Abstract

BackgroundBrain abscesses often present with headache, altered state of consciousness, and/or fever. Depending on their location, they may present with other clinical manifestations. Gerstmann syndrome, characterized by acalculia, agraphia, digital agnosia, and right-left confusion, occurs classically with lesions of the dominant parietal lobe.

Case DescriptionA 50-year-old immunocompetent female presented to the emergency department with seizures, headaches, and visual hallucinations. Brain magnetic resonance imaging revealed a right space-occupying lesion causing a mass effect consistent with a brain abscess. The patient was promptly started on ceftriaxone and metronidazole, followed by successful surgical drainage of the abscess. Cultures confirmed an infection with Streptococcus intermedius. During follow-up, the patient exhibited symptoms of acalculia, agraphia, digital agnosia, and right-left confusion, consistent with Gerstmann syndrome, attributed to significant postoperative edema. Although these cognitive sequelae showed partial improvement over time, they substantially impacted the patient’s functional abilities and psychological well-being.

ConclusionGerstmann syndrome is traditionally associated with lesions in the left angular gyrus. However, in our case, the lesion was located on the right side. Interestingly, there is only one other documented case of Gerstmann syndrome linked to a brain infection in the medical literature. Furthermore, our patient presented without the typical risk factors for brain abscesses, such as immunosuppression, an identifiable infectious source, or epidemiological connections commonly associated with this pathogen. This case highlights a rare and impactful condition, significantly affecting the patient’s quality of life while also contributing valuable insights to the understanding of this uncommon neurological syndrome.

Keywords: Brain abscess, Case report, Focal epilepsy, Gerstmann syndrome, Streptococcus intermedius

INTRODUCTION

Brain abscesses have an incidence of 0.4–0.9 cases/100,000 people and can be caused by bacteria, mycobacteria, fungi, or parasites. Their clinical presentation is often nonspecific, with common symptoms including headache, altered consciousness, and fever. However, depending on the location of the abscess, symptoms can vary – such as behavioral changes often observed in abscesses affecting the frontal lobe.[ 3 ]

Gerstmann syndrome is a rare neurological disorder marked by four key symptoms: acalculia, agraphia, digital agnosia, and right-left confusion. While it is most associated with vascular pathologies, the syndrome typically results from damage to the dominant parietal lobe. However, cases involving lesions in other brain regions have also been reported.[ 2 , 8 ] We present the case of an immunocompetent patient with a brain abscess in the right parietal lobe, successfully treated with surgical drainage and antibiotic therapy. However, post-treatment, the patient developed Gerstmann syndrome as a lasting neurological sequela.

CASE DESCRIPTION

A 50-year-old, right-handed female patient, a pharmaceutical chemist and researcher, with a medical history of bipolar disorder type I (managed with valproic acid and quetiapine), antiphospholipid syndrome, and migraine, was admitted to the emergency department after being referred from another facility. She had experienced two focal-onset seizures, which evolved into tonic-clonic generalization, along with a right temporal headache and occasional visual hallucinations. Neurological examination revealed generalized hyperreflexia and bilateral extensor plantar response, with no additional abnormalities. An external cerebrospinal fluid study yielded normal results, while a brain magnetic resonance imaging (MRI) showed a right parietal corticosubcortical space-occupying lesion, suggesting differential diagnoses such as brain abscess, neurocysticercosis or an oncological mass.

Empirical antibiotic therapy was initiated with ceftriaxone and metronidazole, alongside anti-seizure management using valproic acid, levetiracetam, and lacosamide. A follow-up brain MRI revealed an increase in the lesion’s size, consistent with a brain abscess causing a significant mass effect [ Figure 1 ]. Given these findings, urgent surgery was recommended for neuronavigation-guided drainage of the intracerebral collection. The procedure was completed successfully, yielding approximately 6 cc of purulent fluid, which was sent for culture. Postoperative computed tomography (CT) imaging showed no bleeding, although persistent vasogenic edema was noted.

Figure 1:

Preoperative brain magnetic resonance imaging. (a) Non-enhanced T1 imaging showing intra-axial corticosubcortical lesion in the right parietal lobe (b) with peripheral ring enhancement after gadolinium injection. (c) The fluid-attenuated inversion recovery demonstrates a hyperintense lesion with perilesional vasogenic edema that causes a 4 mm midline shift. (d) The diffusion-weighted imaging shows diffusion restriction, consistent with a brain abscess.

The culture of the brain abscess sample, along with blood cultures, confirmed the presence of Streptococcus intermedius. The infectious disease department recommended continuing the established antibiotic therapy. Paraclinical tests revealed mild neutrophilia, normal C-reactive protein levels, negative human immunodeficiency virus, and cysticercosis antibodies, and a normal transthoracic echocardiogram. In addition, a CT scan of the paranasal sinuses showed no abnormalities. A dental evaluation did not identify any odontogenic sources of infection. Following a favorable clinical and radiological evolution postoperatively, the patient was discharged with anti-seizure medication, home hospitalization to complete 42 days of antibiotic therapy, and referrals for physical and occupational therapy.

During the monthly follow-up appointment, the patient reported experiencing three seizure episodes, along with dyscalculia and agraphia, which were confirmed during the neurological examination. In addition, she exhibited signs of digital agnosia and right-left confusion, consistent with Gerstman syndrome. The patient also experienced a single episode of right facial asymmetry accompanied by a self-limiting speech arrest. A follow-up brain MRI revealed a significant reduction in the size of the abscess, although persistent vasogenic edema was observed, leading to midline deviation [ Figure 2 ]. Given that surgical intervention was not indicated, the dose of valproic acid was increased, and dexamethasone was prescribed for 1 week.

Figure 2:

1-month postoperative magnetic resonance imaging. (a) Non-enhanced T1, (b) contrast-enhanced T1, (c) fluid-attenuated inversion recovery, and (d) diffusion-weighted imaging sequences demonstrated a decrease in the size of the brain abscess, although there was an increase in perilesional edema, mass effect, and midline shift of approximately 7 mm.

Three months later, a follow-up brain MRI revealed a significant reduction in edema and mass effect [ Figure 3 ]. The patient reported improvements in dyscalculia, agraphia, finger agnosia, and right-left confusion, as confirmed by neuropsychological assessments. A video-electroencephalogram was performed and showed no epileptiform discharges or focal neurologic signs. Paroxysmal events were noted without any abnormalities in the tracing. However, the neurological sequelae continued to impact her functionality and work role, leading to the development of a depressive episode, which was managed through psychiatric care and psychotherapy.

Figure 3:

6-month postoperative magnetic resonance imaging. (a) Fluid-attenuated inversion recovery and (b) contrast-enhanced T1 imaging demonstrate a significant reduction in the size of the brain abscess and a reduction in the perilesional edema, with gliosis and no mass effect.

DISCUSSION

Gerstmann syndrome, first described in 1924, is primarily recognized as a vascular condition, with an occurrence rate of approximately 1% in some studies.[ 2 ] Cases have also been reported as secondary to various conditions, including tumors, multiple sclerosis, progressive multifocal leukoencephalopathy, systemic lupus erythematosus, and mucormycosis. In addition, the syndrome can be induced by cortical stimulation or occur iatrogenically during cerebral angiographies.[ 1 ]

Gerstmann syndrome is thought to arise from lesions in the dominant parietal lobe, typically the left lobe in most individuals, particularly in the angular gyrus with subcortical extension. However, there is controversy regarding the exact localization of this syndrome. There are reports of unexpected localization of this clinical presentation, including subangular and middle frontal gyrus lesions.[ 2 , 8 ] There is only another case report of a 57-year-old ambidextrous man with a right corticosubcortical parietal hemorrhage due to a ruptured arteriovenous malformation with a complete tetrad of Gerstmann syndrome.[ 7 ] The exact pathophysiology of Gerstmann syndrome remains unclear, but two theories have been proposed: first, it may be considered a disconnection syndrome where the corticosubcortical association fibers are disrupted; second, it may involve a dysfunction in the verbal ability to articulate spatial knowledge related to body image.[ 2 ] In our reported case, we suspect that the syndrome may be linked to perilesional edema, which could disrupt the functionality of the surrounding nerve fibers. This aligns with the proposal to conceptualize Gerstmann syndrome as a disconnection syndrome.[ 10 ]

The clinical manifestations of brain abscesses can vary significantly based on their location. For instance, behavioral changes may arise from abscesses situated in the frontal lobe, while cranial nerve palsies can occur with brainstem abscesses and gait disorders may be seen with cerebellar abscesses. Seizures are reported in approximately one-fourth of patients. Brain abscesses often develop in individuals with predisposing factors, such as immunosuppression, damage to the brain’s protective barriers, or underlying para meningeal or systemic infections. Notably, in up to one-third of patients, no identifiable mechanisms facilitating the formation of abscesses can be determined.[ 3 ] Regarding etiology, it has been reported that S. intermedius is identified in isolation in up to 80% of brain abscesses, as in our patients.[ 6 ]

This microorganism is commonly found in dogs and cats and is recognized as a zoonotic pathogen in reported human infections. Interestingly, in 21% of cases, there was no association between animal exposure and the isolation of this pathogen, suggesting that humans may also act as carriers of this microorganism.[ 9 ] Odontogenic and paranasal sinus infections are the primary risk factors linked to this bacterium; however, these sources were ruled out in our patient. Although no formal recommendations exist regarding antibiotic therapy, studies have demonstrated a favorable response to a combined treatment of ceftriaxone and metronidazole over 6 weeks, which aligns with our case.[ 4 ]

The literature contains only one other case of a brain abscess located in the left parietal lobe that presented with Gerstmann syndrome. In that case, the syndrome was not isolated; it was accompanied by paresthesia, apalesthesia, kinetic apraxia in the right extremities, and ipsilateral hemiparesis that progressed to hemiplegia. The patient underwent stereotactic surgery for decompression and biopsy, which confirmed a diagnosis of tuberculous brain abscess. Although the patient experienced significant clinical improvement, he did not achieve complete remission, necessitating multimodal rehabilitation, a path also followed by our patient.[ 5 ]

CONCLUSION

This case highlights a rare clinical presentation in an immunocompetent patient with a parietal lobe brain abscess that resulted in Gerstmann syndrome as a neurological sequela. Although the patient experienced a partial and favorable recovery from the neurological effects, the impact on her functionality was significant. This report adds to the growing body of literature on this neurological condition, which continues to be a subject of controversy.

Ethical approval

The Institutional Review Board approval is not required.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript, and no images were manipulated using AI.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

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