Urinary tract infection in the elderly

Introduction to urinary tract infection in the elderly A urinary tract infection (senileinfection inurinary system) is a common disease in the elderly, ranking second in the elderly for infectious diseases, second only to respiratory infections. basic knowledge The proportion of illness: 1% Susceptible people: the elderly Mode of infection: non-infectious Complications: bacteremia, sepsis, shock, elderly sepsis, chronic nephritis

The cause of urinary tract infection in the elderly

Increased sensitivity of urinary tract epithelial cells to bacteria in the elderly (20%):

Different authors have observed this phenomenon in older men and older women, especially women, the reason is not clear, some people speculate that it may be related to changes in estrogen levels, estrogen stimulation may increase cell surface bacterial receptors Density and increased cell adhesion activity.

The factors of urinary tract obstruction and poor urinary flow in the elderly are significantly increased, making bacteria easy to survive and breed (20%):

The elderly can often have urinary insufficiency or complete obstruction due to prostatic hyperplasia or bladder neck obstruction, urinary calculi, tumors, etc., and the incidence of neurogenic bladder or bladder is also increased. These factors can cause urine. The flow is not smooth, the residual urine in the bladder increases, and the local antibacterial activity of the urothelial cells is reduced, which is easy to cause infection.

The systemic and local immune response capacity of the elderly is reduced (20%):

Due to aging, the humoral immunity and cellular immune function of the elderly are significantly reduced, which reduces their ability to respond to infection and other stress factors. At the same time, the elderly kidney and bladder membrane are in relative ischemic state, pelvic muscle relaxation, habit Sexual constipation can further aggravate the poor circulation of local mucosa, and the secretion of prostate in older men is reduced. These all reduce the local resistance. In addition, the degenerative changes of the elderly kidney are also one of the reasons for the decline of the urinary mucosal defense mechanism.

Other (10%):

The physiological thirst of the elderly is diminished, the drinking water is reduced, the renal tubular urinary concentration, and the dilute function changes have certain influence on the susceptible UTI. At the same time, the elderly are often accompanied by high blood pressure, diabetes and other systemic diseases, malnutrition and long-term bed rest. The chances are increased, and the painkillers, non-steroidal anti-inflammatory drugs, etc. are often abused due to illness, which may lead to UTI or even chronic interstitial nephritis or chronic pyelonephritis.

Pathogenesis

The immune function of the elderly is declining and the ability to resist infection is insufficient. This plays an important role in the pathogenesis of urinary tract infections, and the elderly are often accompanied by high blood pressure, renal artery and renal arteriosclerosis, diabetes and other systemic diseases. In addition, the elderly Renal tubular function and bladder function decrease with age, and also affect urination and defecation function. These are the participating factors of high incidence of urinary tract infection in the elderly, recurrent and difficult to cure, and the renal tubular function of the elderly is reduced. For water, sodium transport function decline and urine concentration decline, radioimmunoassay to determine the increase of urinary 2-MG content, after the exclusion of other diseases, can sensitively reflect the decline of renal tubular function in the elderly, urine penetration of healthy elderly The pressure is 500-700mmol/L, and the urine, blood osmotic pressure ratio and pure water clearance rate (CH2O) are lower than that of the young and middle-aged. In addition, the metabolism of the drug excreted by the kidney is reduced in the elderly, which may cause renal tubular drug poisoning, chemical Injury, on this basis, it is more likely to cause upper urinary tract infection, lower urinary tract with dysfunction due to aging, showing dysuria, nighttime and The number of urination times increased. Brocklehurst et al found that 70% of men and 60% of women in the elderly developed nocturia. Men were more urinary, women often had difficulty urinating, incontinence and stress incontinence. The asymptomatic urinary rate of the elderly is gradually slowing down. The maximum urination speed of the elderly over 65 years old is >13ml/s, which is a normal range. The physiological basis of affecting the urination rate of the elderly is not fully understood, but it is definitely the result of various factors. In addition, local structural changes, such as high-grade elderly renal cysts, kidney stones, mechanical urinary obstruction, vesicoureteral reflux, decreased cardiovascular output of cardiovascular disease, neurogenic bladder of cerebrovascular disease, etc. The rate of urination and urine output, and easy to lead to urinary tract infections.

Urinary system infection prevention in the elderly

Urinary tract infections in the elderly should be based on ideal antibiotics:

1 The antibacterial effect is good, and it is not easy for bacteria to develop drug resistance.

2 The drug has a high concentration in kidney tissue, urine residue and blood.

3 side effects are small, no damage to the kidneys.

4 oral is easy to absorb.

5 is cheap.

Complications of urinary tract infection in the elderly Complications bacteremia septic shock elderly septicemia chronic nephritis

Elderly UTI is highly susceptible to bacteremia, sepsis and toxic shock, which is the main cause of sepsis in the elderly (about 1/3), and should be alert to clinicians.

Symptoms of urinary tract infection in the elderly Common symptoms Frequent urination with urgency and dysuria Urinary incontinence Diuretic lumbosacral soreness, fatigue, urinary frequency, dizziness, loss of appetite, leukocyteuria, abdominal pain

The clinical manifestations of UTI in the elderly are not typical. Most elderly UTI patients have clinical manifestations of non-specific symptoms such as fever, lower abdominal discomfort, lumbosacral pain, loss of appetite, etc. Some elderly people only show fatigue, dizziness or consciousness. UT UT UT UT UT UT UT UT UT UT UT

Examination of urinary tract infection in the elderly

Urine analysis

Increased urinary leukocyte excretion suggests urinary tract inflammation, which is also important in diagnosis. The correlation between leukocyteuria and urinary tract infection has long been recognized. The incidence of pyuria in asymptomatic bacteriuria is about 37%, and leukocyte excretion >10/mm is an exception.

Aseptic pyuria is also a manifestation of renal tuberculosis, stones, analgesic abuse, a small number of aerobic and anaerobic infections, urinary tract injuries such as chlamydial urethritis, glomerulonephritis and nephropathy.

Urinary tract infections without pyuria are seen in leukopenia caused by drugs and aplastic anemia, and distal infectious diseases of the renal collecting system (such as renal cortical abscess), occasionally in obstructive uropathy.

White blood cell urine is not a constant feature of urinary tract infection. The white blood cell count of urine samples varies several times. The single urine sample cannot detect white blood cells should not be regarded as evidence of sterile urine. Pyuria depends on urine flow and urine pH. The urine bacteria count can also be different within 1 day. Generally speaking, it is advisable to check the morning urine specimen.

Leukocyte cast is a reliable evidence of inflammatory disease of the upper urinary tract, but it is not unique to infections like the granular cast. These casts are often not found in active pyelonephritis, and fresh urine specimens must be used for tube counts.

Microscopic hematuria is not a reliable evidence of bacterial infection. No proteinuria can exclude urinary tract infection. Most urinary tract infection patients have urinary protein excretion less than 2.0g/24h.

2. Bacterial culture

The most common pathogen of urinary tract infections is Gram-negative bacilli, E. coli is the first (90%), followed by Klebsiella and Proteus mirabilis. It is meaningful that these bacteria are also common in children, but in adulthood. Rarely, it has been suggested that prostate secretion may shorten the survival of these bacteria, which may explain the higher incidence of urinary tract infection after prostatectomy in elderly men.

Many coagulase-negative staphylococci can multiply in the bladder, which often occurs in elderly patients with catheterization. Coagulase-negative staphylococci are part of the intrinsic flora of the distal urethra and can enter the bladder through the catheter. Urinary tract infections caused by Staphylococcus aureus are rare, and anaerobic bacteria in the normal vaginal flora occasionally cause urinary tract infections, especially when the urinary tract is abnormal.

L-type bacteria should be considered for chronic urinary tract infections, especially recurrent pyelonephritis. L-type bacteria are bacteria without solid cell walls. The bacteria can be exposed to substances that damage the surface such as antibiotics or antibody-complement-lysozyme. Turned into L-type bacteria, the high tension state of the renal medulla is conducive to its survival, L-type bacteria have low virulence, and the virulence can return to normal after conversion to normal bacteria. It is reported that the elderly in chronic urinary tract infection L-type bacteria were isolated.

Urine culture specimens use clean mid-stage urine. Older women can use the catheterization method when they are difficult to obtain specimens. The suprapubic aspiration is not suitable for the elderly. The specimens should be stored in the refrigerator without being cultured immediately after the specimens are taken. The urine specimens are placed at room temperature. More than 2h bacteria can proliferate.

The method of bacterial culture is simple in operation by the oblique inoculation method, and the result is reliable. For patients who are using antibiotics, urine containing various microorganisms, suprapubic puncture, diagnostic catheterization or evaluation of chronic prostatitis, urine culture using conventional methods should be used. The method of automatic screening and examination is not reliable. The choice of medium is suitable for the growth of all urinary pathogens. The well-conditioned laboratory can check the slow-growing CO2-dependent bacteria and anaerobic bacteria.

Imaging techniques (including excretory urography and gallium scans) are helpful in urinary tract infections in the elderly.

Diagnosis and diagnosis of urinary tract infection in the elderly

Diagnostic criteria

The test methods and diagnostic procedures available to UTI for the elderly are the same as for adults, but the following points are worth noting:

1. The white blood cell urine of the elderly is not parallel to the clinical manifestations of bacteriuria or UTI

Some patients with UTI may have no leukocyteuria, and another patient may have leukocyteuria due to prostate lesions or genital mucosal lesions without UTI, so urinary sediment microscopy can only be used as an auxiliary diagnostic condition.

2. Most of the elderly are asymptomatic bacteriuria, effective bacteriological examination is the key to the diagnosis of UTI

However, urinary tract obstruction, urinary incontinence or frequent urination, long-term use of antibiotics and improper retention of specimens can often affect the results of bacteriological examinations. It should be noted that there are reports that elderly male patients with incontinence can use the external penis to retain urine. The method is simple and easy, and the urine culture is repeatedly negative, but the upper urinary tract infection is still suspected, and the method of urinary retention by using the drinking water plus diuretic and the bladder catheter multiple times (every 10 to 15 minutes in 2 hours) It can detect that about 50% of patients have bacteria from the urinary tract. For elderly UTI patients, continuous bacterial culture is emphasized and observed during the treatment. If necessary, special culture can increase the detection rate.

3. Special inspection

Because the elderly often have urinary tract obstruction factors and cause UTI refractory, easy to relapse, so the elderly UTI should routinely carry out related urological examination and B-mode ultrasound.

Clinically, it must be differentiated from pyelonephritis and cystitis.

The material in this site is intended to be of general informational use and is not intended to constitute medical advice, probable diagnosis, or recommended treatments.