| Abstract|| |
Among the various intraabdominal abscesses, renal abscess is a rare entity, especially in children and accounts for a number of cases of "missed diagnoses." Drainage of pus and appropriate antibiotic therapy is the gold standard for treatment. Here we report a case of left renal abscess in a 6-year-old female child secondary to renal calculus. The patient presented with abdominal pain and mild fever for three months and the diagnosis was made by X-ray in the kidney, ureter and bladder (KUB) region, intravenous pyelography and ultrasonography of the abdomen. Escherichia coli was isolated from pus obtained by percutaneous drainage under sonographic guidance. The patient responded to intra-venous ceftriaxone, amikacin, and percutaneous drainage.
|How to cite this article:|
Baradkar V P, Mathur M, Kumar S. Renal abscess due to Escherichia coli in a child. Saudi J Kidney Dis Transpl 2011;22:1215-8
| Introduction|| |
The perinephric renal abscesses are a rarity among the various intraabdominal abscesses.  The incidence of renal abscesses is higher in the elderly due to the widespread use of antibiotics for skin infections or trauma,  but it is very rare in the pediatric age group. Here we report a case of renal abscess secondary to renal calculus caused by Escherichia More Details coli in a 6-year-old female child, who was treated successfully with the drainage of pus along with intravenous ceftriaxone (750 mg BD) and amikacin (75 mg 8 hourly).
| Case Report|| |
A 6-year-old female child was admitted with the complaint of pain in the abdomen and left lumbar region, for three months associated with fever and chills on and off for the same duration. There was no history of nausea, vomiting, hematuria, edema, and burning micturition. There was no history of similar complaints or any other major illness in the past. There was no family history of tuberculosis or any other significant illness. On examination the child was afebrile, with pulse rate of 90/min, respiratory rate of 18/min, and blood pressure of 100/80 mmHg. There was no edema, cyanosis, icterus, or lymphadenopathy observed. The findings of the cardiorespiratory system were within normal limits. The abdomen was soft and nontender.
The hematologic investigations showed a hemoglobin of 8.8 gm%, red blood cell (RBC) count 4.20 million/mm 3 , packed cell volume of 30%, total leukocyte count of 11,200/mm 3 , neutrophils 55%, lymphocytes 39%, eosinophils 4%, and monocytes 2%, platelets 4.37 million/mm 3 , blood sugar 79.2 mg/dL, blood urea nitrogen 10 mg%, and serum creatinine was 0.5 mg%. The routine urine examination showed the presence of trace proteins, pus cells 3-5/high power field, no RBCs, no casts, and crystals were observed. The culture of urine revealed no growth in culture.
Initially a plain X-ray (KUB) of the abdomen was performed, which showed a radiopaque calculus at the left pelvi-ureteric region at the level of L2 vertebra. No radiographic density was noted in the right kidney, right ureter, and bladder region. Both psoas margins were clear. The ultrasonography (USG) of the abdomen was performed, which revealed a moderate hydronephrosis of left kidney with an obstructive echogenic calculus at the left pelvi-ureteric region [Figure 1].
|Figure 1: The ultrasonography of the abdomen was performed, which revealed a moderate hydronephrosis of left kidney with an obstructive echogenic calculus at the left pelvi-ureteric region.|
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Intravenous urography was performed, which revealed normal concentration and excretion of the dye on the right side and the pelvicalyceal system and right ureter appeared normal [Figure 2]. On the left side, there was visualization of the nephrogram, which was becoming mildly dense. There was no evidence of excretion of the contrast medium on the left side even in the film taken at 24 h interval. Full bladder showed smooth margin and no residual urine was seen in the postvoid bladder film. Based on these evidences, the diagnosis of left renal abscess due to calculus was made. Left pyelolithotomy was performed and the pus sample was collected by percutaneous drainage under USG guidance. The Gram-stained smear showed the presence of pus cells and Gram-negative bacilli. The pus sample was cultured on blood agar and MacConkey agar and processed by the standard bacteriologic procedures. The culture yielded growth of E. coli, which was sensitive to ceftriaxone, cefotaxime, amoxycillin + sulbactam, ciprofloxacin, amikacin, and penicillin. The patient meanwhile was started on intravenous ceftriaxone (750 mg BD) and amikacin 75 mg 8 hourly. The patient responded well to the drainage and antibiotic therapy with subsidence of the fever and pain. The patient was discharged after ten days of intravenous antibiotic therapy, and oral ciprofloxacin 500 mg BD for another seven days. On subsequent follow-up, the patient had no complaints or remission of symptoms and a repeat USG revealed no renal collection.
|Figure 2: Intravenous urography revealing normal concentration and excretion of the dye on the right side and the pelvicalyceal system and right ureter appeared normal. On the left side, there was no evidence of excretion of the contrast medium even in the film taken at 24-h interval.|
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| Discussion|| |
Renal subcapsular abscess is a very rare disease that is defined by suppurative process, localized to a space between the renal capsule and the renal parenchyma.  This entity is rare in children and the diagnosis difficult in children because in most of the patients, symptoms are non-specific. ,,,, Most children present with fever, flank pain, with or without a palpable mass; raised leukocyte count and raised erythrocyte sedimentation rate. In the present case, the presenting symptom was pain in the abdomen and fever with chills. Other symptoms of urinary tract infections, such as burning micturition, frequency, and urgency, were absent, which is usually present in lower urinary tract infection. Hence the diagnosis is greatly facilitated by X-ray, intravenous pyelography, and USG. Several risk factors have been identified for the development of renal abscess, such as renal stones, structural abnormality, and history of urologic surgery, trauma, or any other cause of obstruction. ,,,,,
In the present case renal calculus (stone) acted as the predisposing factor for the development of renal abscess. Predominant organisms causing renal abscesses are Gram-negative organisms, the most common being E. coli followed by Staphylococcus aureus. ,, Bhat  reported a case of renal abscess in an 18-day-old neonate. S. aureus was isolated from the pus, which was collected by percutaneous drainage, under ultrasound guidance. The patient responded to Cloxacillin and percutaneous drainage.
Paul B et al,  from Ajmer, Rajasthan also reported S. aureus as the pathogen causing renal abscess in 30 year old female, who responded to Ceftriaxone therapy (1 g IV BD), along with the drainage of pus. A large retrospective study from North India,  showed that E. coli was isolated from 31% of the cases, Proteus species in 17% and Pseudomonas aeruginosa in 11% cases. In 19 out of 29 cases of renal abscesses, calculi was the commonest predisposing factor followed by diabetes mellitus in ten cases and end stage renal disease in three cases. The study showed that out of the 29 cases, 16 (55%) patients had complete resolution, with conservative management (antibiotics alone or with urinary drainage), percutaneous drainage was required in nine (31%). Four (14%) patients had complete destruction of the renal parenchyma with the presence of gas in the kidney and retroperitoneum, requiring nephrectomy in three cases and one died.
Early diagnosis is a key factor in the management of these patients. 
Gram-negative bacterial abscess commonly develop due to rupture of corticomedullary abscess while the staphylococcal infection develops due to rupture of a renal cortical abscess. Approximately 30% cases are attributed to hematogenous dissemination from other sites of infection such as wound infection, furuncles or pulmonary infection. Abscess can also occur from ascending urinary tract infection, the presenting symptoms of which are nonspecific.  In the present case, we could not find out any primary focus of infection; the calculus itself might have acted as a nidus for the development of renal abscess. In conclusion, as renal abscess is uncommon in pediatric age group, a high degree of suspicion is required if the patient presents with abdominal pain.
USG helps in the diagnosis, while antibiotics along with percutaneous drainage resolve most of the cases and rarely surgery, such as nephrectomy may be required to treat the renal abscess, so that the complications such as extension to the peritoneal cavity, skin, or chest , may be prevented.
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V P Baradkar
Lecturer, Department of Microbiology, Lokmanya Tilak Municipal Medical College and General Hospital, Sion, Mumbai 400022
[Figure 1], [Figure 2]