Preseptal and Orbital Cellulitis
Jamie Lea Schaefer
Jimmy Truong
CLINICAL CHALLENGE
Periorbital infections are a relatively common presenting complaint in the emergency and urgent care settings, especially for children.1 The extent of infection is what distinguishes preseptal from orbital cellulitis, and differentiation between the two is important because morbidity and treatment can vary greatly.2 Preseptal cellulitis is an infection that has not extended posterior to the orbital septum with vision and eye movements typically unaffected, whereas orbital cellulitis extends deep into the tissues of the orbital socket and is often marked by changes to ocular function.2,3 Furthermore, noninfectious or associated etiologies, such as idiopathic orbital inflammation, complicate the differential diagnosis and must be considered.
PATHOPHYSIOLOGY
The orbital septum is a fibrous connective tissue barrier that separates the preseptal eyelid skin and orbicularis muscle from the orbital tissues—the globe, extraocular muscles, orbital fat, and neurovascular tissues.
Common portals through which pathogens enter the periocular tissues include the mucosal surfaces of the eye, respiratory and digestive tracts, as well as the skin.3,4,5 Ingress from the skin may result from insect bites, trauma, and other inflammatory conditions of the Meibomian glands and hair follicles along the eyelid margin. Sinusitis, dental abscesses, infections of the lacrimal sac (dacryocystitis) (Figure 30.1), or other adjacent infections can extend into the periorbital region as well. The ethmoid sinuses are often the source of orbital cellulitis—the thin bone of the lamina papyracea, bordering the medial side of the orbit, is perforated by numerous vessels and nerves and can allow extension of sinusitis.2,6
Most periorbital infections are secondary to the Staphylococcus, Streptococcus, and Haemophilus species.2,5 Importantly, there has been a rise in the occurrence of methicillin-resistant Staphylococcal infections, whereas the incidence of infection in children by Haemophilus has decreased significantly with the advent of immunization against H influenza type B. This reduction secondary to immunization, however, has not been seen with PCV7 vaccination against Streptococcus pneumonia. Moraxella catarrhalis, in addition to anaerobic organisms of the upper respiratory tract, has also been implicated in periorbital infections. Peptococcus, Peptostreptococcus, and Bacteroides are organisms known to cause cellulitis after human or animal bites. In patients who are pregnant or otherwise immunocompromised, fungal organisms of Mucormycosis and Aspergillosis should be considered. Following trauma, S aureus and S pyogenes are the most common pathogens.
 Figure 30.1: Right dacryocystitis with preseptal cellulitis. |
Preseptal Cellulitis
Preseptal cellulitis occurs approximately 4 times more often than orbital cellulitis and is more frequent in children, particularly those younger than 5 years of age (Figure 30.2). Clinical features include swelling, erythema, and pain of the eyelid with the area of maximal inflammation indicating the likely source of infection. Inflammation may induce ptosis of the upper eyelid and may also be associated with tearing, conjunctival injection, and therefore accompanying blurred vision. This disease is often preceded by an upper respiratory infection, sinusitis, dental pathology, insect bite, trauma or surgery, or other infections in the surrounding area. Conjunctivitis may also develop into preseptal cellulitis. Preseptal cellulitis is often distinguished from deeper orbital infections clinically by the absence of globe displacement, restrictions in ocular motility, or raised ocular or orbital pressure. In uncertain cases, orbital or sinus computed tomography (CT) scans are obtained to rule out orbital cellulitis.
Orbital Cellulitis
Orbital cellulitis (Figure 30.3) most commonly extends from infections of the ethmoid sinus, although it may also be acquired from other adjacent structures.5,7 Less common causes include endophthalmitis, implants, retained foreign materials, or orbital tumors. Hematogenous spread is relatively rare. Orbital cellulitis occurs in all ages, but mostly in children 7 to 12 years old (older age than preseptal cellulitis) and has similar prevalence in males and females except in causes of trauma
where there is a male predominance. Children younger than 10 years are usually infected by a single aerobic pathogen, whereas older children and adults have more complex infections involving aerobic and anaerobic pathogens and are more likely to be polymicrobial.
where there is a male predominance. Children younger than 10 years are usually infected by a single aerobic pathogen, whereas older children and adults have more complex infections involving aerobic and anaerobic pathogens and are more likely to be polymicrobial.
 Figure 30.2: Left preseptal cellulitis. |
 Figure 30.3: External photographs (A and B) of right orbital cellulitis with erythema and swelling confined within the orbital rims associated with proptosis and ophthalmoplegia. Coronal (C) and sagittal (D) orbital computed tomography images of a large right superior and small medial subperiosteal abscess with inferior displacement of the rectus musculature and globe with associated multifocal sinus disease. |
Clinical features include pain, swelling, and erythema of the conjunctiva and eyelids, usually confined within the orbital rims. Between the bony orbital walls and the periorbita, or periosteum of the orbit, the potential subperiosteal space provides an area for potential accumulation and may lead to a subperiosteal abscess with mass effect similar to a tumor. Proptosis is usually present, and the globe may be displaced with the presence of an abscess. Abscesses larger than 10 mm and those that are in a nonmedial location should be evaluated for surgical drainage. Orbital inflammation may lead to raised intraocular pressure and restricted and painful eye movements with diplopia. Compressive optic neuropathy from orbital compartment syndrome can lead to severe permanent vision loss.
Venous drainage of the orbit through the cavernous sinus connects the orbit to the central nervous system, making severe intracranial infections a possible complication. Cranial nerves III, IV, V1, and VI traverse the cavernous sinus and can be affected with the spread of orbital cellulitis. Intracranial extension with cavernous sinus thrombosis should be suspected when the patient has progressive cranial nerve palsies, fever, headache, and altered consciousness (see Table 30.1).
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