treatment regimen can achieve the same efficacy, 40% of pregnant women with pyelonephritis initially often have symptoms of lower urinary tract infection. If a single dose treatment regimen is adopted, it is necessary to exclude the existence of kidney infection first. In addition, it is also appropriate to increase water intake or intravenous fluid to facilitate bladder irrigation and drainage.

　　2. Prognosis

　　After the cure of acute cystitis, just like patients with asymptomatic bacteriuria, follow-up is required during pregnancy, although the recurrence rate is only half of asymptomatic bacteriuria (ASBU), but still need to do repeated midstream urine culture. Traditional Chinese medicine treatment methods for acute cystitis during pregnancy.