Ординатура / Офтальмология / Английские материалы / Clinical Ophthalmic Echography_Harrie_2008

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FIG. 241. Microscopic anatomy of cavernous hemangioma

to as “cavernous,”’ as correlated to the microscopic structure of the tissue (Fig. 241). The angle kappa, as described by Ossoinig, refers to the slope of a line drawn along the tops of the vertical spikes within the

Case Study 135. Cavernous Hemangioma

FIG. 242. Diagram of angle kappa

lesion (Fig. 242). These tumors have a significant angle kappa because sound energy is absorbed and scattered as the beam travels through the tumor.

Another vascular lesion that can put pressure on the optic nerve is a lymphangioma. This lesion can entwine itself around orbital structures and will sometimes undergo spontaneous hemorrhage into its cystic spaces with marked expansion of the cyst with resultant pressure on orbital tissue.

CM is a 7-year-old girl who presented to her pediatrician with sudden proptosis of her left eye over the course of one day. Examination found marked proptosis and numerous tiny serous-filled cysts of the conjunctiva in the inferior fornix. She was urgently referred to an ophthalmologist for evaluation. He found vision in her right eye of 20/20 and her left eye of 20/50-2 with a 2+ afferent pupil defect. Hertel exophthalmometry measured the anterior position of the right eye at 11 mm and the left at 17 mm.

Echography was performed with B-scan showing a large, low reflective lesion adjacent to the optic nerve with multiple smaller cysts adjacent to it. A-scan revealed an 11-mm encapsulated cystic structure with very low internal reflectivity (Fig. 243). Spontaneous vascularity was not detected. The optic nerve thickness was thicker on the left, measuring 4.2 mm compared to the right, which measured 3.4 mm. There was a mildly positive 30° test with the left nerve reducing to 3.6 mm when she looked to the left. The diagnosis of an orbital lymphangioma with spontaneous hemorrhage was made. A multicystic lesion was confirmed on MRI scan (Fig. 244).

Because of the concern about optic nerve compression, an orbital surgeon was contacted and needle aspiration of the cyst was performed under ultrasound guidance. Ten cubic centimeters of blood was extracted and the eye immediately became less proptotic on the operating table. Examination in the office the next day showed an exophthalmometry measurement of 14 mm and improvement in visual acuity to 20/25. It was elected to not attempt surgical removal of the tumor because of its extensive entanglement

FIG. 243. Top: A-scan of orbital lymphangioma (vertical arrows). Bottom: B-scan of lymphangioma with large cyst and several smaller cysts (arrows)

with the optic nerve and extraocular muscles, but to manage the patient conservatively by aspiration of cyst fluid contents as needed to protect

HN is an 80-year-old male who presented with rapidly progressive proptosis and reduced vision over the period of a month. He gave a long history of smoking and no past history of thyroid disease. Examination found visual acuity OD of 20/100 and OS of 20/200. Intraocular pressures were 23 mm in the right eye and 24 mm in the left. Hertel exophthalmometry measured 22 OD and 23 mm OS. He had moderate lid edema and conjunctival chemosis. Slit-lamp examination showed mild corneal epithelial stippling bilaterally with poor tear film coverage. Fundus examination was unremarkable except for age-related macular drusen and retinal pigment epithelial changes. Visual field testing showed moderate peripheral depression.

Echography was performed with B-scan showing diffuse enlargement of the extraocular muscles. A-scan found significant enlargement of both superior recti with the right measuring 7.75 mm and the left 7.5 mm. The other muscles were diffusely enlarged. Internal reflectivity was generally heterogeneous but the superior recti were relatively medium reflective (Fig. 245). The optic nerves measured 4.5 mm OD and 4.3 mm OS with an equivocal 30° test on the right and a negative test on the left. CT scan demonstrated obvious thickening of the extraocular muscles at the orbital apex with apparent compression of the optic nerve.

He was urgently referred to an orbital surgeon, started on high-dose intravenous (IV) steroids and scheduled for surgery the next day. Orbital decompression was performed and the patient noted improvement in his vision later that evening. The IV steroids were continued for several days and he was discharged on oral prednisone after his visual acuity had been documented to substantially improve in both eyes.

FIG. 245. Top: A-scan of markedly enlarged extraocular muscle (vertical arrows). Bottom: B-scan of muscle (arrow)

Optic nerve dysfunction can occur in the setting of Graves’ disease by other mechanisms than compression by enlarged extraocular muscles.

GB is a 26-year-old woman who presented with complaints of reduced vision in her right eye over several weeks. Examination showed moderate lid lag and stare bilaterally with mild exophthalmos of 19 mm OD and 18 mm OS. Visual acuity was 20/50 OD and 20/25 OS with a 1 to 2+ afferent pupil defect on the right.

Echography was performed and demonstrated essentially normal extraocular muscle and optic nerve measurements bilaterally. There was an increase in the orbital fat volume on A-scan examination (Fig. 246), more on the right than on the left. CT scan confirmed an increase in orbital fat volume and showed straightening of the optic nerve (Fig. 247).

It was concluded that she had an optic nerve “on stretch” due to relative exophthalmos from

increased orbital fat and connective tissue volume without significant extraocular muscle involvement. An orbital decompression was performed to reduce orbital volume and reduce the tension on the optic nerve. Her visual acuity was noted to improve.

Orbital inflammatory processes can involve the optic nerve directly, as in optic neuritis, or secondary to the involvement of other ocular tissues. Echography is most helpful in imaging the retrobulbar portion of the nerve with the appearance of the T sign where the nerve sheaths merge with inflamed sclera. Otherwise, ultrasound is less useful in demonstrating inflammatory changes of the orbital portion of the nerve, which is better shown on MRI scanning after injection of enhancing agents (Fig. 248).

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FIG. 247. Computed tomography scan of increased orbital fat (arrow).

Case Study 138. Increased Orbital Fat in Graves’ Disease

FIG. 248. Magnetic resonance imaging scan of optic neuritis (arrows).

CW is a 25-year-old woman who presented with complaints of pain and reduced vision in her left eye for about a week. Examination found visual acuity of 20/20 OD and of 20/60-2 OS with a 3+ afferent pupil defect. The left eye was mildly proptotic. Fundus examination showed a normal right optic disc and moderate edema of the left disc with several focal hemorrhages. Some perivascular sheathing was noted peripherally.

Echography of the left orbit revealed increased lucency of subtenon’s space and the optic nerve sheaths with the appearance of a T sign (Fig. 249). A-scan measured the right optic nerve to be 3.5 mm and the left 3.7 mm, which was within normal limits for optic nerve thickness.

Magnetic resonance imaging scan showed optic nerve sheath enhancement after contrast injection, but no white plaques were noted in the brain as would be expected in demyelinating disease, such as multiple sclerosis. Systemic evaluation found a significantly positive antinuclear antibodies (ANA), which supported the diagnosis of systemic lupus erythematosis. She was treated with high-dose IV steroids with improvement in her vision in the left eye to 20/25. She subsequently experienced recurrences of her optic neuritis with response to steroids, but she began to have similar episodes in the right optic nerve. She eventually

FIG. 249. T sign–scleral thickening (large arrow) and adjacent optic nerve thickening (small arrow)

suffered some atrophy of both nerves but maintained functional vision.

Idiopathic inflammation at the orbital apex, such as in the Tolosa-Hunt syndrome, can result in reduction of vision in conjunction with motility disturbances. This syndrome usually presents with the abrupt onset of painful ophthalmoplegia involving the third, fourth, and sixth nerves. There is often associated hypesthesia of the skin in the distribution of the first division of the fifth trigeminal nerve.

JC is a 71-year-old woman who presented with the complaints of pain and reduced vision in her left eye for several days. Examination found visual acuity of 20/70 OD with a 3+ afferent pupil defect and acuity of 20/25 OS. Two millimeters of proptosis of the right eye was measured. She was also noted to have almost total ophthalmoplegia and reduced sensitivity of the periorbital skin. The remainder of the examination was normal except for mild nuclear sclerotic cataracts in both eyes.

Echography with B-scan was normal, but A-scan revealed thickening in the orbital apex in the area of the superior orbital fissure (Fig. 250). The extraocular muscles and optic nerve in the midand anterior orbit were of normal thickness. MRI scan was performed and showed enhancement of the cavernous sinus and superior orbital fissure (Fig. 251). A systemic workup was negative except for mild elevation of her sedimentation rate.

She was diagnosed with the Tolosa-Hunt syndrome and treated with high doses of oral prednisone. Her painful ophthalmoplegia rapidly improved, as did her visual acuity. She had only slight residual sixth nerve palsy after 2 weeks and the steroids were slowly tapered over another 3 weeks.

Pathology of the anterior orbit can cause visible abnormalities of the eyelids or periorbital tissue. A change in appearance of these areas even in the absence of other symptoms, such as pain, visual loss, or diplopia, can be the basis for presentation to the ophthalmologist.

FIG. 250. Top: A-scan of thickened orbital apex in the right eye (arrows). Bottom: A-scan of normal apex in the left eye (arrows)

CB is a 1-year-old boy who was noted by his parents to have some bluish swelling of the left upper eyelid shortly after birth. They attributed it to birth trauma but became alarmed when the swelling increased dramatically over 2 weeks. They observed that the lid became more swollen and reddish when the baby cried vigorously. The pediatrician, who obtained a CT scan that same day that was interpreted as showing diffuse orbital swelling, saw the child. A mass such as rhabdomyosarcoma could not be ruled out. The patient was referred to a pediatric ophthalmologist with the operating room on call for a possible emergency biopsy that evening.

A-scan revealed an orbital lesion that occupied the midand anterior orbit. A-scan showed heterogeneous internal reflectivity with areas of medium-to-high reflectivity interspersed with a relatively low area (Fig. 252). Rapid spike movements were detected consistent with arterial blood flow. This was confirmed when a hand-held obstetrical Doppler unit with a special probe adapted for the orbit was held against the lid. There was a moderately loud sound of arterial blood flow that persisted when the probe was angled in different directions. This was consistent with a highly vascular lesion. The combination of irregular internal reflectivity and arterial blood flow was most consistent with a hemangioma of the infantile type, or capillary hemangioma (benign hemangioendothelioma).

FIG. 252. A-scan of infantile hemangioma (vertical arrows)

Biopsy was cancelled and the child was treated with high-dose oral steroids with reduction in size of the tumor over several weeks. The parents were advised that the lesion would spontaneously involute over the next year or two and treatment should only be considered if the vision was threatened by amblyogenic factors, such as a ptotic lid occluding the visual axis or asymmetric astigmatism caused by pressure of the lesion on the globe.

Treatment of capillary hemangiomas often involves the use of the intralesional injection of steroids that reduces the systemic side effects versus a higher risk with the oral route.