Plastics/Orbit Flashcards
What divides the orbital and palpebral lobe of the lacrimal gland
Lateral horn of the levator aponeurosis
accessory lacrimal glands
Krause - superior and lower conj fonix Wolfring - Upper lid superior tarsal border
Drainage system anatomy
punctal opening .3mm, ampulla 2mm and perpendicular to lid margin Canaliculus 8-10mm Valve of rosenmuller, 90% of the time these merge into a common canaliculus lacrimal sac is about 12-15mm vertically, the duct exits at valve of hasner under the inferior turbinate 25-30mm posterior to the to the lateral margin of the anterior nostril.
Approach to tearing
Either overproduction or impaired drainiage.
Over production of tears
Neurologic (VII abberant regeneration - crocodile tears) Ocular Surface Lid and Lash Malposition Inflammation (uveitis)
Blocked drainage
Punctal malposition - laxity/ectropion Pump Failure - CNVII palsy Punctal senosis - toxic meds (, trauma, radiation, autoimmune) Canaliculitis (think actinomyces) NLDO - Congenital vs. Aquired (Primary involutional stenosis), Secondary (infection/tumour)
Test for laxity, how many mm= positive distraction Snap Back test, how long hanging out without blink = positive snap
8mm, 6 sec
Dye disappearance ?Jones 1 test ?Jones 2 test
dye still there at 5 min = probable blockage Jones 1 = put fluorescein in the eye, use a q-tip to see if you recover any from the nose Jones 2 = put fluorescein in the, flush the punctum and now see if you get fluorescein on your nose q-tip
Which bacteria are responsible for canaliculuitis
Actinomyces (anerobic gram + bacilli, sensitive to Pen, sulfur granules) , fusarium and nocardia
U/s high reflectivity
Anything calcified in the eye: - Choroidal osteoma - ONH drusen - RB, retinocytoma - phthisis Orbital hemangioma Dermoid maybe (if it has bone/teeth in it)
Orbital hemorrhage
Trauma Orbital surgery Bleeding diathesis Retro-bulbar anaesthetic injection Vascular tumors (varix, hemangioma, lymphangioma)
Proptosis - broad categories
Orbital mass/inflammation Orbital hemorrhage Axial proptosis (e.g. high myopia) Lid retraction Contralateral enophthalmos
Proptosis in childhood (broad categories)
Orbital mass/inflammation Orbital hemorrhage Axial proptosis (e.g. high myopia, congenital glaucoma) Lid retraction Contralateral enophthalmos
Enlarged EOM
Thyroid Myositis, IOI Hematoma/bruising Mets to muscle Inflammatory infiltration (e.g. sarcoid?) CCF
Bilateral proptosis
Thyroid Axial length Bilateral lid retraction CCF Inflammatory (wegener, sarcoid, IOI, myositis) Structural (craniofacial) Neoplastic (lymphoma, leukemia, neuroblastoma, mets, glioma)
Pseudo-proptosis
Lid retraction Contralateral enophthalmos Contralateral ptosis High axial length (myopia, cong glaucoma) Assymetric orbit size (e.g. craniofacial disorders)
Pulsatile proptosis
Brain: (sphenoid wing gone) - mucocele - encephalocele - NF1 - removal of orbital roof (surgical) - lytic bone lesions (?) Vascular - CCF - dural cavernous fistula - varix
Hyperostosis
Fibrous dysplasia Ossifying fibroma paget’s disease
Lytic skull lesions
Metastatic dz Histiocytosis X (Langerhans histiocytosis)
Triad of proptosis, lytic bone lesions, DI
Hand Schuller Christian Dz (type of histiocytosis X)
Bloody tears
Canalicular/NLD: - trauma - tumor - infection - inflammation - iatrogenic (after probing, DCR) - foreign body
T1 vs T2 - how to tell apart
Vitreous is dark on T1 (think when you go into a room, it’s always dark to begin with - i.e. T1)
Which MRI is best for MS?
T2
Lid retraction/lid lag
Thyroid Aberrant regeneration 3rd Myaesthenia Congenital fibrosis CN7 palsy Iatrogenic (after ptosis/bleph repair) Parinaud’s dorsal midbrain syndrome Contralateral ptosis (herring’s law)
Calcified orbital mass
Dermoid Cavernous hemangioma Meningioma Phlebolith
Enophthalmos
Pseudo - other side proptotic Breast Ca mets (only orbital met to cause enophthalmos) Floor # Phthisis Trauma (ruptured globe)
Cystic orbital lesions
Dermoid Epidermoid Pleimorphic adenoma
Blue cell tumor
B-cell lymphoma: - MALT - diffuse large B cell - Merkel cell Leukemia Neuroblastoma Rhabdomyosarcoma RB Ewing’s sarcoma Wilm’s tumor (kidney)
5 types of adenoid cystic ca (on histology)
(CBC, ST) - Tubular - Sclerosing - Comedo - Cribiform - Basaloid
Sinus things that come to the orbit
- Mucocele - Burkitt’s lymphoma - scc, mucoepidermoid ca
DDx of major orbital inflammation
Infectious Inflammatory - IOI - Sarcoid - Wegener - RA - SLE - PAN - GCA
Orbital metastatic tumors
Adults: Breast, lung, ovary Kids: neuroblastoma, Ewing’s sarcoma
6 paraneoplastic syndromes in the eye
MAR CAR BDUMP Eaton Lambert Horner’s Opsoclonus
5 cancers that give paraneoplastic syndromes
Lung ca Breast Ovary Neuroblastoma Melanoma (there are others)
Orbital neural tumors
Schwannoma Glioma Meningioma
Orbital mesenchymal tumors
Fibrous histiocytosis Rhabdo Fibrous dysplasia Ossifying fibroma Liposarcoma, fibrosarcoma, chondrosarcoma, osteosarcoma
Orbital lymphoid tumors
Benign lymphoproliferative hyperplasia Lymphoma: - MALT - CLL - follicular - large B cell - Burkitt’s lymphoma
Xanthogranuloma (4 syndromes)
JXG Necrobiotic xanthogranuloma Erdheim Chester Adult onset xanthugranuloma
Sources of orbital cellulitis
Trauma Extension from skin Extension from sinus dz Extension from lacrimal drainage system (canaliculitis, dacryocystitis) Dental Endogenous
Lacrimal gland tumors
Infectious Inflammatory: sarcoid, Wegener, idiopathic, Sjogren’s, PAN, GCA Neoplastic benign: pleimorphic adenoma Neoplastic malignant: malignant mixed tumor, adenoid cystic ca Systemic syndromes: Sjogren, Muciklz (sarcoid)
Orbital vacular tumors
Cavernous hemangioma Capillary hemangioma Lymphangioma Varix Hemangiopericytoma AV fistula (CCF, DCF)
Subperiosteal orbital abscess - indications for surgical drainage in children
- >9 years old - ON involvement - frontal sinusitis - non-medial location of abscess - large abscess - recurrent/chronic infection - dental source - gas on CT (anaerobic)
Punctal stenosis - risk factors
Female Age Trauma Inflammation (OCP, SJS) Tumor
Most common orbital mets in men and women
Women: breast Men: lung
Canalicular stenosis - risk factors
Female Age Trauma Infection Inflammation Tumor Radiation, dacryolith, allergy, canaliculitis
NLDO obstruction ddx
Congenital Trauma Infection Tumor (lymphoma, SCC, mucoepidermoid) Nasal polyp, nasal cancer Sinuz dz Granulomatous inflammation (sarcoid, wegener)
Risks of retro-bulbar anaesthesia
Retro-bulbar hemorrhage Globe perforation ON damage Brainstem anaesthesia
What are the symptoms of brainstem anaesthesia
Decreased RR LOC Hypotension, decreased HR
How do you manage brainstem anaesthesia
Supportive. Call code, intubate, etc. ABC’s
Ddx of retro-orbital mass (behind the globe)
Glioma Meningioma Abscess Inflammatory (IOI, other) AV fistula, varix Mets
Ddx of supero-nasal orbital mass
Most likely: Mucocele, encephalocele Sinus carcinoma Less common: Dermoid, epidermoid Vascular Inflammatory
Ddx of infero-nasal orbital mass
Dacryocystitis Mucocele Canalicular/NLD/sac tumor
Ddx of supero-lateral orbital mass
Dermoid Epidermoid Lipodermoid Enlarged lacrimal gland (inflammation, tumor, infection)
Ddx of bilateral orbital proptosis
TED Axial myopia Bilateral lid retraction Metastatic disease (not breast) Bilateral vascular or other tumors Bilateral CCF
Which sinus is first to aerate
Ethmoid
When does the frontal sinus aerate
6 years old
When does the sphenoid sinus aerate
Puberty
Which is the largest sinus
Maxillary
Where does the annulus of zinn originate from
Peri-osteum
What tissue does the orbital septum come from
Peri-osteum
What 3 things are behind the septum
- orbital lobe of lacrimal gland - lateral canthal tendon - SO trochlea
Where does the septum insert into the levator (relative to the tarsus)
2-5 mm above tarsus (in asians, somewhere further down on the tarsus)
Where does the levator insert into the tarsus
Inferior half of tarsus on the anterior surface
How long is the levator
40 mm
How long is the levator aponeurosis
15-20 mm
What is the correlate in the lower lid of Whitnall’s ligament
Lockwood ligament
What is the correlate in the lower lid of the levator aponeurosis
capsulopalpebral fascia
What is the correlate in the lower lid of Muller’s
Inferior tarsal muscle
How tall is the tarsus in the upper lid? Lower lid?
10 mm upper 4 mm lower
What bone is fractured in a tripod #
Zygoma in 3 places. (so no IR entrapment)
How many LeFort’s are there and what is each one
I - maxilla above teeth, no orbital involvement II - orbital floor III - orbital floor, med + lateral walls, +/- optic canal
What are the signs of thyroid eye disease
Lid retraction Lid lag Proptosis Decreased EOM/diplopia Corneal exposure keratitis Decreased lacrimation (inflammation of lacrimal gland) ON compromise Conj injection, congested vessels
What is the order of muscle involvement in TED
I’M SLO inferior > medial > superior > lateral > obliques
How long does the eye need to be quiet for in TED before you can offer strab surgery
6 months
What is the order of surgeries in TED
decompression then strab then lids
How long does radiation take to work in TED
2-4 weeks So if it’s an acute problem (ON compromise), can’t rely on radiation to quickly get it done
What are your options for treating the hyperthyroidism in TED
Anti-thyroid meds (methimazole, PTU) Radiation (RAI) Surgical (thyroidectomy)
What are your options for treating optic neuropathy in TED
Steroids (not for acutely severe dz) Radiation (takes 2-4 weeks) Decompression (most effective)
What are your options for treating exposure keratitis in TED
Lubrication, plugs, moisture chamber goggles, etc Tarsorrhaphy Amniotic/gunderson flap for severe
What workup should you do for orbital lymphoma (bx proven)
Check systemic LN’s (on exam) Bone scan, Bone marrow bx CBC, SPEP CT chest/abdo Refer to heme/onc
What are the signs of Wallenburg’s lateral medullay syndrome and what vessel obstruction causes this
PICA obstruction - ipsilateral Horner - ipsilateral facial decreased pain/temp - contralateral trunk decreased pain/temp - nystagmus, skew - dysarthria, dysphagia, dysphonia - ataxia
What are the pituiary hormones (ant and post)
FLAT PIG, OA Anterior: - FSH - LH - ACTH - TSH - Prolactin - GH Posterior: - Oxytocin - ADH
What are the features of JXLR? Visual prognosis? FA findings?
Macular schisis in NFL Sometimes peripheral retinoschisis Vitreous cells, syneuresis, hemorrhage Hyperopia 20/200 range Fa = CME that doesn’t leak
What do oblate and prolate mean
Describes an oval ball. Depends on the axis that it spins on. Oblate = like a lentil (short and fat, spinning axis is short) Prolate = like a football (long spinning axis)
What are the path features of BCC
- nests of basaloid cells - peripheral pallisading - retraction of nests from surrounding stroma - little cytoplasm - rare mitotic figures
What are the path features of SCC
- atypical nests of squamous cells - infiltrating past BM into dermis - inter-cellular brides - perineural and lymphatic invasion
What are the signs and symptoms of OIS on exam and how do you treat
Symptoms: pain and decreased Va Signs: conj injection K edema AC rxn may have NVI, NVG retinal MA’s delayed choroidal and retinal filling on FA Investigate with carotid doppler Endarterectomy
How do you do a gram stain
“VIAS” Cyrstal violet x 60 sec Iodine x 60 sec Alcohol x 5 sec Safranin x 60 sec (rise in between each one)
What are the features of anterior segment ischemia on exam? How do you treat it? How do you prevent it?
Pain and decreased Va Conj injection, maybe edema K edema AC rxn Rx with steroids Avoid by never doing 4 muscle surgery If you really have to, some say you can avoid it if you wait like 10 years before operating on the 4th muscle (but this doesn’t seem to be consistent in the literature)
What machine uses the Badal principle
Lensometer
What are two ways to estimate Va through a dense cataract
PAM Laser interferometry (two bright dots and creates an interference pattern)
What are the signs of malignant hyperthermia
First: Muscle rigidity Respiratory acidosis (high CO2) / metabolic acidosis Then: High temp High HR High RR
How do you treat malignant hyperthermia
- stop operating - IV dantrolene - hypertenvilate with 100% O2 - cooling blanket - cooled IV NS - calcium, bicarb, glucose
How do you treat Bartonella
Oral doxy
What are the features of bartonella infection
Parinaud’s (granulomatous follicular inflammation, lymph node) Neuro-retinitis (ON inflammation + macular star) Chorioretinitis
Explain the optics of a slit lamp (same as operating microscope)
You –> astronomical telescope –> inverting prism –> galilean telescope –> pt’s eye
How does a Hruby lens help you see the fundus? What about handheld lenses (78, 90). What about Goldmann 3 mirror?
Cornea is high plus, so would never let you see beyond the anterior vitreous. 3 options to see farther: - contact lens to neutralise K power (Goldmann) - high minus lens to diverge the light a lot (hruby) - hand-held lens creates an astronomical telescope (inverted image - e.g. 78, 90)
Explain the optics of a lensometer
Target object Known lens (Badal lens) Unknown lens then astronomical telescope then your eyes (observer) The target object moves such that, after it’s light passes through teh badal lens and the back vertex of the unkonwn lens, the light emerges parallel. This light then goes into the little astronomical telescope at the eyepiece, which you look into. Moving the object is linearly related to power of the unknown lens. It’s linear because of the Badal lens.
How does a keratometer work? What are the 2 different kinds and how do they differ?
Keratometer works on the principal that the cornea is a reflecting surface of known index of refraction. It takes an object and it’s reflected image, uses the relative sizes of the two to figure out the reflecting power. From there you can back-calculate to the radius of curvature (if you know the index of refraction which is the same for all eyes), and from that figure out the refractive power. It only measures the central 3 mm of the cornea. There are 2 designs: - Hemholtz - fixed object size, measures the image size - Javal-Schiotz - changes object size to get a known image size You always have to line up 2 images which is beacuse of a ‘doubling prism’ that it uses - something to do with minimising the effect of the person moving their eye, shaking, etc during the keratometry measurement.
