Author: Li Jiao, Liu Jiaying, Zhao Xin, Wang Xuan, Xuan Yun
Unit: Department of Clinical Laboratory, Second Hospital of Hebei Medical University
preface
Urinary tract infections are divided into upper and lower urinary tract infections according to the site of infection; according to the relationship between the two infections, they can be divided into isolated or sporadic infections and recurrent infections, which can be divided into re-infection and persistent bacteria, which are also called relapse; and according to the urinary tract status at the onset of infection, they can be divided into simple urinary tract infections, complicated urinary tract infections and urine sepsis.
More than 95% of urinary tract infections are caused by a single bacterium.
Among them, 90% of outpatients and about 50% of inpatients, the pathogen is Escherichia coli, the serotype of this bacteria can reach 140 species, the urinary sense of Escherichia coli isolated from the patient's feces is the same type of bacteria, mostly in asymptomatic bacteriuria or uncomplicated urinary sensation;
Proteus, Aerobacterium, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus faecalis, etc. are seen in patients with reinfection, indwelling urinary catheters, and urinary tract infections with complications;
Candida albicans and Cryptococcus novelis infections are more common in patients with diabetes mellitus and those using glucocorticoids and immunosuppressive drugs, as well as after kidney transplantation;
Staphylococcus aureus is more common in bacteremia and sepsis caused by skin trauma and drug users; viral and mycoplasma infections, although rare, have gradually increased in recent years.
A variety of bacterial infections are seen indwelling urinary catheters, neurogenic bladders, stones, congenital malformations, and vaginal, intestinal, and urethral fistulas.
Case introduction
The patient, male, 35 years old, more than 3 months ago, the patient had urinary frequency, urgency, dysuria, accompanied by lower abdominal discomfort, and was treated in a local hospital, the urine culture showed positive Escherichia coli, and the symptoms improved after 11 days of anti-infection treatment, and he was discharged from the hospital. More than 1 month ago, the patient had frequent urination, urgency, and painful urination again, without low back pain, accompanied by lower abdominal discomfort, and was admitted to our hospital on August 2, 2021, and was discharged from the hospital after 20 days of treatment. 5 days ago, he had back pain again, accompanied by painful urination and lower abdominal discomfort, and now he is requesting further diagnosis and treatment and will be admitted to our hospital again on October 12, 2021.
Case after
On the morning of October 22, I received a call from the director of the Department of Nephrology to pay attention to the patient's coordinated search for the cause, and reflected that the patient had repeated urinary tract infections, this was the second hospitalization, and after 4 days of meropenem anti-infection treatment, the white blood cells in the urine dropped from 169.1 to 85.8/μl, and the white blood cells rose to 103.3/μl on the 20th, and the white blood cells rose to 361.2/μl again on the 22nd.
First of all, the patient did not use a catheter, so is repeated urinary tract infection caused by long-term antibiotic therapy that leads to bacterial resistance? We reviewed all the microbial results since our first admission to the hospital and found that each anti-infective treatment was effective, just always repeated. This is not due to failure of bacterial resistant anti-infective therapy.
At the same time, we looked at the patient's urine routine since the first admission to our hospital and found that urine leukocytes have been present at a high and low time, most of which are higher than the normal reference range, indicating that there has been inflammation.
So why?
So we reviewed the electronic medical record and found that the patient had checked the cystoscope in July 2021 to consider the suspicious bladder fistula, the pathology was a bladder tumor, cystography and colonoscopy did not see the fistula, so we were given electroresection of the transurethral bladder tumor, and no fistula was seen in the bladder during the operation.
So is there a fistula?
Then call the doctor in charge for consultation, the doctor did not completely rule out the existence of fistula, and the doctor described an interesting thing, the patient had diarrhea on the 19th (which had not occurred before), and most of the urine on the 22nd was clear and occasionally sometimes cloudy.
So after communicating with the clinician, when the patient's urine is cloudy, the specimen specification is left for examination, and through microscopic observation, it is found that there are plant fibroblasts and some food residues in the patient's urine, indicating that the patient may really have a fistula, so the results are informed to the clinic.
So the clinician asked the anorectal surgery consultation to recommend a review of cystography, but the re-examination of CT pelvic flat scan (cystography) did not see the intravesical contrast agent leaking into the colon, but the later follow-up patients did fistula repair surgery after the urinary tract infection was completely cured, indicating that the culprit that caused the patient's repeated urinary tract infection was the bladder intestine basket.
Case summary
General bladder fistula routine examination items include: urine routine examination, blood routine examination, barium enema, sigmoidoscopy, contrast examination, cystoscopy and vaginal examination, etc., patients can only confirm what their condition is like through these corresponding examinations, because the disease of bladder fistula includes: bladder intestinal fistula, bladder vaginal fistula, bladder appendage fistula three, different conditions, need different examination items to confirm the diagnosis, any one of the examination items with positive finger disease can not exclude the possibility of bladder basket.
So why did the patient undergo two CT pelvic flat scans (cystography) and not find a fistula? Possible causes are:
1. The bladder is not fully filled, the pressure in the bladder is less than the pressure in the intestine, and the contrast agent cannot enter the intestine through the very small fistula;
2. The fistula is very small, and the CT sweep time is not long enough to capture the leakage of the contrast agent;
3. The fistula is single-pass not double-pass, and there is a membrane (similar to a valve) that can only enter the bladder from the intestine and not from the bladder into the intestine.
Bladder intestinal basket generally has the phenomenon of mixing stool with urine, stool mixed with urinary microscopy is generally not easy to find abnormalities, but when it is found that urine is mixed with stool, especially a male patient, the examiner should communicate with the clinic, ask the specimen retention method, see if it is qualified, and check the electronic medical record to understand the basic situation of the patient.
With the increase in the number of patients with urinary system diseases and kidney diseases, the shortcomings of some treatment options have gradually emerged, and in order to improve the detection rate and clinical efficacy of related diseases, improving the accuracy of related tests is the key. Urinary microscopy is an important item in urine testing and plays a pivotal role. Urine microscopy can show some of the formation components more intuitively, can find abnormal changes in disease-related components, and is still the "gold standard" for urine formation tests. Especially for the examination of patients with kidney disease, the results of urinary microscopy are used as an observation index and an important reference basis for the final diagnosis.
Cases of unexplained infections in practical work are common, requiring the search for the true cause and requiring multidisciplinary and multi-departmental discussion and cooperation. As an inspector, when in doubt, you should communicate more with the doctor in charge, view the patient's medical records, fully understand the patient's diagnosis and treatment process, and rely on your accurate business knowledge and testing skills to provide important evidence for the clinic.
【Reference】
1.Qin Xinfang,Li Qingchu,Zou Disha,Wu Minsheng. Research progress of complicated urinary tract infection[J].Department of Internal Medicine,2018,13(3):363-366.
2. Chinese Expert Consensus Writing Group for diagnosis and treatment of urinary tract infections. Diagnosis and treatment of urinary tract infections and 2.Chinese expert consensus (2015 edition)——Complicated urinary tract infections[J].Chinese Journal of Urology,2015,36(4):241-244.
3.LI Guanghui. Diagnosis and treatment of urinary tract infection[J].Chinese Journal of Anti-Infective Chemotherapy,2001,1(1):58-60.
Source: Clinical Laboratory Medicine
Editor: Ren Mileage Reviewer: Xiao Ran