Occipital Nocardia Abscess Presenting With Positive Visual Phenomenon and Quadrantanopsia

A 74-year-old man with chronic obstructive pulmonary disease, glaucoma, and Stage IIIB squamous cell lung cancer experienced several minutes of flashing lights in his right visual hemifield, followed by onset of a right visual field defect. On examination, the patient had a right homonymous hemianopsia that was most dense inferiorly by confrontation testing. Emergent CT scan of the head revealed a 2.5 × 3 cm hypodensity in the left occipital lobe, which was interpreted as an acute stroke. Continuous EEG monitoring captured left posterior quadrant seizures that were temporally correlated to the positive visual phenomena. Subsequent MRI of the brain with and without contrast revealed a conglomerate of centrally necrotic and peripherally enhancing mass lesions. On biopsy, a thick purulent material was drained and Gram stain of the sample revealed gram-positive beaded rods, which speciated to Nocardia farcinica . The patient was treated with a six-week course of intravenous meropenem and a one-year course of oral trimethroprim-sulfamethoxazole. On follow-up, the patient experienced resolution of the right visual field deficit.

Clinical-Pathological Case Study Section Editors: Daniel R. Gold, DO Marc Levin, MD, PhD Occipital Nocardia Abscess Presenting With Positive Visual Phenomenon and Quadrantanopsia Alexander S. Fein, MD, Sean M. Kelly, MD, PhD, Eddie Louie, MD, Matthew G. Young, DO, Rajan Jain, MD, Christopher M. William, MD, PhD, Steven L. Galetta, MD, Scott N. Grossman, MD Abstract: A 74-year-old man with chronic obstructive pulmonary disease, glaucoma, and Stage IIIB squamous cell lung cancer experienced several minutes of flashing lights in his right visual hemifield, followed by onset of a right visual field defect. On examination, the patient had a right homonymous hemianopsia that was most dense inferiorly by confrontation testing. Emergent CT scan of the head revealed a 2.5 · 3 cm hypodensity in the left occipital lobe, which was interpreted as an acute stroke. Continuous EEG monitoring captured left posterior quadrant seizures that were temporally correlated to the positive visual phenomena. Subsequent MRI of the brain with and without contrast revealed a conglomerate of centrally necrotic and peripherally enhancing mass lesions. On biopsy, a thick purulent material was drained and Gram stain of the sample revealed gram-positive beaded rods, which speciated to Nocardia farcinica. The patient was treated with a six-week course of intravenous meropenem and a one-year course of oral trimethroprim–sulfamethoxazole. On follow-up, the patient experienced resolution of the right visual field deficit. Journal of Neuro-Ophthalmology 2023;43:430–433 doi: 10.1097/WNO.0000000000001938 © 2023 by North American Neuro-Ophthalmology Society venous thrombosis on apixaban presented to his ophthalmologist after experiencing acute onset of flashing lights in his right visual hemifield lasting few minutes. These visual hallucinations were followed by onset of a right visual field defect, with a tendency to bump into objects on his right side. Confrontational visual field testing in the office revealed a right homonymous hemianopsia, and so he was directed to the emergency room for evaluation. A noncontrast head CT, CT angiography, and CT perfusion were obtained. Radiology (Dr. Young and Dr. Jain) Noncontrast head CT revealed a hypodensity in the medial left occipital lobe involving the cuneus (Fig. 1), with mild local mass effect. In this clinical setting, these findings were concerning for an acute to early subacute infarct involving the left posterior cerebral artery territory. CTA of the head and neck showed no large vessel occlusion or high-grade stenosis. CT perfusion did not reveal a core infarct or ischemic penumbra. Dr. Fein and Dr. Grossman Dr. Fein and Dr. Grossman A 74-year-old man with a history of chronic obstructive pulmonary disease on chronic corticosteroid therapy, Stage IIIB squamous cell lung cancer (treated with chemotherapy and radiation in 2014, with recurrence in 2019 status post further radiation and left pneumonectomy, with recent radiation treatment for recurrent lung nodules), and deep Department of Neurology (ASF, SMK, SLG, SNG), New York University Grossman School of Medicine, New York, New York; Division of Infectious Diseases (EL), Department of Medicine, New York University Grossman School of Medicine, New York, New York; and Departments of Radiology (MGY, RJ) and Department of Pathology (CMW), New York University Grossman School of Medicine, New York, New York. The authors report no conflicts of interest. Address correspondence to Scott N. Grossman, MD, NYU Grossman School of Medicine, 222 East 41st Street, 15th Floor, New York, NY 10017; E-mail: [e-mail] 430 Intravenous tPA was not administered because the patient was on therapeutic anticoagulation for a prior deep venous thrombosis. The patient was admitted to the inpatient stroke service for further workup and management of his stroke. Given that his initial symptom involved positive visual phenomena, continuous EEG monitoring was obtained to evaluate for seizure. The following day, a left posterior quadrant seizure was captured on EEG while the patient was experiencing recurrence of the same right-sided flashing lights that initially led him to seek evaluation (Fig. 2). Levetiracetam was initiated for seizure prevention, and EEG over the following 24 hours showed seizure freedom. An MRI of the brain with and without contrast was obtained. Radiology (Dr. Young and Dr. Jain) The MRI of the brain revealed a peripheral thin rimenhancing lesion with a central necrotic region showing restricted diffusion and mild-to-moderate surrounding vasogenic edema (Fig. 3). Imaging findings were most Fein et al: J Neuro-Ophthalmol 2023; 43: 430-433 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study Dr. Fein and Dr. Grossman Given the uncertainty of diagnosis, neurosurgery was consulted and a biopsy of the lesion was obtained for diagnostic clarity. Intraoperatively, there was thick, purulent material within the lesion. Gram stain of the sample revealed gram-positive beaded rods, which later speciated to Nocardia farcinica on culture. No malignancy was observed on pathologic examination. The patient was treated with a six-week course of intravenous meropenem, followed by a yearlong course of oral trimethoprim– sulfamethoxazole. On neuro-ophthalmic follow-up, he had resolution of his right visual hemifield defect. Although he initially experienced release hallucinations of animals and people, these also recovered over the course of weeks without further intervention. Pathology (Dr. William) The tissue received consisted of multiple fragments of brain with reactive gliosis, microglial activation, and scant perivascular lymphohistiocytic inflammation, likely representing tissue adjacent to the infection (Fig. 4). FIG. 1. Computed topography of the head without contrast showing a relatively well-defined hypodensity in the medial left occipital lobe, concerning for an acute to early subacute infarct considering the clinical history, although other infectious or neoplastic etiologies are not completely excluded. consistent with a pyogenic abscess, although the differential diagnosis included metastatic disease considering the history of lung cancer. Final Diagnosis N. farcinica abscess causing occipital lobe seizure and homonymous hemianopsia. Dr. Fein and Dr. Grossman Our patient presented numerous clinical dilemmas. His initial CT scan was read as consistent with acute infarction, FIG. 2. Continuous EEG monitoring revealed left posterior quadrant rhythmic delta activity correlating with the patient’s positive visual symptoms of flashing lights. Fein et al: J Neuro-Ophthalmol 2023; 43: 430-433 431 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study FIG. 3. MRI of the brain with contrast showing a peripheral thin rim-enhancing necrotic lesion in the medial left occipital lobe. The central necrotic portion of the rim-enhancing lesion showing restricted diffusion and with associated surrounding mild-tomoderate vasogenic edema. Peripheral enhancement of the lesion shows smooth internal margin as well as small adjacent daughter lesions coalescing with the larger lesion. Imaging findings were most consistent with a pyogenic abscess, although the differential diagnosis included metastatic disease considering the history of lung cancer. which would adequately explain his acute right-sided homonymous visual loss. Transient positive visual disturbances are often related to migrainous phenomena, but as our patient demonstrates, seizures and ischemia are other important considerations, especially when symptoms are side-locked. The evolution and persistence of the hemifield defect after the flashing lights had resolved supports the presence of an underlying structural abnormality. MR FIG. 4. Brain biopsy. A–B. Hematoxylin and eosin–stained sections demonstrate mildly hypercellular brain with reactive astrocytes (arrows, B) (·200 magnification for A, ·400 magnification for B). C. A GFAP immunostain highlights reactive astrocytes (·400 magnification). D. A CD163 immunostain highlights perivascular macrophages (arrows) and activated microglia (arrowheads) (·400 magnification). D–E. Rare T cells (D) and B cells (E) are highlighted on CD3 and CD20 immunostains, respectively (·400 magnification). Scale bar in each image = 100 mm. 432 Fein et al: J Neuro-Ophthalmol 2023; 43: 430-433 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Clinical-Pathological Case Study imaging confirmed a peripherally enhancing mass lesion; given the patient’s history of lung cancer, this was initially concerning for metastasis. However, the presence of restricted diffusion within the necrotic center was more suggestive of abscess. The classic symptoms of brain abscess include headache (69%), fever (53%), and focal neurologic deficits (48%); however, the full triad of symptoms are present together in only approximately 20% of cases.1 The patient was afebrile and was not experiencing headache at the time of presentation, and thus, biopsy was pursued for further clarification. Abscesses typically arise through direct extension from nearby infectious sources (e.g., from dental procedures, mastoiditis), hematogenous spread from distant sources, or direct inoculation (i.e., head trauma, surgical procedures).2,3 In cases of Nocardia abscesses, the most common source is the lung.4 Seizures are a common sequela of brain abscess, with frontal rather than occipital lesions proving more epileptogenic and with frequent delay to epilepsy diagnosis (median of 9 months after symptom onset).5 EEG coinciding with an episode of flashing lights in the right hemifield confirmed ictal activity in the left posterior hemisphere. Seizures manifesting with positive visual phenomena most commonly originate from the occipital lobes, but may localize to other regions of the brain.6 These phenomena may be broadly classified as hallucinations. Simple hallucinations are most common and are described as flashes of color or light, simple in shape. They may be static or mobile and may be seen in one or both visual fields. More complex hallucinations such as images of people or animals usually indicate involvement of the temporal lobe. Visual illusions may also result from seizures and involve an altered perception of a real stimulus.7 Common ictal illusions include distortions of size (macropsia or micropsia), color (dyschromatopsia), shape (metamorphosis), or distance (teleopsia). Images may persist (palinopsia), become wavy (dysmorphopsia), or begin moving (kinetopsia).6–8 Our patient’s initial automated visual field test at presentation did not clearly demonstrate a homonymous field defect. His binasal defects related to his glaucoma may have initially obscured the hemifield defect. Thus, his visual field at presentation showed only monocular right-sided depression in the left eye, while the right eye had losses in both nasal and temporal fields. His confrontation visual field examination more readily con- Fein et al: J Neuro-Ophthalmol 2023; 43: 430-433 firmed the hemifield defect both by finger counting and by testing with a red stimulus. In conclusion, there should be a high suspicion for brain abscess in patients with a peripherally enhancing and diffusion restricting lesion on MRI, particularly those on chronic corticosteroids. Although infarction should always be considered in patients with acute onset of focal neurologic symptoms corresponding to a vascular territory, the onset of positive visual symptoms particularly when recurrent over hours should lead to consideration of ictal activity, and further investigation into etiologies other than ischemia should be initiated. STATEMENT OF AUTHORSHIP Conception and design: A. S. Fein, S. N. Grossman, S. M. Kelly, S. L. Galetta; Acquisition of data: A. S. Fein, S. N. Grossman; Analysis and interpretation of data: A. S. Fein, S. N. Grossman, S. L. Galetta, R. Jain, M. G. Young, C. M. William, E. Louie. Drafting the manuscript: A. S. Fein, S. Grossman; Revising the manuscript for intellectual content: A. Fein, S. N. Grossman, S. L. Galetta, R. Jain, M. G. Young, C. M. William. Final approval of the completed manuscript: A. S. Fein, S. M. Kelly, S. N. Grossman, S. L. Galetta, R. Jain, M. G. Young, C. M. William, E. Louie. REFERENCES 1. Brouwer MC, van de Beek D. Epidemiology, diagnosis, and treatment of brain abscesses. Curr Opin Infect Dis. 2017;30:129–134. 2. Brouwer MC, Coutinho JM, van de Beek D. Clinical characteristics and outcome of brain abscess: systematic review and meta-analysis. Neurology. 2014;82:806–813. 3. LaPenna PA, Roos KL. Bacterial infections of the central nervous system. Semin Neurol. 2019:39;334–342. 4. LaHue SC, Guterman EL, Mikhail M, Li Y, Cha S, Richie MB. Clinical and radiographic characteristics of Nocardia vs nonnocardia brain abscesses. Neurol Clin Pract. 2023;13:e200134. 5. Bodilsen J, Duerlund LS, Mariager T, et al. Risk factors and prognosis of epilepsy following brain abscess: a nationwide population-based cohort study. Neurology. 2023;100:e1611– e1620. 6. Taylor I, Scheffer IE, Berkovic SF. Occipital epilepsies: identification of specific and newly recognized syndromes. Brain. 2003;126:753–769. 7. Kasper BS, Kasper EM, Pauli E, Stefan H. 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