الجمعة، 19 أكتوبر 2012

MCQs In Pediatric Dermatology And Ophthalmology

Q 1: 

You are asked to evaluate a 5-year-old boy for dry skin that has been present since infancy and has been resistant to treatment with emollients. The boy's father also has dry, scaly skin and allergic rhinitis. 
The physical examination demonstrates generally dry skin, with thin scales that have a "pasted-on" appearance on the extensor surfaces of the legs and buttocks.
Of the following, the MOST appropriate therapy is

A. ammonium lactate topically
B. cephalexin orally
C. isotretinoin orally
D. tacrolimus topically
E. triamcinolone topically

The Answer :

A

Explanation :

The child described in the vignette has features of ichthyosis vulgaris, an autosomal dominant disorder that usually becomes apparent between 3 months and 5 years of age. 

Affected individuals develop thin scales that have elevated edges, creating the appearance that the scales have been “pasted-on

.” The extensor surfaces of the lower extremities are affected primarily, although the trunk and upper extremities may be involved.

 Typically, the face and antecubital and popliteal fossae are spared.

Ichthyosis vulgaris is a chronic disorder that tends to improve over time. 

Although it can be managed effectively, there is no cure, and scaling returns if therapy is discontinued. 

Initially, treatment involves frequent emollient application that prevents evaporation of moisture from the skin. If the response to this treatment is unsatisfactory, a product containing an alpha hydroxy acid (eg, ammonium lactate, citric acid, lactic acid, and glycolic acid) may be applied to hydrate the skin and cause skin cells to detach. 

Alternately, a urea-containing emollient or propylene glycol may be applied to enhance water binding or a product that contains salicylic acid used to reduce scale. 

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Q 2:


You are evaluating a 4-week-old boy for tearing of the right eye that has worsened over the past week. Physical examination reveals slight tearing but no evidence of purulent exudate or conjunctival erythema. All other findings are normal.
Of the following, the MOST appropriate initial management is:

A. administration of amoxicillin
B. endoscopic dacrocystorhinostomy
C. instillation of silver nitrate into the eyes
D. observation with intermittent massage of the duct
E. surgical dilation of the nasolacrimal duct

Answer :

D


Congenital nasolacrimal duct obstruction is the most common abnormality of the infant’s lacrimal system. 

Almost 5% of infants manifest nasolacrimal duct obstruction, and 30% of affected infants have bilateral obstruction. The obstruction is usually at the distal end of the nasolacrimal system.

 Most typically, infants present with tearing and crusting of the eyelashes. Massage of the duct will reveal clear-to-mucopurulent material. Conjunctival inflammation, photophobia, blepharospasm, corneal clouding, or other eye abnormalities are notably absent.

            Natural resolution rates as high as 95% have been reported by 13 months of age. Complications are rare and include development of nasolacrimal duct cysts with nasal obstruction or dacryocystitis.

            Because of the favorable natural history, recommended treatment is conservative. Digital massage of the duct two to three times a day may help to open the occluded system.

            Topical antibiotics are indicated only for mucopurulent conjunctivitis. Silver nitrate is indicated for the prevention of gonococcal ophthalmia, but may cause chemical conjunctivitis. Systemic antibiotics may be necessary for treatment of dacryocystitis, a bacterial infection of the lacrimal sac manifested by edema, erythema, and tenderness over the sac.

            Nasolacrimal duct probing is appropriate if symptoms persist beyond 13 months of age. Probing usually is performed under general anesthesia and generally is curative. Tube placement or dacrocystorhinostomy (surgical opening of the lacrimal system into the lateral nasal wall) are indicated for persistent duct obstruction that does not respond to conservative medical and surgical management.

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Q 3


A mother brings her 4-month-old infant to the emergency department because the infant has been excessively irritable for 10 hours. She has been feeding normally. The mother reports that the infant seems to be rubbing her right eye. On physical examination, the child is afebrile, interactive, and soothes temporarily in her mother's arms, but she has frequent outbursts of crying. There is tearing in the right eye, with scant conjunctival injection.
Of the following, the evaluation that is MOST likely to aid in the diagnosis is:

A.  conjunctival swab for Chlamydia trachomatis
B.  conjunctival swab for Gram stain
C.  fluorescein staining of both eyes
D.  funduscopic examination
E.  measurement of intraocular pressure

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Q4


You are asked to evaluate a 1-day-old healthy term African-American infant who has a rash. Findings on physical examination include scattered pustules without surrounding erythema involving the trunk and forehead and several small hyperpigmented macules, some of which possess a collarette of scale.
Of the following, the MOST likely diagnosis is:

A.  candidiasis
B.  erythema toxicum
C.  neonatal herpes simplex virus infection
D.  Staphylococcus aureus infection
E.   transient neonatal pustular melanosis

Answer

E


         The physical findings described for the infant in the vignette are those of transient neonatal pustular melanosis. Pustules and small (2 to 3 mm in diameter) hyperpigmented macules are present at birth. The macules are surrounded by a collarette of scale that represents the remnant of a pustule roof. Although the clinical diagnosis usually is straightforward, if there is uncertainty, a Gram or Wright stain of pustule fluid will reveal polymorphonuclear neutrophils (PMNs) without organisms.

            Candidiasis in the neonate may be acquired in utero or at the time of delivery. Infants who have congenital candidiasis exhibit diffuse scaling and erythema or erythematous papules and pustules at birth. Those who acquired infection natally have similar physical findings that begin days to weeks after delivery. A potassium hydroxide preparation performed on scale or a pustule roof demonstrates pseudohyphae and spores.

            Erythema toxicum is a benign, self-limited eruption that occurs in approximately 50% of term newborns. It is characterized by erythematous macules 2 to 3 cm in diameter that have a central papule, vesicle, or pustule. The eruption typically begins at 24 to 48 hours of life and lasts for 4 to 5 days. A Wright stain of the contents of a vesicle or pustule reveals numerous eosinophils.

            Neonatal herpes simplex virus infection usually is acquired from passage through an infected birth canal. The clinical hallmark of infection is clustered vesicles on an erythematous base. Although lesions may be present at birth, more often they appear during the first week of life.

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Q 5


An 8-year-old girl is having trouble keeping up with her class in reading. She holds her book closely while reading, but has normal distance vision. Results of the physical examination are normal.
Of the following, the most appropriate intervention is to:

A.  arrange for large print books to be available in her classes
B.  limit the amount of time she spends reading
C.  make sure lighting is appropriate when she is reading
D.  refer her for ophthalmologic examination
E.   refer for educational evaluation

Answer

E


The most common ophthalmologic problem in young children is myopia or near-sightedness. Many children at the age of the girl described in the vignette hold books closely and have no difficulty focusing at close distances. By age 40, most people have lost the ability to read at near distance and begin to use reading glasses. The normal results on a physical examination of the eye to exclude inflammation and normal distance vision reported for this girl make an ophthalmologic etiology unlikely for her school difficulty. Accordingly, arranging for large print books, limiting the amount of time she spends reading, making sure lighting is appropriate for reading, or referring her for ophthalmologic examination are not appropriate interventions. The most likely cause of this child’s difficulty is educational. She should be referred for achievement cognitive testing to help clarify her academic strengths and weaknesses.

            The eye evaluation for children changes from birth to school age. From birth to 2 years of age, it should include examination of the eyelids and orbits for symmetry and function; external evaluation of the conjunctiva, sclera, cornea, and iris; assessment of ocular motility and muscle balance with the corneal light reflex; and examination of the posterior segment of the eye with the red reflex. The unilateral cover test is useful in infants and toddlers who are able to fixate on an object. If the infant becomes fussy when one eye is covered, poor vision in the uncovered eye is a possibility.

            Examination of children ages 2 to 4 years includes the previously noted tests and two additional measures. Ophthalmoscopic examination may be possible in very cooperative 3- to 4-year-old children. Vision testing should be attempted with pictures by 3 years of age, although some younger children may be able to perform the Allen card test. The Allen card test is known for its commonly used symbols of a truck, house, birthday cake, bear, telephone, horse, and tree. Complete evaluation of a child should be attempted by age 3 and repeated in 6 months if not initially successful. If the repeat examination also is unsuccessful, the child should be referred to a pediatric ophthalmologist for testing. Similar testing should occur at age 5 years, but children ages 5 to 10 years should be tested annually due to the high frequency of refractive errors noted in this age group. After age 10 years, children and adolescents should have vision screening every 2 to 3 years.


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Q 6


During your evaluation of an infant in the nursery, you note that the red reflex in one eye seems paler than in the other.
Of the following, the MOST appropriate next step is to:

A. apply a cycloplegic to the infant's eyes for examination before discharge
B.  perform the corneal light reflex test
C.  perform the cover-uncover test
D.  re-evaluate the red reflex in 1 to 2 weeks
E.  refer the infant to a pediatric ophthalmologist

Answer

E



The red reflex is evaluated using a direct ophthalmoscope that is held 12 to 24 inches from the eyes. In an alert infant, both eyes may be visualized at once. The reflected light from the retina will be orange-red and should be of equal color and intensity in each eye. Abnormalities in the pupillary red reflex suggest cataracts or intraocular pathology and warrant an immediate ophthalmologic referral.

 Leukocoria (white pupillary reflex) can be caused by cataract, tumor (retinoblastoma), chorioretinitis, retinopathy of prematurity, or a persistent hyperplastic vitreous.

            It is not necessary to dilate the infant’s eyes with a cycloplegic to examine the light reflex. If the infant closes his or her eyes during the examination, holding him or her and tipping the head forward and backward will take advantage of the tonic labyrinthine and neck reflexes. Most infants will open their eyes during this maneuver. The red reflex should be examined at each visit during infancy because leukocoria may develop after the newborn period. Because there is no expected change in the red reflex during infancy, waiting to re-examine the infant’s eye until 2 to 3 weeks of age is not recommended.

            The corneal light reflex test screens for ocular alignment and is performed by shining a light on both eyes at the same time. The reflected light noted on the corneal surface should be in the same position on each pupil. A deviation of 2 mm or more is indicative of ocular misalignment.

            The cover-uncover test evaluates for eye muscle imbalance and visual acuity. The infant or child must be able to fixate on an object, usually a toy or a light. The examiner first moves the object in front of the child to gain his or her interest and to see whether the eyes move together. The examiner then covers one eye with his or her hand and moves the toy to see if the child can focus and track with the uncovered eye. A child who consistently objects to one eye being covered should be suspected of having decreased visual acuity in the uncovered eye and referred for evaluation.

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Q 7


At a 4-month health supervision visit, a mother expresses concern that her infant son does not see well. Birth and postnatal history are unremarkable. On physical examination, you note horizontal nystagmus with jerking eye movement when the child looks to the left. Occipitofrontal circumference is 43.0 cm (75th percentile). Red reflex is normal, as are findings on brain magnetic resonance imaging.

Of the following, the MOST likely diagnosis is:

A. congenital nystagmus
B.  neuroblastoma
C. retinoblastoma
D. seizures
E. spasmus nutans

Answer

A


Nystagmus is a rapid, rhythmic oscillation of the eyes that usually is bilateral. It can be a worrisome sign of serious eye or central nervous system pathology and may warrant referral to a neurologist. Congenital nystagmus is characterized by pendular nystagmus in primary gaze that becomes jerkier with lateral gaze, as described for the infant in the vignette. Frequently, there is a null point at which nystagmus is least and vision is best. Visual acuity often is diminished. Typically the child’s distance vision is worse than near vision because nystagmus is dampened with convergence. Congenital nystagmus may be associated with ocular albinism and head titubation (bobbing). Onset of the disorder is typically between 2 and 6 months of age. Many of these children will have lifelong visual impairment.

            Spasmus nutans is a triad of nystagmus, head nodding, and head tilt. The nystagmus may be quick and pendular (shimmering) and asymmetric. Onset is typically at 4 to 12 months, and it resolves by 4 years. Rarely, patients have an associated optic pathway pilocytic astrocytoma.

            Nystagmus can be seen during a seizure, but it is absent interictally. Downbeating vertical nystagmus is pathognomonic of disease at the cervicomedullary junction, particularly a Chiari malformation. Upbeat nystagmus can be seen with lesions in the low brainstem or cerebellum.

            Opsoclonus is distinct from nystagmus, lacking the latter’s rhythmicity and regularity. Rather, it is characterized by irregular, chaotic, conjugate rapid eye movements in all planes. It can be associated with encephalitis, ingestion of toxins, or hydrocephalus, but the finding should trigger a search for occult neuroblastoma. Retinoblastoma is characterized by leukocoria from the tumor producing loss of the red reflex.


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