Diagnosis
- Catheterization of the ureters and renal pelvis for urinalysis and culture (unnecessarily invasive)
- Routine urinalysis
- Bacterial antibodies (false positives)
- The Fairley bladder washout test
- Radiographic methods include:
- Excretory urography
- Tc-99m DMSA or glucoheptonate nuclear renal scans
- Voiding cystourethrography
- Renal biopsy with bacterial culture (not condemned due to excessive risk to the patient)
- Pediatric patient: should be studied with voiding cystourethrography and nuclear renal scanning to evaluate for vesicoureteral reflux and renal scarring/dysfunction, respectively.
***** - Acute pyelonephritis: usually diagnosed on clinical grounds
- Chronic pyelonephritis: diagnosed by radiologic and pathologic means
- CT scanning or ultrasonography to search for predisposing risk factors
Clinical Characteristics
- Fever, flank pain, costovertebral angle (CVA) tenderness, and infected urine
- Clinical presentation may vary from acute sepsis to cystitis with mild flank pain
- Systemic malaise, nausea, and vomiting
- Lower urinary tract symptoms of dysuria, increased urinary frequency
- History of previous lower urinary tract infections
- Severe cases may cause sepsis, hypotension, and death in a compromised host
***** - Acute pyelonephritis: can be self-limited. Multiple bouts can lead to progressive loss of tubules, thereby impairing renal concentrating ability. This is followed by glomerular damage late in the course (chronic pyelonephritis), producing azotemia and hypertension
- Chronic pyelonephritis: history of recurrent urinary tract infections, may be asymptomatic, radiologically or secondary to complications of chronic azotemia
Special Case: XANTHOGRANULOMATOUS PYELONEPHRITIS (XGP)
Diagnosis
- The usual symptoms of pyelonephritis
- Nonfunction of the affected kidney and the process is invariably unilateral
- Radiologic imaging; reveals renal calculi and a renal mass
- Perirenal fat may be involved with adjacent subcapsular inflammatory response
- Bacteriology; Proteus and E. coli
- The presence of large, often branched calculi in the presence of a renal mass associated with either focal or global renal nonfunction
Complications
Renal Abscess
May follow insufficient treatment of focal bacterial nephritis (lobar nephronia).
Diagnosis:
- CT, ultrasound, and needle aspiration
Perinephric Abscess
Diagnosis:
- Similar diagnosis for renal abscess
Emphysematous Pyelonephritis
Diagnosis:
- Intrarenal parenchymal gas defined by plain x-ray, CT scan, or ultrasound.