WHEN IS SURGICAL INTERVENTION NECESSARY?

When the optic nerve or retinal function is compromised by mass effect of an abscess, the patient should have emergent surgical intervention regardless of patient age. While a canthotomy or cantholysis will help decrease intraocular pressure, globe distortion and traction will not be eliminated without evacuation of the subperiosteal space (2,6). Urgent drainage (within 24 hours) should occur in large subperiosteal abscesses that do not affect vision but cause significant discomfort, as well as in patients with intracranial complications or frontal sinusitis.

WHEN IS MEDICAL TREATMENT OF ORBITAL CELLULITIS APPROPRIATE?

In selected cases, close observation (including monitoring for development of afferent pupillary defect as often as every 6 hours and monitoring of defervescence within 36 hours of treatment) while hospitalized with IV antibiotics is appropriate. Occasionally, mild cases of orbital cellulitis or abscess may resolve with medical management, especially in children. Harris (7) demonstrated the age- associated variations in complexity and responsiveness of subperiosteal abscess. In children younger than 9 years, he found negative drainage culture results after drainage of subperiosteal abscesses (or complete resolution without surgery) in patients treated with appropriate antibiotic coverage. The cultures that were positive were single isolate aerobes. However, patients 15 years or older all had positive cultures despite at least 3 days of antibiotic therapy (proven to be sensitive in vitro). All of these patients had anaerobic infections and all but one had polymicrobial infections. The 9- to 14-year-old demonstrated a transition between the two extremes (7).

POSSIBLE COMPLICATIONS OF UNTREATED ORBITAL CELLULITIS

• Optic neuropathy
• Optic atrophy
• Cavernous sinus thrombosis
• Superior orbital fissure syndrome
• Orbital apex syndrome
• Meningitis
• Cerebritis
• Subdural empyema
• Blindness
• Death.

FOLLOW-UP IMAGING

Follow-up CT scan is not always necessary, and should be pursued on a case-specific basis. In the acute setting, it may be used to rule out silent frontal lobe abscess. Otherwise, follow-up CT imaging is less useful to follow patients’ course, as the CT findings may worsen and lag behind the clinical course during the first days to weeks of hospitalization and treatment (8).

ABOUT THIS CASE

The patient had a more complicated medical history than was initially reported. The patient had new onset diabetes mellitus and diabetic ketoacidosis and had a history of alcohol abuse, both of which were managed by the medicine service. How does this change your approach to treatment?

• One should be aware that immune suppression may complicate the potential infectious etiology and that potentially life-threatening mucormycosis or other invasive sino-orbital fungal infection may develop.

Initially, one difficulty with this case was the differentiation of hemorrhage from purulent exudate on CT. Determining the Hounsefield unit measurement that corresponds to the tissue abnormality in question, as well as the presence and pattern of tissue enhancement, may aid in differentiating blood from purulent exudate.