MCQs In Pediatric Neurology

Q 1:

You are seeing a 5-year-old boy who has developed diplopia, dysphagia, dry mouth, diarrhea, weakness in his arms, and shortness of breath over the past 18 hours. According to his records, he received his diphtheria, tetanus, acellular pertussis (DTaP), poliovirus inactivated (IPV), measle-mumps-rubella (MMR), and varicella booster immunizations about 1 month ago. He attended a class picnic 3 weeks ago that was held in a state park. He has no history of unusual exposures or ill contacts, and except for falling off his bike 5 days ago and scraping his arm, he has had no other trauma. Physical examination reveals an awake and alert boy who complains of "seeing double" and of pain with swallowing. His pupils are 3 mm bilaterally and
sluggish, and his mucous membranes are dry. He takes shallow breaths, but his lungs are clear, and his abdomen is mildly distended. His left arm has a 4x4-cm abrasion that is mildly swollen, erythematous, and tender, with some serosanguineous drainage. His left arm has 2/5 strength and decreased tone. He has 1+ reflexes in the upper and lower extremities. Of the following, the MOST likely cause of this patient’s condition is

A. botulism
B. cerebral vascular accident
C. Guillain-Barré syndrome
D. tetanus
E. tick paralysis

Answer :

A

Explanation :


The classic presentation of botulism is acute, bilateral cranial nerve palsies associated with symmetric descending weakness.

 Fever is absent, sensory deficits do not occur, and the patient remains responsive, with a normal level of consciousness.

Foodborne disease usually develops between 12 and 36 hours after toxin ingestion.

The initial symptoms include nausea, dry mouth, and diarrhea.

 Disease progresses to cranial nerve dysfunction, most commonly starting with the eyes (diplopia, blurry vision), and descending to include dysphagia, upper extremity weakness, respiratory dysfunction, and lower extremity weakness.

The symptoms of wound botulism are similar to that of food-borne disease, although the incubation period is 4 to 14 days from the time of injury until the onset of symptoms.

Also, in many cases, the wound may not appear to be healing, as described for the boy in the vignette. Infant botulism develops 3 to 30 days from the time of exposure to the spore-containing material. Infants present with constipation, which is followed by feeding difficulties, hypotonia, increased drooling, a weak cry, diminished gag reflex, truncal weakness, cranial nerve palsies, and generalized weakness with ventilatory failure. Progression occurs for 1 to 2 weeks, followed by stabilization for another 2 to 3 weeks before recovery starts.

An important element in the treatment of all forms of botulism is meticulous supportive care.

In addition, patients who have suspected foodborne and wound botulism should be treated with
equine trivalent antitoxin.


Immediate administration of antitoxin is critical for successful therapy because it arrests the progression of paralysis but does not reverse it.

Patients who have wound botulism also should undergo wound debridement, even if the wound
appears to be healing.

The role of antibiotic therapy is unknown, but penicillin G or metronidazole frequently is recommended.


Human-derived botulinum antitoxin (botulism immune globulin intravenous) (BIGIV) is used in the treatment of infant botulism caused by type A or type B C botulinum toxin. BIGIV therapy should be initiated as early in the illness as possible.

 Antibiotic therapy is not recommended for infant botulism.

About other mentioned diagnoses :


Patients who have cerebral vascular accidents usually do not present with bilateral symmetric weakness or the other symptoms demonstrated by the patient in the vignette.

Patients who have tetanus have persistent, painful tonic spasms of the muscles of the neck, jaw, and trunk and are very rigid.

The paralysis of tick paralysis is ascending, beginning in the lower extremities and ascending symmetrically to involve the trunk, upper extremities, and head within a few hours.

Patients who have Guillain-Barré syndrome typically present with numbness and paresthesias of the hands and feet, followed by progressive weakness involving all four extremities. Motor impairment begins in the lower extremities and progresses in an ascending pattern to involve the upper extremities, trunk, and cranial nerves.




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Q2

A 3-year-old girl presented with a 2-day history of coryzal symptoms, with a sudden onset of floppiness and difficulty breathing. She was initially treated with antibiotics, bronchodilators and intravenous steroids. She developed an increasing oxygen requirement, with jerky respiratory movements. She had a progressive weakness starting in her upper limbs and then her lower limbs. On neurological examination she had a head circumference between 2nd and 9th centile, normal eye examination, gag reflex was intact, a flaccid

quadraparesis with downgoing plantars and urinary retention.

1. What is the differential diagnosis?

(a) Guillan-Barre syndrome

(b) Poliomyelitis

(c) Transverse myelitis

(d) Migraine

(e) Craniopharnygioma

2. Apart from neuro-imaging what other investigation would confirm your diagnosis?

(a) Blood cultures

(b) Lumbar puncture

(c) Viral serology

(d) Spirometry

(e) Autoimmune screen

Answer 

1. (c) The patient’s symptoms fit with an acute spinal cord lesion. At this stage the most likely cause is associated with his history of viral illness, however, a spinal cord tumour cannot be excluded. Guillan Barre is

typically ascending and progresses over a longer time period. Poliomyelitis does not have any autonomic

involvement.

2. (b)

Comment :

Transverse myelitis is a condition caused by inflammation of the spinal cord. The peak age of presentation in children is 10–19 years.1 It can affect one level or segment of the cord leading to a variety of presentations depending on the position of the lesion.

 The inflammation leads to destruction of the myelin sheath around the spinal cord and nerves presentation is typically limb weakness, bowel and bladder dysfunction, back pain and sensory disturbance. At the level

of the lesion patients can describe areas of hypersensitivity.

Transverse myelitis has many known causes and can also be idiopathic. It can occur in association with an infection typically:

Viral:

Herpes simplex virus (HSV),

Herpes zoster,

Cytomegalovirus (CMV),

Enteroviruses,

Human immunodeficiency virus,

Epstein-Barr virus (EBV),

Influenza,

Rabies.

Bacterial:

Mycoplasma pneumoniae,

syphilis,

tuberculosis.

It can also be seen in association with autoimmune diseases such as SLE and sarcoidosis.

 The differential diagnoses would include: 

1- An initial presentation of multiple sclerosis—particularly in adolescents

2- Acute disseminated encephalomyelitis

3-  Spinal cord compression

4- Tumour

5- Trauma.

Investigation to elicit the diagnosis would initially be MRI, this typically shows swelling and inflammation at the level of the lesion. Further investigations include nerve conduction studies.

 Then the investigations would be aimed at finding the cause :

 Blood tests include: autoimmune screen, viral serology (EBV, CMV, hepatitis A/B/C,), bacterial (mycoplasma serology, treponemal, Borrelia, Legionella). 

Blood cultures. CSF samples for protein, glucose, MC+S, viral studies, cytospin for tumour cells, oligoclonal bands.

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Q 3 :


A 6-year-old boy is referred to you for evaluation of café au lait patches. You note seven patches measuring at least 5 mm in diameter as well as axillary freckling. Subsequent head magnetic resonance imaging reveals an optic nerve glioma. Neither parent has café au lait patches, skinfold freckling, tumors, or other evidence for this disorder.NOf the following, the MOST accurate information to give to the boy's parents about their son's conditionNis that

A. 50% of cases result from a new mutation
B. boys are more severely affected than girls
C. inheritance is autosomal recessive
D. there is a 50% recurrence risk to the parents
E. this condition is associated with reduced penetrance

Answer :

A

Q 4 :

Which of the following is not among  the  diagnostic criteria for neurofibromatosis (type 1) :

A- Presence of two or more iris Lisch nodules.
B- Presence of sphenoid dysplasia.
C- Presence optic gliomas.
D-Presence of  vestibular schwannomas.
E-Presence of  plexiform neurofibromas.

Answer :

D

Q5 :

Which of the following is  true about  neurofibromatosis (type 1) :

A- Cafe-au-lait macules   increase in size and pigmentation but not in number.
B-  Learning disability is one of the diagnostic criteria.
C- Precocious puberty is a recognized clinical manifestation.
D- Skinfold freckling usually appears between 6 and 8 yr of age.
E- Cafe-au-lait spots and skin neurofibromas are much more  common in NF-2 than in NF-1


Answer :

C

Q 6 :

Which of the Following statement about NF1  is false  :

A- In childhood, the most common complication of NF1 is cognitive impairment.
B- Cafe´ au lait spots  may be the only sign present in infancy.
C- White matter T2 hyperintensities, also known as unidentified bright objects (UBOs),are  common to NF1
     patients.
D- The NF1 gene localizes to chromosome 17q11.2
E- Optic nerve gliomas  usually develop after  age of 10 year and can be insidious in their onset.


Answer :

E

Comment :

Neurofibromatosis type 1 (NF-1) :

It is an autosomal dominant condition. Fifty percent of cases result from spontaneous mutations in the gene that encodes neurofibromin on chromosome 1. 

Males and females are equally affected.

 The gene abnormality shows full penetrance.

 The recurrence risk to offspring of an affected person is 50%.

The gene that causes NF-1 is large, and most affected individuals have unique mutations, which makes DNA testing cumbersome. Therefore, NF-1 is diagnosed according to the National Institutes of Health diagnostic criteria established in 1987. The diagnosis requires at least two of the following: 

 • Six or more café au lait macules measuring greater than 0.5 cm in diameter in prepubertal individuals and   
         greater than 1.5 cm in those who are postpubertal 
 • More than two neurofibromas of any type or more than one plexiform neurofibroma
• Freckling  in the axillary and/or inguinal regions
• Optic glioma
• More than two Lisch nodules (iris hamartomas) 
 • A characteristic osseous lesion (eg, dysplasia of the sphenoid bone or dysplasia or thinning of long bone cortex)
• A first-degree relative who has NF-1 NF-1 is caused by mutations in a tumor suppressor gene.



Children with NF-1 are susceptible to neurologic complications. MRI studies of selected children have shown abnormal hyperintense T2 weighted signals in the optic tracts, brainstem, globus pallidus, thalamus, internal capsule, and cerebellum . These signals, “unidentified bright objects (UBOs),” tend to disappear with age; most have disappeared by 30 yr of age.


Optic nerve gliomas are pilocytic astrocytomas involving the optic nerve, chiasm, or tract. They usually develop prior to age 7 and can be insidious in their onset.


In childhood, the most common complication of NF1 is cognitive impairment.


 Patients with NF-1 are at risk for hypertension, which may result from renal vascular stenosis or a pheochromocytoma.

Precocious puberty may become evident in the presence or absence of lesions of the optic chiasm and hypothalamus.


The workup for NF1 is aimed at the early identification of potential complications, with tumor formation
being the main concern.

 The American Academy of Pediatrics Committee on Genetics recommends yearly physical examinations and ophthalmologic assessments.

The physical examination focuses on the organ systems involved.
The skin is screened for new neurofibromas or plexiform neurofibromas.
Blood pressure is followed to assess for renal or endocrine abnormalities.
 A skeletal examination looks for pseudoarthrosis of the tibia, bowing of the long bones, scoliosis, and orbital
    defects.
The neurological examination may reveal macrocephaly, learning disabilities, or cognitive impairment.
The ophthalmologic evaluation helps exclude optic nerve gliomas, choroidal hamartomas, and Lisch nodules.

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Q 7 :


A 12-year-old 40-kg girl presents for a health supervision visit. Physical examination, including vital signs, yields normal results. The mother notes that the girl had to come home from school three times last semester due to headaches. Her typical headaches are bifrontal, with sensitivity to light and sound and often nausea. They last 1 to 6 hours. During the headache, she feels and looks sick and prefers to lie in a dark room. The mother requests an acute treatment plan for her daughter. You provide education about migraine headaches and discuss lifestyle issues, including good sleep hygiene, exercise, diet, hydration, and stress management. For abortive headache treatment, you explain that it is ideal to treat within 30 minutes, even at school.
Of the following, the PREFERRED abortive treatment for this girl is

A. butalbital (50 mg), acetaminophen (325 mg), caffeine (40 mg) orally
B. ibuprofen (400 mg) orally
C. promethazine (12.5 mg) rectally
D. sumatriptan (5 mg) intranasally
E. topiramate (25 mg) orally

Answer :

B

The girl described in the vignette has an idiopathic, nonprogressive headache disorder consistent with migraine.

She does not describe any aura, but the headaches are severe enough for her to miss school.

 Although painful and lasting for hours, they are relatively infrequent.

In addition to lifestyle and healthy habits education, it is important to have a plan for abortive treatment. The preferred abortive treatment for migraine is ibuprofen because it is readily available and inexpensive, does not require a prescription, and can be administered at home or school.

 Studies in adolescents suggest that ibuprofen and acetaminophen are as effective as the triptans, with fewer adverse effects.

Combination products such as butalbital plus acetaminophen plus caffeine are not considered first-line treatments.

 Sumatriptan and other triptans act through 5HT (serotonin) 1B 1D receptor antagonism. Although shown to be effective in some placebo-controlled studies, they have a higher adverse effect risk and can, therefore, be deferred until after implementation of healthy habits and appropriate use of ibuprofen or acetaminophen.

Dopamine receptor-blocking agents such as metoclopramide and promethazine may be considered, but they are not used as first-line therapy because of possible adverse effects such as akathisia and acute dystonic reactions.

Rectal administration is advantageous in the presence of nausea but has other disadvantages in the adolescent population.

Topiramate is not used for acute treatment of migraine, although studies support its use at doses of 25 to 75 mg twice a day as a daily medication for migraine prevention.

 Daily preventive medications are generally considered when disabling headaches are more frequent (at least weekly) than described for the girl in the vignette.

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Q8 :

An infant has a seizure disorder and a large, violaceous patch that involves much of the right side of the face, including the periorbital region.

Of the following, the MOST likely diagnosis is:

A.         Kasabach-Merritt syndrome

B.         Klippel-Trenaunay-Weber syndrome

C.         neurofibromatosis type-1

D.         Sturge-Weber syndrome

E.         tuberous sclerosis

Answer :

D

The presence of a facial port-wine stain (PWS) and seizures is consistent with Sturge-Weber syndrome (SWS).

 Although a PWS may occur anywhere on the body, lesions located on the face, especially around the eye, may be associated with central nervous system (CNS) or ophthalmic involvement.

In children who have SWS, the vascular malformation involves not only the skin, but also the ipsilateral leptomeningeal vessels, particularly those in the parieto-occipital region. Slow flow through these vessels causes hypoxic injury that, in turn, may result in seizures or contralateral hemiparesis. The vascular malformation also may affect the ipsilateral eye. 

Abnormalities of the choroid and episcleral vessels may lead to retinal detachment or glaucoma, respectively. For these reasons, an experienced pediatric neurologist and pediatric ophthalmologist should be consulted whenever a child who has a facial PWS is suspected of having SWS.

            Although infants who have Kasabach-Merritt or Klippel-Trenaunay-Weber syndromes have cutaneous vascular anomalies, clinical features of these disorders permit their differentiation from SWS. Infants who have Kasabach-Merritt syndrome develop a solitary, often rapidly enlarging, atypical-appearing hemangioma (actually a hemangioepithelioma) that sequesters platelets and fibrinogen, causing thrombocytopenia and a localized consumptive coagulopathy.

Klippel-Trenaunay-Weber syndrome is a condition in which a PWS or other vascular malformation located on an extremity is associated with overgrowth of that extremity.

            Infants who have neurofibromatosis type-1 (NF-1) or tuberous sclerosis do not exhibit characteristic cutaneous vascular anomalies. NF-1 is an autosomal dominantly inherited disorder; café au lait  macules are the hallmark of the disease and often are the earliest manifestation. Children who have NF-1 also may exhibit axillary or inguinal freckling, but neurofibromas  generally do not appear until adolescence. 

Tuberous sclerosis, another neurocutaneous disorder, is characterized by seizures, mental retardation, and adenoma sebaceum . The earliest cutaneous sign of tuberous sclerosis, often present at birth, is the ash-leaf macule . These hypopigmented spots may be single or multiple and typically are located on the trunk and extremities. Other characteristic skin findings, including the shagreen patch, adenoma sebaceum, and periungual fibromas , generally do not occur until late childhood or adolescence.

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Q  9:

A 5-year-old girl presents with a 6-month history of intermittent vertigo that lasts up to 2 hours. One episode has been associated with a headache. Family history is positive for migraines. Findings on physical examination and audiometry are unremarkable.

Of the following, the MOST likely diagnosis to explain these findings is:

A.  acoustic neuroma

B.  benign paroxysmal vertigo of childhood

C.  brainstem stroke

D.  Ménière disease

E.  vestibular neuronitis


Answer :

B

Vertigo is an uncommon symptom in children. It is described classically as a sensation of spinning and may be difficult to differentiate from the more general sensation of dizziness, particularly in children, who may not be able to describe symptoms adequately. Vertigo must be distinguished from light-headedness or presyncope, which is also described as dizziness by children. The most common causes of dizziness or vertigo in children include otitis media, seizures, migraines, benign paroxysmal vertigo (BPV) of childhood, and vestibular neuronitis.

            The clinical history is very important in the evaluation of children who present with dizziness. Characteristics of the event, prodromal and associated symptoms, and the duration and nature of recurrence are important. Unless examined at the time of an event, results of the physical examination in most children are normal. Careful assessment for middle ear disease, cranial nerve abnormalities, and nystagmus may provide important diagnostic clues.

            Vertigo may have a central or peripheral (ear) origin. Otitis media has been described as a common peripheral cause of the sensation of dizziness in the pediatric population that usually occurs in younger children who have acute disease and resolves with resolution of the infection. Perilymph fistula is an uncommon, usually traumatically induced leak of inner ear fluid into the middle ear. Recurrent or progressive dizziness and hearing loss are common symptoms. Vestibular neuronitis is a presumed inflammatory process of the vestibular system or vestibular nerve that spares the cochlea. The onset typically is sudden, and vertigo may be severe and associated with nystagmus. The vertigo subsides over days to weeks, with no associated sequelae or recurrence. Acoustic neuromas are uncommon benign neuromas of the vestibular nerves that can present with vertigo, hearing loss, or facial nerve weakness. Symptoms often are progressive. Acoustic neuromas are extremely rare in children. Ménière disease consists of the triad of recurrent vertigo, hearing loss, and aural fullness and also is rare in children. Seizures are the most common cause of central vertigo in children. Usually other symptoms related to seizures (eg, stereotypical movement, staring spells) can be elicited on careful questioning.

            Migraines and a migraine variant, BPV of childhood, are other common causes of childhood dizziness and vertigo. A family history of migraines is common to both entities. Throbbing, unilateral headache preceded by a visual aura represents a classic migraine. Migraine variants may present with an aura of vertigo, and in basilar artery migraine, vertigo, ataxia, dysarthria, drop attacks, loss of consciousness, and quadriparesis may occur.

            A more subtle migraine variant is BPV of childhood, which is seen predominantly in children between ages 2 and 6 years. BPV episodes occur spontaneously, with a sudden onset of vertigo, pallor, and nystagmus. The child may appear to hold on to objects for stability or remain very still. The episodes last minutes to hours, as described for the girl in the vignette, and resolve without sequelae. Headaches may occur in association with BPV, and the development of true migraines by adolescence is common.

            Although a brainstem stroke may present with dizziness, symptoms are usually persistent, and associated brainstem abnormalities are common. Brainstem tumors and multiple sclerosis are other rare causes of dizziness in children

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Q 10:

A 10-year-old girl presents with lower extremity weakness of 1 week's duration and newly developed pain in a band distribution around the lower thorax. On physical examination, she has left facial weakness, areflexia, and normal sensation.

Of the following, the procedure MOST likely to reveal the diagnosis is:

A. computed tomography of the head

B. electroencephalography

C. electromyography with nerve conduction velocities

D. magnetic resonance imaging of the spine

E. muscle and nerve biopsy

Answer :

C

The lower extremity weakness with loss of reflexes exhibited by the child in the vignette is indicative of a peripheral nerve process. Although pain in a band distribution can be observed with transverse myelitis, herpes zoster, and spinal cord infarction, the peripheral nerve presentation combined with facial weakness in this child is typical of Guillain-Barré syndrome.

 Lumbar puncture often reveals elevated cerebrospinal fluid protein levels with little or no pleocytosis (albuminocytologic dissociation). Electromyography reveals a reduction in motor unit recruitment. More importantly, nerve conduction velocities show prolonged or absent F-wave responses. F waves measure conduction in the proximal portion of the motor nerve and root, a typical site of demyelination in Guillain-Barré syndrome.

            Except for the facial weakness, there are no focal signs indicative of a cerebral process that would prompt computed tomography of the head for the child in the vignette. The absence of reflexes localizes the process of the peripheral nerve. Electroencephalography also is used to assess patients who have cerebral disorders such as seizures or depressed mental status. Emergent magnetic resonance imaging of the spine is appropriate if there is suspicion of a spinal cord process. Muscle and nerve biopsies are most useful in the evaluation of chronic weakness from a myopathy or peripheral neuropathy.

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Q 11:

A 4-month-old previously well boy presents with his head tilted posteriorly toward his left shoulder. Physical examination reveals a left esotropia and facial palsy. Findings on the remainder of the examination are normal.

Of the following, the MOST likely diagnosis is:

A.  congenital contracture of the sternocleidomastoid muscle

B.   paroxysmal torticollis

C.   posterior fossa tumor

D.   Sandifer syndrome

E.   spasmus nutans

Answer :

C

Head tilt has a wide differential diagnosis that includes torticollis. By strict definition, torticollis is a unilateral contracture of the sternocleidomastoid muscle with torsion of the neck that is characterized by the head tilted toward the shortened muscle and the chin pointed toward the opposite shoulder. However, the term torticollis frequently is used nonspecifically to describe a wide variety of causes for head tilt.

            Congenital muscular torticollis often is recognized only as an infant develops head control, when he or she tilts the head, and there is a palpable mass in the affected sternocleidomastoid muscle. There are no associated cranial nerve abnormalities. Musculoskeletal anomalies, such as hip dysplasia, metatarsus adductus , and talipes equinovarus, may be associated with congenital torticollis. The torticollis is corrected in most cases with 3 to 6 months of physical therapy.

            In contrast, paroxysmal torticollis is a benign, self-limited condition characterized by recurrent episodes of head tilt, vomiting, pallor, irritability, ataxia, or drowsiness, but not cranial neuropathies. Attacks lasting hours or occasionally days begin in infancy and disappear by age 1 to 5 years. This disorder may be related to migraine. The initial episode should be evaluated carefully for other potential causes of head tilt.

            Head tilt can be the presenting sign of gastroesophageal reflux (Sandifer syndrome), bony defects (eg, Klippel-Feil syndrome, Sprengel deformity, atlanto-axial rotary subluxation), dystonia, benign paroxysmal positional vertigo, cervical adenitis, retropharyngeal abscess, hearing loss, strabismus (most commonly from a trochlear nerve paresis but also occurring with abducens or oculomotor nerve palsies), and spasmus nutans. Spasmus nutans encompasses the triad of episodic nystagmus, head nodding, and head tilt and arises at 4 to 12 months of age and resolves by age 4 years.

            Most concerning of the possible diagnoses for head tilt is a posterior fossa mass. The head tilt arises from increased intracranial pressure pushing inferiorly on cervical nerve roots, generating discomfort that is alleviated by turning the head. Head tilt with a cranial neuropathy should increase the index of suspicion for a posterior fossa mass, such as medulloblastoma, ependymoma, astrocytoma, or brainstem glioma. The finding of esotropia and facial palsy, likely from involvement of the abducens and facial nerves, accompanying head tilt in the infant in the vignette is very suspicious for a posterior fossa tumor.

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Q 12:

While at school, a 6-year-old boy is noted by his teacher to experience 10- to 20-second lapses in consciousness, sometimes with clonic movements of the face. His parents have not noticed this behavior at home. Electroencephalography shows 3 per second generalized spike and wave discharges.

The MOST appropriate therapy for this boy is:

A. carbamazepine

B.  gabapentin

C.  ketogenic diet

D.  methylphenidate

E.   valproic acid

Answer :

E

Drug selection for the child who has recurrent seizures or epilepsy is based on seizure classification, which is established by history and electroencephalographic findings. Carbamazepine, phenytoin, phenobarbital, and primidone are used for generalized tonic-clonic seizures and partial seizures. Valproic acid is useful for generalized tonic-clonic, absence, atypical absence, and myoclonic seizures. Ethosuximide is effective for absence seizures. Gabapentin is employed as a second or add-on drug for refractory partial seizures. Lamotrigine is used in generalized seizures, including tonic-clonic, absence, myoclonic, and atonic, and in patients who have Lennox-Gastaut syndrome. The newer agents, tiagabine and topiramate, appear to be useful adjunctive treatments in partial seizures.

            Absence (petit mal) seizure are staring spells that last 5 to 20 seconds and are characterized by cessation of motor activity, blank facial expression, and sometimes flickering of the eyelids. The onset typically is at age 5 to 6 years. The seizures are not associated with an aura and do not produce a postictal state. Multiple episodes occur daily and can be mistaken for daydreaming or attention deficit disorder. Hyperventilation for 3 to 4 minutes frequently will provoke a seizure, as will photic stimulation. Characteristic electroencephalographic findings are 3 per second generalized spike and wave discharge.

            Atypical absence seizures are associated with automatic behaviors or myoclonic movements of the face or body that even can include loss of body tone that results in the child falling. Electroencephalography may show spike and wave discharges of 2 to 4.5 per second. Many clinicians manage atypical absence seizures initially with valproic acid and typical absence seizures with ethosuximide. The clonic movements of the face reported for the child in the vignette raise the possibility of atypical absence seizures, making valproic acid a logical choice for treatment, although a trial of ethosuximide also would be reasonable. Carbamazepine could exacerbate absence epilepsy.

            Attention deficit disorder, with or without hyperactivity, can mimic absence seizures, and delineation of the two sometimes requires electroencephalography. Attention disorders frequently are treated with methylphenidate, dextroamphetamine, or pemoline. These stimulants have little impact on seizure disorders when they coexist with attention deficit disorder.

            The ketogenic diet employs a meal plan restricted to fats and protein, with very limited carbohydrates, to induce ketosis. The mechanism by which this controls seizures in children is unclear. The diet typically is indicated for children who have generalized seizure disorders that are refractory to polytherapy or for patients who experience intolerable side effects from anticonvulsants.

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Q 13

The mother of an 18-month-old boy is concerned because her son is not yet walking. Developmental screening reveals that he does not have any words. Results of physical examination are notable for macrocephaly, mildly coarsened facial features, and hepatosplenomegaly.

Of the following, the MOST appropriate laboratory test to obtain is:

A.  molecular testing for fragile X mental retardation

B.  peripheral blood chromosome analysis

C.  thyroid function tests

D.  TORCH titers

E.   urine mucopolysaccharide levels

Answer

E

The findings of coarse facies, macrocephaly, and hepatosplenomegaly, as described for the child in the vignette, are suggestive of a lysosomal storage disease. This class of disorders typically results from deficient enzyme activity and the consequent lysosomal accumulation of its substrate. The disorders include the lipidoses (eg, Tay-Sachs disease), glycoproteinoses, mucolipidoses, and mucopolysaccharidoses.

The diagnosis of the mucopolysaccharidoses (MPSs), such as would be suspected for the child in the vignette, can be confirmed by measuring the urinary excretion of mucopolysaccharides.

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Q 14

A 5-month-old baby develops constipation followed by poor feeding with weak suck. After several days, she displays ptosis. On physical examination, the baby is afebrile and has loss of head control, with mild weakness of the upper extremities. Deep tendon reflexes are diminished.

After initial stabilization, the MOST appropriate diagnostic study to obtain is:

A.  blood lead level

B.  genetic testing for spinal muscular atrophy

C.  serum assay for botulinum toxin

D.  urine porphobilinogen

E.  urine screen for heavy metals

Answer

C

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Q 15

A previously healthy and developmentally normal 18-month-old boy presents with status epilepticus. There is no past or family history of seizures. The child is stabilized, and the seizure is halted. Subsequent physical examination reveals a playful child who has a temperature of 102.7°F (39.2ºC) and nasal discharge. Findings on the remainder of the examination are normal.

The child's status epilepticus is MOST likely due to:

A.  bacterial meningitis

B.  cortical dysplasia

C.  fever

D.  hypoglycemia

E.  mesial temporal sclerosis

Answer :

C

Febrile seizures are the most common convulsions during childhood, affecting about 4% of children between the ages of 6 months and 5 years. Peak onset is at about 18 months. Nearly 25% of status epilepticus stems from febrile seizures. These convulsions rarely develop into epilepsy. 

            Symptomatic seizures are caused by central nervous system infection, cerebral dysgenesis, trauma, anoxia, metabolic disturbance, or toxins. At any age, encephalitis may present with a seizure, and epilepsy may be a long-term complication of meningitis. The child described in the vignette has no viral prodrome or encephalopathy, also typical of encephalitis. In addition, the quick return to normal sensorium makes bacterial meningitis unlikely. Children who have cortical dysplasia are often developmentally delayed, unlike the child in this vignette.