A 6-month-old female with fever and increased head circumference.
A brain abscess begins as a focal area of intracerebral infection which develops into a collection of purulent fluid. (1) Intracranial abscesses account for 2-5% of all intracranial masses in humans and are very rare in infants. (2) Approximately 25% of brain abscesses occur in children. (3) Major risk factors include cyanotic congenital heart disease and known infections of the structures of the head, (3) in addition to a history of penetrating trauma or neurosurgical manipulation. Predisposing factors are found in approximately 85% of cases. (4)
The clinical manifestations will differ depending upon the extent of disease, the involved pathogen, the host's immune status, and the location of the lesion. (1) Presenting symptoms may include fever, focal neurologic deficits, hydrocephalus, bulging fontanelle, seizure activity, poor feeding, emesis, decreased consciousness, decreased tone, and increased irritability. (5)
Here, we describe the presentation and management of a large intraparenchymal brain abscess in an infant with a history of premature birth and extremely low birth weight, but without other known predisposing factors. We find this case to be unique for two reasons. The causative organism, methicillin-sensitive Staphylococcus aureus (MSSA), is an extremely rare intraparenchymal pathogen without any known trauma, surgical manipulation, or bacteremia. Also, all of the previously described cases of Staphylococcus aureus brain abscess occurred in infants three months of age or less.
A 6-month-old female presented to our institution due to a dramatic increase in head circumference noted during a well child visit. Her grandmother reported a change in the firmness of the patient's fontanelle over the past week. The patient had been increasingly irritable for the past two weeks, but her grandmother had attributed this to daily fevers of 38.8-39.6C. Her history was significant for premature birth at 25 weeks gestation and a three-month NICU stay. She was born via cesarean section with difficult extraction, resulting in an avulsion injury of the right ear. Maternal antibiotics were administered for foul-smelling amniotic fluid and leukocytosis, so she was immediately cultured and started on antibiotics. After 48 hours of negative cultures, the antibiotics were discontinued. Her NICU course was significant for bilateral grade 2 intraventricular hemorrhages and suspected candidal pneumonia treated with Amphotericin B and Fluconazole with resolution. Of note, she had a nasal swab obtained during the admission which demonstrated colonization with methicillin-resistant Staphylococcus aureus (MRSA). She had been doing well since discharge and was up to date on her immunizations.
On admission, the physical examination revealed a non-toxic appearing infant who was febrile at 38.8 C. She was macrocephalic with a head circumference of 44.5 cm (93rd percentile, uncorrected for gestational age). She had a firm anterior fontanelle with a splayed sagittal suture. She was irritable but easily consolable. Her neurological exam was significant for moderate hypotonia, but was otherwise benign. The remainder of the examination was unremarkable.
Laboratory evaluation revealed a leukocytosis with white blood cells of 23,600/[micro]L (23.6 x [10.sup.9]/L), 47% neutrophils, and 1% bands. Inflammatory markers including C-reactive protein and erythrocyte sedimentation rate were markedly elevated at 20.8 mg/dL and 79 mm/ hr, respectively. Blood and urine cultures were sent. An emergent computed tomography (CT) scan revealed extensive vasogenic edema with a large, low-density, well-circumscribed dorsal collection involving the right cerebral hemisphere with significant midline shift (Figure 1). The diagnosis of an intracerebral brain abscess was made. She was emergently taken to the operating room for stereotactic-guided drainage. Cultures obtained intra-operatively revealed the presence of MSSA. She received an 8-week course of Nafcillin and Rifampin, as well as two weeks of Gentamicin, with subsequent improvement. An immunodeficiency workup was normal for age.
Given her hypotonia, she has been receiving physical therapy. She has been responding nicely, although her neurodevelopmental outcome is still to be determined.
We have described an infant with a MSSA brain abscess without any known nidus of infection or other major risk factor, aside from a history of prematurity and very low birth weight. There are scattered case reports in the literature of Staphylococcal brain abscesses in infants. El-Khasab et al, describe a two month old infant with no apparent predisposing factors who developed a Vancomyin-sensitive Staphylococcus aureus cerebellar abscess mimicking an intracranial tumor. (2) Arora describes a former 29 week infant with a history of MRSA bacteremia presenting on day of life 52 with multiple MRSA brain abscesses. (7) Woodlief describes a former 26 week infant known to be colonized with methicillin-resistant Staphyloccus aureus (MRSA) presented with rapidly increasing head circumference at 3 months of age found to have more than 20 separate MRSA brain abscesses without bacteremia. (6) Lastly, Eser et al, describe a 45 day old infant who developed an intracerebral hematoma which was later complicated by a brain abscess. The infant's blood culture ultimately grew Staphylococcus aureus but the abscess culture did not grow an organism.
A causative organism is not identified in approximately 30% of brain abscesses. (9) In most cases of brain abscess, surgical drainage with antibiotic therapy is considered the treatment of choice, (4) although antibiotic therapy may be used alone for small or hard-to-access abscesses. Broad-spectrum antimicrobial regimens are often chosen at diagnosis, which is then de-escalated if and when the culture results reveal the causative organism. In our case, the initial empiric antibiotic regimen consisted of Vancomycin, Ceftazidime, and Metronidazole which was subsequently changed to Nafcillin, Rifampin, and Gentamicin.
Our case is interesting in that not only is the organism extremely rare and to our knowledge one of the first known cases of a culture-proven MSSA brain abscess in an infant, but also unique in that this particular case occurred in an infant who was six months of age chronologically. This is three months older than the oldest infant previously reported in the literature. Typically, the immune system in infants reaches it peak maturity between three to six months of age after passive immunity has waned. It is plausible that our infant's extreme prematurity may have played a role in the development of this abscess, even at a relatively older age, due to potentially delayed maturity of the immune system, even though testing done at the time of diagnosis appeared to reveal a relatively well-functioning immune system.
We described a 6-monthold, former 25 week, infant who developed an intracerebral abscess from MSSA without any of the major risk factors. While these infections are rare, they should be included in the differential diagnosis for infants with a prolonged febrile illness and macrocephaly, especially those born prematurely.
(1.) Celik iH, Demirel G, Erdeve O, Uras N, Dilmen U. Multiple large brain abscesses in a newborn that may have resulted from intrauterine infection. The Turkish Journal of Pediatrics 2011; 53: 561-566.
(2.) El-Khashab M, Zonouzi TH, Naghani IM, Nejat F. Cerebellar Staphylococcal Abscess Accompanied with High Alfa-Fetoprotein in a Young Infant. Iran J Pediatr Dec 2012; Vol 22 (No 4): 539-542.
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(5.) Sidaras D, Mallucci C, Pilling D, Yoxall WC. Neonatal brain abscess--potential pitfalls of CT scanning. Childs Nerv Syst 2003; 19: 57-59.
(6.) Woodlief RS, Markowitz JE. Unrecognized Invasive Infection in a Neonate Colonized with Methicillin-Resistant Staphylococcus aureus. The Journal of Pediatrics 2009; 155: 943.
(7.) Arora P, Kalra VK, Pappas A. Multiple Brain Abscesses in a Neonate After Blood Stream Infection with Methicillin-Resistant Staphylococcus aureus. The Journal of Pediatrics 2012; 161:563.
(8.) Hershenson JA, Baker PB, Rowland DG. Ruptured Myocardial Abscess Causing Left Ventricle to Pulmonary Artery Communication in an Infant With Community-Associated Methicillin-Resistant Staphylococcus aureus Endocarditis. Arch Pathol Lab Med August 2011; 135: 1057-1060.
(9.) Seydoux C, Francioli P. Bacterial brain abscesses: factors influencing mortality and sequelae. Clin Infect Dis 1992; 15: 394-401.
Collin C. John, MD, MPH
Ashley Jenkins, MD
Hilary Morley, MD
West Virginia University School of Medicine, Department of Pediatrics
Corresponding Author: Collin John, MD, MPH, West Virginia School of Medicine, Department of Pediatrics, PO Box 9214 Morgantown, WV 26505, email@example.com.
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|Title Annotation:||Case Report|
|Author:||John, Collin C.; Jenkins, Ashley; Morley, Hilary|
|Publication:||West Virginia Medical Journal|
|Date:||Mar 1, 2016|
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