Description: When I look at Figure 4.1, my attention is drawn to the left eye proptosis, conjunctival chemosis, lid erythema, and the most important limitation of adduction of the left eye (Fig. 4.1).

Differential Diagnosis: Her diagnosis is orbital cellulitis until proven otherwise. This condition is an ophthalmic emergency. Other conditions that should be considered when presented with proptosis and limitation of eye movement are orbital tumors, orbital inflammatory syndrome, thyroid disease, and lymphangioma.

History: Because orbital cellulitis is the most common cause of childhood proptosis, and she has a fever, I would ask about recent constitutional upper respiratory syndrome such as malaise, chills, sweats, and pain with eye movements. Also of importance is asking her about a decrease in vision or color perception.

Exam: On exam, I would look for optic neuropathy (afferent pupillary defect [APD]) and check vision closely. I would defer dilation, as pupils are an important monitoring tool when watching for orbital cellulitis progression. I would look at the optic nerve with a direct ophthalmoscope. I would check for eye movement restriction carefully in all gazes. Limitation of eye movement is a key finding in orbital cellulitis that is absent in preseptal cellulitis.

Workup: I would order a complete blood count with differential in addition to a stat computed tomography (CT) scan with contrast. On the CT, I would look for concurrent sinus disease and fat stranding typically seen with orbital cellulitis. I would also look for any orbital abscesses typically seen adjacent to the sinus.

Treatment: If there is an abscess, surgical intervention may be necessary, but first I would admit the girl for intravenous broad-spectrum antibiotics. If there are any signs of optic neuropathy (vision loss or APD), I would move to urgent decompression and/or drainage of the abscess.

Advice: I would discuss with the parents of the patient the natural history of orbital cellulitis and the good prognosis with immediate and aggressive intervention but the real risks associated with this condition if left untreated.

Follow-up: I would see the patient twice a day initially and then daily until improvement is seen. Improvement should occur over a 48- to 72-hour period.

Description: Figure 4.2 is a collage of a patient with bilateral asymmetric lid retraction, and bilateral proptosis that is worse in the right eye. I am concerned that the patient may have some degree of globe displacement in both eyes. I do not see any obvious corneal disease, conjunctival injection, or external trauma.

Differential Diagnosis: The number one cause of proptosis in an adult is thyroid eye disease. Other causes of proptosis include infections such as orbital cellulitis, tumors of the orbit, and inflammatory causes such as orbital pseudotumor. The patient’s use of propylthiouracil provided me evidence that he is being treated for hyperthyroidism.

History: I would start by asking if he has been diagnosed with thyroid disease. I would also ask about any of the symptoms associated with hyperthyroidism such as hyperactivity, heat intolerance, diarrhea, and sweating.