Presurgical Hospital Course

An 18-year-old left-handed male with a history of histoplasmosis-induced pericarditis 7 years earlier and recent travel to Florida initially presented to a referring institution with fever, cough, altered mental status, left hemiparesis and ophthalmoplegia, and ataxia. Emergent computed tomography of the head without contrast demonstrated numerous lesions suspicious for brain abscesses. CSF was obtained by lumbar puncture, empirical vancomycin and cefepime were given, and he was emergently transferred to our facility.

On arrival, he was afebrile with similar examination findings. Contrast brain magnetic resonance imaging (MRI) demonstrating > 30 ring-enhancing lesions in both cerebral hemispheres and the left cerebral peduncle, with layering in the occipital horn of the left lateral ventricle were consistent with ventriculitis (Fig. 1). A medical workup into the source is summarized in Table 1.

Sagittal (left) and axial (right) postcontrast T1-weighted MRI sequences demonstrating the cervical abscess. The axial section was selected at the level where an ultrasound-guided needle was placed orthogonally through the dure into the abscess.

Upon arrival, his empirical antimicrobial coverage was expanded to cover anaerobic and fungal organisms, including vancomycin (1750 mg 3 times/day), ceftriaxone (2000 mg twice/day), metronidazole (500 mg 4 times/day), and liposomal amphotericin B (444.5 mg every day). Vancomycin and metronidazole were discontinued on hospital day 3 and 4, respectively. No improvement in the patient’s cranial nerve examination, weakness, or fluctuating encephalopathy, as well as a lack of microorganism growth, prompted cranial surgery.

Cranial Surgery

The goals of surgery included CSF diversion for management of ventriculitis, catheter aspiration of the cerebral peduncle abscess, and specimen acquisition for optimal microbiological diagnosis. A small left frontal frameless stereotactic craniotomy was performed, through which we used ultrasound guidance to (1) drain 2 superficial left frontal abscesses, (2) place an antibiotic-impregnated catheter in the left cerebral peduncle abscess, and (3) place a left lateral ventricle external ventricular drain (EVD).

A total of 15 mL of liquid purulence was evacuated and sent for culture, including 9 mL from the cerebral peduncle catheter. Intrathecal vancomycin and gentamicin were placed through the EVD into the left lateral ventricle. The left lateral ventricle EVD and the midbrain abscess drain were leveled at 20 and 0 cm H₂O above the tragus, respectively.

Postoperative Course

The abscess cultures ultimately did not recover any bacteria or fungi; however, few gram-positive cocci were evident on microscopy and vancomycin was restarted. The patient had improved left hemiparesis and the midbrain drain was discontinued due to no output. He continued to have persistent fever spikes and on postoperative day (POD) 3, he developed acutely worsening left-sided weakness and new right upper extremity weakness most notable in the deltoid muscle. Emergent brain MRI demonstrated expected evolution of multifocal brain abscesses; however, MRI of the spine revealed C4–6 intramedullary abscess with associated edema from the obex to T1; this pathology correlated with the decline in neurological examination and we returned to the operating room for drainage.

Spinal Surgery

We performed C5 and C6 laminotomies and ultrasound-guided transdural needle aspiration of an intramedullary spinal cord abscess using a 14-gauge angiocatheter. Intraoperative neuromonitoring using somatosensory evoked potentials and motor evoked potentials were improved following aspiration of 2.5 mL of purulent exudate. Intraoperative neuro-ultrasound showed successful evacuation without residual abscess, which was redemonstrated on postoperative spine MRI (Fig. 2).

Preoperative (A) and postoperative (B) sagittal (left) and axial (right) postcontrast T1-weighted MRI demonstrating successful drainage of the intramedullary abscess resulting in a small T1 contrast-enhancing lesion.

Postoperative Course

Universal 16S RNA polymerase chain reaction (PCR) analysis identified, as a sole detectable pathogen, Streptococcus intermedius, and allowed for better tailoring of the antimicrobial regimen. The turnaround time for the positive PCR identification was approximately 48 hours. The patient became afebrile following cervical spine abscess drainage on POD 4. The patient had slow improvement in neurological function with persistent weakness and hyperreflexia. The EVD was ultimately weaned without replacement. Flow cytometry was negative for chronic granulomatous disease. CSF and blood cultures remained negative throughout admission. The expected evolution of multifocal CNS abscesses continued with radiographic lag, and dexamethasone (10 mg once followed by 4 mg every 6 hours) was added on hospital day (HD) 16 to his medical regimen, leading to significant improvement in neurological function. He was transferred to acute inpatient rehabilitation on HD 19, improved significantly, and ultimately discharged on HD 48.

Upon completing 80 days of intravenous vancomycin, his antimicrobial therapy was converted to oral linezolid, which he received for an additional 4 weeks. At follow-up 6 months after diagnosis, he had no residual neurological deficits and normal gait and mobility. Neuroimaging demonstrates only minimal persistent enhancement of spinal cord abscesses and complete resolution of brain abscesses (Fig. 3).

(A) Postoperative postcontrast T1-weighted MRI demonstrating minimal residual enhancement of the cervical cord. (B) Preoperative (left) and postoperative (right) axial postcontrast T1-weighted MRI demonstrating complete resolution of brain abscesses with resultant gliotic scars.

Immunological and Genetic Findings

Upon initial immunological evaluation (HD 11), he was found to have a low complement total (total hemolytic, complement 50 [CH50] level 83, reference range 101–300). This normalized at 2-month follow-up (CH50 level 120). On initial evaluation, he had normal immunoglobulin (Ig) A (IgA; 218 mg/dL; reference range 60–400), IgG (826 mg/dL; reference range 700–1,500), IgM (80 mg/dL; reference range 60–300), IgE (18 kU/L; reference range 2–114), and mannose binding lectin (2574 ng/mL; normal ≥ 51) levels. He had neither neutrophil oxidative burst deficiency nor a T-cell function deficiency. He also underwent formal genetics evaluation, and no underlying genetic predispositions were found.

Observations

Here, we present a rare case of concomitant intramedullary spinal cord and multifocal brain abscess formation. Acute-onset tetraparesis led to identification of a large C4–5 intramedullary abscess. Emergent laminotomy with transdural ultrasound-guided needle drainage was performed with improvement in neurological symptoms.

Intraparenchymal brain and intramedullary spine abscesses generally occur in isolation. There are only a handful of pediatric cases reported with multifocal brain abscesses with coincident intramedullary spinal cord abscess, and these are secondary to brucellosis, tuberculosis, and Bacteroides.^9,12–14

Dermal sinus tracts represent the most common cause of isolated spinal cord abscess, while hematogenous spread and cardiopulmonary pathology are more common in multifocal lesions.¹⁵ The patient’s infectious workup revealed S. intermedius exclusively by 16S RNA PCR, supporting his arguably classical imaging findings.^16–19 Universal PCR can screen for a broad range of bacterial, fungal, and mycobacterial targets, and discounted the presence of other pathogens and the possibility of a polymicrobial process. Other published case studies suggest that S. intermedius alone can cause severe CNS infections in addition to deep tissue infections, even in otherwise healthy individuals without immunocompromise.^17–19

Limitations

This single case study adds to the neurosurgical literature but is not the sole evidence for management of concomitant spinal cord and brain abscess. The article highlights the importance of iterative and frequent full neurological examinations and presents the feasibility of this minimal-access neurosurgical treatment approach. It is hoped that this allows others to compare their findings when presented with a similar case and expand the current literature.

Lessons

A detailed neurological examination must be performed in patients presenting with multifocal brain abscesses, and any signs of symptoms unexplained by cranial imaging should warrant strong consideration for complete neuroaxis imaging. In the case of spinal cord or brain stem abscesses, given the small area of highly eloquent tissue, one should consider early drainage given the natural history of these lesions to slightly enlarge as they evolve despite antibiotics.^20,21 In our patient, acute tetraparesis was unexplained by his brain MRI, prompting radiographic evaluation of his spinal cord and subsequent aspiration.

Intraparenchymal and intramedullary abscesses are rarely present simultaneously. In these cases, the neurological examination is complicated by multifactorial etiologies, including perilesional edema, ventriculitis, seizures, and encephalopathy. Alternative surgical strategies involve complete extirpation or open drainage of abscesses; both of these approaches have the potential to cause severe corridor-associated morbidity. This case report demonstrates why unexpected neurological deficits should prompt further imaging and, in this case, led to needle drainage of a spine abscess. Needle- and ultrasound-guided catheter drainage of CNS abscesses should be considered for symptomatic lesions. Testing via 16S RNA broad-range PCR sequencing can increase the potential for pathogen detection and provide an opportunity to tailor medical therapy.