Life-Threatening Orbital and Intracranial Sequelae of Odontogenic Sinusitis: 3 Complex Cases

Introduction

Odontogenic sinusitis (ODS) – starting as maxillary sinus inflammation secondary to dental pathology or procedures – is frequently underrecognized, due to overlap with rhinogenic disease and nonspecific symptoms. Contemporary reviews emphasize that ODS has distinct microbiology, radiologic patterns, and treatment pathways compared with non-odontogenic rhinosinusitis, with important implications for complications and outcomes [1–3].

ODS carries a disproportionately high risk of severe orbital and intracranial complications due to direct anatomical and pathophysiological factors [4,5]. Disruption of the maxillary sinus floor, lamina papyracea, anterior skull base, or creation of an oroantral communication (OAC) provides a low-resistance pathway for rapid extension of infection. In addition, valveless venous networks can lead to further progression and result in cavernous sinus thrombosis. Systematic and narrative reviews of complicated ODS highlight that orbital complications predominate (representing 60–70% of complicated cases), with intracranial and osseous complications comprising the remainder. Reported vision-loss rates are high when orbital abscess is present, underscoring the need for early recognition and aggressive, multidisciplinary care [4–7].

Intracranial extension from odontogenic or paranasal sources presents as epidural or subdural empyema, brain abscess, meningitis, or venous sinus thrombosis – entities associated with significant morbidity and mortality if treatment is delayed. Recent case reports and series continue to document odontogenic origins of intracranial infections, reinforcing the necessity of dental source control alongside neurosurgical and otolaryngologic intervention [8–10].

Anaerobe-rich polymicrobial infections promote aggressive spread and abscess formation, distinguishing ODS from rhinogenic sinusitis in both severity and clinical behavior [5,11,12].

Management of ODS-related orbital and intracranial complications hinges on 3 coordinated pillars: prompt broad-spectrum intravenous antibiotics with reliable anaerobic coverage, prompt surgical drainage (endoscopic sinus surgery [ESS] with maxillary antrostomy±ethmoidectomy, orbital subperiosteal or intraconal abscess drainage, and neurosurgical drainage where indicated). Definitive dental source control (endodontic therapy, apicoectomy, or extraction) is necessary. While high-quality, unified guidelines are lacking – particularly for orbital subperiosteal abscess – expert reviews and consensus statements advocate early, team-based decision-making driven by clinical status (vision, afferent pupillary defect, ophthalmoplegia), imaging, and response to initial therapy [4,5,13–15]. Recent series describe amoxicillin-clavulanate as a common oral step-down, with clindamycin plus metronidazole in β-lactam–allergic patients. However, culture-guided therapy remains essential [16,17]. The aim of this study is to describe the clinical spectrum, diagnostic approach, and management of orbital and intracranial complications of ODS through a series of 3 representative cases.

Case Reports

CASE 1:

A 23-year-old previously healthy man initially presented to the emergency department and was admitted to an infectious diseases ward with altered mental status and suspected bacterial meningitis. According to collateral history, he had experienced around 10 days of worsening headache and facial pain prior to presentation, without preceding trauma. No recent dental procedures were initially reported. Bacterial meningitis of unclear etiology had been suspected, as cerebrospinal fluid (CSF) collection showed pleocytosis (250 cells/μL). He rapidly deteriorated, requiring intensive care unit (ICU) admission, intubation, and empiric antimicrobial therapy with ceftriaxone, vancomycin, metronidazole, acyclovir, and corticosteroids. MRI demonstrated diffuse sinus opacification with early frontal and temporal lobe parenchymal involvement without a well-formed abscess, favoring urgent sinus and dental source control over neurosurgical drainage. Imaging revealed periapical pathology involving the left maxillary molars, identifying a previously unrecognized odontogenic source (Figure 1). The absence of a capsule and the patient’s rapid neurological decline supported immediate ESS combined with aggressive antimicrobial therapy, so he was transferred to the Ear-Nose-Throat (ENT) department.

Otolaryngological endoscopic examination demonstrated purulent drainage from the left nasal cavity and an OAC was suspected. Urgent ESS was performed, including left antro-ethmo-spheno-frontal sinusotomy, right antrostomy, septoplasty, and extraction of teeth 26 and 27 (left first and second maxillary molar, respectively), with evacuation of frank pus. Pus was also drained from the periapical lesion around tooth 26. Intraoperative cultures yielded Acinetobacter pittii, an opportunistic gram-negative organism increasingly reported in healthcare-associated infections and occasionally in sinonasal disease. Although not a classic oral anaerobe, its isolation in the context of clear odontogenic pathology supported polymicrobial infection with partial suppression by prior empiric therapy. As Acinetobacter pittii strains often exhibit resistance to cephalosporins, ampicillin, piperacillin, clindamycin, and sulfonamides, initial broad-spectrum antimicrobial coverage was subsequently adjusted based on susceptibility testing and switched to meropenem.

Postoperatively, the patient improved, was weaned from mechanical ventilation on day 2, and continued on targeted intravenous antibiotics. The diagnosis of ODS complicated by brain abscess and meningitis was established. Imaging follow-up was coordinated with the neurosurgery department to monitor for intracranial sequelae. The patient completely recovered after prolonged targeted antibiotic therapy for 7 weeks, with no neurological defects.

CASE 2:

A 27-year-old man first sought medical attention from his general practitioner for unilateral purulent nasal discharge and progressive frontal headache of approximately 2 weeks’ duration and was treated empirically with amoxicillin-clavulanate without clinical improvement. He subsequently presented to the emergency department with acute neurological deterioration, severe frontal headache and agitation. On admission, his state promptly worsened as he was disoriented, required intubation, and was transferred to the ICU.

MRI revealed a left frontal lobe abscess measuring 57×39×22 mm with intraventricular rupture, extensive cerebral edema, and left sigmoid sinus thrombosis. CT demonstrated bony erosion of the left ethmoid roof with complete opacification of the left maxillary sinus, ethmoids, and frontal sinus, as well as right-sided opacification of the sinus’ frontal compartment (Figure 2).

The patient underwent bilateral endoscopic sinus surgery (antrostomy, ethmoidectomy, and left-side frontal sinusotomy with extraction of tooth 17, the right second maxillary molar). Broad-spectrum antimicrobial therapy was initially administered (ceftriaxone, vancomycin, and metronidazole). This was reduced to ceftriaxone and metronidazole after a microbial susceptibility panel. Serial CSF cultures initially grew Streptococcus constellatus but later became sterile. S. constellatus, a member of the Streptococcus anginosus group, is strongly associated with abscess formation and odontogenic and sinus-derived intracranial infections.

Despite the abscess size, gradual radiological regression under antimicrobial therapy allowed neurosurgical drainage to be deferred, highlighting the role of serial imaging in guiding conservative vs surgical intracranial management.

Additional medical history obtained after surgical intervention and stabilization revealed a history of extraction of tooth 26 a month prior to the hospital admission, suggesting a potential odontogenic trigger, but the exact data on tooth disease was missing. Over subsequent weeks, he improved, was extubated, and discharged home, neurologically intact after 2 months of inpatient treatment with intravenous antibiotics.

CASE 3:

A 28-year-old man initially presented to the ophthalmology department with 3 days of progressive periorbital swelling and ocular pain. He denied visual loss, diplopia, or fever. Further evaluation revealed concurrent sinusitis symptoms with purulent secretions, post-nasal drip, and facial pain. No dental symptoms were recorded. CT, presented in Figure 3, demonstrated near-complete opacification of the left paranasal sinuses with erosion of the lamina papyracea, subperiosteal orbital phlegmon of 6 mm thickness, without intraconal extension or optic nerve compression, and a premaxillary abscess. Multiple periapical dental lesions with OAC were also identified.

The patient was admitted to the hospital, where endoscopic septoplasty with ESS was proposed, but he did not consent to surgery. Instead, he underwent extraction of teeth 25, 26, and 28 and was treated with systemic antibiotics (amoxicillin-clavulanate, clindamycin). Intraoperative cultures grew Corynebacterium durum, a commensal organism of the oral cavity, supporting a dental source of infection. Given the absence of visual compromise and the patient’s refusal of surgery, targeted oral antibiotics with anaerobic coverage were continued. In accordance with published criteria [4,18], absence of visual impairment and limited collection size supported initial conservative management after dental extraction.

He showed gradual resolution of orbital swelling without visual impairment. At follow-up, mild nasal obstruction and mucopurulent discharge persisted, but there was no progression of orbital or intracranial disease. Table 1 summarizes the clinical description of the 3 presented cases.

Discussion

This 3-patient series illustrates the breadth and severity of extrasinus complications of ODS, ranging from orbital cellulitis with subperiosteal spread to meningitis and large frontal lobe abscess with intraventricular rupture and dural venous sinus thrombosis. Several shared themes emerge that are consistent with the current literature.

ODS may masquerade as “rhinogenic” disease until complications declare themselves. Unilateral symptoms and signs, coexistent dental pathology (periapical disease, OAC), and failure of standard chronic rhinosinusitis therapy should trigger focused dental and sinus evaluation and imaging. Contemporary reviews and consensus statements emphasize that ODS requires diagnostic and therapeutic pathways distinct from non-odontogenic rhinosinusitis [2,5,17].

Moreover, orbital and intracranial spread are not rare in complicated ODS and may be vision- or life-threatening, as the lamina papyracea and anterior skull base are vulnerable conduits for spread. Recent systematic reviews indicate that orbital complications account for approximately 60–70% of complicated ODS cases, while intracranial complications such as brain abscess, meningitis, and venous sinus thrombosis represent a smaller but clinically significant proportion [4–6,18]. Mortality and permanent morbidity remain substantial when diagnosis is delayed. The favorable outcomes observed in our series align with reports emphasizing early dental and sinus source control and prolonged anaerobe-active antimicrobial therapy [4,5].

Compared with rhinogenic sinusitis, ODS is associated with a higher incidence of severe sequelae due to direct dental–sinonasal communication, frequent bony erosion, and polymicrobial anaerobic infection [1,2,5,11]. Commonly reported organisms include Prevotella, Fusobacterium, Peptostreptococcus, and members of the Streptococcus anginosus group, which are frequently isolated in complicated ODS and are strongly associated with abscess formation [5,11,19,20]. This anaerobe-rich ecology has important therapeutic implications, as empiric regimens typically used for community-acquired rhinogenic sinusitis may provide inadequate coverage.

In cases complicated by orbital or intracranial extension, expert reviews and consensus statements recommend early initiation of broad-spectrum intravenous antibiotics with reliable anaerobic and streptococcal coverage, most commonly a third-generation cephalosporin combined with metronidazole or a β-lactam/β-lactamase inhibitor regimen [4,5,13,17]. Resistance patterns reported in ODS include β-lactamase production among anaerobes and variable susceptibility of oral streptococci, reinforcing the importance of culture-directed therapy whenever feasible [11]. In the present series, microbiological findings directly influenced antimicrobial management: identification of Streptococcus constellatus – a member of the S. anginosus group – supported prolonged intravenous therapy given its established association with intracranial abscess formation [19,20]. Isolation of less typical organisms such as Acinetobacter pittii and Corynebacterium durum likely reflected polymicrobial infection with partial suppression from prior antibiotics, justifying continued broad-spectrum, anaerobe-active coverage. These observations are consistent with literature emphasizing that microbiological data, even when limited, play a critical role in guiding antimicrobial selection, duration, and de-escalation in complicated ODS [5,11,17].

Imaging is central to both diagnosis and management of ODS, particularly when orbital or intracranial complications are suspected. CT is the primary modality for identifying odontogenic sources, bony erosion of the sinus walls, lamina papyracea defects, and orbital collections, while MRI provides superior evaluation of intracranial involvement, including cerebritis, abscess formation, venous sinus thrombosis, and meningeal enhancement [12,21,22].

Current literature supports surgical intervention when imaging demonstrates well-defined abscesses, progressive disease despite appropriate antimicrobial therapy, bony erosion facilitating extrasinus spread, or clinical signs of neurological or visual compromise [4–6,13]. In orbital complications, factors favoring surgical drainage include decreased visual acuity, afferent pupillary defect, ophthalmoplegia, intraconal extension, or subperiosteal abscesses exceeding 5–10 mm in thickness, whereas selected patients with smaller collections, preserved vision, and favorable clinical response may be managed conservatively under close monitoring [6,12,21].

In intracranial disease, imaging characteristics such as abscess size, capsule formation, mass effect, ventricular rupture, and response on serial imaging guide the balance between neurosurgical intervention and conservative management [8–10,20]. In the present series, imaging findings informed individualized decision-making: early ESS was prioritized to achieve sinonasal and dental source control, while neurosurgical drainage was deferred in a patient demonstrating radiological regression under antimicrobial therapy. These cases align with contemporary recommendations that management of complicated ODS should be driven by a combination of imaging severity, clinical status, and multidisciplinary assessment rather than rigid size-based criteria alone [4,5,13,22].

All 3 presented cases received broad-spectrum, anaerobe-active intravenous therapy with subsequent de-escalation as microbiology assessment returned negative results. ESS both drains infected sinuses and improves source control. Dental intervention (endodontic therapy or extraction) is required for odontogenic foci. Case 2 underscores that even with a large frontal abscess, selected patients can improve radiologically and clinically under close neurosurgical surveillance after ESS and dental extraction. The principles of management are supported by reviews and expert consensus recommending early, multidisciplinary decision-making including otolaryngology, dentistry, and/or oral-maxillo-facial surgery, neuroradiology, neurosurgery, and ophthalmology specialists [6,13,23,24].

Evidence for anticoagulation in septic cerebral venous sinus thrombosis (CVST) is evolving and remains individualized. The main aim is to control the source of infection and provide targeted antimicrobials, with multidisciplinary discussion on anticoagulation risks-to-benefits ratio [5].

Definitive dental source control is essential in the management of ODS. However, the optimal timing relative to ESS remains debated. In the setting of complicated ODS with orbital or intracranial extension, priority should be given to prompt sinus drainage and control of life-threatening complications [2,4,5]. When immediate dental intervention is unavailable, ESS combined with broad-spectrum anaerobe-active antimicrobial therapy may be performed as an initial step, with dental treatment completed as soon as feasible. Available evidence and expert consensus suggest that while same-setting dental and sinus surgery is ideal, staged dental intervention does not appear to compromise outcomes provided that sinonasal drainage and antimicrobial therapy are promptly instituted [22–24].

Optimal management of complicated ODS requires close collaboration among otolaryngologists, dental or oral–maxillofacial surgeons, neuroradiologists, neurosurgeons, ophthalmologists, and infectious disease specialists. Otolaryngologists coordinate sinus drainage and nasal source control; dental specialists address the odontogenic focus; neuroradiology guides diagnosis and follow-up; neurosurgery evaluates intracranial involvement; ophthalmology assesses visual risk; and infectious disease specialists guide prolonged, culture-directed antimicrobial therapy. Early multidisciplinary discussion is critical for favorable outcomes [13,17]. The clinical decision-making algorithm for complicated ODS is illustrated in Figure 4.

Conclusions

ODS is a distinct clinical entity that may lead to severe orbital and intracranial complications when diagnosis and treatment is delayed. Successful outcomes were achieved through a combination of broad-spectrum antimicrobial therapy with anaerobic coverage, urgent ESS, and definitive dental source control. Neurosurgical and ophthalmological input was essential in selected cases.

Clinicians should suspect odontogenic sinusitis in cases of unilateral maxillary sinus disease, particularly when dental pathology, OAC, or poor response to standard rhinosinusitis therapy is present. Features favoring ODS over rhinogenic sinusitis include unilateral symptoms, anaerobe-predominant microbiology, and early orbital or intracranial involvement. Prompt imaging, early multidisciplinary evaluation, broad-spectrum anaerobe-active antibiotics, and definitive dental source control are essential to prevent life-threatening complications. Increased awareness of these diagnostic and therapeutic principles may significantly improve patient outcomes.