EM@3AM: Periorbital Cellulitis

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Answer: Periorbital cellulitis

Definition^{1, 2}

• Infection of the skin, soft tissue, and surrounding structures anterior to the orbital septum including the upper and lower eyelids
• Also known as preseptal cellulitis

• Often confused with orbital cellulitis which is a serious infection posterior to the orbital septum within the orbit that requires parenteral antibiotics and sometimes emergent surgical intervention

Epidemiology^{2, 3}

• Can occur in individuals of all ages, but more commonly occurs in children under the age of 10
• Several etiologies have been linked to the development of periorbital cellulitis which include:
  • Bacterial
    • This is the most common cause with the most frequently isolated bacteria being Staphylococcus aureus and the Streptococcus species
      • Less commonly linked to Pseudomonas, Acinetobacter, Proteus, Neisseria, Nocardia, Pasteurella, Mycobacterium, and Bacillus
  •  Viral
    • Less common cause
    • Adenovirus, herpes simplex, and varicella zoster have been implicated as causes of periorbital cellulitis
  • Fungal
    • Very rare and more often seen in immunocompromised individuals
    • Reported cases with Aspergillus and Mucor

Pathophysiology²

• Typically results as a complication of progressing rhinosinusitis but can also occur secondary to oral, upper respiratory, auricular, lacrimal, and other facial infections
  • Associated with Haemophilus influenza type b in unvaccinated children and more universally, Streptococcus pneumoniae
  • Orbits are bordered by the paranasal sinuses and lined with periosteum
  • Ethmoiditis is the most common rhinosinusitis leading to periorbital cellulitis as the lamina papyracea separating the ethmoid sinus and orbits are very thin and permeable facilitating easy spread of infection
    • The lamina papyracea is made of Zuckerkandl’s dehiscence which are small fenestrations allowing neurovascular structures to pass through as well as microbial organisms leading to infection
•  Can also arise after trauma to the area as a skin defect can be a nidus for infection
  • Associated with Staphylococcus aureus and Staphylococcus epidermidis
• Other causes include hematogenous seeding and expansion of pre-existing impetigo

Clinical Presentation^{1, 2, 4}

• Patients often times, but not always presents with a history of recent trauma (e.g., insect bite, scratch, etc.) or nearby infection (e.g., URI, dacryocystitis, blepharitis, impetigo, hordeolum, etc.)
• Characterized by edema, erythema, warmth, and tenderness of the eyelid and surrounding tissue
  • Symptoms and signs are usually unilateral
  • Can be rapidly progressive
  • Can have difficulty opening eyelids secondary to the degree of eyelid edema
  • Erythema and edema will often expand beyond the arcus marginalis (region where orbital septum attaches into the periosteum)
    • In orbital cellulitis, the erythema and edema can abruptly stop at this landmark
• Can have systemic symptoms such as fever and generalized malaise although not always present
• Usually, the patient will not have pain or limitations of extraocular eye movement, visual changes, chemosis, proptosis, globe displacement, or pupillary defects
  • If these symptoms are present, it is likely the patient has orbital cellulitis, but in severe cases of periorbital cellulitis there can be limitations with extraocular movements secondary to eyelid edema
  • Intraocular pressures are normal in periorbital cellulitis

Diagnosis^{1, 4, 5}

• This is a clinical diagnosis made through history and physical exam
  • Does not typically require ophthalmology consultation
• Physical examination will demonstrate mild to marked eyelid erythema and edema, but normal intraocular pressures, visual acuity, and globe motility
• If the exam/history is equivocal or limited secondary to age (i.e., pediatric population), an orbital and/or sinus CT scan with IV contrast can be performed to assist with diagnosis
  • Will demonstrate eyelid edema, but should not show proptosis or orbital fat streaking which suggest post orbital septal involvement and orbital cellulitis
  • Can also be obtained if suspicious for periorbital infection complications, those with marked symptoms (e.g., swelling, chemosis, fever, etc.), no improvement after 24-48 hours after initiating antibiotics

Complications¹

• Periorbital cellulitis rarely leads to the development of serious complications, but infections can propagate through the venous system of the face
  • This system is valveless allowing for facile and rapid dissemination of infection to the orbits, cavernous sinuses, and eventually the intracranial structures
• Can spread and develop into orbital cellulitis, cavernous sinus thrombosis, subperiosteal abscess, and orbital abscess
• Very rarely necrotizing fasciitis can develop when the infection is secondary to β-hemolytic Streptococcus
  • Presents with rapidly progressive symptoms with impressive violaceous skin changes

Treatment^1-3

• Mainstay of treatment is antibiotics with S. aureus, Streptococcal, and anaerobic coverage
  • Often can treat with oral antibiotics for 5-7 days, but if symptoms are severe, the patient has significant co-morbidities and/or is immunocompromised, or occurs in children less than two-years-old, hospital admission for parenteral antibiotics should be considered
• For outpatient empiric MRSA coverage, one of the following antibiotics should be given:
  • Trimethoprim-sulfamethoxazole (TMP-SMX) 160mg/800mg to 320mg/1600mg BID
  • Clindamycin 300mg every eight hours
  • Doxycycline 100mg BID
    • Not recommended in children under 8 years
•  In combination with one of the following to cover group A strep:
  • Amoxicillin-clavulanate 875mg BID
  • Cefpodoxime 400mg BID
  • Cefdinir 300mg BID
• For children, follow weight-based dosing for appropriate coverage
• For inpatient treatment, the following regimen is typically used:
  • Vancomycin 25-35mg/kg IV as a loading dose then 15-20mg/kg IV two to three times daily in combination with one of the following:
    • Ampicillin-sulbactam 3g IV QID
    • Ceftriaxone 2g IV QD
    • Levofloxacin 750mg IV QD
    • Cefotaxime 2g IV every four hours

Prognosis²

• Majority of cases will resolve with treatment
• If not improving, consider changing antibiotics or evaluating for orbital cellulitis and other differentials

Pearls

• Periorbital cellulitis is a generally benign condition that involves infection of the eyelids and surrounding tissue without orbital involvement
• Majority of cases are a result of bacterial infection secondary to rhinosinusitis, but can result from trauma or other nearby infections
• It is clinically diagnosed but careful physical examination should be performed to distinguish it from orbital cellulitiswhich is an ophthalmic emergency
• Treatment for most individuals includes oral antibiotics that cover staph, strep, and anaerobes, but parenteral antibiotics should be considered for those with significant co-morbidities or young children
• Complications are rare