What is Pyelonephritis?

Pyelonephritis (pyelonephritis) is inflammation of the renal pelvis and kidney parenchyma caused by pathogenic microorganisms, often accompanied by lower urinary tract infections. Most of them are caused by Gram-negative bacilli, and are divided into acute and chronic types. Acute pyelonephritis is manifested as acute interstitial inflammation and tubular necrosis associated with infection. Patients have symptoms such as fever, frequent urination, urgency, dysuria, and bacteriuria. If there are no complex factors, the use of effective antibacterial drugs can quickly cure. Chronic pyelonephritis mostly occurs on the basis of urinary tract anatomy or dysfunction. In addition to bacterial urinary sensation, there are also scars formed in the renal pelvis and kidney. The shape of the kidney is not smooth or the size of the two kidneys is different. Seizures can cause chronic renal insufficiency.

Basic Information

English name

pyelonephritis

Visiting department

Nephrology

Common causes

Gram-negative bacteria

Common symptoms

Fever chills, nausea and vomiting, back pain, frequent urination and urgency

Causes of pyelonephritis

The majority of the pathogens are Gram-negative bacilli, and E. coli is the most common. The main infection route is ascending infection, that is, the pathogenic bacteria enter the bladder from the urethra and cause cystitis, which then spreads upward along the ureter to the kidneys, leading to pyelonephritis. Normal people have a small amount of bacteria in the urethral opening 1 to 2 cm, but generally do not cause infection, because the urethral mucosa has a certain antibacterial ability; urine can dilute bacteria and excrete them; urine also contains some bacteriostatic substances. When the body's resistance decreases or the urinary tract mucosa is slightly damaged (such as menstrual period, after sexual life, etc.) or the urinary system is deformed and the urinary tract is poorly flowed (such as ureteral stones, prostate hypertrophy, urethral stricture, urinary tract tumor, etc.) Into the kidney, a large number of reproduction in the pelvis, and kidney disease. Because the female urethra is short and wide, the baby girl's urethral opening is easily contaminated with feces, so they are prone to disease.

A few patients with pyelonephritis originate from hematogenous infections. The main pathogens are Staphylococcus aureus, Salmonella, Pseudomonas aeruginosa, and Candida. When the structure of the kidney is damaged (such as polycystic kidney disease) or patients with diabetes, long-term use of glucocorticoids and immunosuppressive agents, and other chronic wasting diseases, resistance decreases, and bacteria can easily enter the kidney from the bloodstream. Lesions are often bilateral.

Clinical manifestations of pyelonephritis

Acute pyelonephritis

The disease can occur at various ages, but it is most common in women of childbearing age, with rapid onset, varying severity, and severe cases can develop into sepsis. The main symptoms are as follows:

(1) Systemic symptoms: fever, chills, loss of appetite, nausea, and vomiting. The body temperature is usually between 38 and 39 ° C, and can reach 40 ° C. With headache, sore body, sweating during fever.

(2) Low back pain Unilateral or bilateral low back pain, mostly blunt or sore, varying degrees, a few have abdominal cramps, radiate along the ureter toward the bladder, and there is significant tenderness in the spine and rib angles during physical examination and positive renal pain.

(3) Bladder irritation symptoms such as frequent urination, urgency, and dysuria. Some patients may not have obvious urinary tract symptoms, and those with blood-borne infections first have systemic symptoms such as fever, and then bladder irritation.

2. Chronic pyelonephritis

Chronic pyelonephritis has complicated clinical manifestations, is prone to recurrent episodes, has a hidden course, and can sometimes be manifested as asymptomatic bacteriuria and / or intermittent frequent urination, urgency, and dysuria. May have the manifestations of chronic interstitial nephritis, including impaired urinary concentration, hypotonicity, low specific gravity urine, increased nocturia, and renal tubular acidosis. In the later stages, glomerular function impairment can occur, with azotemia up to uremia.

Pyelonephritis test

Urine test

(1) Routine urine test is the simplest, quickest and more reliable test method. It is advisable to leave the urine in the first mid-morning in the morning (the vulva should be washed before urination to eliminate pollution). Under the microscope, more than 5 (> 5 / HP) white blood cells in each high-power field are called pyuria. Some patients with pyelonephritis can also find cast urine and microscopic hematuria.

(2) Urine Bacterial Examination Clean colony urine culture colony count> 10 / ml has clinical significance.

(3) Urine sensation localization test The urine culture method after bladder irrigation and sterilization has high accuracy, is simple and easy to use, and is commonly used in clinical practice. Urine concentration function, determination of N-acetyl--D glucosidase in urine, measurement of ₂ microglobulin, and analysis of urinary antibody-coated bacteria all help distinguish upper and lower urinary tract infections.

2. Imaging examination

(1) X-ray examination. Because acute urinary tract infection itself is prone to bladder ureteral reflux, intravenous or retrograde pyelography should be performed 4 to 8 weeks after the infection is eliminated. Acute pyelonephritis and recurrent urinary tract infection without complications Routine pyelography is not recommended. For patients with chronic or chronic illness, plain radiography, intravenous pyelography, retrograde pyelography, and bladder ureterography during urination can be performed as needed to check for obstruction, stones, ureteral stricture or compression, renal ptosis, urinary congenital Malformations and bladder ureteral reflux. In addition, you can understand the structure and function of the renal pelvis and calyx to distinguish it from renal tuberculosis and renal tumors. Renal angiography can show varying degrees of distortion of the tubules in chronic pyelonephritis. If necessary, a renal CT scan or magnetic resonance scan can be performed to rule out other kidney diseases.

(2) Ultrasound is currently the most widely used and easiest method. It can screen for urinary dysplasia, congenital malformations, polycystic kidney disease, renal artery stenosis caused by renal artery stenosis, stones, tumors, and prostate diseases. .

(3) Isotope nephrogram examination can understand renal function, urinary tract obstruction, bladder ureteral reflux and residual bladder urine. The nephrogram of acute pyelonephritis is characterized by backward peak movement, the emergence of the secretory segment is delayed by 0.5 to 1.0 minutes, and the excretory segment declines slowly. The slope of the chronic pyelonephritis secretory segment decreases, the peak becomes blunt or widens and then moves backward, the start of the excretory segment is delayed, and it is parabolic. But the above changes are not obviously specific.

3. Blood test

During routine blood tests for acute pyelonephritis, the number of white blood cells increased, the percentage of neutrophils increased, and the erythrocyte sedimentation rate was faster. In the early stage of chronic pyelonephritis, serum creatinine and urea nitrogen are normal, and they increase in the later stage.

Pyelonephritis diagnosis

Diagnosis is mainly based on medical history, physical signs, and urinary bacteriological examination. Pay attention to the history of lower urinary tract infection and infection of other parts of the body.

Acute pyelonephritis usually has the typical symptoms of urinary tract irritation, plus a positive urinary bacteriological culture, the diagnosis can be made. If there is only high fever and the urinary tract symptoms are not obvious, two consecutive cultures 10 / ml, For the same bacteria, the diagnosis can be confirmed.

Chronic pyelonephritis usually has insignificant urinary symptoms or intermittent urinary abnormalities, so the diagnosis cannot be simply based on the length of onset. Urinary tract infection should be confirmed by repeated inspection of urine routine and urinary bacterial culture, and pyelonephral scar formation should be confirmed by intravenous pyelography.

Differential diagnosis of pyelonephritis

Acute patients need to be distinguished from acute cystitis, cholecystitis, pancreatitis, pelvic inflammatory disease, perrenal abscess, and appendicitis. Those who have high fever and urinary tract symptoms are not obvious, should be distinguished from various febrile diseases.

Chronic pyelonephritis should be distinguished from diseases such as renal tuberculosis, chronic glomerulonephritis, and chronic prostatitis. Chronic pyelonephritis with hypertension also needs to be distinguished from essential hypertension.

Pyelonephritis Treatment

The purpose is to alleviate symptoms, control infection, clear infected lesions, correct urinary tract abnormalities or reflux, prevent complications, prevent recurrence, and reduce renal parenchymal damage.

General treatment

Encourage patients to drink more water, urinate frequently, and not to urinate, in order to reduce the osmotic pressure of the medulla, improve the body's phagocytic function, and flush out the bacteria in the bladder. Have fever and other symptoms of systemic infection should stay in bed. If you have bladder irritation, you can give sodium bicarbonate to alkalize your urine to relieve the symptoms. If there is bladder ureteral reflux, the "second urination method" is feasible, that is, urinate again after 5 minutes.

2. Acute pyelonephritis

(1) Mild patients are treated with oral antibiotics for 14 days. Collect urine for bacterial culture and susceptibility test before medication. First, choose drugs that are effective against Gram-negative bacilli, such as quinolone, semi-synthetic penicillin, and cephalosporins. After 72 hours of treatment, evaluate whether to continue the application according to the efficacy. If the symptoms are improved, effective antibiotics should be selected according to the drug sensitivity test. After 14 days of treatment, the urine was re-examined. If the positive bacteriuria was still present, the treatment was continued for 6 weeks with sensitive antibiotics.

(2) Patients with severe symptoms of systemic poisoning should be given intravenously with sensitive antibiotics and combined with drugs if necessary. After normal body temperature, improved clinical symptoms, and negative urine culture, they should be changed to oral drugs to complete a course of treatment of not less than 2 weeks. Attention should be paid to complications such as pyelema and perirenal abscess.

(3) Infants and young children Acute pyelonephritis in newborns, infants, and children under 5 years of age is mostly associated with urethral malformations and dysfunction, so it is not easy to eradicate, but some dysfunctions such as bladder ureteral reflux can disappear with age. One or more urinary tract infections form focal scars in the kidney tissue, and even affect kidney development. In recent years, it is advisable to do as much as possible urinary bacterial culture before medication. Urine should be reviewed at 2, 4, and 6 weeks after drug withdrawal Cultivate for timely discovery and processing.

3. Chronic pyelonephritis

(1) Correction and removal of susceptible factors The key to the treatment of chronic pyelonephritis is to actively seek out and remove the susceptible factors, and to correct and remove as far as possible the anatomical abnormalities, stones, obstruction and reflux of the urinary system of the patient.

(2) Anti-infective treatment The treatment for acute episodes is the same as that for acute pyelonephritis. After a urine sample is taken for bacterial culture, an effective drug treatment for Gram-negative bacilli is given immediately. If due to bacterial resistance or scar formation at the diseased site, poor blood flow, and insufficient antibacterial concentration in the lesion, a larger dose of bactericidal antibacterial treatment can be tried for 6 weeks. If the obstruction factor is difficult to remove, then choose an appropriate antibacterial drug for 6 weeks according to the drug sensitivity, or consider low-dose treatment for a long time. Generally, choose an antibacterial drug with low toxicity.

(3) Glucocorticoids and non-steroidal anti-inflammatory drugs can reduce the occurrence and development of kidney scars caused by infection.

(4) Protecting renal function Increased blood pressure can accelerate the deterioration of renal function, so care should be taken to control blood pressure in the long-term treatment of chronic pyelonephritis. Improve microcirculation, improve blood supply to the kidneys, and prevent further damage to kidney function. Patients with renal insufficiency should be treated according to chronic renal insufficiency, given a low-protein diet, and kidney toxicity drugs are prohibited.