**7. Orbital infections**

**Figure 12.** Toxocara chorioretinitis. Note the whitish lesion that may represent shrinked larva. Traction retinal detach‐

**Figure 14.** Acute retinal necrosis. Note the whitish lesion without retinal hemorrhages. The lesion is blurred by the

**Figure 13.** Cytomegalovirus (CMV) retinitis. Note the white lesions and intraretinal hemorrhages.

ment may occur.

14 Advances in Common Eye Infections

inflammation in the vitreous.

The hallmarks of orbital cellulitis include proptosis (exophthalmos) and limited ocular motility and/or involvement of the optic disc (decreased best‐corrected visual acuity, positive afferent pupillary defect (Marcus Gunn) and/or swelling of the optic disc) [14, 15] (**Figure 15**). These findings differ from the signs of preseptal cellulitis in which swelling, erythema, heat and sensitivity of the eyelids occur. In both cases, the disease is usually unilateral. Orbital cellulitis in diabetic or immunocompromised patients should be considered as mucormycosis unless otherwise proven. Eschar of the oropharynx or the nose appears late and only in 10% of the patients with mucormycosis. Therefore, it should not be a sign to relay on. Bilateral orbital cellulitis may suggest of cavernous sinus thrombosis and diagnosis is made by computerized tomography. The clinical findings of cavernous sinus thrombosis are exophthalmos, unilateral or bilateral external and internal ophthalmoplegia that are usually accompanied by malaise and systemic fever (**Figure 16**). Nuchal rigidity as part of meningeal signs may also occur. Confirmation of the diagnosis is made by lumbar puncture. In orbital cellulitis and cavernous sinus thrombosis, blood cultures should be obtained when the body temperature increases to or over 39°C. In older patients, blood cultures are being obtained even if the temperature is normal. The source of the infection should be established by physical examination of the nose and mouth and imaging techniques (computed tomography and/or magnetic resonance imaging of the orbits and head. In contrast to preseptal cellulitis that is caused by infection from superficial skin wound, orbital cellulitis is most commonly caused by sinusitis (ethmoi‐ dal). Other sources may be upper jaw tooth abscess, otitis, mastoiditis, orbital osteomyelitis or extension from neglected preseptal cellulitis. Contamination may be by direct spreading through natural dehiscence sites and openings (foramina), veins, which are valveless or even nerves.

**Figure 15.** Cavernous sinus thrombosis in a diabetic patient. There was external ophthalmoplegia. The cause was mu‐ cormycosis.

**Figure 16.** Orbital abscess as a result of tooth abscess. Note the erythema and swelling of both eyelids and chick.

Orbital abscess is a complication of orbital cellulitis (**Figure 16**) [16, 17]. It should be suspected when orbital cellulitis aggravates despite treatment. When aggravation occurs, repeated orbital computerized tomography assists in confirming the diagnosis of orbital abscess. In such a case, drainage of the abscess and continuing systemic antibiotics is required. The source of the infection should also be treated by surgical drainage. In cases of sinusitis, functional endoscopic sinus surgery (FESS) or other procedures with removal of the sinus mucosa may be required to prevent recurrences.

Note: The antibiotic dosage is for adults. The author is not responsible for the dosage or for any use of antibiotics.
