| Abstract|| |
Brain abscess is an uncommon and serious life-threatening infection in children. Focal intracranial infections caused by Salmonella spp. in this age group are also rare. We report the case of a 4-month-old male infant with a frontoparietal brain abscess caused by Salmonella typhimurium , the presence of which was not suspected clinically.
Keywords: Brain abscess, infant, intra-cranial infection, salmonella
|How to cite this article:|
Samal B, Oommen S, Swami A, Maskey M, Shastri J. Salmonella brain abscess in an infant. Indian J Pathol Microbiol 2009;52:269-70
| Introduction|| |
Brain abscess is an uncommon and a serious life-threatening infection in children. Approximately 25% of all brain abscesses occur in children less than 15 years of age, with a male preponderance. ,, A brain abscess below the age of 2 years is extremely rare.  Brain abscesses caused by Salmonella More Details spp. are rarer, with the most common serotypes being typhi, typhimurium and enteritides. , This occurs more frequently in adults with precipitating factors such as meningitis, trauma and intracranial hematoma. The present case is an extradural abscess in the frontoparietal region caused by Salmonella typhimurium.
| Case Report|| |
A 4-month-old male infant was admitted in the medical ward of our hospital in September 2005 with a history of right focal tonic clonic convulsions associated with post-ictal drowsiness. The child had a history of fever since 3 days, which was mild and intermittent initially, progressing to high-grade continuous fever (102°F). There was no history of incontinence, diarrhea, vomiting and otorrhea. There was no past history of convulsions, prolonged fever, meningitis, traumatic injury or any major illness.
The infant was immunized and had attained milestones as per the age. Posterior fontanella was closed, and the anterior fontanella was about 2 × 2cm and nonbulging. No abnormality was found on general and systemic examination including the central nervous system and ENT examination.
Two similar tonic clonic seizure episodes occurred in the ward in 2 days interval.
Investigations done on admission revealed hemoglobin (Hb) 10gm%, total leucocyte count (TLC) of 8000/cmm, differential leucocyte count (DLC) was neutrophils - 73%, Lymphocytes - 20%, Monocytes - 1% and erythrocyte sedimentation rate (ESR) was 20mm in the first hour. Blood and clot cultures were bacteriologically sterile. Widal test was found to be negative. Examination of the cerebrospinal fluid (CSF) showed the following picture. Proteins: 450 mg%, sugar: 46mg% and leucocyte count: 450, of which 70% were mononuclear cells. Bacterial as well as mycobacterial culture of the CSF did not yield growth. Both the mother and the child did not show the presence of antibodies to HIV-1 and HIV-2. Ultrasonography of the skull showed the presence of an extradural collection in the frontoparietal region. Computed tomography (CT) scan of the brain was then done, which also showed a large extra-axial collection in the left frontoparietal region with enhancing medial margin, causing mass effect with midline shift to the right, giving the impression of an old hematoma and abscess. The lesion was aspirated, and pus was sent to the microbiology laboratory for culture and sensitivity. Growth on MacConkey agar showed smooth, translucent, nonlactose fermenting colonies. Blood agar showed nonhemolytic, easily emulsifiable colonies. The isolated organism was identified by conventional biochemical reactions and later by 20E API (99.9% concordance) as Salmonella paratyphi B/ typhimurium/enteritidis .  It was further confirmed by slide agglutination with polyvalent salmonella O and O4 antisera. It belonged to Group B of the Kauffman-White scheme of classification of Salmonella serotypes. The isolate was confirmed as Salmonella typhimurium after agglutination with H phase antisera. Repeated stool cultures were negative for Salmonella spp. Anaerobic and mycobacterial cultures of the abscess pus yielded no growth. Sickling test was negative.
Antimicrobial susceptibility testing was done as per the National Committee for Clinical Laboratory Standards (NCCLS).  The organism was found to be sensitive to ampicillin, cotrimoxazole, chloramphenicol, cefuroxime, ceftriaxone and amikacin. The patient was treated with aspiration of the abscess after a burr-hole placement along with antibiotic therapy consisting of ceftriaxone (100mg/kg - 12hourly) and amikacin (15mg/kg/day - 12hourly) for 2 weeks. The patient responded satisfactorily to this line of therapy. Cefuroxime was then prescribed for 4 weeks, and the patient was discharged. A repeat CT scan could not be done as the patient did not come for follow up.
| Discussion|| |
Brain abscesses develop in four clinical settings. 
a) In association with a contiguous spread from a suppurative focus b) after haematogenous spread from a distant focus c) after trauma d) cryptogenic (no focus is recognized in approximately 15%-20% of the cases). Bacteremia, sepsis and meningitis are relatively common in children with Salmonella infection. But intracranial abscesses are very rare. The most common serotypes associated with brain abscess are typhi, typhimurium and enteritidis . ,
Siriven et al .  have reviewed nontyphoidal Salmonella infection in infants without an underlying lesion and found that infants of 0-6 months of age were at a high risk of these infections, which may present as bacteremia, bone and joint infections and meningitis. This correlates well with our case, who also did not present with any underlying conditions like sickle cell anemia, hemorrhagic neoplasm, trauma and prolonged exposure to the organism and immunosuppression. , Mahapatra et al .,  in their experience of 6 cases of intracranial Salmonella infections in the pediatric age group, reported four cases in which Widal and blood culture were negative. In the present case also, Widal and blood culture were negative. Our patient had no past history of diarrhea, fever or trauma. Repeated stool cultures were also negative for Salmonella spp.
Antimicrobial therapy of brain abscess is generally long. However, a shorter course may be given if surgical drainage is achieved.  Ceftriaxone is the drug of choice, especially in children in whom ciprofloxacin is contraindicated. Relapse rate is also low with this antibiotic.
Thus, a high index of suspicion, early diagnosis, prompt evacuation and antibiotic therapy lead to satisfactory results in the prognosis of brain abscess caused by Salmonella infection.
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Department of Microbiology, College building, Room no. 313, TNMC and BYL Nair Hospital, Mumbai Central, Mumbai - 400 008
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