Acute pyelonephritis

Acute pyelonephritis is acute pyogenic inflammation of the renal pelvis, calyces and parenchyma caused by bacteria, course under 6 months. Two routes: ① ascending infection, bacteria from ureter to pelvis then parenchyma; 70% arise this way. ② hematogenous infection, bacteria from blood into tubules and pelvis, about 30%, mostly staphylococcal. Urinary obstruction and stasis are the commonest causes.

Common Symptoms

Chills; tubulointerstitial nephritis; high serum level; nocturia; fever with frequency; lower abdominal pain; narrowed renal artery; dysuria; urgency

Causes

Bacteria mainly ascend from the urethra; colonic bacteria from the perineum ascend via urethra, bladder and ureter. Obstruction and stasis favor growth. Over 70% are gram-negative bacilli, mainly E. coli, then Proteus, Klebsiella, Aerobacter, Pseudomonas; 20% gram-positive, mainly streptococci and staphylococci. P-fimbriated E. coli with class II adhesins are strongly associated. Ascending infection accounts for about 95%: normally a few bacteria live 1-2 cm above the meatus; only when resistance falls or mucosa is injured do they invade. Risk factors: catheterization, stones, trauma, tumor, prostatic hyperplasia, congenital anomalies, VUR, neurogenic bladder. Hematogenous infection is under 3% but renal blood flow is 20%-25% of cardiac output. Women have a short (3-5 cm) wide urethra near the anus, 8-10 times more prone to UTI. Virulence factors and O antigens (O1, O2, O4, O5, O7, O16, O18, O75) account for 80% of E. coli pyelonephritis. Pathologically, bacterial clones reach the calyces and tubules; neutrophilic infiltration, tubular epithelial necrosis, and small abscesses form.

Treatment

Medication, rehabilitation therapy

Prevention

1. Drink water and urinate often to flush the bladder. 2. Keep the perineum clean. 3. Avoid urinary instruments; use strict asepsis. 4. Recurrent cases may take a nightly prophylactic antibiotic (co-trimoxazole, furadantin, amoxicillin or cefradine) for over a year; urinate and take a dose after intercourse.

Recommended Department

It is recommended to visit the nephrology department; before the visit you may first book an appointment and connect with experts through this platform.

Warm reminder: The above information is provided for health education reference only and cannot replace professional medical diagnosis. If you have related symptoms, please seek care at a regular hospital in time.