Multifocal intracranial aneurysms and a clinical diagnosis of ruptured retinal arterial macroaneurysm in presumed hepatitis B-associated polyarteritis nodosa: A case report

Abstract

Polyarteritis nodosa (PAN) is a necrotizing medium-artery vasculitis; intracranial aneurysms are rare. A woman in her early thirties with hypertension and hepatitis B surface antigen (HBsAg) positivity presented with thunderclap headache, vomiting, and blurred vision. Available records described intracranial hemorrhage associated with a right posterior cerebral artery (PCA) aneurysm, but the index computed tomography/angiography images and full report were unavailable to classify the hemorrhage. The aneurysm was coil embolized with intentional parent-vessel sacrifice. Subsequent magnetic resonance imaging showed right occipitotemporal and thalamic infarction with hemorrhagic transformation—an expected consequence of right PCA sacrifice. A small acute left caudate infarct outside the treated territory raised a separate multifocal or embolic mechanism. Time-of-flight magnetic resonance angiography showed the partially occluded right P2p/P3 PCA aneurysm and 2 distal left internal carotid artery aneurysms. During the same admission, subhyaloid and intraretinal hemorrhage led to a clinical diagnosis of ruptured retinal arterial macroaneurysm; no fundus photograph, fluorescein angiogram, or optical coherence tomography angiography was available, and follow-up structural optical coherence tomography did not show the lesion. Elevated inflammatory markers, neuropathic symptoms, multifocal aneurysms, and HBsAg positivity led rheumatology to a working diagnosis of HBV-associated PAN. Because no biopsy or visceral angiography was performed and accepted classification criteria were not securely met, the diagnosis is described as presumed. The teaching point is attribution: the dominant stroke was iatrogenic; the contralateral infarct and multifocal aneurysms prompted systemic evaluation; ocular hemorrhage may be a clue but does not establish shared vasculitic causation.

Introduction

Polyarteritis nodosa (PAN) is a necrotizing arteritis of medium or small arteries without glomerulonephritis or vasculitis of arterioles, capillaries, or venules [1,2]. Arterial wall injury may produce stenosis, thrombosis, aneurysm formation, and downstream ischemia [1,3]. Central nervous system involvement is uncommon, and intracranial aneurysms are rare compared with the better-recognized visceral arterial abnormalities [4,5].

Hepatitis B virus (HBV) can be associated with classic PAN, but hepatitis B surface antigen (HBsAg) positivity alone is supportive rather than confirmatory; diagnosis requires clinicopathologic or angiographic correlation and exclusion of mimics [2,6,7]. This distinction is particularly important when the observed aneurysms are saccular intracranial lesions, which are compatible with but not specific for PAN.

We describe multifocal intracranial aneurysms, a small infarct outside the treated vascular territory, and a clinical diagnosis of ruptured retinal arterial macroaneurysm (RAM) in a patient given a working diagnosis of HBV-associated PAN. To our knowledge, reviews of neurologic PAN, intracranial aneurysms in PAN, and ocular vasculitis have not described this exact constellation [4,5,8]. The novelty is the concurrent clinical association; the available evidence does not prove a common vasculitic mechanism.

Case presentation

A woman in her early thirties with systemic hypertension presented in April 2021 with thunderclap headache, vomiting, and blurred vision. The original index computed tomography (CT) and CT angiography images and the complete radiology report were not available among the records supplied for retrospective review. Contemporaneous documentation described intracranial hemorrhage associated with a saccular right posterior cerebral artery (PCA) aneurysm, but did not specify whether the hemorrhage was subarachnoid or intraparenchymal or record its precise distribution. The index hemorrhage therefore cannot be further classified or illustrated from the available material. She underwent endovascular coil embolization of the right PCA aneurysm with intentional parent-vessel sacrifice.

Within days of embolization, a magnetic resonance imaging (MRI) stroke protocol demonstrated acute infarction of the right occipitotemporal region (approximately 8.2 × 3.8 × 5.0 cm) and posterior right thalamus (approximately 1.5 × 1.2 × 1.4 cm) (Fig. 1D–F). Because both lesions lie within branches of the deliberately sacrificed right PCA, they are attributed primarily to the procedure and represent an expected ischemic consequence of parent-vessel occlusion, rather than independent evidence of vasculitic or embolic stroke. Susceptibility-weighted imaging showed hemorrhagic transformation within the right occipitotemporal and thalamic infarcts, with mild local mass effect and no midline shift or herniation. A separate acute infarct in the body of the left caudate nucleus (approximately 0.8 × 0.7 × 1.2 cm) was outside the treated territory. This contralateral lesion raised a distinct multifocal vascular process, although a peri-procedural embolus could not be excluded.

Fig. 1.

Postembolization intracranial and brain magnetic resonance imaging. Axial 3-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) at the level of the posterior cerebral arteries (A) and sagittal maximum-intensity-projection reconstruction (C) show the partially occluded 6.5 × 4.0-mm aneurysm of the P2p/P3 segment of the right posterior cerebral artery (PCA) (white arrow in each panel). In (B), 2 white arrows identify the 2 patent distal left internal carotid artery aneurysms, distal to the left posterior communicating artery. Axial diffusion-weighted imaging (D), corresponding apparent diffusion coefficient map (E), and fluid-attenuated inversion recovery imaging (F) show the dominant right occipitotemporal infarct and smaller posterior right thalamic infarct (2 white arrows in each panel). These right PCA-territory infarcts are the expected downstream consequence of intentional parent-vessel sacrifice. Hemorrhagic transformation was identified on susceptibility-weighted imaging, which is not included in this composite. The small left caudate infarct described in the text lies outside the treated territory but is not separately depicted in this figure.

Post-embolization 3-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) demonstrated a slightly smaller caliber right PCA than the left without abrupt cutoff. Axial source images and sagittal maximum-intensity-projection reconstruction showed a partially occluded saccular aneurysm of the right P2p/P3 PCA segment measuring approximately 6.5 × 4.0 mm with a 1.5-mm neck (Fig. 1A and C). Two additional patent saccular aneurysms arose from the distal left internal carotid artery (ICA), distal to the left posterior communicating artery, measuring approximately 4.3 × 3.0 mm and 3.5 × 3.0 mm and separated by approximately 3.5 mm (Fig. 1B). No anterior-circulation stenosis or occlusion was identified.

During the same admission, the patient reported new visual difficulty and bilateral lower-limb pain that was clinically interpreted as neuropathic. Ophthalmic examination documented markedly reduced right-eye visual acuity, macular subhyaloid hemorrhage, and scattered intraretinal hemorrhages; the left fundus was unremarkable. These findings led to a clinical diagnosis of ruptured RAM and conservative management. No fundus photograph, fluorescein angiogram, or optical coherence tomography angiography image was available in the submitted record to confirm or localize the macroaneurysm. Figure 3 is a later structural OCT study and does not demonstrate the RAM or the acute subhyaloid hemorrhage.

Fig. 3.

Structural optical coherence tomography (OCT) of the right (A) and left (B) maculae at follow-up. The white arrow in (A) identifies premacular membrane/internal limiting membrane separation; no macular atrophy is present. The left macula (B) is unremarkable. This follow-up structural OCT does not demonstrate the clinically diagnosed retinal arterial macroaneurysm or the acute subhyaloid hemorrhage.

Systemic evaluation showed an erythrocyte sedimentation rate of 51 mm/h, C-reactive protein of 20–29 mg/L, and HBsAg positivity. Recorded screening included negative antinuclear antibodies and negative hepatitis C and human immunodeficiency virus tests. No tissue biopsy or visceral angiography was performed during the acute admission, and the available record did not document a specific reason for biopsy omission. On the combined clinical, laboratory, and vascular imaging findings, rheumatology made a working diagnosis of HBV-associated PAN. Treatment comprised pulse intravenous methylprednisolone followed by high-dose oral corticosteroids and azathioprine, with hepatology-directed antiviral management.

By July 2021, central visual acuity had recovered to 6/6 in each eye. Humphrey 24-2 automated perimetry showed a persistent congruous left homonymous hemianopic defect (Fig. 2), consistent with the right occipital infarct. Structural OCT showed no macular atrophy; the right eye had premacular membrane/internal limiting membrane separation, and the left macula was unremarkable (Fig. 3).

Fig. 2.

Humphrey 24-2 visual fields of the right (A) and left (B) eyes. The white arrow in each panel points to dense left hemifield loss, together demonstrating a congruous left homonymous hemianopic defect consistent with the right occipital infarct.

Discussion

This case is most appropriately interpreted as multifocal intracranial aneurysms with a clinically inferred systemic vasculopathy, rather than as proof that every neuro-ophthalmic finding resulted from PAN. Intracranial aneurysms and hemorrhage have been reported in PAN, often with multiple lesions, but remain uncommon [4,5]. Saccular morphology and multiplicity are compatible with PAN yet are not pathognomonic, particularly without visceral angiography or tissue confirmation.

Diagnostic confidence is limited when the case is mapped to accepted frameworks. The 1990 American College of Rheumatology classification scheme requires at least 3 of 10 items [6]. HBsAg positivity is the only item securely documented here. A history of hypertension was recorded, but a diastolic pressure greater than 90 mm Hg was not supplied; lower-limb pain was considered neuropathic, but mononeuropathy or polyneuropathy was not objectively documented; and the cerebral aneurysms do not satisfy the criterion of a visceral arteriographic abnormality. No biopsy was performed. The 2012 Chapel Hill Consensus Conference definition is a nomenclature framework—necrotizing arteritis of medium or small arteries without glomerulonephritis or small-vessel vasculitis—not a diagnostic score [2]. Evidence on diagnostic test accuracy in PAN is limited [9]. Thus, the available data do not securely meet a classification threshold. The combination of inflammatory marker elevation, clinically interpreted neuropathic symptoms, multifocal aneurysms, and HBsAg positivity led the treating rheumatology team to presume HBV-associated PAN; HBsAg positivity supports but does not confirm that attribution [7].

The dominant right occipitotemporal and thalamic infarction should be separated etiologically from the systemic diagnosis. It occurred after deliberate right PCA parent-vessel sacrifice, involves the expected downstream territory, and is therefore attributed primarily to the intervention. The small left caudate infarct is the lesion outside the treated territory that supports a multifocal process. Even that lesion is not specific for vasculitis because peri-procedural embolism remains a plausible alternative.

Other aneurysmal vasculopathies were considered but cannot be conclusively excluded from the available record. Infectious (mycotic) aneurysms were not supported by a documented infectious source, but blood-culture and echocardiographic results were not supplied [10,11]. A connective-tissue disorder was less favored by the negative antinuclear antibody result and absence of a documented syndromic phenotype, although no targeted genetic or connective-tissue evaluation was recorded. Segmental arterial mediolysis is a noninflammatory medium-artery vasculopathy that commonly produces dissection, hemorrhage, and aneurysms; the inflammatory findings and HBV context favored PAN clinically, but the absence of visceral angiography and histology prevents definitive exclusion [12]. Primary or hypertension-associated intracranial aneurysms therefore also remain possible.

RAM is an acquired focal retinal arteriolar dilatation associated particularly with systemic hypertension and may present with subhyaloid or intraretinal hemorrhage and sudden visual loss [[13], [14], [15]]. The clinical ophthalmic pattern in this case was compatible with rupture, and the hemorrhage resolved with observation. However, no fundus photograph, fluorescein angiogram, or OCT angiography image was available to demonstrate the lesion. Moreover, hypertension provides an independent conventional explanation. The RAM should therefore be treated as a clinical diagnosis and a possible concurrent clue, not as established retinal involvement by PAN. The follow-up structural OCT in Figure 3 does not show the macroaneurysm.

Published reviews describe neurologic PAN and intracranial aneurysms, and ocular reviews describe a range of vasculitic manifestations [4,5,8]. To our knowledge, the concurrence of multiple intracranial aneurysms and a clinically diagnosed ruptured RAM in presumed HBV-associated PAN has not previously been reported. This novelty claim concerns the observed association and should not be interpreted as proof of shared causation.

The congruous left homonymous hemianopic defect localizes to the right retrogeniculate visual pathway and is concordant with the right occipital infarct (Fig. 2). Retinal nerve fiber layer or ganglion-cell thinning can emerge later through retrograde trans-synaptic degeneration after post-geniculate injury; serial OCT may provide a complementary structure–function measure [[16], [17], [18], [19]].

This report has several limitations. It describes 1 patient and cannot establish causality. PAN was diagnosed clinically without tissue confirmation or visceral angiography, and the available data do not securely satisfy the 1990 classification threshold. The index CT/CT angiography images and complete report were unavailable, so the presenting hemorrhage pattern and aneurysm appearance could not be independently reviewed or illustrated. No fundus photograph, fluorescein angiogram, or OCT angiography documented the RAM. The dominant right PCA-territory infarction is confounded by—and is most directly attributable to—intentional parent-vessel sacrifice; the contralateral caudate infarct could also have been peri-procedural. Finally, the recorded work-up was insufficient to exclude all infectious, heritable, and noninflammatory arteriopathies (Table 1).

Table 1.

Clinical timeline.

Time	Key events and imaging findings
April 2021—presentation	Thunderclap headache, vomiting, and blurred vision. Available documentation recorded intracranial hemorrhage associated with a saccular right PCA aneurysm; the index CT/CT angiography images and complete report were unavailable, so the hemorrhage compartment and distribution could not be verified
April 2021—treatment	Endovascular coil embolization of the right PCA aneurysm with intentional parent-vessel sacrifice
Late April 2021—post-procedure imaging	MRI showed right occipitotemporal and posterior thalamic infarction with hemorrhagic transformation, attributed primarily to intentional right PCA sacrifice. A small acute left caudate infarct outside the treated territory raised a separate multifocal or peri-procedural embolic mechanism. TOF-MRA showed the partially occluded right P2p/P3 PCA aneurysm and 2 distal left ICA aneurysms (Fig. 1)
Same admission—ophthalmic assessment	Macular subhyaloid and intraretinal hemorrhage led to a clinical diagnosis of ruptured RAM. No fundus photograph, fluorescein angiogram, or OCT angiography was available to demonstrate the RAM
May 2021—systemic evaluation	Inflammatory markers were elevated and HBsAg was positive. Without biopsy or visceral angiography, rheumatology made a working diagnosis of HBV-associated PAN and initiated immunosuppressive therapy with hepatology-directed antiviral management
July 2021—follow-up	Visual acuity was 6/6 in each eye. Automated perimetry showed persistent congruous left homonymous hemianopia (Fig. 2). Structural OCT showed no macular atrophy and did not demonstrate the RAM (Fig. 3)

Conclusion

Multifocal intracranial aneurysms and an infarct outside a treated vascular territory in a young patient warrant evaluation for systemic and infectious arteriopathies. In this case, the right PCA-territory infarction was an expected consequence of parent-vessel sacrifice, while the left caudate infarct and additional left ICA aneurysms prompted broader evaluation. HBsAg positivity and inflammatory findings supported a presumed, not confirmed, diagnosis of HBV-associated PAN. Concurrent ocular hemorrhage may offer a clinical clue, but without confirmatory retinal imaging it cannot establish a shared vasculitic mechanism.

Ethics approval

Formal institutional ethics committee approval was obtained for this single-patient case report.

Author contributions

Alain Mbongo: Conceptualization, data curation, writing—original draft. Fred Otieno: Clinical care, laboratory/clinical correlation, writing—review and editing. Jacquiline Mavuti: Imaging interpretation, writing—review and editing. Jabir Mohamed: Clinical care, writing—review and editing. Edwin Mogere: Supervision, project administration, writing—review and editing. All authors approved the final manuscript.

Declaration of generative AI and AI-assisted technologies in the manuscript preparation process

During preparation of this work, the authors used ChatGPT (OpenAI) for language polishing and manuscript organization. The authors subsequently reviewed and edited the content and take full responsibility for the content of the article.

Patient consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.