Ординатура / Офтальмология / Английские материалы / Clinical Ophthalmic Echography_Harrie_2008

LL is a 25-year-old woman who presented with the sudden onset of pain around her right eye and noted a “blood blister” under the upper eyelid with some lid ecchymosis. Echography revealed widening, echolucency, and low reflectivity of the subperiosteal space (Fig. 149). She was treated with cold compresses and the discontinuation of aspirin products. Follow-up ultrasound demonstrated a multicystic lesion consistent with an orbital lymphangioma or orbital varix. She had a history of a similar lesion under her tongue.

Less common causes of pain around the eye and orbit include metastatic tumors from distant sites or secondary invasion from contiguous areas, such as the paranasal sinuses. This pain is especially severe in rapidly expanding lesions that often induce an inflammatory reaction, in cases of perineural invasion, and also in those with bone destruction.

Metastatic invasion of the orbit may give a V pattern of reflectivity on the A-scan. This appearance is due to the manner of infiltration of the orbital tissue by the malignant cells. The area of invasion becomes relatively low reflective because of the dense homogeneity of the neoplastic cell population with a relative paucity of interfaces between

different tissue types. Adjacent to the central concentration of cells are areas of higher reflectivity and heterogeneity as malignant cells less densely infiltrate normal orbital tissue. The A-scan spikes in such an area are reflected more strongly by the multiple tissue interfaces. Metastatic tumors in the orbit are generally quite firm to compression when they are imaged on the paraocular examination.

FIG. 149. A-scan of subperiosteal hemorrhage (vertical arrows)

LT is a 45-year-old woman with a history of breast carcinoma treated 5 years previously with mastectomy, radiation, and chemotherapy. She had been in remission since that time but presented with painful proptosis of her right eye. She also complained of diplopia and was found to have some restriction of her extraocular motility. Fundus examination did not reveal any choroidal tumors.

The A-scan demonstrated an orbital mass superiorly that was quite hard to compression by the probe on the paraocular examination. Internal reflectivity of this lesion was irregular with a V pattern of higher peripheral spikes that decreased in height towards the center of the lesion and rose again on the opposite side (Fig. 150). The differential diagnosis in this patient included metastatic breast carcinoma of the orbit. This was later confirmed on needle biopsy and she underwent a course of palliative orbital radiation that temporarily relieved her symptoms.

Invasion and destruction of the orbital walls creates high reflective tissue interfaces that are dis-

FIG. 150. A-scan of metastatic tumor in the orbit with a V pattern of reflectivity (vertical arrows)

played outside the normal boundaries of the orbit. The invasive process erodes the bony walls of the orbit and the ultrasound beam is able to penetrate more deeply than it can normally. The display of signals beyond the usual limits is a clue to the absence of bone.

FIG. 151. A-scan of invasion of nasal orbit (arrows)

FIG. 152. Computed tomography scan of carcinoma (arrow)

ing any significant degree of orbital pain. Such patients may complain of a low level of discomfort or a vague sense of pressure inconsistent with the size of the tumor. The consistency of the orbital fat and connective tissue is rather elastic. The low resistance anteriorly allows forward proptosis of the globe to an advanced stage before symptoms become apparent.

AL is a 50-year-old man who noted occasional mild sensations of pressure around his right eye that were more apparent when he bent over to pick up something. He lived alone and was not aware of the progressive prominence of his right eye until a friend who had not seen him for several years mentioned it. Examination found 8 mm of axial proptosis with normal visual acuity and full extraocular movements.

Echography demonstrated a high reflective, multiseptate, well-outlined tumor within the muscle cone with a moderately positive angle kappa. It measured 19.13mm in greatest diameter. The A-scan

probe was reapplied with moderate pressure to the globe for 30 seconds, after which the tumor was remeasured and the lesion showed delayed compressibility by reducing in size to 17.53 mm (Fig. 153). Echographic characteristics were quite characteristic of a cavernous hemangioma and the growth was easily removed in total by an orbital surgeon with the subsequent pathological verification of the diagnosis.

The resistance of the orbital tissue is low to forward expansion of tumors even with explosive growth. The degree of discomfort is generally relatively mild even in cases of marked proptosis.

AM is a 10-year-old boy who was playing with a wiffle ball when it struck his left eye. There was no apparent injury and he continued playing after a few minutes. The next day his parents noted some mild redness and swelling of his lids on that side, but he had no complaints and went off to school. By that evening the swelling had increased dramatically but he mentioned only a mild pressure feeling. The parents were concerned and took him to the emergency room. An ophthalmologist was called in for a consultation and felt the child had suffered an orbital hemorrhage from the ball. A CT scan showed diffuse orbital opacity with increased tissue volume compatible with the diagnosis of hemorrhage (Fig. 154).

Echography demonstrated a large, firm, very low reflective lesion within the orbit measuring over

Fig. 154. Computed tomography of rhabdomyosarcoma (arrow)

FIG. 155. A-scan of rhabdomyosarcoma (vertical arrow)

19.0 mm in greatest dimension (Fig. 155). It was moderately firm to compression. Spontaneous vascularity was noted. The differential included orbital hemorrhage, but a solid mass such as rhabdomyosarcoma could not be ruled out. He was urgently referred for orbital biopsy and frozen sections revealed that it was a rhabdomyosarcoma. The orbit was extenerated, which was standard therapy at that time. Current treatment protocols generally avoid such radical therapy and are based on orbital radiation and chemotherapy.

Echography is a valuable ancillary test in the evaluation of ocular and orbital pain. Its judicious use can often result in the correct diagnosis or aid in the selection of the most effective subsequent testing modality.

Blurred vision is the sine quo non of visual system symptoms. Concern about loss or reduction of the ability to see is a fundamental concern to any normal individual. Rarely, a psychotic patient may mutilate his own eye and suffer permanent damage. This can occur because of distorted feel-

ings of guilt that drive the sufferer to harm himself as punishment for the perceived sin of misuse of his eyes. In the Greek tragedy Oedipus, the king puts out his own eyes when he realizes that he has inadvertently killed his father and taken his own mother as wife.

TH is a 45-year-old Hispanic woman who was referred for echography to evaluate her eyes regarding any potential for vision. At the age of 25 she had suffered a psychotic episode and stuck a fork into each of her eyes. She had been unable to see light since that time and was mentally stable on medication. Examination found questionable bare light perception in the right eye and no light perception (NLP) in the left. Dense corneal opacities precluded visualization of the fundi.

Echography revealed bilateral phthisis bulbi with total retinal detachments, plaquelike choroidal calcification (Fig. 156), and short globes with axial lengths of 20.34 in the right eye and 21.1 in the left. The referring ophthalmologist was informed that there was no visual potential in either eye.

When the patient presents with the complaint of a reduction in vision, a careful history is essential. Just as with eye pain, historical information must be

FIG. 156. B-scan of phthisical globe with calcified choroid (arrow)

gathered in a systematic way. The benefits of careful attention to the patient’s specific complaint are immediate. The subtle nuances that emerge when looking directly at her while she relates the problem in her own words may lead the examiner in a different direction than was initially intended. Really listening, asking pertinent questions, and restating points for clarification are vital history-taking skills that pay important dividends in the final balance sheet of effective, caring medical practice.

The change in vision is analyzed regarding its character. Is it total or partial? Is it persistent or transient? The patient may describe it as a film over the eye or a cloud or a veil. It may be a dark spot in the center or a curtain covering a quadrant of the field of vision. Some patients may find it difficult to articulate the nature of the problem. One elderly lady said, “My vision just doesn’t seem right. I can’t look at something very long before it goes funny.” She had not used the word double to describe the problem but on direct questioning she realized that she was seeing two objects. When either eye was covered her symptoms went away.

The location of the visual deficit is important to elicit. The central scotoma of optic neuritis is different than the visual dysfunction of a homonymous hemianopsia. Some patients are not very good at explaining their symptoms and this requires the examiner to ask simple and direct questions to refine exactly where in the field of vision the difficulty lies. It is helpful to ask the patient to look at the examiner’s nose at a distance of 1 to 2 feet and first describe what is seen with the normal eye in a case of unilateral visual loss. This eye is then covered and the affected eye is directed at the practitioner’s nose. “Now, tell me what you see as you

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focus on my nose but notice the face around it.” This is a valuable technique that can pick up a central or paracentral scotoma, an altitudinal defect, or a general depression in visual perception.

The onset and duration of the decrease in vision is then noted. The sudden catastrophic visual loss of a central retinal artery occlusion occurs over a few minutes to an hour. The slow progressive loss of an optic nerve sheath meningioma can happen over years without the patient being aware of it until it has resulted in substantial depression of vision. Amaurosis fugax is Latin for temporary blindness and describes episodes of gray-outs or black-outs of vision that last from seconds to minutes. These fleeting snatches of blindness often have a vascular basis due to transient embolic or vasospastic phenomena. In some cases it is obvious to the clinician that the process resulting in visual loss has occurred over a long time period but the patient has only recently become aware of it. In such cases the patient briefly closed the normal eye and suddenly became aware that the vision was blurred in the opposite eye.

Case Study 70. Phthisis Bulbi

The degree of the reduction in vision is important to note. The evaluation and treatment of profound visual loss is usually urgent. The catastrophic loss of vision of a central retinal artery occlusion is often permanent, but in some cases reversible if heroic measures are taken within the first hour. The vascular occlusion of arteritic optic neuropathy must be emergently treated with high-dose steroids to prevent further visual reduction and to protect the opposite eye. The descending curtain of a detaching retina must be promptly repaired before the macula separates and markedly worsens the prognosis for visual recovery.

The clinician must also pay attention to more subtle degrees of reduction of vision. The patient whose vision is recorded by the technician as 20/20-2 could easily be passed off as normal. However, when that patient is observed while reading the eye chart, it is apparent that it is not a sharp, crisp 20/20, but a slow and hesitating one. This requires the practitioner to deviate from his busy schedule and devote adequate time to more carefully evaluate the problem. Amsler grid testing, pupil evaluation, and possible formal visual field testing may be required.

TM is an 8-year-old boy who had undergone strabismus surgery for esotropia and was also treated with glasses and patching for amblyopia. He had responded over 6 months to treatment with improvement to the 20/30 level of vision in the amblyopic right eye. However, on the next 3-month appointment he had dropped the visual acuity in that eye to 20/40-2. His ophthalmologist felt this was unusual with his parents’ careful adherence to the glasses and patching regimen. A careful examination of the optic nerve was performed and early disc pallor was noted that had not been previously observed.

Echography was performed and revealed right optic nerve thickening to 7.45 mm with a negative 30° test, meaning that the nerve thickness stayed the same on abduction of the eye. This suggested a solid enlargement of the nerve versus one due to increased intrasheath fluid (Fig. 157). Magnetic resonance imaging (MRI) scanning was then per-

FIG. 157. A-scan of optic nerve glioma (vertical arrows)

FIG. 158. Magnetic resonance imaging of glioma with involvement of chiasm (arrow)

formed and demonstrated fusiform enlargement of the nerve with extension into the optic chiasm (Fig. 158). Neurosurgical exploration later confirmed an optic nerve glioma. The child has been closely followed with repeat scans and thus far the tumor has not grown.

A low threshold of suspicion is very important for the patient in whom “things just don’t fit together.” The examiner is obligated to explain why a given patient cannot be refracted to 20/20. This is more difficult in someone with existing pathology, such as a cataract or macular degeneration. This can create a trap because the reduced visual acuity can be ascribed to the identifiable problem and the examination stops at this point and a more serious underlying disease process is missed.

TH is a 62-year-old man who saw his ophthalmologist with the complaint that his glasses were not adequately correcting his vision. Examination found visual acuity at the 20/50 level in both eyes and a mild nuclear sclerotic cataract bilaterally. His reduced vision was attributed to the cataracts and he was offered surgery, but the patient stated he functioned adequately in daily life and opted to return in a year. A few months later he experienced severe headaches and sought care at the local emergency room. An MRI scan was performed and a large pituitary tumor was identified with chiasmal compression (Fig. 159). He was sent to a neuro-ophthalmologist for baseline testing before neurosurgery was scheduled to remove the tumor.

FIG. 159. Pituitary tumor with chiasmal compression (arrow)

The consultant recorded bilateral temporal optic disc pallor and a visual field documented a severe bitemporal field defect.

Any associated symptoms can provide helpful clues to the diagnosis of the etiology of the change in vision. A rapid and variable change in refraction in association with increased thirst and urination is suggestive of diabetes. A 35-year-old woman who presents with reduced vision in one eye associated with pain on movement of the eye and paresthesias in her hand over the past year is likely to have a demyelinating disease, such as multiple sclerosis. It is important to ask the patient specific questions about such systemic problems as she may not see the correlation to the visual system and fail to volunteer the information.

Once a thorough history has been taken, the examination should start with a careful refraction to document the best corrected vision. This is the starting point in the evaluation of decreased vision. The eye practitioner speaks in terms of best corrected vision. The patient is usually more concerned about uncorrected vision: “Doctor, I can’t see the big E on the chart without my glasses. Does that mean I am legally blind?” The evaluation of early disease processes can only begin in the context of an accurate best corrected visual acuity. The refraction is often relegated to a technician and the patient sees the doctor after this has been done and the pupils dilated. Unfortunately these two critical pieces of information are not available for direct confirmation by the eye professional. If there is any question about their accuracy the patient is asked to return in a day or so to allow the doctor to get a feeling for the refraction and perform a meticulous pupil examination.