مراجعه رمد case و questions
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مراجعه رمد case و questions
من طرف Just a doctor السبت أغسطس 28, 2010 3:22 am
السلام عليكم ورحمة الله وبركاته
اسئله وcases و مراجعه مهمه واسئله تجميعات تفهم الماده منها ان شاء الله
1. Which conjunctivitis is least likely to occur bilaterally?
a. allergic
b. viral
c. bacterial
d. vernal
Answer: The correct answer is (c) bacterial. Allergies are likely to
affect both eyes and present with itching and watering. Vernal is a type
of seasonal allergy you see in young boys. Viral conjunctivitis usually
starts in one eye, but hops to the other eye as it is very contagious.
Bacterial conjunctivitis can occur bilaterally, but of the available
choices is most likely to occur in just one eye.
2. You’re consulted by an intern from the ICU because his ventilated
patient, with a head injury, has a fixed and dilated pupil. The intern
is concerned for acute glaucoma. What do you tell him?
a. find a Tono-Pen and check the pressure
b. call his upper-level fellow immediately
c. taper the patient’s benzos
d. increase the PEEP ventilator setting
Answer: Well, you need more history, of course, but any blown pupil in a
trauma-ICU makes me think of an uncal-herniation and impending death.
Tell him to (b) find his senior resident immediately and call you back
if they still want an eye-consult.
3. Which optic nerve finding is most concerning for glaucomatous damage?
a. large disk size
b. horizontal cupping
c. vertical cupping
d. disk tilt
Answer: The correct answer is (c) increased vertical cupping, which
would go against the ISNT rule (the Inferior and Superior neural rim is
normally the thickest). Many patients have large myopic (near-sighted)
eyes with resulting large optic disks and disk “tilting” from the angle
at which the nerve enters the back of the eye - this is physiologically
normal and not concerning for glaucoma.
4. A young 23-year-old black man presents with a hyphema in the right
eye after blunt injury. All of the following are acceptable initial
treatments except?
a. sleep with the head elevated
b. prednisolone steroid eye drops
c. cyclopentolate dilating drops
d. carbonic anhydrase inhibitor pressure drops
Answer: The correct answer is (d). For patients with hyphema (blood in
the eye) advise them to avoid straining and sleep with their heads
elevated to allow the blood to settle. Use steroids to decrease the
inflammation and a medium-acting cycloplegic to dilate the eye for
comfort and to keep the inflamed iris from “sticking” to the lens
underneath. If the pressure is high, you can use pressure drops, but we
avoid CAIs in African Americans as it induces RBC sickling in
sickle-cell patients. You can get a sickle prep if you are suspicious
for this disease.
5. A 7-year-old boy presents with a grossly swollen eyelid. His mother
can’t think of anything that set this off. What finding is most
characteristic of orbital cellulitis?
a. chemosis
b. warmth and erythema of the eyelid
c. physically taut-feeling eyelid
d. proptosis
The correct answer is (d). With any eyelid cellulitis, you must
determine if the infection is pre-septal or post-septal (i.e. orbital
cellulites). While chemosis is certainly seen with orbital infection,
proptosis is even more indicative of orbital infection. Other signs
include decreased eye-movement, pain with eye-movement, and decreased
vision.
6. What location for a retinal detachment would be most amenable to treatment by pneumatic retinopexy?
a. inferior rhegamatogenous detachment
b. superior tractional retinal detachment
c. superior rhegamatogenous detachment
d. traumautic macular hole
Answer: This question covers several concepts. Rhegamatogenous
detachments are the classic detachment occuring from a break in the
retina. A pneumatic retinopexy is the technique of injecting a gas
bubble into the eye that floats and tamponades the break. Gas bubbles
require careful head-positioning and work best for superior breaks
(patients can’t stand on their heads for weeks for inferior breaks). The
correct answer is therefore (c).
7. A mother brings in her two-year old child because she is concerned
that her baby is cross-eyed. Which of the following is an inappropriate
statement:
a. the baby may maintain 20/20 vision
b. the esotropia could could lead to permanent vision loss
c. the esotropia might be corrected with glasses alone
d. surgical treatment should be delayed until adolescence
Answer: Answer (d) is the inappropriate statement. Esotropia
(cross-eyed) is a common finding in the pediatric clinic. There are many
causes, and one of them is poor vision in one eye. Spectacle vision can
help anisometropic eyes fuse images properly and correct the alignment
problem. This condition should be treated promptly, via spectacle
correction, and possibly patching the strong eye to avoid amblyopia – if
the crossing doesn’t correct with these measures, then you procede to
surgical options. A child may maintain good vision in each eye if the
kid learns to cross-fixate (switch eye dominance depending upon what
direction the child is looking). There is no point in waiting until
adolescence – you want to avoid an amblyopic eye and give the child a
chance to develop good stereopsis at an early age.
8. Which of the following is the biggest risk factor for primary open angle glaucoma?
a. Asian ancestry
b. smaller diurnal pressure IOP changes
c. thin corneas
d. large optic disks
Answer: Asians are more likely to develop acute angle-closure glaucoma,
not POAG. Everyone has diurnal eye pressure changes, and there is some
evidence that glaucomatous patients have larger shifts in their pressure
throughout the day. Large optic disks aren’t concerning, though large
cupping of a disk could indicate nerve fiber loss from glaucoma. Thin
corneas ARE associated with glaucoma, as shown by the famous OHTS
clinical trial. We measure every new glaucoma patient’s corneal
thickness with a small ultrasound pachymeter. The correct answer is (c).
9. A 27-year-old contact lens wearer presents to the ER complaining of
ocular irritation. On exam he has a small 2mm corneal abrasion. You
should
a. treat with erythromycin ointment
b. treat with ciprofloxacin drops
c. bandage contact lens for comfort and speed reepitheliazation
d. patch the eye and follow-up in 72 hours
Answer: You need to be concerned for pseudomonas infection in any
contact lens wearer. Erythromycin is great stuff, but these higher risk
patients should get something stronger like a fluoroquinolone (cipro). A
bandage contact lens can help with painful abrasions, but I’d avoid one
in this patient as the abrasion isn’t big, and you typically don’t
patch ulcers. Patching can also be used to help with lubrication and
comfort, but I never patch a potential infection, as bacteria like to
grow in dark warm environments. If you decide to patch, you need to see
daily to make sure nothing is brewing under that lens. The most
appropriate answer is (b).
10. A woman presents to you complaining of a red, watering eye for the
past two days with stinging and some photophobia. Her vision has dropped
slightly to 20/30. She has a history of diabetes and taking drops for
glaucoma, but is otherwise healthy. The most likely cause of her redness
is:
a. angle-closure glaucoma
b. viral conjunctivitis
c. diabetic retinopathy
d. papilledema
This woman probably has a history of POAG (primary open angle glaucoma)
if she is on drops. If she were to have an acute angle closure, then her
eye would be very painful and the vision would have gotten much worse
from corneal edema. Diabetic retinopathy is usually a background finding
of leaky vessels in the retina and doesn’t create this picture. She
merits a full eye exam, but her symptoms are consistant with “pink eye”
with viral conjunctivitis being the most common cause in an adult. The
correct answer is therefore (b).
11. A patient presents after MVA with a fracture of the orbital floor.
What would be the indication for surgery in the near future?
a. double vision that worsens with upgaze
b. chemosis and moderate proptosis
c. restricted forced ductions
d. decreased extraocular movement
Answer: Floor fractures are very common and these patients always look
impressively bad on exam, with marked swelling and subconjunctival
bleeding. They can have decreased EOMs and proptosis from this swelling
alone, which shouldn’t concern you. More worrisome is entrapment of the
inferior rectus muscle in the orbital floor – this entrapement can only
be determined by forced ductions … grab the limbus with forceps and tug
on the eye to see if movement is restricted. The correct answer is (c).
12. A 64-year-old man presents to you with new onset of “crossed-eyes.”
His left eye can’t move out laterally and he has a chronic mild headache
that he attributes to eyestrain. Which of the following is least likely
the cause of his condition:
a. hypertension
b. diabetes
c. aneurysm
d. increased intracranial pressure
Answer: The most common causes of all the ocular nerve palsies are from
vasculitic events secondary to diabetes or hypertension. It sounds like
this patient has a CN6 palsy as he can’t abduct his eye. With abducens
palsy you should always consider increased intracranial pressure. A
internal carotid aneurysm could hit the 6th nerve in the cavernous
sinus, but you would expect other findings with these cavernous lesions.
Aneurysms in general cause more third nerve palsies. Thus, the correct
answer is (c).
13. The abducens nucleus would be most affected by a brainstem lesion at:
a. pons
b. mid-brain
c. medulla
d. foramen magnum
To answer this question you need to know where the 6th nerve nucleus is
located. One useful aid is the “4-4 Rule,” which states that the bottom
four nuclei (CN 12,11,10,9) are in the medulla, while the next four
nuclei (CN 8,7,6,5) are in the pons. The correct answer is therefore
(a).
14. The pupillary defect that affects the afferent arm of the pupillary response is the:
a. Marcus Gunn pupil
b. Argyl Robberson pupil
c. Adies pupil
d. Horners pupil
A Marcus Gunn pupil is the classic afferent pupillary defect (APD) that
we check with the swinging light test. The Argyl Robberson is the
syphilitic pupil that reacts with near vision, but doesn’t respond to
light. Horners and Adies are disorders of the sympathetic and
parasympathetic efferent pupil response. The correct answer is (a).
15. Aqueous fluid is produced in which chamber?
a. anterior chamber
b. vitreous chamber
c. posterior chamber
d. trabecular chamber
There are actually three chambers in the eye. Aqueous is produced in the
posterior chamber where it flows forward into the anterior chamber and
drains through the trabecular meshwork into the canal of Schlemm. The
vitreous chamber is the big one in the back that is filled with
jelly-like vitreous humor. The correct answer is therefore (c).
16. Which orbital bone is most likely to fracture with blunt trauma to the eye?
a. zygomatic
b. maxillary
c. ethmoid
d. sphenoid
Answer: The orbital floor, which is formed by the maxillary bone, is the
most commonly fractured wall of the orbit. Orbital fat will commonly
herniate through this bone and muscle can get stuck if the break acts
like a trapdoor. The ethmoidal lamina papyracea is also often broken
because it is the thinnest, but this occurs less often because of
extensive bolstering. The lateral zygomatic component of the orbit is
rarely broken, nor the more posterior sphenoid. The correct answer is
(b)
17. When a patient focuses on near objects, the lens zonules:
a. rotate
b. contract
c. relax
d. twist
Answer: The zonules connect to the lens periphery and suspend the lens
like a trampoline to the surrounding ciliary muscle. With near vision,
the ciliary body contracts like a sphincter, causing the zonules to
relax, and the lens to get “rounder.” This rounding of the lens
increases its refractive ability and allows focusing of near objects.
With age, the lens hardens and loses its ability to round out – a
process called presbyopia. The correct answer here is (c).
18. What is glaucoma?
a. retinal damage from high intraocular pressure
b. optic nerve death caused by mechanical stretching forces
c. ischemic nerve damage from decreased blood perfusion gradients
c. none of the above
Answer: The best answer here is probably the last one, as no one really
understands the pathogenesis of glaucoma. Ultimately, it involves death
of the nerve fibers and it seems associated with high ocular pressure –
this is certainly the only risk factor that we can treat. However, there
are plenty of patients out there with glaucoma damage and normal eye
pressure, so pressure isn’t the “ultimate cause.” There are many
mechanical and biochemical theories that explain glaucoma damage, and
each has its merits and faults.
19. Which condition would result in an inaccurately high reading with applanation pressure measurement?
a. thin cornea
b. thick cornea
c. edematous cornea
d. keratoconus
Answer: We measure pressure by pushing the cornea with a weighted device
– a process I compare to kicking a car tire to determine the air
pressure. Patients with thick “truck-tire corneas” are going to feel
hard when you measure them. Conversely, people with thin “bicycle-tire”
corneas are going to feel softer. Corneal edema also makes the eye feel
squishy (giving a falsely low pressure) and patients with keratoconus
often have thin corneas. The correct answer here is (b).
20. Gonioscopy overcomes the concept of:
a. angled biomicroscopy
b. spherical abberation
c. total internal reflection
d. specular microscopy
Answer: The trabecular meshwork can’t be visualized directly because
light coming from this angle bounces off the inner cornea back into the
eye because of Snell’s Law and total internal reflection. By placing a
hard glass lens onto the eye, the cornea-air interface is broken and
light can escape and be seen through the microscope. The correct answer
is therefore (c).
21. A 32-year-old white man with a history of type-1 diabetes presents
to you complaining of decreased vision. He has not seen an eye doctor in
years. On exam, you find numerous dot-blot hemorrhages, hard exudates,
and areas of abnormal vasculature in the retina. Pan-retinal
photocoagulation might be done in this patient to:
a. kill ischemic retina
b. tamponade retinal tears
c. ablate peripheral blood vessels
d. seal off leaking blood vessels
Answer: PRP is performed to kill areas of peripheral ischemic retina. By
doing so, less VEGF is produced, leading to cessation and regression of
neovascularization. While it is true that we sacrifice some of the
peripheral retina with PRP, it is worth it to save important central
vision. Lasers can be used to help peg down retinal tears and to help
with leaking vessels … but this is called “focal laser therapy.” The
correct answer here is (a).
22. Which of the following is a risk factor for retinal detachment?
a. black race
b. male sex
c. presbyopia
d. myopia
The correct answer is (d) myopia. Myopic (near-sighted) eyes are large
eyes with a stretched-out retina that is more likely to tear at the
periphery. Neither blacks nor males are at higher risk of RD. Presbyopic
lens hardening doesn’t have anything to do with the retina.
23. A 57-year-old man complains of flashing lights and a shade of
darkness over his inferior nasal quadrant in one eye. On exam you find
the pressure a little lower on the affected eye and a questionable
Schaffer’s sign. What condition would lead you to immediate
treatment/surgery?
a. macula-off rhegmatogenous retinal detachment
b. epi-retinal membrane involving the macula
c. dense vitreous hemorrhage in the inferior nasal quadrant
d. mid-peripheral horseshoe tear with sub-retinal fluid
Answer: Schaffer’s sign is when you see pigment behind the lens on
slit-lamp exam, and occurs with retinal detachments and the release of
pigment into the vitreous chamber. A macula-off retinal detachment is
unfortunate, but isn’t an immediate emergency - it certainly needs to be
repaired, but can wait for a few days if necessary, as the damage to
the detached macular photoreceptors has already occured. Epi-retinal
membranes are common and aren’t an emergency unless actively creating a
tractional detachment. Vitreous hemorrhages are not emergencies either,
assuming there isn’t a detachment behind that blood on your ultrasound.
Smaller retinal tears, however, need to be treated early to make sure
they don’t progress and peel off the macula. The answer is (d).
24. Oral doxycycline helps blepharitis patients by:
a. therapeutic antibiotic tear secretion
b. changing lipid viscosity
c. inhibiting cytokine release
d. improved lacrimal gland excretion
Doxycycline changes the lipid viscosity of the meibomian gland
secretions, improving oil secretion from the gland into the tear film.
This superficial lipid layer is needed to keep the tears from
evaporating too quickly. The correct answer is (b).
25. Put the following retinal layers in order from inside (next to the vitreous) to outside:
a. Ganglion nerves, photoreceptors, choroid, then sclera on the outside.
b. Photoreceptors, ganglion nerves, choroid, then sclera on the outside.
c. Choroid, photoreceptors, ganglion nerves, then sclera on the outside.
d. Choroid, ganglion nerves, photoreceptors, then sclera on the outside.
Answer: The correct answer is (a). This question illustrates a few
important concepts. The first is that the photoreceptor cells lie
relatively deep in the retina, such that light has to pass through many
layers to reach them. One of these layers is the ganglion layer of nerve
fibers that form the surface of the retina as they travel to the optic
nerve. The choroid is a deeper bed of blood vessels that nourishes the
photoreceptors from below, while the sclera is the tough collagen matrix
that forms the outer wall of the eye.
26. In the absence of lens accommodation, a myopic eye focuses images:
a. in front of the lens
b. In front of the retina
c. behind the retina
d. Behind the cornea
Answer: The correct answer is (b). Myopic, or near-sighted eyes, are
typically large eyes that focus images in the middle of the eye, in
front of the retina within the vitreous chamber. These eyes require a
minus concave-shaped lens in their glasses - this effectively weakens
the overall refractive power of the eye, allowing images to focus
further back on the retina.
27. A man calls the office complaining of splashed bleach in his eye. You should instruct him to:
a. patch the eye and immediately go to the office
b. irrigate the eye for 15 minutes and then go to the office
c. immediately apply lubricating ointment and then go to the office
d. immediately wash the eye with contact saline solution and go to the office if he notices any change in vision
Answer: The final visual outcome for a chemical burn is going to depend
upon how quickly the chemical is washed out of the eye, so have your
patient wash out their eye immediately! Chemical injury is one of the
few eye problems that you treat prior to checking vision. The correct
answer here is (b).
28. What antibiotics would you use in a newborn with suspected chlamydial conjunctivitis?
a. Ciprofloxacin drops
b. Erythromycin drops
c. Oral Doxycyline
d. Erythromycin drops and oral erythromycin
Answer: Chlamydia is one cause of conjunctivitis you should suspect in
the newborn. Treatment involves topical drops such as erythromycin and
systemic coverage because of concurrent respiratory symptoms these kids
can develop (as chlamydia infects mucous membranes and give a
pneumonitis). You don’t use doxy in children. Fluoroquinolones might
work, but we don’t use them in children because of theoretical bone
suppression. The correct answer is (d).
29. You are measuring the deviation in a child with strabismus. The
corneal light reflex is 2mm temporal to the pupil in the right eye. How
much deviation would you estimate?
a. 10 diopters esotropia
b. 20 diopters exotropia
c. 30 diopters esotropia
d. 40 diopters exotropia
Answer: You can estimate deviation using the Hirshburg rule – for every
mm the reflex is decentered, equals 15 diopters of deviation. This child
has 30 diopters of deviation, and an esotropia, so (c) is the correct
answer.
30. Steroids typically induce what kind of cataract?
a. Nuclear sclerotic
b. Posterior polar
c. Posterior subcapsular
d. Cortical
Answer: Steroids and diabetes are classically known to cause posterior
subcapsular cataracts on the back surface of the lens. Nuclear sclerotic
cataracts are common and usually from aging. Posterior polar cataracts
are often congenital. Cortical cataracts are also common and have many
causes. The correct answer is (c).
عدل سابقا من قبل Elfak Elmoftary في الثلاثاء أغسطس 31, 2010 3:16 am عدل 1 مرات
Just a doctor- من شموس شمسولوجي
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تاريخ التسجيل : 20/07/2010
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تاريخ التسجيل : 24/08/2010
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