ophtho.orbital-cellulitis.core.v1PRODUCTION

ophtho.orbital-cellulitis.core.v1

Orbital cellulitis (vs preseptal)

general_internal_medicineacutesubacuteadultpediatric

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0 / 12

Care setting:

Encounter flow

12/12 authored

Canonical 12-phase frame with authored status for this dossier.

Current phase

Frame

Detailed

Frame around the ORBITAL SEPTUM: preseptal (Chandler I — eyelid only, no proptosis/EOM/acuity change) vs orbital/postseptal (Chandler II-V — the emergency). Orbital cellulitis is overwhelmingly secondary to ethmoid sinusitis and is pediatric-predominant. Source-sinusitis, cavernous-sinus-thrombosis, meningitis, sepsis, ROCM, and the optic-nerve arm are recognised and routed OUT by engine_id, not re-authored here (Chandler Laryngoscope 1970 PMID 5470225; Sansa-Perna 2020 PMID 32389323).

Inputs

Actions

Advance rule

Set

Advance when

septum-based scope confirmed; not-this-engine concerns routed by engine_id

Patient inputs (17)

ophthalmoplegia_pain_on_eye_movement*symptom • CONTEXT

Painful / restricted extraocular movements indicate postseptal (intraorbital) involvement and contribute to the surgical-need prediction (Moreddu 2025 — ophthalmoplegia OR 14.2; Chandler 1970)

chemosis*symptom • CONTEXT

Conjunctival chemosis indicates orbital congestion / postseptal disease and, when bilateral or progressive, raises concern for cavernous sinus thrombosis (Chandler 1970 — stage V)

sinusitis_source*history • CONTEXT

not present

Ethmoid sinusitis is the source in the majority — defines the source pathway and surgical (endoscopic-sinus) drainage target; routes to ent.acute-sinusitis.core.v1 (Sansa-Perna 2020 — orbital = 60-75% of complicated rhinosinusitis)

age*demographic • CONTEXT

Age is the central Garcia-Harris medical-vs-surgical SPA decision axis (<9 y high non-surgical success absent other criteria) and orbital cellulitis is pediatric-predominant (Garcia & Harris Ophthalmology 2000 PMID 10919887; Harris 1993 PMID 8140703)

temperature*vital • CONTEXT

Fever raises the infective/postseptal prior and Chandler progression; high fever with toxicity feeds the sepsis screen (Chandler 1970; Cirks Mil Med 2025)

proptosis*symptom • ENTRY

Proptosis is the single cardinal sign separating postseptal (orbital) from preseptal cellulitis and a strong predictor of surgical need (Moreddu J Otolaryngol HNS 2025 — clinical exophthalmos OR 25.0; Le J AAPOS 2014)

contrast_ct_orbits_and_sinuses*imaging • INITIAL_WORKUP

not present

Contrast CT orbits + paranasal sinuses is the decisive test: confirms postseptal disease, stages Chandler III-IV, measures SPA volume, identifies the source sinus and intracranial extension (Le J AAPOS 2014 PMID 24924283; Todman & Enzer 2011 PMID 21415801)

visual_acuity_and_colour_vision*symptom • RED_FLAGS

Decreased visual acuity / dyschromatopsia signals optic-nerve compromise — a vision-threatening emergency and a hard surgical-drainage trigger (Garcia & Harris Ophthalmology 2000; Chandler 1970)

rapd_relative_afferent_pupillary_defect*symptom • RED_FLAGS

An RAPD is objective evidence of optic-nerve dysfunction — mandates emergent decompression and routes to the acute-vision-loss arm (Le J AAPOS 2014; Chandler 1970)

bilateral_signs_or_cranial_neuropathy*symptom • RED_FLAGS

Bilateral orbital signs, fixed dilated pupil, or multiple cranial neuropathies (III/IV/V1/VI) → cavernous sinus thrombosis / intracranial extension — route OUT (Chandler 1970 stage V)

sbp*vital • RED_FLAGS

Hypotension / systemic toxicity with an orbital source → route OUT to id.sepsis.core.v1 (sepsis pathway not authored here)

immunocompromise_or_dka*history • RED_FLAGS

not present

Diabetes/DKA, haematologic malignancy, neutropenia, transplant change the differential toward ROCM mucormycosis — black eschar / rapid CN march is an emergency (Reid Semin Respir Crit Care Med 2020 PMID 32000287)

recent_sinus_dental_ocular_surgery_or_traumahistory • CONTEXT

not present

Recent sinus/dental/ocular surgery, orbital trauma, or retained foreign body alters the portal and pathogen spectrum and the surgical target (Cirks Mil Med 2025)

wbclab • INITIAL_WORKUP

Leukocytosis supports the infective/postseptal prior and tracks Chandler progression; very high WBC predicts surgical need (Moreddu 2025 — leucocytes >15,600 OR 7.7)

crplab • INITIAL_WORKUP

CRP > 60 mg/L is an independent predictor of surgical intervention and tracks response (Moreddu J Otolaryngol HNS 2025 — CRP >60 OR 6.9)

pregnancyhistory • TREATMENT

not present

Antibiotic-safety gating for the IV empiric regimen and amphotericin (avoid where alternatives exist; vancomycin AUC monitoring) — special-population branch

creatininelab • TREATMENT

Renal function gates vancomycin AUC dosing and amphotericin B nephrotoxicity monitoring in the IV empiric / ROCM regimens

* = hard-required. Engine cannot meaningfully run until these are filled.

Severity triggers (8)

8 need judgement

informationallife_threateningoptic_nerve_compromise_vision_threat
Decreased visual acuity, dyschromatopsia, or RAPD — optic-nerve compromise from orbital cellulitis / orbital-apex involvement (Garcia & Harris Ophthalmology 2000 PMID 10919887; Chandler 1970 PMID 5470225)
Trigger could not be auto-evaluated — needs clinician judgement.
informationallife_threateningcavernous_sinus_thrombosis_route_out
Bilateral orbital signs, multiple cranial neuropathies (III/IV/V1/VI), fixed dilated pupil, or rapid bilateral progression — Chandler V cavernous sinus thrombosis (Chandler Laryngoscope 1970 PMID 5470225)
Trigger could not be auto-evaluated — needs clinician judgement.
informationallife_threateningintracranial_extension_meningitis
Meningismus, altered mental status, seizure, or imaging subdural/intracranial abscess with an orbital/sinogenic source (Chandler 1970 PMID 5470225)
Trigger could not be auto-evaluated — needs clinician judgement.
informationallife_threateningrocm_immunocompromised_emergency
Diabetic ketoacidosis / haematologic malignancy / neutropenia / transplant WITH black necrotic nasal-palatal eschar, rapid cranial-nerve march, or non-response to antibacterials — rhino-orbital-cerebral mucormycosis (Reid Semin Respir Crit Care Med 2020 PMID 32000287)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalseveresubperiosteal_or_orbital_abscess
Chandler III subperiosteal abscess (large/non-medial, age ≥9, or SPA volume >3.8 mL) or Chandler IV orbital abscess on contrast CT (Le J AAPOS 2014 PMID 24924283; Garcia & Harris Ophthalmology 2000 PMID 10919887)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalseveresystemic_toxicity_route_to_sepsis
qSOFA ≥2, hypotension on adequate fluids, or NEWS2 escalation with an orbital/sinogenic source
Trigger could not be auto-evaluated — needs clinician judgement.
informationalseverepediatric_systemic_or_airway_compromise
Young child with high fever, toxic appearance, poor feeding, or airway compromise from extensive periorbital/sinogenic disease (orbital cellulitis is pediatric-predominant; Garcia & Harris Ophthalmology 2000 PMID 10919887; Sansa-Perna 2020 PMID 32389323)
Trigger could not be auto-evaluated — needs clinician judgement.
informationalseverenon_response_at_24_48h
No improvement in orbital signs / inflammatory markers at 24-48 h of appropriate IV empiric therapy (Le J AAPOS 2014 PMID 24924283; Garcia & Harris Ophthalmology 2000 PMID 10919887)
Trigger could not be auto-evaluated — needs clinician judgement.

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Recommended regimen

Postseptal (orbital) cellulitis — IV broad-spectrum empiric + surgical-drainage decision + ROCM arm

axis: orbital_cellulitis_iv_empiric_and_surgicalstep 1 - Step 1 — Septum triage gate (preseptal vs postseptal) before committing the IV pathway

Selected step "Step 1 — Septum triage gate (preseptal vs postseptal) before committing the IV pathway" — Periorbital swelling: assess proptosis, painful/restricted EOM, acuity/colour, RAPD, chemosis. Postseptal if ANY present; preseptal (Chandler I) if all absent and well

septum_triage_decision_gate_preseptal_vs_postseptal
first line
decision_gate
triggers: proptosis, painful_ophthalmoplegia, acuity_or_colour_drop, rapd, chemosis
Chandler Laryngoscope 1970 (PMID 5470225) — the orbital septum defines preseptal (I) vs orbital/postseptal (II-V). Postseptal = admit + IV + ophtho/ENT; preseptal-well = ambulatory/oral (Brugha Pediatr Emerg Care 2012 PMID 22344208).

ed playbook — drug actions (3)

1. vancomycin (postseptal, MRSA cover)
rxcui 11124
AUC-guided ≈15-20 mg/kg • IV • q8-12h
trigger: Any postseptal sign — start immediately, do not await CT (Cirks Mil Med 2025 PMID 39172646)
25% of S. aureus MRSA — empiric anti-MRSA required
2. ceftriaxone (sinogenic/streptococcal backbone)
rxcui 2193
2 g adult / 50 mg/kg paeds • IV • q12-24h
trigger: Postseptal cellulitis with sinogenic source (Cirks Mil Med 2025)
Broad β-lactam for streptococci incl. S. anginosus group (Vloka Orbit 2021 PMID 33386062)
3. metronidazole (anaerobe / intracranial cover)
rxcui 6922
500 mg adult / 7.5 mg/kg paeds • IV • q8h
trigger: Anaerobic cover when ceftriaxone backbone; intracranial extension (Cirks 2025)
Anaerobes ~13% of isolates; CNS-penetrant

Auto-drafted A&P note

Subjective

- Possible entry pathways: Periorbital erythema/oedema WITH proptosis, restricted/painful eye movements, or chemosis — postseptal (orbital) cellulitis until excluded (Chandler Laryngoscope 1970 PMID 5470225; Le J AAPOS 2014 PMID 24924283); Eyelid erythema/oedema with NORMAL acuity, motility, and globe position — preseptal (Chandler I) candidate; the septum-defining triage (Brugha Pediatr Emerg Care 2012 PMID 22344208); Acute (ethmoid) rhinosinusitis developing new orbital signs — orbital complication of sinusitis (60-75% of complicated rhinosinusitis; Sansa-Perna Acta Otorrinolaringol Esp 2020 PMID 32389323).

Objective

- No vitals, labs, or imaging entered for this encounter.

Assessment

**Orbital cellulitis (vs preseptal)** (ophtho.orbital-cellulitis.core.v1).
Phenotype framing: Terminal differential with named pivots: orbital (postseptal) cellulitis vs preseptal cellulitis (proptosis + painful EOM + acuity/RAPD pivot — the septum) vs idiopathic orbital inflammation/orbital pseudotumour (subacute, steroid-responsive, often no fever/leukocytosis pivot) vs thyroid eye disease (bilateral, lid retraction/lag, no fever, chronic pivot) vs orbital tumour/rhabdomyosarcoma (progressive painless mass, child, no infective markers pivot — biopsy) vs ROCM mucormycosis (DKA/immunocompromise + black eschar + rapid CN march pivot) vs cavernous sinus thrombosis (bilateral + CN III/IV/V1/VI pivot — route OUT)
Scope: Frame around the ORBITAL SEPTUM: preseptal (Chandler I — eyelid only, no proptosis/EOM/acuity change) vs orbital/postseptal (Chandler II-V — the emergency). Orbital cellulitis is overwhelmingly secondary to ethmoid sinusitis and is pediatric-predominant. Source-sinusitis, cavernous-sinus-thrombosis, meningitis, sepsis, ROCM, and the optic-nerve arm are recognised and routed OUT by engine_id, not re-authored here (Chandler Laryngoscope 1970 PMID 5470225; Sansa-Perna 2020 PMID 32389323).

No severity triggers fired against current inputs.

Plan

Regimen axis: **Postseptal (orbital) cellulitis — IV broad-spectrum empiric + surgical-drainage decision + ROCM arm** — step "Step 1 — Septum triage gate (preseptal vs postseptal) before committing the IV pathway".
1. septum_triage_decision_gate_preseptal_vs_postseptal (decision_gate, first line) — Chandler Laryngoscope 1970 (PMID 5470225) — the orbital septum defines preseptal (I) vs orbital/postseptal (II-V). Postseptal = admit + IV + ophtho/ENT; preseptal-well = ambulatory/oral (Brugha Pediatr Emerg Care 2012 PMID 22344208).

Setting playbook (ed) — Septum triage (preseptal vs postseptal), recognise + route the vision/CST/intracranial/sepsis/ROCM emergencies, start IV empiric for any postseptal sign, obtain contrast CT orbits+sinuses, engage ophthalmology + ENT (Chandler 1970 PMID 5470225; Moreddu 2025 PMID 40652356)
2. vancomycin (postseptal, MRSA cover) AUC-guided ≈15-20 mg/kg IV q8-12h — Any postseptal sign — start immediately, do not await CT (Cirks Mil Med 2025 PMID 39172646) (25% of S. aureus MRSA — empiric anti-MRSA required)
3. ceftriaxone (sinogenic/streptococcal backbone) 2 g adult / 50 mg/kg paeds IV q12-24h — Postseptal cellulitis with sinogenic source (Cirks Mil Med 2025) (Broad β-lactam for streptococci incl. S. anginosus group (Vloka Orbit 2021 PMID 33386062))
4. metronidazole (anaerobe / intracranial cover) 500 mg adult / 7.5 mg/kg paeds IV q8h — Anaerobic cover when ceftriaxone backbone; intracranial extension (Cirks 2025) (Anaerobes ~13% of isolates; CNS-penetrant)

Non-pharmacologic actions:
- STAT ophthalmology + ENT consults for any postseptal sign (Chandler 1970)
- Contrast CT orbits + paranasal sinuses (decisive test; do not delay antibiotics) (Le J AAPOS 2014 PMID 24924283)
- Route OUT by engine_id: optic compromise → ophtho.acute-vision-loss.core.v1; bilateral/CN → neuro.cavernous-sinus-thrombosis.core.v1; meningismus → neuro.bacterial-meningitis.core.v1; qSOFA≥2 → id.sepsis.core.v1; ROCM → id.invasive-fungal-sinusitis.core.v1
- Preseptal (Chandler I), well, reliable → oral or ambulatory IV with 24 h review (Brugha Pediatr Emerg Care 2012 PMID 22344208)

AVOID / contraindication checks:
- Vancomycin AUC monitoring and renal dose adjust (nephrotoxicity; trough/AUC guided — Cirks Mil Med 2025)
- Amphotericin B nephrotoxicity and electrolyte monitoring (use liposomal; monitor creatinine/K/Mg — Reid Semin Respir Crit Care Med 2020)
- Penicillin severe allergy substitute clindamycin plus vancomycin (avoid ceftriaxone/ampicillin sulbactam in anaphylaxis)
- Pregnancy avoid where alternatives exist and monitor (vancomycin AUC; amphotericin only if ROCM life threat — route to fungal sinusitis engine)
- Do not delay IV antibiotics or surgery for imaging (postseptal disease is sight  and life threatening — Chandler 1970)

Monitoring

Regimen monitoring:
- serial visual acuity colour pupil RAPD motility proptosis q4h (more frequent if optic compromise — Garcia & Harris Ophthalmology 2000)
- CRP WBC trend expect improvement by 24-48h (failure → re-CT + surgical re-evaluation — Le J AAPOS 2014)
- vancomycin AUC and renal function (Cirks Mil Med 2025)
- amphotericin creatinine potassium magnesium if ROCM (Reid 2020)

Setting (ed) monitoring:
- Visual acuity / colour / RAPD / motility / proptosis re-check before disposition and q4h if admitted (Garcia & Harris 2000)
- Return precautions if discharged preseptal: any vision change, increasing proptosis, new diplopia, fever, headache (Brugha 2012)

Follow-up plan: Complete IV→PO course (typically 2-3 weeks total guided by source-sinusitis and complication); ENT follow-up for the source ethmoid sinusitis and FESS planning (route to ent.acute-sinusitis.core.v1 for definitive sinus management); ophthalmology follow-up for residual diplopia / optic-nerve / motility sequelae; recurrence-driver control (treat the source sinus disease); ROCM survivors → prolonged antifungal + reconstruction. Counsel return precautions: any vision change, increasing proptosis, new diplopia, headache, or altered mental status → emergency return.
- Close-out criterion: antibiotic course + ENT/ophthalmology follow-up + source-sinus management plan documented; return precautions given

Monitoring phase: Serial visual acuity, colour vision, pupillary (RAPD), motility, and proptosis checks every 4 h (or more frequently if optic compromise) — deterioration mandates urgent re-imaging + surgical drainage (Garcia & Harris Ophthalmology 2000 — non-surgical SPA needs close observation). CRP/WBC trend; expect improvement within 24-48 h of correct IV therapy; failure to improve by 24-48 h triggers re-CT + surgical re-evaluation, NOT silent antibiotic continuation (Le J AAPOS 2014).

Disposition

Current setting: ed — Septum triage (preseptal vs postseptal), recognise + route the vision/CST/intracranial/sepsis/ROCM emergencies, start IV empiric for any postseptal sign, obtain contrast CT orbits+sinuses, engage ophthalmology + ENT (Chandler 1970 PMID 5470225; Moreddu 2025 PMID 40652356)

Disposition criteria:
- Any postseptal sign (Chandler II-V) → ADMIT, IV antibiotics, ophthalmology + ENT co-management (Chandler 1970)
- Chandler I preseptal, well, reliable, no orbital signs → ambulatory IV / oral with mandatory 24 h review (Brugha Pediatr Emerg Care 2012 PMID 22344208)
- Vision / CST / intracranial / ROCM / sepsis → admit + route OUT by engine_id with carryover

Escalation triggers (move to higher acuity):
- Optic compromise (acuity/colour drop, RAPD) → emergent decompression + route to ophtho.acute-vision-loss.core.v1 (Garcia & Harris 2000)
- Bilateral signs / multiple cranial neuropathies → cavernous sinus thrombosis → route to neuro.cavernous-sinus-thrombosis.core.v1 (Chandler 1970)
- Black eschar / rapid CN march in DKA/immunocompromise → ROCM → route to id.invasive-fungal-sinusitis.core.v1 (Reid 2020)
- qSOFA ≥2 / hypotension → route to id.sepsis.core.v1

Earlier-Return Triggers

Return-precaution thresholds (watch for):
- [LIFE_THREATENING] Decreased visual acuity, dyschromatopsia, or RAPD — optic-nerve compromise from orbital cellulitis / orbital-apex involvement (Garcia & Harris Ophthalmology 2000 PMID 10919887; Chandler 1970 PMID 5470225)
- [LIFE_THREATENING] Bilateral orbital signs, multiple cranial neuropathies (III/IV/V1/VI), fixed dilated pupil, or rapid bilateral progression — Chandler V cavernous sinus thrombosis (Chandler Laryngoscope 1970 PMID 5470225)
- [LIFE_THREATENING] Meningismus, altered mental status, seizure, or imaging subdural/intracranial abscess with an orbital/sinogenic source (Chandler 1970 PMID 5470225)

Citations

- Chandler classification (Chandler JR et al, Laryngoscope 1970) — the universal five-stage orbital-complication-of-sinusitis frame — anchored by the Garcia-Harris non-surgical-SPA criteria (Garcia & Harris, Ophthalmology 2000; Harris, Trans Am Ophthalmol Soc 1993), CT SPA-volume thresholds (Le, J AAPOS 2014; Todman & Enzer, Ophthalmic Plast Reconstr Surg 2011), contemporary surgical-need predictors (Moreddu, J Otolaryngol Head Neck Surg 2025), MRSA-era microbiology / empiric cover (Cirks, Mil Med 2025; Vloka, Orbit 2021), orbital-complication epidemiology (Sansa-Perna, Acta Otorrinolaringol Esp 2020), preseptal ambulatory-IV evidence (Brugha, Pediatr Emerg Care 2012), and the ROCM mucormycosis emergency (Reid, Semin Respir Crit Care Med 2020). AAO/Wills-aligned. No 2024-2026 society guideline supersedes the Chandler frame. [PMID:5470225](https://pubmed.ncbi.nlm.nih.gov/5470225/)
- Cited evidence (PMID 10919887) [PMID:10919887](https://pubmed.ncbi.nlm.nih.gov/10919887/)
- Cited evidence (PMID 8140703) [PMID:8140703](https://pubmed.ncbi.nlm.nih.gov/8140703/)
- Cited evidence (PMID 24924283) [PMID:24924283](https://pubmed.ncbi.nlm.nih.gov/24924283/)
- Cited evidence (PMID 21415801) [PMID:21415801](https://pubmed.ncbi.nlm.nih.gov/21415801/)

Last reconciled with current guidelines: 2026-05-17.

References

Chandler classification (Chandler JR et al, Laryngoscope 1970) — the universal five-stage orbital-complication-of-sinusitis frame — anchored by the Garcia-Harris non-surgical-SPA criteria (Garcia & Harris, Ophthalmology 2000; Harris, Trans Am Ophthalmol Soc 1993), CT SPA-volume thresholds (Le, J AAPOS 2014; Todman & Enzer, Ophthalmic Plast Reconstr Surg 2011), contemporary surgical-need predictors (Moreddu, J Otolaryngol Head Neck Surg 2025), MRSA-era microbiology / empiric cover (Cirks, Mil Med 2025; Vloka, Orbit 2021), orbital-complication epidemiology (Sansa-Perna, Acta Otorrinolaringol Esp 2020), preseptal ambulatory-IV evidence (Brugha, Pediatr Emerg Care 2012), and the ROCM mucormycosis emergency (Reid, Semin Respir Crit Care Med 2020). AAO/Wills-aligned. No 2024-2026 society guideline supersedes the Chandler frame. — PMID:5470225
Cited evidence (PMID 10919887) — PMID:10919887
Cited evidence (PMID 8140703) — PMID:8140703
Cited evidence (PMID 24924283) — PMID:24924283
Cited evidence (PMID 21415801) — PMID:21415801