Orbits

Question 1

superior orbital fissure contents

Answer 1

CN III, CN IV, CN V1, CN VI, superior opthalamic vein

Question 2

inferior orbital fissure contents

Answer 2

CN V2 (maxillary division)

provides innervation to eyelid, upper lip, nose; infraorbital artery

Question 3

compartments of the orbit

Answer 3

preseptal, post septal (extraconal, conal, intraconal; globe)

Question 4

orbital infection types

Answer 4

preseptal, orbital cellulitis/phlegmon, subperiosteal abscess, orbital abscess, cavernous sinus thrombosis

may be caused by paranasal sinuses, trauma, foreign body, odontogenic infection

Question 5

orbital hemangioma

Answer 5

cavernous and capillary hemangioma

cavernous: adults; progressive proptosis; intraconal

capillary hemangioma: children; similar to port-wine stain/strawberry hemangioma

Question 6

orbital lymphoma

Answer 6

lacrimal gland typically involved; painless downward proptosis

hyperdense on CT and hypointense on T1/2

may mold to the globe

Question 7

lymphangioma globe

Answer 7

hamartomatous lesion in pediatric population; low flow lymphatic malformation

involve extraconal compartment typically; multilocular cystic mass

Question 8

schwannoma/neurofibroma

Answer 8

neurofibroma/schwannoma are indistinguishable when they occur in orbit, although schwannoma is more common

most commonly affect V1 in the superior orbit

Question 9

metastasis to orbits

Answer 9

breast, lung, thyroid, RCC, melanoma

metastatic scirrhous breast cancer can prevent exopthalmous or cause frank enopthalmos due to fibrosis

Question 10

lacrimal gland lesions

Answer 10

epithelial tumors (pleomorphic adenoma) and malignancy (adenod cystic, mucoepidermoid carcinoma)

sarcoid and lymphoma may also impact lacrimal gland

also enlarged with orbital pseudotumor

Question 11

thyroid ophthalmopathy (thyroid eye disease)

Answer 11

orbital inflammation due to lymphocytes that cause fibrosis of extraocular muscles

increase in intra-orbital fat&raquo_space; stranding&raquo_space; enlargement of muscles

I’M SLOW : inferior, medial, superior, lateral rectus muscles

Question 12

pseudotumor vs thyroid ophhalmopathy

Answer 12

thyroid ophthalmopathy: b/l and I’M SLow enlargmeent of extraocular muscles; spares muscle tendons

pseudotumor: isolated lateral rectus enlargement

Question 13

optic nerve glioma

Answer 13

most common tumor in the optic nerve-sheath complex

low grade astrocytoma, associated with NF1/bilateral in children

optic nerve glioma in adults is usually anaplastic astrocytoma or GBM

Question 14

appearance of optic nerve glioma peds/adults

Answer 14

peds: fusiform enlargement; may have cyst/nodule appearance
adults: enhancing mass which extends intracranially to involve optic chiasm; may involve optic radiations

Question 15

optic nerve meningioma

Answer 15

second most common optic nerve sheath tumor; arises from archnoid cells within leptomeninges

middle aged female with slowly progressive visual impairment

Question 16

imaging appearance of optic nerve meningioma

Answer 16

circumferentially thickened; uniform contrast enhancement

tram track sign

Question 17

optic neuritis

Answer 17

inflammation of optic nerve&raquo_space; subacute vision loss, reduced color perception

oftend ue to MS, although from viral infection, sarcoid, vasculitis, toxin exposure

Question 18

imaging appearance of optic neuritis

Answer 18

optic nerve enlargement, T2 prolongation; enhancement = active disease

chronically, optic nerve atrophies

most will also have brain white matter lesions

Question 19

Devic syndrome

Answer 19

optic neuritis + spinal demyelination without brain lesions

Question 20

globe lesions

Answer 20

retinoblastoma, coat disease, retinopathy of prematurity, persistent hyperplastic primary vitreous (PHPV), coloboma

Question 21

retinoblastoma

Answer 21

most common primary malignant tumor of globe; leukocoria (white pupillary reflex) in kids < 5yo

usually unilateral; bilateral with p53 tumor suppressor mutation assocation

hyperattenuating enhancing retinal mass with calcification

Question 22

trilateral retinoblastoma

Answer 22

bilateral retinoblastoma with pineal gland pinealblastoma

Question 23

quadrilateral retinoblastoma

Answer 23

b/l retinoblastoma + pinealblastoma + suprasellar retinoblastoma

Question 24

coat disease

Answer 24

vascular disease of retina; lioproteinaceous subretinal exudates&raquo_space; retinal detachment

normal globe, but features subretinal soft tissue that does not enhance

Question 25

retinopathy of prematurity (ROP)

Answer 25

premature infants, prolonged oxygen therapy; abnormal vascular development, hemorrhage, retinal detachment

both eyes affected equally; bilateral micropthalmia with increased attenuation (prior hemorrhage)

distinguish from retinoblastoma by small orbits (micropthalmia)

end stage is phthisis bulbi

Question 26

persistent hyperplastic primary vitreous (PHPV)

Answer 26

persistent embryonci vasculature within vitreous&raquo_space; loss of vision from hemorrhage, cataracts, detachment

full term infants

small eyes (microphtalmea) with increased attenuation of vitreous; no calcifications

Question 27

coloboma

Answer 27

incomplete fusion of embryonic intraocular&raquo_space; long/malformed globe

associations trisomy 13/18; CHARGE, VATER

cone/notch-shaped deformity; outpouching posteriorly

morning glory deformity`

Question 28

congenital orbital lesions

Answer 28

sphenoid wing dysplasia, septo-optic dysplasia

Question 29

sphenoid wing dysplasia

Answer 29

NF1; transmission of CSF pulsation through sphenoid wing defect may classically produce pulsatile exopthalmos

Question 30

septo-optic dysplasia

Answer 30

optic nerve hypoplasia, agenesis of septum pellucidum

associated with schizencephaly; full thickness cleft in cerebral hemisphere