|IMAGES IN NEPHROLOGY
|Year : 2007 | Volume
| Issue : 2 | Page : 87-88
Acute pyelonephritis complicated with renal abscesses
Anupam Lal, Manphool Singhal
Department of Radiodiagnosis, PGIMER, Chandigarh, India
Department of Radiodiagnosis, PGIMER, Chandigarh
|How to cite this article:|
Lal A, Singhal M. Acute pyelonephritis complicated with renal abscesses. Indian J Nephrol 2007;17:87-8
A 26-year-old female presented with fever, dysuria and recurrent vomiting of one week duration. She had a full term normal vaginal delivery at a primary health center two weeks back. Clinical examination revealed a temperature of 39 o C and exquisite tenderness in both renal angles and suprapubic area. Blood counts showed marked leukocytosis with polymorphonuclear predominance. The blood urea was 180 mg/dl and serum creatinine 3 mg/dl. Urine examination showed marked pyuria.
The ultrasound examination [Figure - 1],[Figure - 2] revealed large bulky kidneys with increased cortical echogenicity. The renal sinus was compressed by the swollen renal parenchyma. The corticomedullary distinction was preserved, but the medulla showed a distorted morphology. Of note, there were multiple focal hypo- to anechoic lesions in the cortex and medulla. Such lesions were seen in both kidneys. In the setting of urinary tract infection these findings are suggestive of acute pyelonephritis complicated with multiple renal abscesses.
Urine and blood cultures grew E. coli . She was treated with appropriate antibiotics; fever responded in 48 h and the serum creatinine came down to 1.4 mg/dl in one week's time. She was discharged after 10 days.
Urinary tract infection (UTI) is common in young children and sexually active women. By convention, UTI is defined either as a lower tract (acute cystitis) or upper tract (acute pyelonephritis) infection. Acute pyelonephritis is a potentially organ-damaging and life-threatening infection that characteristically causes some scarring of the kidney with each infection and may lead to acute renal failure, abscess formation, sepsis syndrome, shock and multiorgan system failure. Despite the upper tract involvement, most episodes of acute pyelonephritis are considered to be uncomplicated and resolve with appropriate medical therapy.
Acute pyelonephritis usually develops as an ascending infection from the lower urinary tract. A subset of E. coli, the uropathogenic E. coli (UPEC) account for most infections. Other microorganisms are Staphylococcus saprophyticus, Klebsiella pneumoniae, Proteus mirabilis, Enterococci, Staphylococcus aureus, Pseudomonas aeruginosa d Enterobacter species. Hematogenous spread to the kidney can occur in intravenous drug abusers and those with infective endocarditis; Staphylococcus aureus is the most frequently isolated organism in such cases. 
Pyelonephritis can be complicated by bacteremia in those with structural or functional urinary tract abnormalities, history of recent urinary tract instrumentation or those with metabolic conditions predisposing to UTIs.
Failure of medical treatment can lead to suppurative inflammation ranging from acute focal (lobar nephronia) or multifocal bacterial nephritis, xanthogranulomatous pyelonephritis (in the presence of stones) and emphysematous pyelonephritis (more common in diabetics). 
Renal ultrasonography is a rapid and relatively inexpensive initial screening tool for detecting parenchymal lesions and anatomic abnormalities. The presence of an ill-defined renal mass with low-amplitude internal echoes and disruption of the corticomedullary junction is suggestive of an intrarenal abscess. 
Computed tomography scanning is by far the study of choice in evaluating intrarenal abscesses and helps in characterizing infections as diffuse or focal, for detecting the presence of gas and to determine perinephric extension.  Magnetic resonance imaging usually offers no additional information. Plain radiography may show radio-opaque stones in the case of calculus-induced obstruction or intraparenchymal gas in patients with emphysematous pyelonephritis.
In the past, surgical debridement, drainage and nephrectomy were widely used to treat corticomedullary abscesses. With the advent of effective antibiotics along with percutaneous techniques, the open surgical approach is now reserved for only more severe, refractory cases.
| References|| |
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|2.||Yen DH, Hu SC, Tsai J, Kao WF, Chern CH, Wang LM, et al. Renal abscess: Early diagnosis and treatment. Am J Emerg Med 1999;17:192-7. [PUBMED] [FULLTEXT]|
|3.||Shen Y, Brown MA. Renal imaging in pyelonephritis. Nephrology (Carlton) 2004;9:22-5. [PUBMED] |
[Figure - 1], [Figure - 2]