Fungal urinary tract infection

　　Primary fungal infection is caused by the invasion of dermatophyte blastomycosis, histoplasmosis, and Sporothrix schenckii through the respiratory tract, which produces primary lesions in the lung. When the body's resistance is reduced or other diseases are present, varying degrees of pulmonary infection or systemic infection may occur. The pathogenesis of opportunistic fungal infection is due to various susceptible factors in patients, which weaken the body's defense function; causing the occurrence of opportunistic fungal infection.

　　Different complications may occur in various types of urinary tract fungal diseases, such as large fungal balls and granuloma formation in the cystitis type; anuria and renal pelvis effusion may occur in the ureteral obstruction type; bladder colonic fistulas and urinary tract skin fistulas may occur in the fistula type.

　　1. Infertility:Long-term urethritis can complicate infections such as prostatitis, causing changes in the composition of seminal fluid, leading to male infertility.

　　2. Cause impotence and premature ejaculation:Due to the缠绵难愈，various symptoms and discomfort are aggravated after the disease, or they may directly affect the feeling and quality of sexual life, leading to a sense of aversion, resulting in phenomena such as impotence and premature ejaculation.

　　3. Cause chronic renal failure:The most distinctive feature of urethritis is that it is very easy to become chronic, and severe cases can cause chronic renal failure.

　　4. Cause urethral stricture and difficulty in urination:Urethritis can directly affect the epithelium of the urethra, forming scars locally during infection, and in severe cases, it can cause urethral stricture, leading to difficulty in urination for patients.

　　5. Cause cystitis and prostatitis diseases:Due to the invasion of bacteria hidden in the urethra into the prostate, vas deferens, epididymis, and testes, it can easily cause complications such as cystitis, prostatitis, paraurethral abscesses, and urethral fistulas.

　　The disease may be asymptomatic with only pyuria, or it may present with typical urinary tract infection symptoms, even leading to renal failure. In patients with systemic fungal infections, there are often systemic symptoms such as fever and chills, and urinary tract fungal diseases have the following types:

　　1. Pyelonephritis type:Its clinical manifestations are similar to those of bacterial pyelonephritis, and it can manifest as acute or chronic, mainly in two forms: one is multiple renal cortical abscesses; the other is diffuse fungal infiltration in the collecting ducts or papillae, which may have papillary necrosis. Both forms often occur simultaneously and are often accompanied by fungal ball formation.

　　2. Cystitis type:More common in women, often secondary to the cure of bacterial cystitis, with main symptoms including frequent urination, urgency, nocturia, cloudy or bloody urine, and occasionally gasuria (due to the fermentation of Candida in urine sugar), sometimes large fungal balls and granuloma formation can be seen in the bladder.

　　3. Ureteral obstruction type:Caused by fungal balls, when the fungal balls migrate to the ureter, renal colic may occur. If both ureters are completely obstructed, anuria and renal pelvis effusion may occur.

　　4. Renal papillary necrosis type:Clinical manifestations are similar to those of general renal papillary necrosis, with multiple irregular small cavities visible on IVP due to the shedding of papillary necrosis.

　　5. Fistula type:There are reports that interstitial coccidioidomycosis, histoplasmosis, and new Cryptococcus urinary tract infections can lead to vesicocolonic fistulas and urinary tract skin fistulas.

　　To prevent fungal urinary tract infection, it is first necessary to control the source of infection, eliminate the primary disease and susceptible factors, pay attention to hygiene, cut off the transmission route, and can effectively prevent the occurrence of the disease.

　　1. Instruct patients to avoid sexual activity before being cured; avoid alcohol, spicy foods, and drink more water.

　　2. In the family, necessary isolation should be done, such as using separate towels, basins, bathtubs, and toilets, or disinfecting them after use.

　　3. Tell patients what safe sex is, what risky sex is, and how to avoid risky sex.

　　4. Encourage the use of condoms.

　　There is currently no sufficient data to provide a standard that is accepted by everyone to distinguish between normal urinary tract fungal flora and fungal infections.

　　1. The criterion for usually judging urinary tract fungal infection is: urinary catheter fungal quantitative culture ≥ 10,000/ml of bacterial colony count, which is often fungal urinary tract infection. While fresh urine specimens without precipitation are examined under a microscope, if there are 1 to 3 fungi per high-power field in an average of 10 fields, it is equivalent to a bacterial colony count ≥ 10,000/ml, which has diagnostic significance, with an accuracy of 80%; fungi reproduce and multiply slowly at room temperature, and their division period is usually more than 5 hours, so the examined urine can be stored for a longer time without increasing the number of fungi.

　　2. In the clean middle urine samples of males or the catheterized urine samples of females, any positive fungal culture indicates urinary tract fungal infection. Candida exists in urine in two forms: yeast and fungal filaments. Some people believe that the presence of fungal filaments indicates invasion, but there is still controversy. The determination of serum antifungal antibodies (serum precipitins, agglutinins, etc.) is helpful for diagnosis, and the positive rate of serum precipitins in patients with renal candidiasis is 83%, but there are about 10% of false positives.

　　3. Fungal urinary tract infections can be caused by blood-borne dissemination or ascending infection. If the infection is limited to the urinary system, it is mostly ascending, so fungal vaginitis and intestinal fungal infection are prone to be accompanied by urinary tract fungal infection.

　　4. Cystoscopy and percutaneous urethral biopsy can help with diagnosis.

　　Patients with fungal urinary tract infections should supplement vitamin C, which can increase the acidity of urine, making it difficult for various bacteria that cause urethral infections to survive. Therefore, drinking orange juice, citric acid, kiwi juice, and other vitamin-rich beverages is beneficial for preventing urinary tract infections. In terms of diet, it is important to eat less sugary foods, avoid spicy and刺激性 foods, and pay attention to drinking more water, having a rich diet, and maintaining a balanced nutrition. Pay special attention to eating more vegetables and fruits to ensure the intake of vitamins.

(One) Treatment

Currently, there is no unified method for treating candidal urinary tract infections. The measures adopted in clinical practice now include the following:

1. Eliminate susceptible factors, which is the best method for preventing and treating fungal urinary tract infections, such as avoiding long-term use of antibiotics, immunosuppressants, and resolving urinary tract obstruction, controlling diabetes and other diseases that weaken the body's resistance, and minimizing catheterization and long-term retention of urinary catheters.

2. Urine Alkalinization Since fungi multiply rapidly in acidic urine, sodium bicarbonate should be taken orally at a dose of 1.0g, three times a day, to alkalinize the urine and create an environment that inhibits fungal growth.

3. Drug Treatment Commonly used effective drugs are amphotericin B, fluconazole (5-FC), fluconazole, and itraconazole. The routes of administration include local and systemic applications.

(1) Local Application: For catheter-related candidal urinary tract infections, the catheter can be removed and replaced with a three-way catheter, and 50mg/L of amphotericin B can be infused into the bladder for irrigation, once a day, for 7-10 days; the success rate of treatment is more than 75%. If other factors such as hypertriglyceridemia, the use of corticosteroids, and the widespread use of antibiotics can be eliminated at the same time, the success rate will be even higher. It can also be inserted through the urethra with nystatin 2 million U/L, once every 6 hours, until the urine fungus is negative. It is suitable for bladder fungal infections.

(2) Systemic Application: For mild cases, fluconazole (5-FC) can be taken orally at a dose of 150mg/(kg·d), for 1-3 months in a row. Since 95% of it is excreted by the kidney, it is effective for renal fungal infections. Fluconazole (200mg/d) and itraconazole (400mg/d) can also be used. For severe cases with disseminated fungal infections or focal infections that do not subside, amphotericin B can be used, starting with intravenous infusion of 0.1mg/(kg·d), gradually increasing to 1mg/(kg·d). The drug solution should be infused slowly and protected from light. For those with poor tolerance, the dose can be adjusted accordingly; for those with poor clinical efficacy, the dose can be increased appropriately; for severe cases, the daily dose can be up to 60mg, and then changed to 25-35mg/d after the condition stabilizes. This drug has a nephrotoxic effect, and in cases of renal failure, it should be dosed according to the creatinine clearance rate. During the medication process, blood creatinine and blood urea nitrogen should be measured once a week. If drug-induced renal damage occurs, the medication should be discontinued or changed promptly. Indications for discontinuing antifungal drugs: During the treatment process, urine should be tested once a week. Antifungal treatment can be stopped only when there are two consecutive urine samples showing no bacteria or when voiding cystography confirms that the filling defect has disappeared.

4. Transfer Factor In recent years, there have been introductions to the treatment of fungal infections with transfer factors, which are believed to have the effect of adjusting the body's immune function.

(II) Prognosis

If this disease can be diagnosed early and treated appropriately, the efficacy is quite good and the prognosis is good.