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‘Pulling Sensation’ in the Eye. Is a CT Warranted?

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“It’s all about how you play the game,” you explain to your intern. “As an EM physician, you are a healer, an educator, a detective, a diagnostician, and a master strategist all rolled into one.” He still appears rather frustrated that the internal medicine team is trying to “block” his admissions for the 65-year-old gentleman with newly diagnosed metastatic lung cancer and the 52-year-old lady with CHF and a BNP of 16,000 ng/L. They’ve told him that the patients don’t meet “admission criteria” and that they are refusing to consult on the patient. He’s tried being polite, and when that didn’t work, he tried the more assertive route, to no avail. You and your senior residents provide your eager intern with some helpful hints about how to sell a better story and reiterate that we must be our patient’s best advocates – especially in their time of need. You offer to talk to the consultant yourself, but your intern decides he wants to try to take care of it himself. He says he’s going to go see one more patient, calm down, and then redirect his energy into getting the first two admitted.

After about 10 minutes, you go and check on your intern with the new patient he’s picked up in room 33. The patient is a 41-year-old male who presents to the ED with concerns that his left eye is progressively getting more swollen. He’s had some increasing eye pain and purulent drainage over the past six days. At first he thought that he was just having really bad seasonal allergies, but today, he started feeling a “pulling sensation” on the medial aspect of his left eye. He denies any headache, diplopia, sinus pain, rhinorrhea, nausea, vomiting, or recent trauma. He does note a subjective fever at home, and his temperature is 38.2°C in the ED. His vital signs otherwise demonstrate tachycardia to 123 bpm, but a normal blood pressure, oxygen saturation, and respiratory rate.

Your intern has asked the nurse to obtain a visual acuity on the patient and he is systematically going through his ocular exam when you walk by the room to check on him. He comes out of the room to give you an update on what he’s discovered so far. The patient has tenderness to palpation over his left medial orbit and possible entrapment on ocular exam. He has no additional pain with extraocular movement and no diplopia, but has so much periorbital edema that it wasn’t possible to get a consistent Tonopen measurement. There doesn’t appear to be any fluorescein uptake on the slit lamp exam, and other than conjunctival injection and the lid swelling, the patient has a normal ocular exam.
It is now about 4:30 pm and you know that in 30 minutes, all consultants turn into pumpkins and their pagers magically stop working. As you are about to ask your intern what he wants to do next, the medical student pulls up the ultrasound machine that the intern asked her to wheel over and hands it to him. He takes the linear array transducer and performs an ocular ultrasound at the bedside. He saves the following images: what do you see?

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What do you see on the ultrasound images? Conclusion in the following

 

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Dx: Periorbital Abscess Medial to the Eye

On the ultrasound images, you can see a 1.5 x 1 cm circular fluid collection just medial to the eye. There is some heterogenous material within the circumscribed area (arrow). Correlating the patient’s symptoms to the ultrasound images, you deduce that he likely has periorbital cellulitis and a periorbital abscess forming just medial to the eye (left image).

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Given what you’ve seen on ultrasound, your intern decides that he is armed with enough information to call ophthalmology and get the patient admitted before the witching hour. As predicted, the ophthalmology fellow on call says “Sure, I’ll come by and see the patient…but can you order a CT scan of his orbits for me?” Attempts to talk the fellow out of exposing the patient to additional radiation are met with profound resistance. Your intern decides its time to start choosing his battles. He orders the CT scan per the ophthalmologist’s request (right image), with the contingency that the fellow will start working on the patient’s admission orders. He was right of course – the CT gives no additional information. He then decides it’s time to call back the internal medicine team for his previous admissions.

You are tickled with pride as you hear your intern say, “Hey, I originally had three admissions for you, but I was able to get ophthalmology to take one of them. Let me tell you about the other two we want admitted for further workup in the hospital…” The internal medicine team decides not to argue with that logic, and your intern was able to arrange for appropriate dispositions for all three patients within a matter of minutes. Patting him on the back for a job well done, you advise him he has just earned the right to add the title of “expert salesman” onto his list of titles and job descriptions.

Tips & Tricks for Performing an Ocular and Periorbital Ultrasound

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01 Use a high frequency linear array transducer (10-13 MHz).

02 In most instances, you can place the ultrasound gel directly onto the patient’s closed eyelid to facilitate the exam. You can also place a small Tegaderm dressing over the patient’s eyelid and then apply the gel over the Tegaderm if you want to prevent any contact between the gel and the patient’s eye. The Tegaderm will not pull off eyelashes or eyebrow hairs when it is removed, and it is thin enough to use as a protective eye shield during your scan.

03 If your ultrasound machine does not have an ocular setting, you can use the nerve or small parts setting during your scan.

04 The eye is a great organ to ultrasound. It is a fluid filled structure that provides excellent visualization of the anterior chamber, the lens, the pupil, the posterior chamber, the posterior globe, and the optic nerve.

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05 To evaluate the posterior chamber for vitreous hemorrhage or retinal detachment, turn up the gain to achieve the best images.

06 You can perform a periorbital scan to evaluate for cellulitis, abscess, foreign body, or mass. Use plenty of gel to ensure you have a good acoustic window and to minimize air pockets between your probe and the area of interest.

07 Periorbital abscesses will appear similar to other soft tissue abscesses on the body. As you scan towards the area of interest, look for a spherical or elliptical collection of hypoechoic or heterogeneous material. The fluid collection may have a bright, hyperechoic border/capsule along the edges.

08 Abscesses may appear hypoechoic or anechoic during the initial stages of formation. As the inflammatory process progresses, the pus may begin to appear more heterogeneous with a mix of hypoechoic and hyperechoic material swirled together.

09 Differentiating between cellulitis and small abscess pockets may be difficult. Apply a small amount of pressure over the area of interest. Fluid collections secondary to cellulitis will redistribute with pressure. Abscess pockets will not diffuse under pressure.

10 Always obtain images in multiple planes (longitudinal, transverse, oblique) to help define the borders. Use the calipers on the ultrasound machine to calculate the dimensions of the abscess pocket.

11 Utilize contralateral organs and adjacent areas of normal appearing tissue for comparison.

12 With bedside ultrasound, there is no substitute for experience. The more scans you do, the better you will be able to differentiate abnormal from normal, even when you may not be sure exactly what the abnormality is.

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