Acute pyelonephritis

Acute pyelonephritis refers to an acute infectious disease of the renal pelvic mucosa and renal parenchyma, mainly caused by infection with Escherichia coli, but also by Proteus, Staphylococcus, Streptococcus faecalis and Pseudomonas aeruginosa. The most serious complication of acute pyelonephritis is toxic shock.

Causes

Clinical manifestations

Typical acute pyelonephritis has an acute onset, with clinical manifestations of paroxysmal chills, fever, low back pain (obvious percussion pain at the costovertebral angle), usually accompanied by abdominal cramps, nausea, vomiting, dysuria, frequent urination and increased nocturia. The disease can occur in people of all ages, but is most common in women of childbearing age, with the following main symptoms.

1. General symptoms: high fever, chills, body temperature is mostly between 38 and 39°C, and can be as high as 40°C. Fever types vary, generally remittent, but can also be intermittent or prolonged, accompanied by headache, body aches, and profuse sweating when the fever subsides. 2. Urinary system symptoms: patients have low back pain, mostly dull pain or soreness with varying degrees. A few have abdominal colic that radiates along the ureter toward the bladder. During physical examination, there is tenderness at the upper ureteral point (the intersection of the outer line of the rectus abdominis and the umbilical line) or the costal waist point (the intersection of the outer edge of the psoas major and the twelfth rib), and positive percussion pain in the renal area. Patients often have bladder irritation symptoms such as frequent urination, urgency, and pain when urinating. In the case of ascending infection, these symptoms may appear before systemic symptoms. 3. Gastrointestinal symptoms: There may be loss of appetite, nausea, vomiting, and some patients may have pain in the upper or middle abdomen. 4. Bacteremia and sepsis: Although patients with symptomatic acute pyelonephritis may develop bacteremia during the course of their disease. 5. Shock and DIC. 6. Pediatric patients: The urinary system symptoms of pediatric patients are often not obvious. In addition to systemic symptoms such as high fever, they often have convulsions and seizures at the onset of the disease. Children under 2 years old may have fever, vomiting, non-specific abdominal discomfort or restlessness.

examine

1. Urinalysis: (1) In case of pyelonephritis, the urine may be clear or turbid and may have a putrid odor. A very small number of patients may have visible hematuria. (2) Microscopic examination: 40% to 60% of patients have microscopic hematuria. Most patients have 2 to 10 red blood cells/HPF. A few have large amounts of red blood cells under the microscope. Leukocytosis (i.e., pyuria) is common. After centrifugation, the urine sediment under the microscope has >5 white blood cells/HPF. In the acute phase, the field of vision is often filled with white blood cells. If white blood cell casts are seen, it provides an important basis for the diagnosis of pyelonephritis. At present, there are blood cell counting discs used in China to check clean, uncentrifuged urine, and pyuria is defined as ≥8 cells/mm3. (3) Urine protein content: In pyelonephritis, the qualitative examination of urine protein is trace to +, and the quantitative examination is about 1.0 g/24 hours, generally not exceeding 2.0 g/24 hours. 2. Quantitative urine bacterial culture: Quantitative urine bacterial culture is an important indicator for determining whether there is a urinary tract infection. As long as conditions permit, midstream urine should be used for quantitative bacterial culture. 3. Urine smear microscopic examination of bacteria: ① Urine smear microscopic examination of bacteria without centrifugation. ②Urine sediment smear microscopic examination for bacteria. 4. Urine chemical test: This method is simple and easy, but the positive rate is low and the value is limited. It cannot replace urine bacterial quantitative culture. 5. Urinary leukocyte excretion rate: Urinary leukocyte excretion rate is a more accurate method to measure leukocyturia. 6. Routine blood examination: White blood cell count and neutrophil count may increase in the acute phase, and red blood cell count and hemoglobin may decrease slightly in the chronic phase. 7. Serological examination: The following methods are more clinically significant: ① Immunofluorescence technology to detect antibody-coated bacteria (ACB). ②Identify the serotype of urine bacteria. ③Tatom-Horsefall (TH) protein and antibody determination. ④ Determination of urine β2-microglobulin (β2-MG). 8. Renal function test: Acute pyelonephritis occasionally causes urine concentrating dysfunction, which can usually be recovered after treatment. Chronic pyelonephritis may cause persistent renal function damage: ① Decreased renal concentrating function, such as increased nocturnal urine volume and decreased morning urine osmotic concentration. ② Decreased renal acidification function, such as increased morning urine pH, increased urine HCO-3, decreased urine NH4, etc. ③ Impaired glomerular filtration function, such as decreased endogenous creatinine clearance, increased blood urea nitrogen and creatinine, etc. 9. X-ray examination: Plain abdominal film may make the kidney shape unclear due to perirenal abscess. Intravenous urography may reveal delayed calyx development and weakened renal pelvis development, which can show primary lesions such as urinary tract obstruction, renal or ureteral malformations, stones, foreign bodies, tumors, etc. 10. CT and B-ultrasound examinations: (1) CT examination shows that the affected kidney is enlarged and a wedge-shaped area of ​​reduced enhancement can be seen, radiating from the collecting system to the renal capsule. The lesions may be single or multiple. (2) Ultrasound examination shows unclear boundaries between the renal cortex and medulla, and there are areas with lower echo than normal. It can also determine whether there is obstruction, stones, etc.

Diagnosis: The diagnosis is confirmed based on the cause, clinical manifestations and various examinations.

treat

1. General treatment: Patients with acute pyelonephritis accompanied by fever, significant urinary tract irritation symptoms or hematuria should rest in bed. They can get up and move around after their body temperature returns to normal and their symptoms are significantly relieved. Generally, you should rest for 7 to 10 days and then return to work after the symptoms completely disappear. For patients with fever and obvious systemic symptoms, liquid or semi-liquid diet will be given according to the patient's general condition. After there are no obvious symptoms, normal daily diet will be changed. Patients with high fever and obvious gastrointestinal symptoms can receive intravenous fluid replacement. The daily water intake should be sufficient, drink more water and urinate more frequently. It flushes the urinary tract, promotes the excretion of bacteria and inflammatory secretions, and reduces the hyperosmotic pressure of the renal medulla and papilla, which is not conducive to the growth and reproduction of bacteria. 2. Antimicrobial drug treatment: Acute pyelonephritis usually has an acute onset and severe condition. The treatment plan should be determined based on the severity of the patient's symptoms and signs. Before collecting urine samples for quantitative bacterial culture and obtaining drug sensitivity reports, the treatment plan should be decided based on the doctor's experience. Given that pyelonephritis is mostly caused by Gram-negative bacteria, antibiotics that are effective against Gram-negative bacteria are generally preferred, but treatment of Gram-positive bacterial infections should also be considered.

After reading the above detailed introduction to the symptoms and manifestations of acute pyelonephritis, I believe that you have a general understanding of it. Acute pyelonephritis is very harmful and can easily lead to life-threatening situations. Therefore, if you have any suspected symptoms or manifestations of this type of disease, you should go to a regular hospital for medical treatment and examination in time to avoid worsening of the disease and leading to irreversible consequences.