Flashcards in Class #9 Deck (112):
What causes bilateral conjunctivitis? unilateral?
BILATERAL= infection, allergens, radiant energy
UNILATERAL= foreign body, chemical/irritation damage
Bacterial/fungal conjunctivitis causes a ________________ discharge
mucopurulent , yellow/green exudate, sticky eyelids
What kind of discharge would you expect to see from a viral infection, an allergen or a foreign body?
What bacterias can cause acute and chronic conjunctivitis?
- H. Influenza
What causes chronic bacterial conjunctivitis?
-obstruction of nasolacrimal duct
-chronic infection of lacrimal sac
How might I know if I have chronic bacterial conjunctivitis?
-burning, itching, morning crusting
What is unique about hyper acute bacterial conjunctivitis?
-chemosis (edema) or conjunctiva
-swollen pre-auricular lymph nodes (in front of the ear)
How do heath care professionals treat hyperacute bacterial conjunctivitis?
-antibiotics based on C&S swab
What are the complications of hyperacute bacterial conjunctivitis if it remains untreated?
What is the leading cause of preventable blindness in the world?
How is chlamydial conjunctivitis transmitted?
What causes viral keratoconjunctivitis? What is the difference between the mild form and the epidemic form?
adenoviruses from inadequately chlorinated swimming pools
MILD: hyperemia, tearing with no discharge, pharyngitis, fever and malaise
EPIDEMIC: visual disturbances
What happens if the epithelial layer of the cornea is damaged?
minor and self-limiting because it that layer of the cornea is able to regenerate itself with no scarring
What eye disorder can cause iridescent vision?
corneal trauma to the endothelia
What might I expect if I poke my cornea deep enough to damage the endothelia?
-edema (dull/hazy cornea)
-decreased visual acuity
Inflammation of the cornea is called...
keratitis, caused by herpes simplex
HERPES SIMPLEX VIRUS CAN CAUSE ALL OF THE FOLLOWING DISORDERS
- viral meningitis
What can cause keratitis?
What is the difference between non-ulcerative and ulcerative keratitis?
Non-ulcerative keratitis affects all layers of the epithelium but leaves it intact
Ulcerative involves either the epithelium, the stroma (outer layer of the iris) or both, but they do not remain intact. This causes scarring, impaired vision, and blindness
What is hyperopia?
far-sighedness, which occurs when the anterior-posterior distance of the eye is too short
What occurs when the image focus is BEHIND the retina?
When would you use a convex lens?
to correct hyperopia
What is myopia?
near-sightedness, which occurs when the anterior-posterior distance of the eye is too LONG. The image here is focussed in FRONT of the retina
What do you use to correct myopia?
asymmetric bowing defect of cornea or lens either from congenital problems or scarring. It causes non-uniform refraction of light onto retina, causing blurry vision
How is astigmatism treated?
glasses, contact lenses, or surgery to remove epithelial section
What is the accommodation reflex? What nerve is it controlled by?
the ability of the eye to adjust the shape of the lens and the size of the pupil through contraction of ciliary muscles
-Controlled by the occulomotor nerve
What are the 2 disorders of accommodation?
Cycloplegia, which is paralysis of the ciliary muscles
Presbyopia, which is age related thickening and hardening of the lens
Age-related thickening and hardening of the lens is called….
What does "second sight" refer to?
in presbyopia, although an individuals ability to accommodate decreases, their ability to see nearer objects improves. This also appears in cataracts
What is the most common cause of blindness?
What are cataracts?
bilateral fiber build-up over time causes layered sclerosis on the lens of the eye that appears cloudy
What causes cataracts?
My grandma has cataracts. How does this affect her vision?
-loss of far vision, acquired myopia (second sight)
-loss of colour discrimination
How can cataracts be treated?
edema of the optic papilla (tissue surrounding the entrance to the optic disc) resulting in compression of blood vessels and nerves
What causes papilledema?
increased intracranial pressure, tumours, subdural hematoa, hydrocephalus, malignant hypertension
What is retinopathy?
change in retinal blood vessel structures
Retinopathies cause what 4 things?
1. microaneurysms, which leak plasma causing edema
2. neovascularization, which are fragile
3. Hemorrhages, which results in ischemia
4. Retinal opacities
What 4 things cause diabetic retinopathy?
What is the difference between non-proliferative and proliferative diabetic retinopathy?
non proliferative is confined only to the retina
proliferative is more severe d/t neovascularization
Define the pathophysiology of non-proliferative diabetic retinopathy
**LOOK THIS UP**
-retinal vein engorgement
-thickened capillary membranes
-capillary microaneurysms cause microinfarcts
-COTTON WOOL SPOTS appear d/t damaged nerve fibers
What are the manifestations of non-proliferative diabetic retinopathy?
-glare from bright lights
-MACULAR EDEMA d/t leakage at the capillary levels
What is the macula?
the area at the back of the eye that collects high acuity images and acts like sunglasses to collect extra UV rays so they don't damage the eye
Describe what occurs in proliferative diabetic retinopathy
it involves neovascularization, in which new vessels attach the vitreous too tightly to the retina, and the resulting tension between the vitreous and the retina causes retinal detachment
What occurs inside the vasculature in hypertensive retinopathy?
increased pressure over time results in :
1. initial vasospasm and hemorrhage
2. persistent or chronic compensatory arteriolar wall thickening
A patient has just come into the ER with a detached retina. What might they be complaining about?
-loss of peripheral vision
-flashing lights, sparks, or floaters in the field of vision
-shadow or dark curtain with progression
Who is most likely to experience retinal detachment?
-myopia, d/t stretch of the retina
What are the 3 types of retinal detachment?
-HTN, inflammation, neoplasm
-scarring from injury, infection, surgery
-vitreous shrinks with age, causing it to separate from the retina, which causes a tear
What is the most common type of retinal detachment?
How can we treat a patient with retinal detachment?
-Laser or cryotherapy to seal the retinal tear without too much scarring
-Scleral buckling, where silicone is placed on the sclera so it attaches to the retina that is loose
Loss of central vision is caused by….
Macular Degeneration, which causes destructive changes to central fovea
What puts someone at risk for macular degeneration?
Describe non-neovascular macular degeneration
-caused by generation/atrophy of retinal cells. These drusen spots enlarge overtime.
causes: minimal vision changes, but it worsens suddenly
Explain neovascular macular degeneration
-age-related neovascularization of the CHOROID
-this causes blood vessels to leak, the fluid buildup pushes retina away from the choroid causing scarring
causes irreversible loss of vision
What is glaucoma?
chronic degenerative optic neuropathy d/t increase INTRAOCCULAR pressure
What occurs to the optic disk in glaucoma?
The disc around the optic nerve gets pushed by the increased intraoccular pressure, and the rim becomes thin and CUPPED over time
**LOOK THIS UP
Explain the pathophysiology of open angle glaucoma
This is the most common type of glaucoma. and it occurs when the trabecular meshwork decreases absorption of AQUEOUS humor, resulting in increased pressure
What angle remains open in open angle glaucoma?
What are the risk factors for glaucoma?
P: hx, myopia
S: inflammation, trauma, tumor, HTN, DM, hyperthyroidism, migraines, corticosteroids
What symptoms may indicate that my patient has open angle glaucoma?
-loss of visual field
Whats the difference between the aqueous humor and vitreous humor?
Aqueous: fluid that moves around to the front of the eye
Vitreous: gell fluid in the middle of the eye
What disorder of the eye is very treatable if caught early but is an absolute emergency if it happens acutely?
closed angle glaucoma, which is where the iris occludes flow of the aqueous humor to the trabecular meshwork.
It puts too much pressure on the optic nerve, which can cause blindness
What causes closed angle glaucoma?
-prolonged dilation of the pupil
-ATROPINE causes excessive dilation of the pupil, which displaces the iris
What are the manifestations of closed angle glaucoma?
-relief with sleep
blindness in one eye
What is it called when half if the visual field is gone in one eye?
What is quadrantanopia?
where a quarter of the visual field in one eye is lost
loss of binocular vision d/t abnormal coordination or alignment in the muscle
What are the 5 types of eye deviations?
Esotropia: medial deviation
Exotropia: lateral deviation
Hypertropia: upward deviation
Hypotropia: downward deviation
Cyclotropia: torsional deviation
What is the difference between concomitant and non-concomitant strabismus?
concomitant shows equal deviation in all directions of the gaze
non-concomitant varies with the direction of the gaze
What is intermittent strabismus?
periods of time where the eyes are parallel
Define monocular strabismus
where the same eye always deviates and the other always fixates
What is non paralytic strabismus?
deviation of the eyes with no obvious defect in the muscles. The amount of deviation is relatively constant. Both eyes can be different
What is paralytic strabismus?
-paresis or plegia of one or more extraoccular muscles
-uncommon in children
What causes paralytic strabismus?
stroke, myasthenia gravis, graves disease, trauma, childhood non-paralytic strabismus
What is the proper word for "lazy eye"?
What is amblyopia?
abnormal visual development in infancy or early childhood that is mostly reversible
What causes amblyopia?
visual deprivation, cataracts, ptosis
I am working in the ER and a patient walks in. She is speaking normally, but when she opens her eyes widely, i notice spontaneous involuntary rhythmic & oscillatory eye movements occurring without head movement or visual stimuli. What is this condition called, and what could be causing it?
-CNS damage (MS)
What are the symptoms of impacted cerumen?
-sensation of fullness
A mom brings her daughter into the clinic because she exhibits itchiness, redness, tenderness, edema, pain and watery, purulent drainage in her ears. She tells you she couldn't even go to swimming practice today, because it hurt so much. What do you suspect?
otitis externa, inflammation of external ear
This can be caused by infection caused by frequent exposure to water, irritation and allergies.
What happens if otitis externa is caused by S. aureas?
What 3 things can cause disorders of eustachian tubes?
1. Abnormal patency when the tubes don't close
2. Functional obstruction when the tubes collapse like in infants who's collagen hasn't developed or cleft palate
3. Mechanical obstruction from allergic reaction of viral infection
What is the most common cause of otitis media?
dysfunction of the eustachian tubes allowing reflux into the middle ear
What are the risk factors for Otitis media?
-infants who are bottle fed vs breast fed
-children around 5 years old
Why are babies who are bottle fed at more risk for otitis media?
-breast milk supplies protective maternal antibodies
-bottle causes babies to swallow air and reflux
-bottles cause babies to lay more horizontally causing reflux
What are the manifestations of otitis media?
-otalgia, increases with perforation of tympanic membrane (purulent drainage)
-erythemic tympanic membrane
-rhinorrhea, vomitting, diarrhea
What is Otitis media with effusion?
Fluid in the middle ear without signs of infection
Otitis media, if untreated, can become complicated in what ways?
-cysts of middle ear
-erosion of ossicles
How can otitis media be treated?
-myringotomy (incision of tympanic membrane) to relieve fluid
-surgery (tympanostomy tubes, adenodiectomy)
What is tinnitus?
perception of abnormal ear/head noises i.e. ringing, buzzing, and roaring
What can cause tinnitus?
-medications (ASA, nicotine, caffeine)
-Foods (MSG, red wine)
-presbycusis (hearing loss d/t aging)
If I have ear wax or another foreign body in my ear, and I am struggling to hear, what kind of hearing loss am I experiencing?
Conductive hearing loss from transmission failure through the outer/middle ear to inner ear
What is sensorineural hearing loss?
When sound waves travel through the outer/middle ear but are distorted by cochlear damage, nerve damage, or damage to the auditory pathway of the brain
What can cause sensorineural hearing loss?
-malformation of inner ear
What is presbycusis?
sensorineural loss of hearing in the elderly that causes
-impaired localization of sound sources,
-slowed central processing
-high frequency sound loss
What particular drug can cause damage to the vestibular system in children?
gentamycin. This damage is not permanent, and the hearing will come back when the drug is stopped
What does irritation of the vestibular organs or nerves cause?
balance issues and vertigo
What is the difference between objective vertigo and subjective vertigo?
O: when the person is stationary but environment moves
S: person is moving and environment is stationary
Why does motion sickness cause vertigo?
repeated rhythmic stimulation of vestibular system
If someone is experiencing vertigo, what would their vital signs be?
rapid respirations cause vasodilation:
What is benign paroxysmal positional vertigo?
most common type of vertigo in 40+ year olds caused by damage to the calcium crystals (otoliths) that line the labyrinth that causes those crystals to float in the endolymph of the posterior canal
What are the manifestations of benign paroxysmal positional vertigo?
-change of head position causes vertigo and rotary nystagmus
-relief when motion ceases, or with continued motion
Inflammation of the vestibular nerve is called….
acute vestibular neuronitis
What kinds of symptoms will my patient with acute vestibular neuronitis exhibit?
-NO AUDITORY OR NEUROLOGICAL SYMPTOMS
What could cause acute vestibular neuronitis?
-recent upper respiratory tract illness
What causes Meniere Disease?
distension of the endolymphatic compartment of the inner ear (cochlea) d/t excess fluid
What 3 things contribute to the excess fluid in meniere disease?
1. increased production of endolymph
2. decreased absorption of endolymph
3. decreased production of perilymph
What puts a patient at increased risk for meniere disease?
What might my patient with meniere disease complain of?
-pallor, sweating, N&V