Orbital Cellulitis

Overview

Orbital cellulitis is a serious bacterial infection of the soft tissues within the eye socket (orbit) that lie behind the orbital septum, a thin membrane that separates the eyelid from the deeper orbital structures. This condition is distinct from the less severe preseptal cellulitis, which affects only the tissues in front of the orbital septum. Orbital cellulitis is considered a medical emergency because it can rapidly progress to cause severe complications including vision loss, brain abscess, meningitis, and even death if left untreated.

The infection typically develops as a complication of sinusitis, particularly ethmoid sinusitis, due to the thin bone (lamina papyracea) separating the ethmoid sinuses from the orbit. It can affect people of all ages but is most common in children, who account for the majority of cases. The condition requires prompt recognition and aggressive treatment with intravenous antibiotics, and sometimes surgical intervention, to prevent serious complications.

Understanding the difference between orbital and preseptal cellulitis is crucial, as orbital cellulitis carries a much higher risk of complications. While both conditions can present with eyelid swelling and redness, orbital cellulitis involves deeper structures and typically causes more severe symptoms including proptosis (bulging eye), ophthalmoplegia (limited eye movement), and vision changes. The mortality rate has decreased significantly with modern antibiotics, but the condition still requires urgent medical attention and hospitalization.

Symptoms

The symptoms of orbital cellulitis typically develop rapidly over hours to days and are more severe than those of preseptal cellulitis. The infection causes inflammation and swelling within the confined space of the orbit, leading to characteristic signs and symptoms that help distinguish it from less serious eye conditions.

Primary Eye Symptoms

Systemic Symptoms

Key Distinguishing Features

• Proptosis: Forward displacement of the eyeball (bulging eye)
• Ophthalmoplegia: Restricted eye movement in one or more directions
• Pain with eye movement: Significant pain when trying to move the eye
• Decreased visual acuity: Blurred vision or vision loss
• Afferent pupillary defect: Abnormal pupil response to light
• Elevated intraocular pressure: From orbital congestion

Symptoms in Children vs Adults

• Children: May be unable to describe symptoms clearly, often present with irritability, poor feeding, lethargy
• Adults: Can better articulate pain, vision changes, and other symptoms
• Progression: Symptoms typically worsen rapidly without treatment

Causes

Orbital cellulitis results from bacterial infection spreading to the orbital tissues. The infection can reach the orbit through several pathways, with sinusitis being the most common source. Understanding these pathways helps in identifying the source and guiding treatment.

Primary Causes

• Sinusitis (60-90% of cases):
  • Ethmoid sinusitis most common due to thin lamina papyracea
  • Maxillary and frontal sinusitis can also spread to orbit
  • Acute or chronic sinus infections
• Direct spread from preseptal cellulitis:
  • Progression through or around orbital septum
  • More common in inadequately treated cases
• Trauma:
  • Penetrating injuries to orbit
  • Retained foreign bodies
  • Orbital fractures
• Dental infections:
  • Upper tooth abscesses
  • Maxillary dental procedures

Less Common Causes

• Dacryocystitis: Infection of the lacrimal sac
• Endophthalmitis: Intraocular infection spreading outward
• Post-surgical: Following eye, sinus, or facial surgery
• Hematogenous spread: Bloodstream infection (bacteremia)
• Extension from:
  • Facial infections
  • Middle ear infections
  • Meningitis

Common Bacterial Pathogens

• Children:
  • Streptococcus pneumoniae
  • Haemophilus influenzae (less common since Hib vaccine)
  • Moraxella catarrhalis
  • Streptococcus pyogenes
  • Staphylococcus aureus (including MRSA)
• Adults:
  • Staphylococcus aureus (including MRSA)
  • Streptococcus species
  • Anaerobes in dental-related cases
  • Polymicrobial infections more common
• Immunocompromised patients:
  • Fungal infections (Aspergillus, Mucor)
  • Gram-negative bacteria

Risk Factors

Several factors increase the risk of developing orbital cellulitis:

Age and Demographic Factors

• Children: Highest risk, especially ages 5-10 years
• Winter months: Higher incidence due to increased upper respiratory infections
• Males: Slightly higher incidence than females

Medical Conditions

• Chronic sinusitis: Recurrent or persistent sinus infections
• Immunodeficiency:
  • Diabetes mellitus
  • HIV/AIDS
  • Chemotherapy patients
  • Immunosuppressive medications
• Previous orbital or sinus surgery
• Anatomical abnormalities: Congenital or acquired

Environmental and Behavioral Factors

• Poor dental hygiene
• Delayed treatment of sinus infections
• Trauma to face or orbit
• Swimming in contaminated water
• Contact lens wear (rare)

Complications Risk Factors

• Delayed diagnosis or treatment
• Age extremes (very young or elderly)
• Fungal infections (higher mortality)
• Bilateral orbital cellulitis
• Presence of subperiosteal or orbital abscess

Diagnosis

Prompt and accurate diagnosis of orbital cellulitis is crucial to prevent serious complications. The diagnosis is based on clinical findings and confirmed with imaging studies. Distinguishing orbital cellulitis from preseptal cellulitis is essential as treatment and prognosis differ significantly.

Clinical Evaluation

• History:
  • Recent sinus infection or upper respiratory infection
  • Facial trauma or surgery
  • Dental problems
  • Speed of symptom onset
  • Previous episodes
• Physical examination:
  • Complete eye examination
  • Visual acuity testing
  • Pupillary responses
  • Extraocular movements
  • Proptosis measurement
  • Sinus tenderness
  • Neurological assessment

Imaging Studies

• CT scan with contrast (preferred initial imaging):
  • Shows orbital inflammation and abscess
  • Evaluates sinuses
  • Detects complications
  • Guides surgical planning
• MRI with contrast:
  • Better soft tissue detail
  • Evaluates intracranial complications
  • Detects cavernous sinus thrombosis

Laboratory Tests

• Blood tests:
  • Complete blood count (elevated WBC)
  • Blood cultures (positive in 5-30%)
  • Inflammatory markers (ESR, CRP)
• Microbiological studies:
  • Sinus aspirate culture (if accessible)
  • Abscess culture (if drained)
  • Conjunctival swab (limited value)

Chandler Classification

Stages of orbital infection:

1. Group I: Preseptal cellulitis
2. Group II: Orbital cellulitis without abscess
3. Group III: Subperiosteal abscess
4. Group IV: Orbital abscess
5. Group V: Cavernous sinus thrombosis

Differential Diagnosis

• Preseptal cellulitis
• Orbital tumor
• Thyroid eye disease
• Orbital pseudotumor
• Cavernous sinus thrombosis
• Orbital hemorrhage
• Severe allergic reaction

Treatment Options

Orbital cellulitis requires immediate hospitalization and aggressive treatment to prevent vision loss and life-threatening complications. Treatment typically involves intravenous antibiotics and may require surgical intervention depending on severity and response to medical therapy.

Medical Management

• Intravenous antibiotics (immediate initiation):
  • Empiric therapy for children:
    • Ceftriaxone or cefotaxime PLUS
    • Vancomycin (for MRSA coverage)
    • Consider metronidazole for anaerobic coverage
  • Empiric therapy for adults:
    • Vancomycin PLUS
    • Ceftriaxone or piperacillin-tazobactam
    • Metronidazole if dental source suspected
  • Duration: IV antibiotics for 1-2 weeks, then oral for 2-3 weeks
• Supportive care:
  • Pain management
  • Fever control
  • Eye lubrication
  • Head elevation

Surgical Intervention

Indications for surgery:

• Subperiosteal or orbital abscess
• No improvement after 24-48 hours of antibiotics
• Visual deterioration
• Complete ophthalmoplegia
• Signs of intracranial extension

Surgical procedures:

• Abscess drainage: External or endoscopic approach
• Sinus surgery: Ethmoidectomy, maxillary antrostomy
• Orbital decompression: For severe cases with compartment syndrome
• Foreign body removal: If present

Monitoring and Follow-up

• Frequent clinical assessments (every 4-6 hours initially)
• Daily visual acuity and pupillary checks
• Serial imaging if not improving
• Ophthalmology and ENT consultations
• Infectious disease consultation for complex cases

Special Considerations

• Fungal orbital cellulitis:
  • Requires antifungal therapy (amphotericin B, voriconazole)
  • Often needs aggressive surgical debridement
  • Higher mortality rate
• MRSA infections: Ensure adequate vancomycin levels
• Immunocompromised patients: Broader antibiotic coverage, consider fungal etiology

Prevention

Prevention of orbital cellulitis focuses on prompt treatment of predisposing conditions and reducing risk factors:

Primary Prevention

• Sinus infection management:
  • Prompt treatment of acute sinusitis
  • Complete antibiotic courses
  • Management of chronic sinusitis
  • Allergy control to reduce sinus inflammation
• Immunizations:
  • Haemophilus influenzae type b (Hib) vaccine
  • Pneumococcal vaccine
  • Annual influenza vaccine
• Dental hygiene:
  • Regular dental check-ups
  • Prompt treatment of dental infections

Risk Reduction

• Avoid trauma to face and eyes
• Proper wound care for facial injuries
• Control of diabetes and other immunocompromising conditions
• Avoid swimming with sinus infections
• Prompt removal of foreign bodies

Early Recognition

• Education about warning signs
• Distinguish from preseptal cellulitis
• Seek immediate care for concerning symptoms
• Follow-up for persistent sinus infections

When to See a Doctor

Orbital cellulitis is a medical emergency. Immediate medical attention is required for any suspected case:

Seek Emergency Care Immediately For:

• Severe eye pain, especially with movement
• Bulging of the eye (proptosis)
• Limited eye movement or double vision
• Decreased vision or vision loss
• High fever with eye swelling
• Eyelid swelling that's getting rapidly worse
• Eye swelling after sinus infection
• Severe headache with eye symptoms
• Confusion or altered mental status

Do Not Delay Treatment

• Orbital cellulitis can progress rapidly (hours)
• Delay increases risk of permanent vision loss
• Life-threatening complications can develop quickly
• Early treatment dramatically improves outcomes

Risk of Complications

Without prompt treatment, complications include:

• Permanent vision loss
• Brain abscess
• Meningitis
• Cavernous sinus thrombosis
• Death (rare with modern treatment)

Related Conditions

References

1. Chandler JR, Langenbrunner DJ, Stevens ER. The pathogenesis of orbital complications in acute sinusitis. Laryngoscope. 1970;80:1414-1428.
2. Chaudhry IA, et al. Inpatient preseptal and orbital cellulitis: Experience from a tertiary care center. British Journal of Ophthalmology. 2023.
3. Wong SJ, Levi J. Management of pediatric orbital cellulitis: A systematic review. International Journal of Pediatric Otorhinolaryngology. 2023.
4. American Academy of Ophthalmology. Orbital Cellulitis. EyeWiki. Updated 2023.
5. Fanella S, et al. Management of pediatric orbital cellulitis and abscess. Pediatric Emergency Care. 2023.
6. Lee S, Yen MT. Management of preseptal and orbital cellulitis. Saudi Journal of Ophthalmology. 2023.