Flashcards in Eye Pathology Deck (29):
What are the three broad classes of causes of red eye? What are major examples of each?
- life-threatening: skull fracture with subconjunctival hemorrhage, conjunctivita neonatorum, scleritis, neoplasms
- sight-threatening: glaucoma, uveitis, keratitis, gonococcal conjunctivitis, penetrating and chemical eye trauma
- common: subconjunctival hemorrhage, foreign body, conjunctivitis, dry eyes
What should we suspect in repeated episodes of red eye in the same eye? What about if the red eye spreads to both eyes? What about painful red eye? What about with a watery discharge? A purulent one?
- repeated episodes of same eye: herpes simplex keratitis (both eyes: allergic)
- rapid spread to both eyes: viral conjunctivitis
- painful: glaucoma, penetrating eye injury, foreign body
- watery: viral infection
- purulent: bacterial infection
What is the most common cause of red eye in the elderly? How does this present? How do we treat it?
- MCC in elderly is subconjunctival hemorrhage
- presents as a unilateral painless red eye
- most are self-limiting and don't require any treatment
- *if it's following trauma, it can be a potential serious injury*
What is conjunctivitis and how does it present? What are the common causes?
- conjunctivitis is inflammation of the eye limited to the conjunctiva
- it presents as a unilateral painless red eye that may progress to bilateral involvement; can be irritating and gritty
- common causes are allergy, viral (MC is adenovirus), and bacterial
- allergy: recurrent, bilateral itchy and watery eyes
- virus (MCC): rapid bilateral involvement, highly contagious, watery discharge, periauricular lymphadenopathy
- bacteria: purulent discharge, highly contagious
What is the local anesthetic test and what does its results mean?
- this is the application of a local anesthetic eye drop
- it is used to determine if a painful red eye is due to a more superficial cause (abrasions, breaks in the corneal epithelium) or a deeper cause (uveitis)
- if it's superficial, the pain will be relieved
What is the purpose of fluorescein dye?
- fluorescein dye will change any abrated/ulcerated areas a yellow-green color
What are the major causes of ocular herpetic disease?
- this is caused by viruses
- major viruses: herpes simplex (HSV) and herpes zoster (VZV)
- other viruses: EBV and CMV
What type of viruses are herpes viruses (HSV and VZV)? Where do these remain latent in infected individuals? What percent of the population carries the virus?
- herpes viruses are DNA viruses
- they can remain latent in the sensory ganglia (commonly in that of the trigeminal nerve/CN V)
- 90% of the population carries the latent virus!
What type of ocular herpetic disease does herpes simplex virus cause?
- HSV causes dendritic keratitis
- this is characterized by TRUE dendritic lesions (they show arborization and terminal end bulbs)
- HSV can follow multiple nerve branches
- the recurrence is more frequent than in VZV, but the episodes are shorter in duration
What type of ocular herpetic disease does herpes zoster virus cause?
- VZV causes herpes zoster ophthalmicus
- characterized by PSEUDO dendritic lesions (vs. HSV, which causes true dendritic lesions)
- VZV tends to follow a single nerve branch (classically V1 if it is to affect the eyes)
- the recurrence is less frequent than in HSV, but the episodes are longer in duration
What are common causes of sudden loss of vision?
- carotid occlusive disease (ophthalmic artery branches from the carotid), embolism, vasculitis; these all result in retinal ischemia (retinal ischemia is indicated by a cherry red spot - a prominent macula in the setting of ischemia - on fundoscopy)
- damage to optic nerve, chiasm, tract, etc.
What are the four leading causes of vision-reducing eye disease in the elderly?
- age-related macular degeneration (ARMD): loss of central vision
- glaucoma: increased pressure damages optic nerve
- cataracts: now treated successfully with surgery
- diabetic retinopathy
What is age-related macular degeneration? How do patients present? What are the two forms of the disease?
- ARMD (or just AMD) is the leading cause of vision loss in patients over 65
- the macula degenerates, resulting in a loss of central vision (complete blindness does not occur)
- patients present with blurred vision, image distortion, central scotoma, and difficulty reading
- 2 forms of the disease: dry and wet
Compare dry vs. wet macular degeneration.
- dry AMD is much more common (90% of cases) and less severe than wet AMD; symmetrical gradual deposits of extraocular material (called drusen) in both macula
- wet AMD is less common (10%), but is responsible for most cases of severe vision loss; wet AMD is an extension of dry AMD and is characterized by abnormal choroidal vessels (choroidal neovascularization), leading to leakage of fluid and blood into the macula
What is glaucoma? How do patients present? How do we treat it?
- glaucoma is the most common cause of blindness in black Americans
- it results from excess aqueous humor leading to raised intraocular pressures that damage the optic nerve
- patients present with progressive peripheral vision loss that moves centrally, headache, nausea, and eyeballs that are hard on palpation (due to the raised IOP)
- we treat it by decreasing the secretion of aqueous humor by the ciliary body (secretion is a sympathetic response, so we give sympathetic antagonists) and by increasing aqueous outflow into the canal of Schlemm (via parasympathomimetics and PG analogs); can decrease pressure by giving mannitol to promote osmotic diuresis for short-term treatment
What is strabismus? What is it also known as? Why don't patients present with diplopia?
-strabismus is when the eyes fail to simultaneously fix on a target of interest
- AKA "cross-eye," "lazy eye," and "squints"
- CHILDREN do not present with diplopia because the drifting eye's image is suppressed by the cortex; but adults with new onset squints DO
What is the major complication of strabismus in children?
- strabismus in children can result in amblyopia (decreased visual acuity) if untreated
- this is because the first 7 to 8 years of life is critical for the neural connections of the visual system to form
What are the major risk factors for childhood strabismus?
- family history
- premature birth and low birth weight
- congenital cataracts
- *retinoblastoma* (make sure to check all children with strabismus for Rb)
- neurological disease
What is the alignment test? What is its role in diagnosing strabismus?
- the alignment test is simply shining a torch at both eyes and noting the position of the corneal reflex of each eye (the corneal reflex is basically where you see the light reflecting back at you)
- normal: reflex in both eyes should be centered
- exotropia: the affected eye has a reflex that is more nasal (this means the eye is slightly turned outward); divergent squint
- esotropia: the affected eye has a reflex that is more temporal (this means the eye is slightly turned inward); convergent squint
What is the cover-uncover test? What is its role in diagnosing strabismus?
- the cover-uncover test is when you cover up the affected eye and look for any movements/shifts of the normal eye
- if the normal eye shifts inward, it indicates exotropia of the affected eye (divergent squint)
- if the normal eye shifts outward, it indicates esotropia of the affected eye (convergent squint)
In a child, what does an absent red reflex indicate? A white red reflex?
- absent: cloudy cornea, congenital cataracts, retinal issue
- *white (AKA leukocoria): retinoblastoma*
What pathology should we consider in any patient over 50 presenting with transient vision loss? What other symptoms should hone us in onto this diagnosis?
- giant cell arteritis (AKA temporal or cranial arteritis)
- patients over 50 are at risk of developing the disease
- associated symptoms: localized headache, jaw claudication, shoulder girdle pain, scalp tenderness, weight loss, night sweats
- ESR and CRP will be elevated
Which of the three layers are more prone to neoplastic growth?
- the middle (uveal tract: iris, choroid, ciliary body) and inner (retina and optic nerve) layers are where eye tumors principally occur
How common is each tumor of the uveal tract?
- choroidal melanomas (90%) are the most common primary intraocular malignancy; most commonly metastasizes to the liver
- ciliary body melanoma (7%); usually cause refractive error
- iris melanoma (3%); uncommon, but has the best prognosis
What is the peak age of incidence for optic nerve gliomas? What about for optic nerve sheath meningiomas? How do patients present?
- optic nerve glioma: 90% occur before 20 years of age
- optic nerve sheath meningioma: peak incidence is between 30 and 60
- in both cases, patients present with gradual painless fogging of vision
What is the most common intraocular malignancy in children? What is the average age of diagnosis? Which intraocular malignancy is the most common in general?
- (most common intraocular malignancy in general is uveal melanoma, specifically choroidal melanoma)
- in children, most common is retinoblastoma (Rb)
- average age at diagnosis is 18 months (unilateral cases are diagnosed at 24 months, bilateral cases at 12 months)
What is the most common presenting feature of retinoblastoma? What are some other common signs?
- leukocaria AKA a white papillary reflex
- others: strabismus, loss of vision, painful blind eye
What are the three types of growth seen in retinoblastomas? What do we see on fundoscopy for each?
- endophytic growth: tumor grows into the vitreous cavity; look for yellow-white mass that progressively fills the entire cavity (can't see the retinal vessels because tumor grows over them)
- exophytic growth: tumor grows towards the sub retinal space, causing retinal detachment; look for the presence of retinal vessels over the tumor
- diffuse infiltrating growth: diffuse retinal involvement; look for retinal thickening rather than a discrete mass