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Pediatric Neurologic Disorders

69 questions

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Question 21Question →

A 7-month-old infant is brought to the pediatric clinic by his parents who report that he has been having recurrent episodes of sudden, brief, symmetric forward flexion of the neck and trunk with arm extension. These episodes occur in clusters, particularly when he is waking from sleep. Physical examination reveals three hypopigmented macules on his trunk that fluoresce under a Wood lamp. Which of the following additional clinical or diagnostic findings are most likely to be associated with this patient's underlying condition? (Select all that apply)

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Answer: Cardiac rhabdomyomas; Subependymal giant cell astrocytomas

Answer

The correct findings associated with this patient's condition are cardiac rhabdomyomas and subependymal giant cell astrocytomas.
The patient presents with infantile spasms (flexion of the neck and trunk in clusters) and ash-leaf spots (hypopigmented macules), which is the classic presentation of Tuberous Sclerosis Complex (TSC). TSC is an autosomal dominant neurocutaneous disorder. Patients with TSC frequently develop benign tumors in various organs, specifically cardiac rhabdomyomas and subependymal giant cell astrocytomas (SEGAs).

Step-by-Step Solution

1
Identify the primary clinical syndrome based on the infant's seizure semiology and skin findings.
The clustered episodes of symmetric forward flexion indicate infantile spasms. The hypopigmented macules fluorescing under a Wood lamp are ash-leaf spots. Together, these findings strongly suggest a diagnosis of Tuberous Sclerosis Complex (TSC).
Recognizing the pathognomonic clinical criteria for neurocutaneous syndromes is the first step in determining associated systemic findings.
2
Determine the systemic hamartomas and tumors classically associated with Tuberous Sclerosis Complex.
TSC is frequently associated with subependymal giant cell astrocytomas (brain), cardiac rhabdomyomas (heart), and angiomyolipomas (kidneys).
The question asks for additional clinical or diagnostic findings related to the identified underlying condition.

Key Concept

Tuberous Sclerosis Complex (TSC) frequently presents in infancy with infantile spasms (flexion spasms in clusters) and ash-leaf spots (hypopigmented macules). It is a neurocutaneous disorder characterized by the development of hamartomas in various organs, including cardiac rhabdomyomas and subependymal giant cell astrocytomas (SEGAs).
Question 22Question →

Parents bring their 3-year-old son to the emergency department out of concern for his sudden onset of unsteadiness. According to his mother, the child began "walking like a drunk person" and falling frequently over the past 24 hours. He had a mild, unspecified febrile illness accompanied by a diffuse maculopapular rash approximately ten days prior to this presentation, which resolved completely without intervention. He has no history of head trauma and no access to medications or toxic substances. His temperature is 37.1∘C37.1^\circ\text{C} (98.8∘F98.8^\circ\text{F}), blood pressure is 92/58 mmHg92/58\text{ mmHg}, heart rate is 105/min105\text{/min}, and respiratory rate is 22/min22\text{/min}. On physical examination, the child is alert, fully oriented, and interactive. Neurologic examination reveals a wide-based, staggering gait and bilateral horizontal nystagmus. He demonstrates marked dysmetria when asked to reach for a toy. Muscle tone, strength, and deep tendon reflexes are normal and symmetric in all extremities. Fundoscopic examination reveals sharp optic disc margins with no evidence of papilledema. Which of the following is the most appropriate next step in the management of this patient?

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Answer: Reassurance and careful outpatient observation

Answer

Reassurance and careful outpatient observation
The correct approach is reassurance and careful outpatient observation. This patient's presentation of an acute-onset wide-based gait, dysmetria, and nystagmus occurring 1 to 2 weeks after a viral illness is highly characteristic of acute cerebellar ataxia. This is a post-infectious autoimmune phenomenon that predominantly affects children aged 1 to 3 years. Because the patient is alert, afebrile, and lacks signs of increased intracranial pressure (e.g., no papilledema, no vomiting) or asymmetric focal neurologic deficits, invasive diagnostic testing or neuroimaging is not indicated. The condition is benign and typically resolves spontaneously within a few weeks, making supportive care the standard management.

Step-by-Step Solution

1
Analyze the core clinical presentation and timeline.
The patient is a 3-year-old with acute-onset ataxia, dysmetria, and nystagmus occurring roughly 10 days after a mild viral illness with a rash.
Establishing the sequence of events is critical for differentiating acute post-infectious processes from acute toxicologic, infectious, or structural neurologic emergencies.
2
Rule out life-threatening etiologies based on the physical examination.
The absence of fever, altered mental status, papilledema, and focal lateralizing neurologic signs significantly lowers the suspicion for bacterial meningitis, encephalitis, or an intracranial mass lesion (e.g., medulloblastoma).
Red flag symptoms dictate whether invasive testing or immediate neuroimaging is required.
3
Establish the most likely diagnosis.
The clinical picture is highly characteristic of acute cerebellar ataxia, a benign autoimmune syndrome.
Acute cerebellar ataxia is the most common cause of acute ataxia in childhood and typically follows a viral infection such as varicella, coxsackievirus, or Epstein-Barr virus.
4
Determine the appropriate management strategy based on the diagnosis.
Because this condition resolves spontaneously over a period of 1 to 3 weeks, supportive care and observation are the standard of care.
Unnecessary imaging or empiric medications expose the child to radiation and adverse effects without clinical benefit.

Key Concept

Diagnosis and management of post-infectious acute cerebellar ataxia
Question 23Question →

A 5-month-old boy is brought to the pediatric emergency department due to a 3-day history of weak crying, poor feeding, and progressively decreased spontaneous movements. His parents report that he has not had a bowel movement for the past 4 days. The infant was previously healthy and exclusively breastfed, but the parents recently began giving him homemade fruit purees sweetened with a small amount of honey. On physical examination, temperature is 37.1°C (98.8°F), heart rate is 130/min, and respiratory rate is 32/min. The infant appears lethargic with profound generalized hypotonia, a weak gag reflex, and poor head control. Pupils are dilated and sluggishly reactive to light. Deep tendon reflexes are diminished bilaterally. Which of the following statements regarding the diagnosis and management of this patient's condition are correct? (Select all that apply)

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Answer: Immediate administration of human-derived botulism immune globulin is indicated.; The underlying pathophysiology involves the prevention of presynaptic acetylcholine release.

Answer

The correct statements are that immediate administration of human-derived botulism immune globulin is indicated, and the underlying pathophysiology involves the prevention of presynaptic acetylcholine release.
The infant is presenting with classic signs of infant botulism, characterized by initial constipation followed by bulbar palsies (sluggish pupils, weak gag reflex, poor feeding) and descending flaccid paralysis (generalized hypotonia, poor head control, weak crying). This condition is caused by the ingestion of Clostridium botulinum spores, which are classically found in honey and environmental dust. Upon ingestion, these spores colonize the infant's intestinal tract and produce botulinum neurotoxin. The toxin is absorbed into the bloodstream and irreversibly binds to presynaptic nerve terminals at the neuromuscular junction, where it cleaves SNARE proteins and prevents the release of acetylcholine. This direct inhibition of neurotransmission leads to flaccid paralysis. Because the toxin binds irreversibly, the primary treatment is the immediate administration of human-derived botulinum immune globulin (BabyBIG). This neutralizes any freely circulating toxin in the bloodstream and halts the progression of the disease, although recovery relies on the regeneration of new nerve terminals.

Step-by-Step Solution

1
Identify the clinical syndrome based on the infant's presentation of constipation followed by descending flaccid paralysis.
The infant's hypotonia, poor head control, weak gag reflex, and sluggish pupils point to a neuromuscular junction disorder, classic for infant botulism.
Recognizing the pattern of descending paralysis and bulbar palsies is the first step in diagnosing infant botulism.
2
Correlate the clinical findings with the patient's dietary history.
The recent consumption of honey is the primary risk factor for the infant's current condition.
Honey frequently contains Clostridium botulinum spores, which can colonize an infant's immature intestinal tract and produce neurotoxin.
3
Determine the appropriate management and understand the mechanism of disease.
Management requires rapid administration of human-derived botulism immune globulin to counteract the toxin, which causes paralysis by blocking presynaptic acetylcholine release.
Because the toxin binds irreversibly to nerve terminals, prompt neutralization of freely circulating toxin is critical to prevent respiratory failure.

Key Concept

Infant botulism: pathophysiology and management
Question 24Question →

An 18-month-old girl is brought to the pediatric neurology clinic by her parents due to recurrent episodes of rhythmic jerking of her right arm and leg. The episodes last about 2 minutes and have occurred three times over the past month. Her past medical history is notable for a large, unilateral, dark red, non-blanching macular lesion over the left side of her face, involving the forehead and upper eyelid, which has been present since birth. Her parents are very anxious and express concern regarding her overall development. They report that she walks independently and has a vocabulary of about 15 words, but they are deeply worried because she cannot yet run, kick a ball, or combine two words into a phrase. Which of the following statements regarding this patient's diagnosis and management are accurate? (Select all that apply)

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Answer: The underlying pathophysiology involves a somatic activating mutation in the GNAQ gene, resulting in capillary-venous malformations.; She is at high risk for ipsilateral glaucoma and requires a comprehensive ophthalmologic evaluation.

Answer

The accurate statements are that the condition is caused by a somatic activating mutation in the GNAQ gene, and the patient requires comprehensive ophthalmologic evaluation due to high glaucoma risk.
The correct statements accurately reflect the underlying genetics and complications of Sturge-Weber syndrome. The syndrome is uniquely caused by a non-inherited, somatic activating mutation in the GNAQ gene, which disrupts vascular development. The resulting vascular malformations frequently extend to the eye, placing the patient at a significant risk for early-onset ipsilateral glaucoma that requires vigilant screening.

Step-by-Step Solution

1
Identify the primary clinical syndrome based on the presenting physical signs.
The presence of a congenital facial port-wine stain in the V1/V2 distribution coupled with focal motor seizures points directly to Sturge-Weber syndrome.
Recognizing the classic triad of facial capillary malformation, leptomeningeal angiomatosis (causing seizures), and ocular involvement is the first step to establishing the diagnosis.
2
Determine the etiology and standard complications of the identified syndrome.
Sturge-Weber syndrome is caused by a somatic mosaic mutation in GNAQ and carries a very high risk of early-onset glaucoma in the ipsilateral eye.
This confirms the accuracy of the statements regarding genetics and ophthalmologic screening.
3
Evaluate the parents' concerns regarding the child's developmental milestones.
The patient can walk and speak 15 words. She cannot run, kick, or use 2-word phrases.
It is critical to distinguish between actual developmental delay, which can occur in Sturge-Weber syndrome, and age-appropriate development.
4
Compare the patient's abilities to standard pediatric milestone charts for an 18-month-old.
Walking and a 15-word vocabulary are completely normal for 18 months. Running, kicking, and 2-word phrases are 24-month milestones.
This rules out the distractors that inaccurately classify the patient as having severe motor or language delays.

Key Concept

Sturge-Weber syndrome is a sporadic neurocutaneous disorder caused by a somatic GNAQ mutation, characterized by a port-wine stain, leptomeningeal angiomatosis, and high glaucoma risk. Furthermore, accurately differentiating between 18-month milestones (walking, 10-25 words) and 24-month milestones (running, kicking, 2-word phrases) is essential in pediatric assessment.
Estimated Time:1m 30s
Question 25Question →

An 8-year-old boy is brought to the pediatric clinic by his parents due to concerns raised by his second-grade teacher. Over the past month, the teacher noted that the child frequently "spaces out" and stops responding during lessons. These episodes consist of blank staring, occasional lip smacking, and last for 10 to 15 seconds. They occur multiple times a day. He does not lose postural tone or fall to the ground. Immediately following the episodes, he resumes his previous activity without any confusion or lethargy. His parents initially thought he was simply daydreaming or distracted, as he recently recovered from a mild respiratory illness with coughing and wheezing. Today in the clinic, his temperature is 37.1°C (98.8°F), blood pressure is 105/65 mm Hg, pulse is 88/min, and respirations are 18/min. A detailed neurologic examination is unremarkable. Having the patient blow on a pinwheel for two minutes in the office triggers an identical staring episode. Which of the following is the most appropriate initial pharmacotherapy for this patient's underlying condition?

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Answer: Ethosuximide

Answer

Ethosuximide
This patient's presentation is highly characteristic of childhood absence epilepsy, which features frequent, brief (10-15 seconds) episodes of impaired consciousness often accompanied by subtle automatisms like lip smacking or eyelid fluttering. A hallmark of absence seizures is the lack of a postictal state, allowing the child to immediately resume their previous activity. The classic trigger for these seizures is hyperventilation, which was demonstrated in the clinic. The first-line treatment for isolated childhood absence epilepsy is ethosuximide, which acts by blocking T-type calcium channels in thalamic neurons.

Step-by-Step Solution

1
Analyze the clinical presentation and triggering factors.
The patient experiences brief (10-15 seconds), frequent staring episodes with automatisms and no postictal state, which are easily triggered by hyperventilation.
Identifying the specific duration, characteristics, and triggers of the episodes differentiates them from behavioral inattention or other types of seizures.
2
Formulate a diagnosis based on the clinical features.
The findings represent the classic triad for childhood absence epilepsy.
Absence seizures typically present in early school-aged children with sudden, profound impairment of consciousness without loss of postural tone, perfectly matching this clinical vignette.
3
Determine the most appropriate initial treatment for the diagnosed condition.
Ethosuximide is the drug of choice.
Ethosuximide specifically targets T-type calcium channels in the thalamus, making it the most effective and preferred first-line pharmacotherapy for isolated absence seizures.

Key Concept

Childhood absence epilepsy presents with brief staring spells and automatisms without a postictal phase, is characteristically provoked by hyperventilation, and is treated first-line with ethosuximide.
Question 26Question →

Parents bring their 16-week-old male infant to the pediatric evaluation center due to persistent, forceful vomiting and extreme fussiness that has worsened over the past two days. The mother notes that the baby's eyes appear to be constantly looking downward, which she describes as a 'setting sun' appearance. Pregnancy and spontaneous vaginal delivery at 39 weeks of gestation were unremarkable. Vital signs show a temperature of 37.2°C (99.0°F), a heart rate of 115/min, and blood pressure of 105/65 mmHg.

On examination, the infant has a noticeably enlarged head with a tense, protruding anterior fontanelle and engorged scalp veins. The sagittal suture is palpably diastatic. Neurologic assessment confirms an upward gaze palsy with light-near dissociation. Lower extremity tone is mildly hypertonic. Dermatologic exam notes a scattering of small, erythematous papules with central pustules confined to the bilateral cheeks. The parents are anxious, mentioning he hasn't learned to roll from his back to his tummy yet, and they are upset with their primary pediatrician for not taking action when his head circumference crossed two major percentile lines a month ago.

A point-of-care cranial ultrasound indicates marked expansion of the lateral and third ventricles, while the fourth ventricle appears normal.

Which of the following interventions represent the most appropriate immediate steps in the management of this patient? (Select 2)

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Answer: Performance of magnetic resonance imaging of the brain; Urgent consultation for cerebrospinal fluid diversion

Answer

The correct steps are the performance of magnetic resonance imaging of the brain and an urgent consultation for cerebrospinal fluid diversion.
The infant's clinical presentation—featuring a rapidly enlarging head circumference, a tense fontanelle, prominent scalp veins, and Parinaud syndrome (upward gaze palsy with a 'setting sun' appearance)—is highly specific for severe hydrocephalus with acutely increased intracranial pressure. The point-of-care cranial ultrasound confirms non-communicating (obstructive) hydrocephalus by demonstrating dilation of the lateral and third ventricles while sparing the fourth ventricle, which localizes the obstruction to the cerebral aqueduct. The most appropriate immediate steps are to obtain an MRI of the brain to delineate the precise anatomy and evaluate for potential anatomical lesions (such as a pineal mass), and to urgently consult neurosurgery for definitive cerebrospinal fluid diversion (e.g., via an endoscopic third ventriculostomy or a ventriculoperitoneal shunt).

Step-by-Step Solution

1
Analyze the physical exam findings and diagnostic imaging.
The infant exhibits classical signs of elevated intracranial pressure (tense fontanelle, diastatic sutures, setting sun sign/Parinaud syndrome) alongside an ultrasound demonstrating enlarged lateral and third ventricles with a normal fourth ventricle.
This establishes the primary diagnosis of non-communicating (obstructive) hydrocephalus, likely localized at the cerebral aqueduct.
2
Determine the necessary diagnostic follow-up for the neurologic condition.
Magnetic resonance imaging (MRI) of the brain is identified as the optimal modality.
MRI provides the high-resolution anatomical detail required to pinpoint the exact etiology, such as aqueductal stenosis or a pineal mass causing the obstruction.
3
Identify the required therapeutic intervention.
Neurosurgical consultation is mandated.
Obstructive hydrocephalus presenting with acute signs of elevated intracranial pressure requires urgent cerebrospinal fluid diversion to prevent permanent brain injury or herniation.
4
Evaluate the secondary parental concerns regarding development, medical error, and skin findings.
The motor development is normal for age (4 months), the medical error requires a systems-based approach rather than punishment, and the facial rash is benign neonatal cephalic pustulosis.
Recognizing these allows the physician to avoid unnecessary interventions like physical therapy referrals, inappropriate punitive legal measures, or unwarranted antiviral medications.

Key Concept

Diagnosis and management of non-communicating hydrocephalus in infants, including the differentiation of acute pathologic neurologic signs from normal developmental and physiologic variants.
Estimated Time:1m 30s
Question 27Question →

An 18-month-old boy is brought to the pediatric neurology clinic by his parents due to a two-week history of progressive unsteadiness. The parents are highly anxious and state, "He only just started running at 17 months, and now he can barely walk! His development has always been terribly slow." They also express concern regarding his past medical history, noting that during his first week of life, he had a blotchy red rash with tiny yellow pustules on his chest that resolved on its own. They fear this was an untreated viral infection that is now damaging his brain. Furthermore, three weeks ago, he had a mild respiratory illness characterized by a low-grade fever, rhinorrhea, and diffuse wheezing, which resolved over a week with supportive care. Vital signs are within normal limits for his age. Physical examination reveals an irritable child with a broad-based, unsteady gait. While sitting quietly, he exhibits rapid, chaotic, multidirectional conjugate eye movements without a predictable pattern. Brief, shock-like contractions of his proximal arm and leg muscles are also noted. Deep tendon reflexes are 2+ bilaterally, and muscle tone is normal. Which of the following is the most appropriate initial diagnostic or management step for this patient?

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Answer: Reassure the parents regarding his prior motor development and obtain computed tomography imaging of the chest and abdomen

Answer

Reassure the parents regarding his prior motor development and obtain computed tomography imaging of the chest and abdomen
The correct action combines addressing the parents' misplaced anxiety with the essential diagnostic step for the child's acute presentation. The child's acute neurologic presentation consisting of ataxia, myoclonus, and chaotic, multidirectional conjugate eye movements is the classic triad of opsoclonus-myoclonus syndrome (often termed 'dancing eyes, dancing feet'). In a toddler, this syndrome is most commonly a paraneoplastic manifestation of an occult neuroblastoma. Therefore, the priority is to locate the tumor using computed tomography (CT) or magnetic resonance imaging (MRI) of the chest, abdomen, and pelvis. Furthermore, the parents' concern regarding the child's development is unfounded; independent walking typically begins between 12 and 15 months, and running typically emerges by 18 months. Therefore, running at 17 months represents normal development, and the parents should be reassured.

Step-by-Step Solution

1
Analyze the acute neurological findings.
The patient exhibits rapid, chaotic, multidirectional eye movements (opsoclonus), myoclonus, ataxia, and irritability.
Recognizing this specific constellation of signs defines Opsoclonus-Myoclonus Syndrome (OMS).
2
Determine the underlying etiology of OMS in a pediatric patient.
OMS is classically a paraneoplastic immune response associated with neuroblastoma.
Identifying the association dictates the necessity of an immediate oncologic workup.
3
Select the appropriate diagnostic imaging.
Computed tomography (CT) or MRI of the chest and abdomen is required.
Neuroblastomas most commonly arise from the sympathetic ganglia in the abdomen, chest, or adrenal medulla.
4
Evaluate the parents' concerns regarding developmental milestones and past rashes.
Running at 17 months is a normal motor milestone. The neonatal rash described is erythema toxicum neonatorum, which is benign.
Addressing these concerns prevents unnecessary genetic, infectious, or developmental workups and allows the physician to reassure the parents.

Key Concept

Paraneoplastic Opsoclonus-Myoclonus Syndrome secondary to Neuroblastoma
Estimated Time:1m 30s
Question 28Question →

A four-month-old female infant is evaluated in the pediatric neurology clinic for progressive generalized weakness and an inability to hold her head up. She was born at term following an uncomplicated pregnancy and delivery. Over the past eight weeks, her parents have noticed a significant reduction in her spontaneous limb movements. Additionally, her feeding has become prolonged, and her cry sounds abnormally weak. On presentation, her respiratory rate is 52/min52/\text{min}, and oxygen saturation is 96%96\% on room air. Physical examination reveals an alert infant who maintains normal eye contact and social smiling. She is positioned supine with her hips abducted and externally rotated. Neurological assessment demonstrates profound global hypotonia and complete absence of deep tendon reflexes in all extremities. Gentle tactile stimulation elicits normal sensory responses. Careful observation of the oral cavity while the infant cries reveals small, rapid, undulating movements of the tongue mucosa. Which of the following is the most appropriate next step in the diagnostic workup?

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Answer: Targeted molecular genetic testing

Answer

Targeted molecular genetic testing
The correct answer is targeted molecular genetic testing. This infant's presentation of progressive profound hypotonia, areflexia, and tongue fasciculations in the setting of preserved cognitive function is highly characteristic of Spinal Muscular Atrophy (SMA) type 1 (Werdnig-Hoffmann disease). SMA is an autosomal recessive motor neuron disease caused by a mutation in the survival motor neuron 1 (SMN1) gene. The most appropriate and definitive diagnostic step is targeted molecular genetic testing for the SMN1 gene deletion, which provides a non-invasive confirmation of the disease.

Step-by-Step Solution

1
Analyze the neurological examination findings.
The infant exhibits profound global hypotonia, absent deep tendon reflexes, and tongue fasciculations, with preserved cognitive and social interactions.
Identifying the specific pattern of neurological deficits is essential for localizing the lesion in a 'floppy infant'.
2
Localize the neuroanatomical lesion.
The combination of severe hypotonia and areflexia without cognitive impairment points to a peripheral motor unit disorder. The presence of tongue fasciculations specifically localizes the defect to the anterior horn cells (lower motor neurons).
Different neuromuscular disorders affect different parts of the motor unit (e.g., anterior horn cells, peripheral nerves, neuromuscular junction, or muscle).
3
Formulate a primary diagnosis.
The clinical picture of progressive lower motor neuron degeneration in early infancy with sparing of extraocular muscles and cognition is pathognomonic for Spinal Muscular Atrophy (SMA) type 1 (Werdnig-Hoffmann disease).
Matching the localized lesion and clinical timeline to a specific disease entity.
4
Determine the most appropriate initial diagnostic test.
Targeted molecular genetic testing for the SMN1 gene deletion is the gold standard, non-invasive method to confirm SMA.
Genetic testing has replaced muscle biopsy and electromyography as the first-line diagnostic step for suspected SMA due to its high sensitivity and specificity.

Key Concept

Spinal Muscular Atrophy (SMA) type 1 presents in early infancy with severe, progressive lower motor neuron signs (hypotonia, areflexia, tongue fasciculations) and paradoxical breathing, while cognitive and social development remain intact. The definitive diagnostic test is targeted molecular genetic testing for the SMN1 gene deletion.
Estimated Time:1m 15s
Question 29Question →

An 8-year-old boy is evaluated in the clinic for unusual behaviors. His parents report that for the past 15 months, he has had intermittent episodes of rapid eye blinking, facial grimacing, and shoulder shrugging. Additionally, for the last 6 months, he has been frequently grunting and sniffing loudly. These actions occur many times a day and worsen when he is stressed about schoolwork. He is fully conscious during the episodes and says he feels a "build-up of tension" that is relieved only by performing the actions. Physical and neurologic examinations are otherwise unremarkable. Which of the following is the most likely diagnosis?

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Answer: Tourette syndrome

Answer

Tourette syndrome
The correct answer is Tourette syndrome. The diagnosis of Tourette syndrome requires the presence of multiple motor tics (e.g., rapid eye blinking, facial grimacing, shoulder shrugging) and at least one vocal tic (e.g., grunting, sniffing) manifesting before age 18. Furthermore, the tics must be present for more than 1 year since the onset of the first tic. This patient's symptoms are preceded by a premonitory urge ("build-up of tension") that is temporarily relieved by performing the action, which is a classic feature of tics.

Here is a summary of pediatric tic disorders:

DisorderCharacteristicsDuration
Tourette syndromeMultiple motor AND ≥1\geq 1 vocal tic>1> 1 year
Persistent (chronic) tic disorderMotor OR vocal tics (but not both)>1> 1 year
Provisional tic disorderMotor and/or vocal tics<1< 1 year

Step-by-Step Solution

1
Analyze the clinical presentation of the patient's movements.
The patient exhibits rapid eye blinking, grimacing, and shoulder shrugging (motor tics), as well as grunting and sniffing (vocal tics).
Identifying the specific types of movements is essential to differentiate tics from chorea, stereotypies, or seizures.
2
Evaluate the timeline and duration of the symptoms.
The motor tics have been present for 15 months, which is greater than the 1-year threshold.
Duration is a critical diagnostic criterion that separates provisional tic disorders from chronic tic disorders.
3
Combine the symptom types and timeline to establish the diagnosis.
The presence of multiple motor tics and at least one vocal tic for >1 year confirms the diagnosis of Tourette syndrome.
Strict application of DSM-5 diagnostic criteria is necessary for accurate diagnosis.

Key Concept

The diagnosis of Tourette syndrome requires the presence of both multiple motor tics and at least one vocal tic for a duration of greater than 1 year.
Question 30Question →

A 5-year-old girl is rushed to the emergency department by ambulance following a rapid decline in mental status. She has a known history of lumbar myelomeningocele and a ventriculoperitoneal shunt. According to the paramedics, the patient's parents reported that she suffered from unremitting headaches and projectile vomiting over the preceding 24 hours. On evaluation, she does not open her eyes or verbalize, and she exhibits decerebrate posturing to painful stimuli. Vital signs demonstrate a blood pressure of 148/92 mm Hg, a pulse of 48/min, and irregular respirations of 8/min. Neurologic examination highlights anisocoria, with the right pupil measuring 7 mm and unreactive to light, while the left pupil is 3 mm and briskly reactive. Determine the most appropriate chronological sequence for the management of this patient.

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Answer

The correct sequence for managing acute intracranial pressure escalation with impending herniation is to first secure the airway with endotracheal intubation, followed by administering hyperosmolar therapy to acutely lower intracranial pressure, then obtaining a non-contrast CT scan of the head to localize the pathology, and finally performing definitive neurosurgical intervention.
The patient is presenting with acute ventriculoperitoneal shunt malfunction leading to severely elevated intracranial pressure and impending right uncal herniation (indicated by a blown right pupil, decerebrate posturing, and the Cushing triad of hypertension, bradycardia, and irregular respirations). The initial management must follow an algorithmic approach. First, the airway must be secured via endotracheal intubation because the patient cannot protect her airway and her respiratory drive is compromised. Second, medical management of intracranial pressure with hyperosmolar therapy (such as hypertonic saline or mannitol) must be administered immediately. Third, once stabilized, the patient requires an urgent non-contrast CT scan of the head to confirm the extent of hydrocephalus. Finally, definitive treatment requires neurosurgical intervention, typically a shunt revision or external ventricular drain placement.

Step-by-Step Solution

1
Identify the need for definitive airway protection.
Rapid sequence endotracheal intubation is selected as the first intervention.
A Glasgow Coma Scale score of 4 and irregular respirations indicate an inability to protect the airway and impending respiratory failure.
2
Address the impending cerebral herniation medically.
Intravenous hyperosmolar therapy is administered as the second intervention.
The patient exhibits Cushing triad and anisocoria, requiring immediate medical reduction of intracranial pressure.
3
Determine the precise etiology of the intracranial crisis.
A non-contrast CT scan of the head is obtained as the third intervention.
Once stabilized, neuroimaging is necessary to identify ventricular size, confirm shunt malfunction, and rule out hemorrhage before proceeding to surgery.
4
Provide definitive treatment for the underlying cause.
Surgical shunt revision is performed as the final intervention.
Medical management only temporizes the condition; mechanical resolution of the cerebrospinal fluid obstruction is required for definitive cure.

Key Concept

The management of impending cerebral herniation in a pediatric patient requires a sequential algorithmic approach: securing the airway (ABCs), initiating acute medical management to lower intracranial pressure, obtaining diagnostic neuroimaging, and consulting neurosurgery for definitive operative intervention.
Estimated Time:1m 30s
Question 31Question →

A 15-month-old girl is brought to the clinic for a well-child visit. She was born prematurely at 28 weeks of gestation. The parents are concerned because she is not yet walking independently and her legs often seem 'stiff' when changing her diaper. On physical examination, there is increased muscle tone, hyperreflexia, and sustained clonus in both lower extremities. She stands on her toes when supported. The pediatrician suspects spastic diplegic cerebral palsy. Which of the following statements regarding this patient's clinical presentation and development are accurate? (Select all that apply.)

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Answer: Prematurity is a major risk factor for developing this type of motor impairment; The findings of hyperreflexia and increased muscle tone are characteristic of an upper motor neuron lesion

Answer

The correct statements are that prematurity is a major risk factor for developing this type of motor impairment, and the findings of hyperreflexia and increased muscle tone are characteristic of an upper motor neuron lesion.
The correct statements correctly highlight fundamental aspects of spastic diplegic cerebral palsy. Prematurity, particularly birth before 32 weeks of gestation, is the most significant risk factor for cerebral palsy due to the vulnerability of the periventricular white matter. Additionally, findings such as increased muscle tone, hyperreflexia, and sustained clonus are classic signs of an upper motor neuron lesion, which forms the underlying pathology of this disorder.

Step-by-Step Solution

1
Identify the suspected clinical condition.
The patient is a premature infant presenting with hypertonia, hyperreflexia, and sustained clonus in the lower extremities, which are classic signs of spastic diplegic cerebral palsy.
Understanding the clinical presentation is necessary to evaluate the pathophysiology and risk factors.
2
Evaluate the risk factors and neurological signs.
Prematurity is confirmed as the leading risk factor for cerebral palsy. The physical exam findings are confirmed as signs of an upper motor neuron lesion.
This confirms the accuracy of the two correct statements.
3
Assess the developmental milestones using corrected age for the premature infant.
A 15-month-old born at 28 weeks has a corrected age of 12 months. Not walking at 12 months, lacking a Moro reflex (normally gone by 6 months), and not speaking three-word sentences (expected at 3 years) are all normal findings for her age.
This step is required to identify why the remaining distractors inaccurately label normal development as pathological.

Key Concept

Cerebral palsy is strongly associated with prematurity and presents with upper motor neuron signs. Furthermore, assessing developmental milestones in premature infants requires adjusting for corrected age to avoid misidentifying normal progress as delayed.
Estimated Time:1m 0s
Question 32Question →

A 5-year-old boy is brought to the emergency department by ambulance due to continuous generalized tonic-clonic movements that started 20 minutes ago. He has no prior history of seizures. On arrival, he is actively seizing. Arrange the following initial management steps for this patient in the correct sequential order according to standard pediatric guidelines for status epilepticus.

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Answer

The correct sequence of management for status epilepticus is: 1) Assess and stabilize airway, breathing, and circulation (ABCs), 2) Administer a first-line abortive medication (e.g., intravenous lorazepam), 3) Administer a second-line antiepileptic medication (e.g., intravenous fosphenytoin), and 4) Initiate a continuous infusion of an anesthetic agent (e.g., continuous midazolam drip).
Status epilepticus is a neurologic emergency that requires a structured, sequential approach. The universally accepted algorithm begins with the ABCs (Airway, Breathing, Circulation) along with checking bedside glucose. Once cardiopulmonary status is stabilized, pharmacotherapy is initiated in stages: first-line therapy with a benzodiazepine (e.g., lorazepam) to rapidly halt clinical and electrographic seizure activity; second-line therapy with a non-sedating antiepileptic (e.g., fosphenytoin, levetiracetam, or valproic acid) for continued seizures or to prevent recurrence; and third-line therapy involving continuous infusions of anesthetics (e.g., midazolam, pentobarbital, or propofol) with intubation for refractory status epilepticus.

Step-by-Step Solution

1
Identify the clinical presentation.
The patient is in convulsive status epilepticus, defined as a continuous seizure lasting more than 5 minutes.
Recognizing status epilepticus is critical for initiating the time-sensitive treatment algorithm.
2
Determine the first priority in management.
Stabilize ABCs.
Basic life support principles dictate that cardiopulmonary stabilization always precedes specific pharmacotherapy.
3
Determine the first-line pharmacotherapy.
Benzodiazepines (e.g., lorazepam, diazepam, or midazolam).
Benzodiazepines are the most rapid and effective class of medications for aborting acute ongoing seizures.
4
Determine subsequent therapies for persistent seizures.
Second-line agents (e.g., fosphenytoin, levetiracetam) followed by third-line continuous infusions if refractory.
A stepwise escalation of antiepileptic therapy is required when initial medications fail to break the status epilepticus.

Key Concept

The stepwise algorithmic management of pediatric status epilepticus, prioritizing cardiorespiratory stabilization followed by sequential escalation of antiepileptic medications.
Question 33Question →

A nine-month-old boy is brought to the pediatric emergency department following a three-minute episode of rhythmic jerking of his left arm and leg. The parents report no fever, trauma, or recent illnesses. He has been sitting without support and babbling, which the parents confirm are his baseline developmental milestones. On physical examination, vital signs are within normal limits for age. A deep red, flat vascular macule is noted over the right forehead and upper eyelid, which the parents state has been present since birth. Neurologic examination reveals mild postictal weakness in the left upper extremity. Which of the following are accurate regarding this patient's suspected diagnosis and management? (Select all that apply)

Select all that apply

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Answer: Neuroimaging is likely to reveal gyriform cortical calcifications in the right hemisphere.; Prompt ophthalmologic evaluation is indicated to screen for ipsilateral glaucoma.

Answer

The correct selections are that neuroimaging will likely reveal gyriform cortical calcifications in the right hemisphere, and that prompt ophthalmologic evaluation is indicated to screen for ipsilateral glaucoma.
The patient's presentation of a facial port-wine stain (nevus flammeus) in the distribution of the ophthalmic branch (V1) of the trigeminal nerve, accompanied by a contralateral focal seizure, is highly characteristic of Sturge-Weber syndrome (SWS). SWS is a sporadic neurocutaneous disorder caused by an activating somatic mutation in the GNAQ gene. It is characterized by capillary-venous malformations of the leptomeninges (leptomeningeal angiomatosis) on the ipsilateral side of the facial lesion. Over time, these vascular malformations cause underlying cortical ischemia and characteristic gyriform or 'tram-track' calcifications that can be seen on neuroimaging. Furthermore, patients with SWS are at a significantly increased risk of developing ipsilateral glaucoma due to vascular malformations in the anterior chamber angle of the eye, making prompt ophthalmologic evaluation a critical step in management.

Step-by-Step Solution

1
Analyze the clinical presentation.
The infant has a congenital vascular macule in the V1 trigeminal distribution and new-onset focal seizures contralateral to the lesion.
Identifying the classic dermatologic and neurologic triad points toward a specific neurocutaneous syndrome.
2
Diagnose the underlying condition.
The constellation of findings is highly characteristic of Sturge-Weber syndrome (SWS).
SWS is characterized by a facial port-wine stain (nevus flammeus), leptomeningeal angiomatosis, and focal seizures.
3
Determine expected findings and management steps for SWS.
Patients with SWS typically have ipsilateral gyriform calcifications on neuroimaging and are at high risk for ipsilateral glaucoma.
Understanding the systemic manifestations of SWS is necessary to select the correct screening and diagnostic options.
4
Evaluate the remaining options for common pediatric misconceptions.
Rule out infectious etiologies for the rash, recognize that the patient's developmental milestones are age-appropriate, and confirm that there are no contraindications to live vaccines.
Eliminating distractors ensures accuracy in a multiple-selection format.

Key Concept

Diagnosis and management of Sturge-Weber syndrome, including its classical presentation, neuroimaging findings, and associated ocular complications.
Estimated Time:1m 30s
Question 34Question →

A 7-month-old infant is evaluated in the neurology clinic for abnormal movements. For the past two weeks, the parents have noticed clusters of sudden, symmetric forward flexion of the neck and trunk, particularly upon awakening. Prior to this, the infant was able to sit with support and babble, but he has recently become less interactive and can no longer sit. On physical examination, vital signs are within normal limits. The infant cannot pull to stand. Skin examination under a Wood lamp reveals three distinct 2-cm hypopigmented macules on the torso. An electroencephalogram demonstrates a high-voltage, chaotic background with multifocal spikes and slow waves. Which of the following are correct regarding the evaluation and management of this patient? (Select all that apply)

Select all that apply

Show answer & explanation

Answer: Initiation of vigabatrin is a first-line pharmacological treatment for this patient's seizure disorder; An echocardiogram should be performed to screen for associated cardiac rhabdomyomas

Answer

The correct steps include initiating vigabatrin for the infantile spasms and performing an echocardiogram to screen for cardiac rhabdomyomas.
The infant's presentation of symmetric flexion spasms, developmental regression, and an electroencephalogram showing hypsarrhythmia is diagnostic of infantile spasms (West syndrome). The presence of hypopigmented macules (ash-leaf spots) strongly points to Tuberous Sclerosis Complex (TSC) as the underlying etiology. In patients with TSC and infantile spasms, vigabatrin is the preferred first-line anticonvulsant due to its high efficacy in this specific population. Additionally, because TSC is a neurocutaneous syndrome associated with benign tumors in multiple organs, an echocardiogram is indicated to screen for cardiac rhabdomyomas, which are the most common cardiac tumors in affected infants.

Step-by-Step Solution

1
Identify the seizure type and EEG pattern
The clinical presentation of cluster flexion spasms with a chaotic, high-voltage EEG (hypsarrhythmia) is diagnostic of infantile spasms.
Accurate seizure classification dictates the specific pharmacological intervention.
2
Correlate seizures with physical exam findings to establish an underlying syndrome
The presence of infantile spasms combined with distinct hypopigmented macules (ash-leaf spots) strongly suggests Tuberous Sclerosis Complex (TSC).
TSC is a neurocutaneous disorder heavily associated with early-onset infantile spasms.
3
Select the appropriate diagnostic and therapeutic next steps based on the syndrome
Vigabatrin is indicated as the first-line treatment for TSC-associated infantile spasms, and an echocardiogram is indicated to screen for cardiac rhabdomyomas.
Standard of care for TSC requires tailored anticonvulsant therapy and systemic tumor screening.

Key Concept

Diagnosis and multisystem management of Tuberous Sclerosis Complex presenting with infantile spasms
Estimated Time:1m 30s
Question 35Question →

An 11-month-old girl is evaluated in the pediatric clinic for a follow-up appointment. The parents happily report that she is already strongly right-handed, consistently reaching for toys, feeding herself, and interacting with objects almost exclusively with her right hand. They note she often keeps her left hand clenched in a tight fist. She was born at 31 weeks gestation and required continuous positive airway pressure for two weeks due to respiratory distress. On physical examination, vital signs are within normal limits. Neurologic examination reveals increased muscle tone and brisk deep tendon reflexes in the left arm and left leg compared to the right. Which of the following is the most appropriate next step in management?

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Answer: Magnetic resonance imaging of the brain

Answer

Magnetic resonance imaging of the brain
Magnetic resonance imaging of the brain is the most appropriate next step. This patient's history of prematurity, combined with early hand preference, a persistently fisted hand, and asymmetric hypertonia/hyperreflexia, is highly concerning for hemiplegic cerebral palsy. Normal infants are ambidextrous; hand preference before 18 to 24 months of age is a major developmental red flag indicating a contralateral motor deficit. A brain MRI is required to evaluate for underlying structural lesions, such as periventricular leukomalacia, perinatal stroke, or congenital brain malformations.

Step-by-Step Solution

1
Evaluate the developmental milestones and physical exam findings.
The patient demonstrates early handedness at 11 months, a persistently fisted left hand, and asymmetric upper motor neuron signs (hypertonia, hyperreflexia) on the left side.
Identifying abnormal neurologic signs is necessary to differentiate normal developmental variations from pathological processes.
2
Correlate the findings with the patient's medical history.
The history of prematurity (31 weeks gestation) places the infant at high risk for perinatal brain injury, such as periventricular leukomalacia or intraventricular hemorrhage.
Prematurity is the most significant risk factor for cerebral palsy.
3
Determine the clinical significance of early hand preference.
Hand preference developing before 18 to 24 months of age is a developmental red flag that strongly suggests a contralateral focal motor deficit, such as hemiplegic cerebral palsy.
Normal infants use both hands symmetrically until toddlerhood.
4
Select the appropriate diagnostic intervention.
Magnetic resonance imaging (MRI) of the brain is indicated.
MRI is the diagnostic modality of choice to identify structural brain abnormalities underlying suspected cerebral palsy.

Key Concept

Early hand preference (before 18-24 months of age) combined with upper motor neuron signs is a developmental red flag that suggests a focal structural brain lesion (e.g., hemiplegic cerebral palsy) and requires evaluation with a brain MRI.
Question 36Question →

A 5-year-old girl is evaluated in the pediatric neurology clinic for progressive unsteadiness. Her parents report that she attained independent walking at 16 months of age, which was considered slightly delayed, but over the past year she has become increasingly clumsy and falls frequently. Additionally, they have noticed that she turns her entire head to follow moving objects rather than moving her eyes. Her medical history is significant for three hospital admissions due to severe bacterial pneumonia since age 2. Physical examination reveals a broad-based, unsteady gait and truncal titubation. Neurologic evaluation demonstrates markedly impaired smooth pursuit eye movements. Closer inspection of her face and eyes reveals prominent, blanching, tortuous vascular networks on the bulbar conjunctivae. Which of the following is the most appropriate management consideration for this patient?

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Answer: Minimization of diagnostic procedures utilizing ionizing radiation

Answer

Minimization of diagnostic procedures utilizing ionizing radiation
The correct management consideration is the minimization of diagnostic procedures utilizing ionizing radiation. This patient's clinical presentation—progressive cerebellar ataxia, oculomotor apraxia, conjunctival telangiectasias, and recurrent severe sinopulmonary infections—is classic for Ataxia-Telangiectasia (A-T). A-T is an autosomal recessive disorder caused by mutations in the ATM (Ataxia-Telangiectasia Mutated) gene. The ATM protein is a serine/threonine kinase that plays a pivotal role in detecting DNA double-strand breaks and halting the cell cycle to allow for repair. Because this repair mechanism is defective, patients with A-T are exquisitely sensitive to ionizing radiation (which induces double-strand breaks). Routine radiographic imaging (X-rays, CT scans) should be strictly limited to essential indications to prevent the development of iatrogenic malignancies, particularly leukemias and lymphomas to which these patients are already highly predisposed.

Step-by-Step Solution

1
Identify the primary neurologic deficit and accompanying physical signs.
The patient has progressive cerebellar ataxia, oculomotor apraxia (turning the head instead of eyes), and bulbar conjunctival telangiectasias.
Recognizing this specific triad is essential for diagnosing the underlying neurocutaneous syndrome.
2
Correlate the neurologic and dermatologic findings with the patient's past medical history.
The history of recurrent, severe sinopulmonary infections indicates a concurrent immunodeficiency.
Combining ataxia, telangiectasias, and immunodeficiency strongly points toward Ataxia-Telangiectasia (A-T).
3
Determine the pathophysiologic mechanism of Ataxia-Telangiectasia.
A-T is caused by an autosomal recessive mutation in the ATM gene, which is responsible for detecting and coordinating the repair of DNA double-strand breaks.
Understanding the molecular defect is required to determine the best management practices and avoid iatrogenic harm.
4
Select the management consideration that directly relates to the genetic defect.
Because the patient cannot repair DNA double-strand breaks, exposure to ionizing radiation (such as X-rays and CT scans) can cause rapid accumulation of mutations and precipitate hematologic malignancies.
Minimizing ionizing radiation is a critical preventative management step for patients with A-T.

Key Concept

Ataxia-Telangiectasia is a multisystem disorder characterized by progressive cerebellar ataxia, oculomotor apraxia, conjunctival telangiectasias, and immunodeficiency. Due to a defect in DNA double-strand break repair (ATM gene), affected individuals are extremely sensitive to ionizing radiation.
Question 37Question →

A 13-year-old boy is brought to the pediatric neurology clinic by his parents due to progressive walking difficulties over the last 18 months. He frequently trips and recently had to stop playing on his school basketball team because he loses his balance easily. The parents note that his 10-year-old brother has also begun to display similar clumsiness. The patient's vital signs are within normal limits. Physical examination reveals high-arched feet and a noticeable lateral curvature of the thoracic spine. Neurological examination demonstrates a wide-based, unsteady gait. Deep tendon reflexes are absent at the knees and ankles, and there is markedly decreased vibratory and proprioceptive sensation in both lower extremities. Motor strength is mildly decreased in the distal lower extremities. Which of the following investigations is most appropriate to evaluate for the leading cause of mortality associated with this patient's underlying condition?

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Answer: Transthoracic echocardiography

Answer

Transthoracic echocardiography is the most appropriate investigation to evaluate for hypertrophic cardiomyopathy, which is the leading cause of mortality in patients with Friedreich ataxia.
The patient's clinical picture is classic for Friedreich ataxia, an autosomal recessive condition caused by a GAA trinucleotide repeat expansion in the FXN gene. This leads to degeneration of multiple spinal cord tracts (spinocerebellar, dorsal columns, corticospinal) and peripheral nerves. Characteristic findings include progressive ataxia, absent lower extremity reflexes, loss of proprioception/vibration, and skeletal abnormalities such as pes cavus and kyphoscoliosis. Up to 90% of patients develop hypertrophic cardiomyopathy, which can cause fatal arrhythmias or congestive heart failure. Because this cardiac involvement is the leading cause of mortality, an echocardiogram is the most critical step in evaluating long-term prognosis and directing appropriate cardiac care.

Step-by-Step Solution

1
Analyze the clinical presentation to establish the most likely diagnosis.
The combination of progressive ataxia, pes cavus, kyphoscoliosis, absent lower extremity reflexes, and sensory loss in a young patient with an affected sibling strongly suggests Friedreich ataxia.
Identifying the underlying autosomal recessive disorder is required before determining its associated complications.
2
Identify the primary life-threatening complication associated with this disease.
Hypertrophic cardiomyopathy is the leading cause of death in patients with Friedreich ataxia.
The question specifically asks for the investigation targeting the most common cause of mortality.
3
Select the appropriate diagnostic modality for the identified complication.
Transthoracic echocardiography is selected to evaluate for cardiac hypertrophy and dysfunction.
Echocardiography is the standard imaging modality to assess for hypertrophic cardiomyopathy.

Key Concept

Friedreich ataxia is an autosomal recessive neurodegenerative disorder characterized by progressive ataxia, loss of deep tendon reflexes, and skeletal deformities (pes cavus, kyphoscoliosis). The most common cause of death is hypertrophic cardiomyopathy, necessitating evaluation with echocardiography.
Estimated Time:1m 0s
Question 38Question →

A 3-week-old boy is brought to the pediatric clinic by his parents due to 'seizures'. The parents report that over the past week, the infant has exhibited repetitive, rhythmic jerking movements of his arms and legs. These movements occur exclusively when he is asleep and cease immediately when his limbs are gently held or when he wakes up. The infant was born at 39 weeks gestation via an uncomplicated vaginal delivery. He is exclusively breastfed, feeds vigorously, and has normal urine and stool output. On physical examination, the infant is alert and has normal tone, reflexes, and pupil reactivity. His anterior fontanelle is flat and soft. Skin examination reveals multiple 1- to 3-mm yellow-white pustules on a broadly erythematous base scattered across his chest and back. Which of the following statements regarding this patient's condition and management are correct? (Select 2 that apply)

Select all that apply

Show answer & explanation

Answer: An electroencephalogram performed during an active episode would not demonstrate any epileptiform discharges.; The abnormal movements are expected to resolve spontaneously without intervention by 2 to 6 months of age.

Answer

The correct statements are that an electroencephalogram (EEG) performed during an active episode would not demonstrate any epileptiform discharges, and the abnormal movements are expected to resolve spontaneously without intervention by 2 to 6 months of age.
The patient's clinical presentation is highly characteristic of benign neonatal sleep myoclonus. This condition presents in the first few weeks of life with repetitive myoclonic jerks that occur exclusively during sleep and immediately cease when the infant is awakened or the limb is restrained. Because this is a non-epileptic phenomenon, an electroencephalogram (EEG) captured during an episode will show a normal background sleep architecture without any epileptiform discharges. The condition is entirely benign and self-limiting, typically resolving spontaneously between 2 and 6 months of age without any long-term neurologic sequelae. Reassurance is the only necessary intervention.

Step-by-Step Solution

1
Analyze the infant's neurologic symptoms.
The rhythmic jerking occurs only during sleep and stops with gentle restraint or upon waking.
These are classic hallmark features of benign neonatal sleep myoclonus, differentiating it from true neonatal seizures which do not stop with physical restraint.
2
Evaluate the dermatologic findings.
Multiple yellow-white pustules on an erythematous base are observed in a healthy, vigorously feeding neonate.
This physical finding perfectly describes erythema toxicum neonatorum, a benign physiologic rash, effectively ruling out infectious etiologies like neonatal herpes simplex virus.
3
Determine the appropriate management and prognosis based on the clinical picture.
The condition is non-epileptic and benign, requiring no antiepileptic drugs, antiviral therapy, or immediate vaccinations.
Recognizing physiologic and benign neonatal conditions is crucial to prevent unnecessary hospitalizations, invasive testing, and inappropriate therapies.

Key Concept

Differentiating benign neonatal sleep myoclonus and erythema toxicum neonatorum from true neonatal seizures and infectious etiologies.
Estimated Time:1m 30s
Question 39Question →

An 18-month-old toddler is transferred to a tertiary care center for progressive unsteadiness, refusal to walk, and unusual eye movements that began two weeks ago. The patient had previously achieved independent ambulation at 13 months. Her parents note she has become exceptionally cranky and exhibits sudden jerky body movements. They also mention they are worried because she speaks about 15 individual words but has not yet started combining them into two-word phrases. She is afebrile, and her vital signs are age-appropriate. Neurologic evaluation reveals chaotic, multi-directional, rapid conjugate ocular movements occurring without a distinct slow phase. She also demonstrates brief, involuntary, shock-like muscle spasms in her proximal limbs and trunk. When seated, she has marked truncal titubation. She was started on intravenous vancomycin and ceftriaxone two days ago; however, blood and cerebrospinal fluid cultures drawn at that time remain sterile, and she has no signs of infection. The medical team plans to initiate high-dose intravenous corticosteroids and rituximab later today.

Which of the following diagnostic or management steps are indicated for this patient? (Select exactly 2 options)

Select all that apply

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Answer: Assessment of urinary homovanillic acid and vanillylmandelic acid levels; Cross-sectional imaging of the thorax, abdomen, and pelvis

Answer

The correct steps are the assessment of urinary homovanillic acid and vanillylmandelic acid levels, and cross-sectional imaging of the thorax, abdomen, and pelvis.
The correct steps address the required diagnostic workup for a toddler presenting with opsoclonus-myoclonus-ataxia syndrome (OMAS), commonly referred to as 'dancing eyes, dancing feet' syndrome. The clinical presentation is defined by rapid, conjugate, multidirectional eye movements without a slow phase, accompanied by diffuse myoclonus and truncal ataxia. In this age group, up to 50% of OMAS cases represent a paraneoplastic syndrome secondary to an occult neuroblastoma. Therefore, it is critical to aggressively screen for this malignancy. The evaluation includes testing urine for elevated catecholamine metabolites (homovanillic acid and vanillylmandelic acid) and performing cross-sectional imaging (such as magnetic resonance imaging or computed tomography) of the thorax, abdomen, and pelvis to locate a primary tumor along the sympathetic chain or in the adrenal glands.

Step-by-Step Solution

1
Identify the patient's clinical syndrome based on the physical examination findings.
The combination of chaotic, multidirectional eye movements (opsoclonus), sudden muscle jerks (myoclonus), and severe unsteadiness (ataxia) establishes the diagnosis of opsoclonus-myoclonus-ataxia syndrome (OMAS).
Recognizing this classic triad is essential to guide the subsequent etiological workup.
2
Determine the most common underlying etiology for this syndrome in a pediatric patient.
In toddlers, OMAS is most frequently a paraneoplastic manifestation of an occult neuroblastoma.
Paraneoplastic immune dysregulation triggered by the tumor causes the central nervous system findings.
3
Select the appropriate diagnostic tests to identify the underlying tumor.
The workup must include measurement of urinary catecholamine metabolites (homovanillic acid and vanillylmandelic acid) and comprehensive cross-sectional imaging (chest, abdomen, and pelvis).
Neuroblastomas typically arise from the sympathetic ganglion chain or adrenal medulla and secrete catecholamines, making these tests highly sensitive for detection.
4
Evaluate the distractors based on pediatric milestones, infectious disease principles, and immunization guidelines.
A 15-word vocabulary is normal at 18 months, ruling out a language delay. Negative cultures at 48 hours in an afebrile patient indicate antibiotics should be stopped. Planned immunosuppression contraindicates live vaccines.
Integrating knowledge from multiple pediatric domains prevents inappropriate management steps.

Key Concept

Opsoclonus-myoclonus-ataxia syndrome in toddlers is a paraneoplastic neurologic disorder that mandates an immediate diagnostic evaluation for an underlying neuroblastoma.
Estimated Time:1m 30s
Question 40Question →

An infant, aged 4 months, is brought to the emergency department by her parents due to a three-day history of a progressively weakened cry and diminished spontaneous movements. The parents note she has been feeding poorly and has not passed a bowel movement for the last five days. The infant was born at term without complications and had been meeting early developmental milestones appropriately. The family recently relocated to a rural agricultural community and is renovating an old farmhouse, exposing the home to significant environmental dust. Vital signs are within normal limits. Physical examination reveals a lethargic infant with profound generalized hypotonia and severe head lag. Bilateral ptosis, sluggishly reactive pupils, and a markedly weak gag reflex are present. Deep tendon reflexes are diffusely diminished. Which of the following is the most appropriate next step in management?

Show answer & explanation

Answer: Administration of human-derived botulism immune globulin

Answer

Administration of human-derived botulism immune globulin
The infant's presentation of constipation followed by acute-onset descending flaccid paralysis, bulbar weakness (ptosis, weak gag, sluggish pupils), and severe hypotonia is classic for infant botulism. The most common source of Clostridium botulinum spores in the United States is environmental dust or soil, often associated with rural areas or construction. Ingestion of spores leads to colonization of the infant's gastrointestinal tract and subsequent in vivo toxin production. The toxin irreversibly inhibits presynaptic acetylcholine release at the neuromuscular junction. The most appropriate initial step in management is the prompt administration of human-derived botulism immune globulin. Treatment should be initiated immediately based on clinical suspicion to neutralize unbound toxin and halt the progression of paralysis; clinicians should not wait for confirmatory stool studies.

Step-by-Step Solution

1
Identify the clinical syndrome
The combination of acute severe constipation followed by descending flaccid paralysis, bulbar palsies (ptosis, poor gag), and autonomic dysfunction (sluggish pupils) in an infant indicates infant botulism.
Recognizing this specific triad of symptoms separates botulism from other causes of infant hypotonia like spinal muscular atrophy or sepsis.
2
Identify the epidemiological risk factor
The exposure to significant environmental dust in a rural agricultural area suggests inhalation or ingestion of Clostridium botulinum spores.
While honey is the classically taught risk factor, environmental soil/dust is actually the most common source of infant botulism in the United States.
3
Determine the definitive, age-appropriate treatment
Select human-derived botulism immune globulin (BabyBIG) as the immediate next step.
Treatment must be initiated based on clinical suspicion to halt paralysis progression. Infants must receive the human-derived formulation to avoid the severe hypersensitivity reactions associated with the equine-derived formulation used in adults.

Key Concept

Diagnosis and specific pharmacotherapy of infant botulism
Estimated Time:1m 30s
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