Chronic pyelonephritis

Disease Description (Causes and Symptoms)

• Definition: Chronic pyelonephritis is a condition in which chronic inflammation and scarring develop in the renal pelvis (calyces) and renal parenchyma, caused by recurrent or persistent pyelonephritis.
• Main causes: Recurrent urinary tract infections (recurrence of acute pyelonephritis), vesicoureteral reflux (VUR), urinary tract obstruction (ureteral stricture, stones, tumors, etc.), neurogenic bladder, congenital anomalies, tuberculosis, analgesics (especially long-term overuse of antipyretic analgesics), etc.
• Pathophysiology summary: Repeated bacterial invasion and inflammation → fibrosis and scar formation in the renal parenchyma → deterioration of renal structure and function (partial atrophy and scarring) → possible progression to chronic kidney disease or hypertension.
• Main symptoms: Symptoms are often less distinct than in the acute phase. General weakness, flank discomfort or dull pain, long-term proteinuria, hematuria, and bacteriuria, urinary symptoms (sensation of incomplete emptying, difficulty urinating), and in some cases, discovery of chronic renal failure despite no symptoms. Acute symptoms such as fever, back pain, and cloudy urine may occur during exacerbations.

Treatment Methods

• Basic principles: Correct the cause (remove urinary tract obstruction, remove stones or tumors, correct VUR, etc.) + control infection + preserve kidney function.
• Medication treatment:
  • Use antibiotics based on culture test results (oral administration for mild cases; intravenous administration for moderate to severe cases or signs of sepsis). Commonly used classes include third-generation cephalosporins, extended-spectrum penicillins, quinolones, and TMP‑SMX, etc. (depending on culture results and the susceptibility of locally prevalent strains).
  • Long-term low-dose antibiotic prophylaxis is determined by the treating physician when recurrences are frequent (especially in children with VUR).
• Procedures and surgery:
  • Correction of urinary tract obstruction (ureteral stricture, large stones, etc.) (endoscopic stone removal, extracorporeal shock wave lithotripsy, surgical removal).
  • VUR corrective surgery may be considered in children or adults with moderate or more severe VUR or progressive kidney damage.
  • In neurogenic bladder, bladder training, intermittent self-catheterization, and medication (bladder smooth muscle inhibitors), etc. are used to reduce residual urine and the risk of infection.
• Lifestyle management:
  • Drink sufficient fluids, do not hold urine, urinate after sexual intercourse, wipe from front to back after bowel movements (women), and maintain personal hygiene.
  • Avoid long-term use of diuretics, NSAIDs, and nephrotoxic drugs (consult a doctor). Excessive use of analgesics may have adverse effects.
• Follow-up:
  • Regular blood tests (creatinine, eGFR), urine tests (urinalysis and urine culture), and blood pressure measurements. DMSA renal scans, ultrasonography, CT scans, and other tests for evaluating scarring are performed as needed.
• Precautions:
  • Do not stop antibiotics arbitrarily (follow the treatment duration based on the culture results).
  • When kidney function is reduced, drug selection and dosage adjustment are necessary.
  • In cases of recurrence, the cause (structural abnormalities, VUR, neurogenic bladder, etc.) must be evaluated.

Checklist Before an Outpatient Visit (Including Items to Prepare and Example Questions)

• Items/information to bring:
  • List of currently used medications (including prescription and OTC medications)
  • Past medical history (urinary tract surgery, stones, tuberculosis, a diagnosis of VUR during childhood, etc.)
  • Copies of recent test results (blood, urine, ultrasound, CT, renal scan, etc.)
  • Symptom records (fever, urinary frequency/pain, flank pain, and the timing of hematuria, if present)
  • Voiding diary (number of urinations per day, sensation of incomplete emptying, nocturia, etc.) and the frequency and timing of fever
  • For women, whether pregnancy is possible
• Information to tell the doctor in advance during the outpatient visit:
  • The number of recent urinary tract infections and the medications used for treatment, including the response
  • Drug allergies and previous adverse effects from antibiotics
  • Whether chronic diseases (diabetes, hypertension, etc.) are present

Examples of General Questions to Ask the Doctor

• "What is the current status of my kidney function (please explain my creatinine and eGFR levels)?"
• "Which antibiotic is recommended for this infection, and what is the expected treatment duration?"
• "What lifestyle habits should I pay particular attention to in order to reduce recurrences?"
• "Which tests do I need, and how often should I have them (blood, urine, imaging tests, etc.)?"
• "Are there any medications or supplements I am taking that I should avoid?"

Examples of Disease-Specific Questions

• "What tests should I undergo to determine whether vesicoureteral reflux is the cause of my pyelonephritis (VCUG/excretory voiding cystourethrography, DMSA, etc.)?"
• "How severe is the renal scarring, and what is the long-term prognosis resulting from it (risk of chronic renal failure and hypertension)? If necessary, what treatment (such as surgical correction) would you recommend to preserve kidney function?"