Developmental and hereditary disorders

Question 1

286. In Hirschsprung’s disease, neural crest cells fail to migrate normally
     early in fetal development and produce potentially fatal complications
     within months of birth because of disturbed
     a. Intestinal motility
     b. Bladder control
     c. Swallowing
     d. Bile secretion
     e. Cardiac rhythms

Answer 1

286. The answer is a.( Victor, p 574.) Infants with this defect in develop-ment of the myenteric plexus are susceptible to intestinal obstruction and
     megacolon development. The affected infants are often misconstrued as
     merely colicky shortly after birth, but recurrent bouts of constipation, diar-rhea, and vomiting point to more serious disturbances of intestinal motil-ity. Intestinal obstruction is likely to become complete within the first year
     of life and may be fatal if not surgically corrected. The failure of migration
     of neural crest cells has been linked to a defect on chromosome 10

Question 2

287. A newborn infant has a cystic swelling at the base of the spine that is
     covered with hyperpigmented skin and some coarse hair. Which of the fol-
     lowing is the most likely explanation?
     a. Mongolian spot
     b. Spina bifida occulta
     c. Nevus flammeus
     d. Meningocele
     e. Encephalocele

Answer 2

287. The answer is d. ( Victor, p 1062.) The Mongolian spot is a benign
     discoloration of the newborn’s skin at the base of the spine. It is usually
     oval, well circumscribed, flat, and slightly hyperpigmented or otherwise
     discolored. Spina bifida occulta is a defect in the superior elements of the
     spinal column that is unassociated with meningeal or spinal cord abnor-
     malities. It may be evidenced superficially by a dimple in the skin or a
     tuft of hair overlying the base of the spine. When there is evagination of
     the meninges (dura mater and pia arachnoid) about the cord or cauda
     equina through the defect in the spine, the condition is called a meningo-
     cele. Extrusion of meningeal and neural elements together is called a
     meningomyelocele. An encephalocele is a defect in the skull with extru-
     sion of brain. Nevus flammeus is a congenital, port-wine spot, usually developing on the face.

Question 3

At age 5, a child is noted to have the loss of ankle jerks. At age 10, limb
ataxia develops, followed by a peripheral neuropathy. During adolescence,
retinitis pigmentosa develops. Acanthocytosis is present.
288. These are all characteristic of which of the following?
a. Multiple sclerosis (MS)
b. Sickle cell disease
c. Abetalipoproteinemia
d. Progressive multifocal leukoencephalopathy (PML)
e. HIV subacute encephalomyelitis

Answer 3

289. The answer is a.( Rowland, pp 552–553.) This disorder appears to be
     due to a mutation in the gene that encodes a subunit of the MTP, which
     results in impaired VLDL formation and consequent decreased vitamin E
     delivery to the peripheral and central nervous system. In addition to an
     abnormal plasma lipid profile, patients have disturbed fat absorption. Pre-
     sumably, it is the disturbed lipid that deforms the erythrocyte cell wall, but
     erythrocyte production levels are relatively normal. Fat is increased in the
     liver, and patients exhibit lactose intolerance. Central nervous system amy-
     loid collections develop in Alzheimer’s disease.

Question 4

Items 288–289
At age 5, a child is noted to have the loss of ankle jerks. At age 10, limb
ataxia develops, followed by a peripheral neuropathy. During adolescence,
retinitis pigmentosa develops. Acanthocytosis is present.

289. In this disorder, chylomicrons, very-low-density lipoprotein (VLDL),
     and low-density lipoprotein (LDL) are largely absent in the serum as a con-
     sequence of a mutation in which gene?
     a. Microsomal triglyceride transfer protein (MTP)
     b. Huntingtin
     c. Amyloid precursor protein
     d. Dystrophin
     e. Transfer RNA (tRNA)

Answer 4

290. The answer is b. (Osborn, pp 815–816.) In the tomogram, the first
     cervical vertebra, or atlas, is incompletely formed. The most ventral ele-
     ments are apparent to the left of the left-pointing arrowhead, but the cor-
     tical bone of these elements is continuous with that of the skull. The
     elements of C1 that have formed have simply fused to the base of the
     skull. This assimilation of the atlas to the base of the skull is a congenital
     abnormality. It is often associated with a Chiari malformation of the hind-
     brain.

Question 5

290. In this tomogram of the base of the skull, the first cervical vertebra is
     a. Unremarkable

b. Fused to the base of the skull
c. Completely absent
d. Displaced dorsally
e. Incorporated into the odontoid process (od)

Answer 5

Question 6

291. The second cervical vertebra extends above the level of the foramen
     magnum and places the patient at high risk of having
     a. A meningoencephalocele
     b. A myelomeningocele
     c. Syringobulbia
     d. Syringomyelia
     e. Brainstem compression

Answer 6

291. The answer is e. (Osborn, pp 815–816.) This abnormally situated
     axis (C2) qualifies as basilar invagination of the skull. If the medulla oblon-
     gata is situated at a normal level, it is at risk of compression, but posterior
     fossa contents may be so caudally displaced that pontine structures are also at risk of compression. Hydrocephalus may develop with this degree of

basilar invagination by virtue of obstruction of the flow of CSF through the
foramen magnum. Syringomyelia or syringobulbia are occasionally associ-
ated with this anatomic variant, but they probably develop as a conse-
quence of cervical cord or brainstem damage.

Question 7

292. In view of the unusually wide separation (double-barbed arrow) of
     caudal elements of the atlas from the odontoid process, one should suspect
     a. Instability of the atlantoaxial joint
     b. Hemorrhage into the atlantoaxial joint
     c. Fusion of C2 to C3
     d. Fracture of the odontoid process
     e. Fracture of the C2 spinous process

Question 8

293. A 5-year-old boy has mental retardation, homonymous hemianopsia,
     and hemiparesis. He had infantile spasm and still has epilepsy. Head CT
     reveals calcifications in the cerebral cortex in a railroad track pattern.
     Which of the following does this child most likely have?
     a. Glioblastoma multiforme
     b. Oligodendroglioma
     c. Acoustic schwannoma
     d. Craniopharyngioma
     e. Sturge-Weber syndrome

Answer 8

293. The answer is e. (Greenberg, 2/e, p 601.) All of these disturbances
     will produce intracranial calcifications in some cases. The calcifications in
     Sturge-Weber syndrome follow the gyral pattern of the cerebral cortex and
     consequently produce the railroad track pattern that is evident on plain
     x-ray of the skull. Calcium is deposited in the brain of the patient with
     Sturge-Weber syndrome, presumably because the abnormal vessels overly-
     ing the brain allow calcium, as well as iron, across the defective blood-
     brain barrier. Craniopharyngioma and acoustic schwannoma produce
     calcifications, but these are obviously outside the cerebral cortex.

Question 9

294. A 35-year-old woman has prenatal testing done. The testing reveals
     that her child will have phenylketonuria (PKU). With PKU, serum may
     exhibit dangerously high levels of
     a. Creatine phosphokinase (CPK)
     b. Nicotinamide
     c. Phenylketone
     d. Lactate dehydrogenase
     e. Phenylalanine

Answer 9

294. The answer is e.( Victor, pp 1008–1009.) Phenylketonuria is inher-
     ited as an autosomal recessive trait. It occurs in at least two forms. In one
     form, intolerance of phenylalanine is extreme, and dietary intake of that
     amino acid must be restricted from birth. Alternatively, some persons have
     hyperphenylalaninemia without PKU. This latter group does not suffer the
     CNS damage seen with in utero exposure to high phenylalanine levels.
     Such in utero exposure will occur if the mother is homozygous for PKU. If
     the mother is normal, infants with PKU are born with essentially normal
     nervous systems. Damage develops after birth in the susceptible group as
     serum phenylalanine levels rise.

Question 10

295. A 4-year-old previously healthy girl develops an intermittent red,
     scaly rash over her face, neck, hands, and legs. This is followed by devel-
     opmental delay, emotional lability, and episodic cerebellar ataxia. She is
     diagnosed with Hartnup’s disease. Her condition may respond to large sup-
     plementary doses of
     a. Vitamin C
     b. Nicotinamide
     c. Thiamine
     d. Pyridoxine
     e. α tocopherol

Answer 10

295. The answer is b. ( Victor, pp 1009–1010.) With Hartnup’s disease
     there is intestinal malabsorption of tryptophan and other neutral amino
     acids. Tryptophan serves as a precursor for nicotinamide, but with more
     than 400 mg of nicotinamide daily, the tryptophan malabsorption becomes
     less problematic. Inheritance appears to be autosomal recessive. Affected
     children develop a scaly erythematous rash on the face similar to that seen
     with pellagra. The ataxia exhibited may be episodic.

Question 11

296. Hepatosplenomegaly is most likely with
     a. Tay-Sachs disease
     b. Niemann-Pick disease
     c. Alpers’ disease
     d. Subacute necrotizing encephalopathy
     e. Wilson’s disease (hepatolenticular degeneration)

Answer 11

296. The answer is b. ( Victor, pp 997–998.) Niemann-Pick disease is
     inherited as an autosomal recessive trait. By 9 months of age, patients with
     the infantile form usually have prominent hepatosplenomegaly. A defi-
     ciency of sphingomyelinase in hepatocytes is diagnostic for the disease.

Question 12

297. A 25-year-old woman with epilepsy is taking divalproex sodium dur-
     ing the first trimester of pregnancy. She is at slightly increased risk of hav-
     ing children with which of the following?
     a. Holoprosencephaly
     b. Defects of neural tube closure
     c. Medulloblastoma
     d. Agenesis of the corpus callosum
     e. Kallmann syndrome

Question 13

298. With agenesis of the corpus callosum, magnetic resonance imaging
     (MRI) will reveal
     a. Atrophy of the frontal lobes
     b. Abnormally shaped lateral and third ventricles
     c. Cerebellar aplasia
     d. Schizencephaly
     e. Encephaloclastic porencephaly

Answer 13

298. The answer is b.(Greenberg, 2/e, p 586–587.) On coronal sections of
     the brain, the lateral ventricles will have a typical batwing conformation if
     the patient has agenesis of the corpus callosum. The third ventricle may be
     dilated and may open onto the surface of the brain. Patients with this con-
     genital anomaly may be asymptomatic or may exhibit a variety of cognitive disorders. In Aicardi syndrome, agenesis of the corpus callosum is associ-

ated with retardation, epilepsy, vertebral anomalies, and chorioretinitis.

Question 14

A boy has the onset of difficulty walking at 16 months. Reflexes are
decreased. Over the course of several months, the patient becomes dysarthric
and mental functioning decreases. Testing reveals that the patient has a defi-
ciency of arylsulfatase A.
299. Which of the following does this patient most likely have?
a. Sandhoff’s disease
b. Tay-Sachs disease
c. Gaucher’s disease
d. Metachromatic leukodystrophy
e. McArdle’s disease

Answer 14

299. The answer is d.( Rowland, pp 521–523.) Hexosaminidase deficien-
     cies produce Sandhoff’s and Tay-Sachs diseases. Glucocerebrosidase is defi-
     cient in Gaucher’s disease. Phosphofructokinase deficiency is usually
     symptomatic as a disturbance of skeletal muscle function. The enzymatic
     defect in metachromatic leukodystrophy is transmitted in an autosomal
     recessive fashion. The affected person usually has retardation, ataxia, spas-
     ticity, and sensory disturbances, but individual elements of this disorder
     may appear alone in less serious cases. The disease is usually symptomatic
     during infancy.

Question 15

A boy has the onset of difficulty walking at 16 months. Reflexes are
decreased. Over the course of several months, the patient becomes dysarthric
and mental functioning decreases. Testing reveals that the patient has a defi-
ciency of arylsulfatase A.

300. This diagnosis can usually be made on the basis of which of the fol-
     lowing?
     a. MRI
     b. Nerve biopsy
     c. Red blood cell (RBC) morphology
     d. Cerebrospinal fluid (CSF) cell morphology
     e. Electroencephalography (EEG)

Answer 15

300. The answer is b.( Rowland, pp 521–523.) Sulfatide granules may be
     evident in nerve tissue, as well as in tissue outside the nervous system, in
     persons with metachromatic leukodystrophy. The disease is usually fatal
     within a few years of obvious symptoms. At autopsy, there may be evidence
     of dysmyelination or demyelination in the CNS, as well as in the peripheral
     nervous system.

Question 16

301. A 15-year-old boy has moderate mental retardation, attention deficit
     disorder, a long face, enlarged ears, and macroorchidism. Development has
     been steady but always at a delayed pace. The most likely cause for this
     patient’s low intelligence is which of the following?
     a. Turner syndrome
     b. Klinefelter syndrome
     c. Fragile X syndrome
     d. Reye syndrome
     e. Tuberous sclerosis

Question 17

302. Women carrying chromosomes for this disorder
     a. Are invariably normal
     b. Have mild retardation in about one-half of cases
     c. Have high-arched palates and hypotelorism
     d. Have hyperextensible joints
     e. Have prominent thumbs

Answer 17

302. The answer is b.( Victor, p 1067.) Men with the fragile X syndrome
     have hyperextensible joints and prominent thumbs, but carrier women
     may appear quite normal. The abnormal chromosome may be detected in
     fetal lymphocytes and fibroblasts, thereby allowing for prenatal screening.
     Epilepsy develops in many affected persons, but the seizures are usually
     easily controlled, unlike the case with other hereditary causes of epilepsy.

Question 18

A 35-year-old man complains of stumbling and slurred speech. Hi
problem started several months ago and has progressed slowly but consis
tently. On neurologic examination, he is found to have scanning speech
nystagmus, limb dysmetria, and kinetic tremor. His intellectual function i
normal.
303. The most appropriate initial investigation is
a. Lumbar puncture
b. Serum drug screen
c. Routine urinalysis
d. Posterior fossa myelogram
e. Precontrast CT scan

Answer 18

303. The answer is e. (Swaiman, pp 539–540.) This man has signs of
     cerebellar dysfunction. That the deficit has been slowly progressive and is
     not associated with cognitive dysfunction makes it especially likely that a
     structural lesion in the posterior fossa is responsible for th e deficit. Because the lesion need not disturb the external shape of the cerebellum, a poste-

rior fossa myelogram will not necessarily yield an answer. The CT scan will
show if there is an intraparenchymal or extraparenchymal lesion. Drug
abuse is not likely to be a factor in this cerebellar syndrome, because all the
phenomena that are observed on examination are coordination problems
rather than combined cognitive and motor functions.

Question 19

A 35-year-old man complains of stumbling and slurred speech. His
problem started several months ago and has progressed slowly but consis-
tently. On neurologic examination, he is found to have scanning speech,
nystagmus, limb dysmetria, and kinetic tremor. His intellectual function is
normal.
304. Admission studies include a hematocrit of 55% and a routine urinal-
ysis, which reveals excess protein and some RBCs in the urine. Urine cul-
ture is negative. The initial physical examination reveals an enlarged liver
and spleen. Additional physical findings will most likely include
a. A Kayser-Fleischer ring around the cornea
b. Hypopigmented (ash leaf) spots on the trunk
c. Telangiectasias in the fundi on retinal examination
d. Bilateral hearing loss
e. Generalized hyporeflexia

Answer 19

304. The answer is c.(Swaiman, pp 539–540.) The association of erythro-
     cytosis with cerebellar signs, microscopic hematuria, and hepatospleno-
     megaly suggests von Hippel-Lindau syndrome. This hereditary disorder is
     characterized by polycystic liver disease, polycystic kidney disease, retinal
     angiomas (telangiectasia), and cerebellar tumors. This is an autosomal dom-
     inant inherited disorder with variable penetrance. Men are more commonly
     affected than women. Although neoplastic cysts may develop in the cerebel-
     lum in persons with von Hippel-Lindau syndrome, these usually do not
     become sufficiently large to cause an obstructive hydrocephalus. Other
     abnormalities that occur with this syndrome include adenomas in many
     organs. Hemangiomas may be evident in the bones, adrenals, and ovaries.
     Hemangioblastomas may develop in the spinal cord or brainstem, as well as
     in the cerebellum. This syndrome is not associated with acoustic schwanno-
     mas that could cause bilateral hearing loss, and it is not accompanied by
     peripheral neuropathy, which could cause diffuse hyporeflexia.

Question 20

A 35-year-old man complains of stumbling and slurred speech. His
problem started several months ago and has progressed slowly but consis-
tently. On neurologic examination, he is found to have scanning speech,
nystagmus, limb dysmetria, and kinetic tremor. His intellectual function is
normal.

305. A postcontrast computed tomography (CT) scan reveals a cyst and
     two smaller masses in the left cerebellar hemisphere. Your recommenda-
     tion is that the patient
     a. Submit to surgical resection of the cerebellar lesions as soon as possible
     b. Submit to radiation therapy of the cerebellar lesions immediately
     c. Have follow-up MRI to look for involution of the lesions
     d. Have a diagnostic lumbar puncture to look for evidence of parasitic infestation
     of the brain
     e. Have a needle biopsy of the cerebellum to establish the histology of the cystic
     lesion

Answer 20

305. The answer is a.(Swaiman, pp 539–540.) The cystic lesion and the
     other cerebellar lesions are most likely hemangioblastomas. These heman-
     gioblastomas often bleed and produce potentially lethal intracranial
     hematomas. Radiation therapy and needle biopsies would increase the risk
     of bleeding. Rather than spontaneously involuting, these lesions generally
     enlarge and become more unstable as time passes. Intracerebellar hemor-
     rhage is increasingly likely as time passes.

Question 21

A 35-year-old man complains of stumbling and slurred speech. His
problem started several months ago and has progressed slowly but consis-
tently. On neurologic examination, he is found to have scanning speech,
nystagmus, limb dysmetria, and kinetic tremor. His intellectual function is
normal.

306. Within 6 years of his initial visit, the patient returns with a patho-
     logic fracture of his spine. Biopsy reveals metastatic cancer. The source of
     the tumor is most likely the
     a. Cerebral hemisphere
     b. Cerebellar hemisphere
     c. Liver
     d. Kidney
     e. Spleen

Answer 21

306. The answer is d. (Swaiman, pp 539–540.) Von Hippel-Lindau syn-
     drome is associated with a high incidence of renal carcinomas. These
     malignant renal tumors usually develop years after the cerebellar heman-
     gioblastomas, liver disease, or polycystic renal disease becomes sympto-
     matic. People surviving intracranial hemorrhages caused by the
     intracerebellar hemangioblastomas often succumb to metastatic renal carcinoma. Treating the intracranial lesions does nothing to reduce the risk of

metastatic renal cancer.

Question 22

An infant has a head CT performed because of a large head and failure
to thrive. The diagnosis of hydrocephalus is made.
307. Congenital hydrocephalus may develop as a consequence of which
first-trimester maternal disorder?
a. Complicated migraine
b. Viral infection
c. Pseudotumor cerebri
d. Chorea gravidarum
e. Intervertebral disk herniation

Answer 22

307. The answer is b.(Greenberg, 2/e, p 597. Rowland, pp 5142–5143.) A
     maternal infection with mumps or rubella virus may produce aqueductal
     stenosis and, as a consequence, hydrocephalus. The aqueduct of Sylvius
     connects the third ventricle to the fourth ventricle. The lateral and third
     ventricles enlarge as the choroid plexus produces fluid that cannot migrate
     to the subarachnoid space to be reabsorbed.

Question 23

An infant has a head CT performed because of a large head and failure
to thrive. The diagnosis of hydrocephalus is made.

308. Uncorrected congenital hydrocephalus will usually produce which
     of the following?
     a. Dolichocephaly
     b. Brachycephaly
     c. Holoprosencephaly
     d. Macrocephaly
     e. Microcephaly

Answer 23

308. The answer is d. ( Victor, pp 661–662.) Congenital hydrocephalus
     usually requires shunting to avoid progressive enlargement of the head and
     thinning of the brain mantle. Dolichocephaly and brachycephaly refer to
     head shapes, the former being a long, narrow head and the latter a broad
     head. Neither of these is necessarily associated with any abnormality. Holo-
     prosencephaly is a failure in development of the midline division of the
     brain, which may give rise to a stillborn cyclops. A variety of conditions
     will produce congenital hydrocephalus, and any condition that produces
     apparent hydrocephalus at birth may produce mental retardation. Correc-
     tion of the hydrocephalus at or soon after birth reduces the probability of
     retardation as a direct effect of the hydrocephalus, but conditions that
     cause damage to the brain as well as obstruct the flow of CSF may leave the
     patient retarded. An uncorrected hydrocephalus may not be lethal for
     many years.

Question 24

309. A 6-month-old child is noted to have head lag, tongue fasciculations,
     and bilateral abducens palsies. MRI scan reveals a type 2 Chiari malforma-
     tion. Which of the following defects would this child be likely to have?
     a. A renal cyst
     b. Pulmonary atelectasis
     c. Spina bifida
     d. Holoprosencephaly
     e. A hepatic cyst

Question 25

A 7-year-old boy is taken by his parents to see a dermatologist. They
have noticed nodules on his face and are concerned. The dermatologist
tells them that their child has adenoma sebaceum.
310. Adenoma sebaceum of the face is especially common with which of
the following diseases?
a. Neurofibromatosis
b. Sturge-Weber syndrome
c. Tuberous sclerosis
d. Ataxia telangiectasia
e. Fragile X syndrome

Answer 25

310. The answer is c.( Victor, pp 1069–1073.) Adenoma sebaceum occurs
     in about 90% of patients with tuberous sclerosis. A depigmented lesion,
     called a shagreen patch, occurs in only about 20% of these patients. Ade-
     noma sebaceum usually becomes apparent over the malar eminences of the face between 2 and 5 years of age and may evolve into difficult-to-treat

angiofibromas of the skin. In ataxia telangiectasia, facial telangiectasias may
develop. Sturge-Weber syndrome is characteristically associated with a port-
wine spot over part of the face. Patients with neurofibromatosis often have
café au lait spots, but these do not usually occur on the face.

Question 26

A 7-year-old boy is taken by his parents to see a dermatologist. They
have noticed nodules on his face and are concerned. The dermatologist
tells them that their child has adenoma sebaceum.

311. This disease is inherited in
     a. A sex-linked recessive pattern
     b. An autosomal dominant pattern
     c. An autosomal recessive pattern
     d. A pattern most consistent with newly arising mutations
     e. A pattern suggesting a mitochondrial gene defect

Answer 26

311. The answer is b. ( Victor, pp 1069–1073.) Although the inheritance
     pattern of tuberous sclerosis is autosomal dominant, the penetrance is vari-
     able. A severely impaired child may be born to a negligibly affected parent.
     Despite the consensus that inheritance is autosomal dominant, estimates of
     spontaneous mutations in affected persons are as high as 70%.

Question 27

A 7-year-old boy is taken by his parents to see a dermatologist. They
have noticed nodules on his face and are concerned. The dermatologist tells them that their child has adenoma sebaceum.

312. Retinal problems with this disease
     a. Include retinal phakomas
     b. Include retinitis pigmentosa
     c. Include retinal telangiectasias
     d. Include retinoblastomas
     e. Are generally not part of the disease

Answer 27

312. The answer is a.( Victor, p 1071.) Retinal phakomas, which require
     no treatment, are a principal criterion for making the diagnosis of tuberous
     sclerosis. Along with adenoma sebaceum and periventricular tubers, they
     are virtually pathognomonic. Other findings that are typical of tuberous
     sclerosis include ash leaf spots, shagreen patches, CNS calcifications, renal
     tumors, cardiac rhabdomyomas, and seizure disorders.

Question 28

A 7-year-old boy is taken by his parents to see a dermatologist. They
have noticed nodules on his face and are concerned. The dermatologist
tells them that their child has adenoma sebaceum.

313. Calcifications evident on the skull x-ray or CT scan of a patient with
     this disease usually represent
     a. Calcified subependymal glial nodules
     b. Calcified meningeal adhesions
     c. Meningeal psammoma bodies
     d. Calcified astrocytomas
     e. Calcified granulomas

Question 29

314. A 50-year-old man complaining of dizziness is found to have a cyst
     occupying 50% of his posterior fossa and incomplete fusion of the cerebel-
     lar elements inferiorly. There is no evidence of an obstructive hydro-
     cephalus. His longevity can be estimated to be
     a. Less than 3 months
     b. Less than 1 year
     c. Less than 5 years
     d. Less than 10 years
     e. Unaffected by this finding

Question 30

315. The treatment of choice for children with infantile spasms is
     a. Carbamazepine (Tegretol)
     b. Phenobarbital
     c. Phenytoin (Dilantin)
     d. Divalproex sodium (Depakote)
     e. Adrenocorticotropic hormone (ACTH)

Question 31

316. A 9-year-old boy has been generally healthy. However, his parents are
     concerned that his many areas of hyperpigmented skin may have some sig-
     nificance. They have been told that these are café au lait spots. Café au lait
     spots are commonly found on patients with
     a. Tuberous sclerosis
     b. Neurofibromatosis
     c. MS
     d. Sturge-Weber syndrome
     e. Ataxia telangiectasia

Answer 31

316. The answer is b. ( Victor, pp 1073–1077.) Café au lait spots in
     patients with neurofibromatosis are usually larger than a few centimeters
     and occur in several locations in individual patients. Some have ragged
     edges and are called coast of Maine spots. They occur with both type 1 and
     type 2 neurofibromatosis, but are much more common with type 1.

Question 32

317. The newborn infant with motor neuron disease is likely to exhibit
     a. Seizures
     b. Hypotonia
     c. Hypsarrhythmia
     d. Moro reflexes
     e. Spina bifida

Answer 32

317. The answer is b.(Swaiman, pp 1164–1169.) The child with congen-
     ital weakness, hypotonia, and muscle atrophy may have Werdnig-
     Hoffmann disease, a congenital motor neuron disease. This is an especially
     lethal form of motor neuron disease and may limit the child’s life
     expectancy to weeks or months. A similar pattern of disease that appears in
     older children is less lethal and is called Kugelberg-Welander disease.
     These types of motor neuron diseases are also known as spinal muscular
     atrophies (SMAs). Anterior horn cell disease is presumed to be a pivotal
     feature of diseases in this category.

Question 33

318. Many children with Tay-Sachs disease develop blindness before they
     die, with retinal accumulation of gangliosides that produces
     a. Optic neuritis
     b. Cherry red spots
     c. Chorioretinitis
     d. Retinal detachments
     e. Waxy exudates

Answer 33

318. The answer is b.( Victor, pp 996–997.) More than 90% of children
     with Tay-Sachs disease develop cherry red spots on the retina. The red
     spot at the fovea develops as retinal ganglion cells become distended with
     glycolipid. There are no ganglion cell bodies overlying the fovea, and so
     the red color of the vascular choroid is apparent in this region but
     obscured by more opaque glycolipid-engorged cells over the remainder
     of the retina.

Question 34

319. The parents of a 10-year-old boy bring their child in to see you. The
     child has been diagnosed with cerebral palsy, and the parents do not really
     understand what this means. As part of your explanation, you tell them
     that cerebral palsy is a static encephalopathy because
     a. Deficits do not appear after birth
     b. The injury to the brain does not progress
     c. Affected persons fail to reach any developmental milestones on time
     d. Affected persons have resting tremors
     e. The EEG exhibits a disorganized background rhythm

Answer 34

319. The answer is b.( Rowland, p 476.) A static encephalopathy is one in
     which brain damage has been arrested but neurologic problems persist.
     Establishing that the brain lesion is not progressive may require extensive
     testing. A young child with a static motor disorder is said to have CP. Neu-
     rodegenerative diseases with slow or stepwise progressions may appear to
     be static encephalopathies over the course of months, but prove to be pro-
     gressive encephalopathies over the course of years. The brain lesion with
     CP is static, but the deficits associated with CP may evolve as the child
     matures.

Question 35

320. A 6-year-old child is brought to the neurologist because of develop-
     mental delay. Her morphological features are typical and chromosome
     analysis confirms a diagnosis of Down syndrome (trisomy 21). The brain of
     this patient is expected to be
     a. Smaller than normal for age and body size
     b. Larger than normal for age and body size
     c. Abnormally long in anteroposterior measurements
     d. Hydrocephalic
     e. Excessively convoluted

Question 36

321. Porencephaly usually develops as a consequence of
     a. Fetal alcohol syndrome
     b. Vascular or other destructive injuries to the fetal brain
     c. Trisomy 13
     d. Trisomy 21
     e. Dandy-Walker syndrome

Answer 36

321. The answer is b. (Osborn, pp 52–56.) In utero damage to the fetal
     brain may be evident at birth as large cysts in the brain. The presence of
     one or more of these intracerebral cysts is called porencephaly. Some
     pathologists believe that schizencephaly, a related abnormality in which
     brain segmentation is abnormal, is caused by similar phenomena, which
     include incidents such as strokes and viral encephalitides in the fetal brain.

Question 37

322. What percentage of patients with tuberous sclerosis have mental
     retardation?
     a. 1
     b. 10
     c. 25
     d. 65
     e. 99

Answer 37

322. The answer is d. (Swaiman, p 534.) Of the 65% of patients with
     tuberous sclerosis who are retarded, half are severely retarded. Seizures are
     invariably associated with retardation. About 20% of patients with tuber-
     ous sclerosis develop the Lennox-Gastaut syndrome with persistent
     seizures and significant mental retardation. These children usually have a
     mixed seizure disorder, whereas those without Lennox-Gastaut syndrome
     most often have complex partial seizures.

Question 38

323. A child is born to a 19-year-old woman who has had two to eight
     drinks per day throughout her pregnancy. What is the major pathologic
     effect of alcohol on the central nervous system of the developing fetus?
     a. Cerebral ischemia
     b. Periventricular hemorrhage
     c. Macrocephaly
     d. Impaired neuronal migration
     e. Holoprosencephaly

Question 39

324. A 37-year-old man has an MRI performed by his primary care doctor
     because of a long history of headaches. It is notable only for the finding
     of a type 1 Chiari malformation. He is sent to a neurologist for further eval-
     uation. A type 1 Chiari malformation usually becomes symptomatic as
     which of the following in adults?
     a. Epilepsy
     b. Hydrocephalus
     c. Ataxia
     d. Dementia
     e. Psychosis

Answer 39

324. The answer is c.(Osborn, pp 15–18.) Both type 1 and type 2 Chiari
     malformations are primarily abnormalities of hindbrain development. With
     the type 1, or adult, abnormality, the cerebellar tonsils extend below the
     foramen magnum. Affected persons do not usually become symptomatic until they are adults, and then the symptoms are largely referable to the

cerebellum. With the type 2 malformation, cerebellar anatomy is usually
much more deranged, and the cerebellar vermis lies well below the foramen
magnum. Type 2 malformations most often become symptomatic at birth or
during infancy and may produce hydrocephalus with retardation.

Question 40

325. A 25-year-old mother develops an illness during pregnancy. A diag-
     nosis of cytomegalovirus (CMV) infection is made by serology. Prenatal
     CMV infections may produce which retinal disturbance?
     a. Chorioretinitis
     b. Cherry red spot
     c. Microaneurysms
     d. Hypervascularity
     e. Hemorrhage

Answer 40

325. The answer is a.( Victor, p 1071.) Microaneurysms and hypervascu-
     larity are typically seen with diabetic retinopathy rather than developmen-
     tal disease. Hemorrhages in the retina would be more typical of
     hypertensive encephalopathy or a coagulopathy. Neurologic problems that
     develop in the infant with a prenatal CMV infection include retardation,
     microcephaly, seizures, and hearing deficits. The virus often causes cho-
     rioretinitis, optic atrophy, and architectural changes throughout the brain.