Neurology

Question 1

A 6-year-old has an episode with the following symptoms:

Loss of consciousness simultaneous with marked, sustained contractions of the entire musculature
Eyes that deviate conjugately upward and dilated pupils
Salivation and diaphoresis
Urinary incontinence
The episode lasts for 10–20 seconds. Then, the patient has a series of brief but progressively longer relaxations of all muscle groups, which interrupt and eventually stop the sustained, tonic muscular spasm. This lasts about 30 seconds. After this, he slowly gains consciousness and is confused and sleepy for about 30 minutes.

What type of seizure did this patient have?

Answer 1

Answer
Tonic-clonic seizure (grand mal seizure)
Explanation
Tonic-clonic seizures are the classic form of generalized seizures. These seizures are rare in infancy but not uncommon in early childhood

Question 2

A neonate presents with a stroke.

What is the most common inheritable cause of stroke?

Answer 2

Activated protein C (APC) resistance (Factor 5 Leiden)
Explanation
APC resistance (Factor 5 Leiden) is the most common inheritable cause of venous thrombosis. It is more common than deficiencies of protein C, protein S, or antithrombin, which are some of the other causes of ischemic stroke. APC resistance can also cause hemiplegic cerebral palsy in neonates.

Question 3

A 2-week-old infant with a history of intrauterine cytomegalovirus (CMV) infection presents with:

Lethargy
Vomiting
A marked increase in head circumference
Dilated scalp veins
What is the likely diagnosis?

Answer 3

Hydrocephalus
Explanation
Hydrocephalus is defined as an excessive volume of intracranial cerebrospinal fluid with ventricular dilatation. There are two main types: communicating (where the ability to absorb CSF is decreased) and non-communicating (where the outflow of CSF through the ventricular system is obstructed). It commonly occurs after intrauterine infection with CMV, rubella, toxoplasmosis, and syphilis. The infections cause an inflammatory reaction of the ependymal linings of the ventricular system and the meninges of the subarachnoid space, resulting in communicating hydrocephalus.

Question 4

You suspect Duchenne muscular dystrophy (DMD) in a 4-year-old boy.

How do you confirm the diagnosis?

Answer 4

Identify mutation on the DMD gene
Explanation
If DMD is clinically suspected, measuring CK level is the next step. It will be elevated in patients with the disease. Diagnosis is confirmed by identifying a mutation of the DMD gene (on X chromosome). Muscle biopsy is typically only used to confirm the diagnosis in patients whose genetic testing is negative.

Question 5

An infant is born with a severe seizure disorder. A CT scan shows bilateral clefts within the cerebral hemispheres.

What is the diagnosis?

Answer 5

Schizencephaly
Explanation
Schizencephaly (literally translated “split brain”) is one of the > 25 neuronal migration disorders. CT/MRI is diagnostic. Infants with bilateral clefts usually have severe epilepsy, microcephaly, severe intellectual disability, and spastic quadriparesis. Those with unilateral clefts often have focal epilepsy and hemiplegic cerebral palsy

Question 6

A 3-hour-old infant is born to a mother who has a neurologic disease. The infant presents with:

Hypotonia
Weak cry
Difficulty feeding
Facial weakness
Ptosis
Respiratory distress
What is the likely cause of the infant’s problems?

Answer 6

Neonatal myasthenia gravis from transplacental transmission of maternal acetylcholine receptor antibodies (AChR-Ab)
Explanation
All of the findings listed can occur—the ptosis and facial weakness should clue you in because nothing else is going to cause this with respiratory distress. Neonatal myasthenia gravis resolves in 2–6 weeks, after the maternal antibodies clear.

Note: This differs from congenital myasthenia gravis, which is an AR disorder and does not have circulating antibodies to acetylcholine receptors.

Question 7

A 14-year-old girl presents with:

Vertigo
Syncope
Dysarthria
Visual alterations
Loss of consciousness
What is this unusual type of migraine?

Answer 7

Answer
Basilar artery migraine
Explanation
Basilar artery migraines present with the symptoms described in this case. (The visual alterations and loss of consciousness occur in some cases.) Basilar artery migraines occur more commonly in adolescent girls.

Question 8

A 5-month-old boy presents with episodes of sudden, simultaneous flexion of his head and trunk, along with flexion and adduction of his extremities. The last episode occurred in a transition period from sleep to wakefulness and occurred in too-numerous-to-count clusters (> 100). The child is no longer able to roll over like he was able to before.

What is the likely diagnosis?

Answer 8

Answer
Infantile spasms
Explanation
Infantile spasms are a unique type of seizure disorder, occurring in infants and children < 1 year of age. The majority of these infants develop spasms between 3 and 7 months of age (< 10% present after 2 years of age). The classic spasm is the jackknife flexor spasm (a.k.a. salaam attack and Blitz-Nick-Salaam-Krämpfe). Most children also have developmental regression, like the child described in the vignette. Infantile spasms resolve over time without specific therapy; however, most surviving children have severe intellectual disability and other types of seizure disorders (most common is Lennox-Gastaut syndrome). Mortality is ~ 20%. Successful treatment of infantile spasms with ACTH, oral prednisolone, or oral vigabatrin possibly improves the long-term prognosis.

Question 9

A 14-year-old girl presents with:

1-year history of recurrent, pulsating, moderate-intensity headaches occurring on the left side of her head
Associated nausea and vomiting
Photophobia
What is the likely diagnosis?

Answer 9

Migraine headache
Explanation
Pediatric migraine without aura is defined as at least 5 attacks that last between 2 and 72 hours and:
Include at least 2 of the following:
Bilateral or unilateral location
Pulsating
Moderate-to-severe pain
Pain made worse with activity
Have at least 1 associated symptom:
Nausea/Vomiting
Photophobia/Phonophobia

Question 10

A 7-year-old girl has the following episode:

It lasts 15 seconds.
Asynchronous clonic movements of the face, neck, and upper extremities
She had an aura before it occurred.
She had a hallucination that a big dog was next to her during the episode.
She never lost consciousness, and she interacted with her mother during the episode.
No postictal confusion
What type of seizure did she have?

Answer 10

Answer
Focal aware seizure
Explanation
Focal aware seizures (a.k.a. focal seizures without impairment of consciousness and formerly called simple partial seizures) are seizures in which patients do not lose consciousness and can still interact with their environment. These seizures can be quite varied in symptoms/signs, depending on where the focus is located: focal motor (from the precentral gyrus), focal somatosensory (from the parietal lobe), or focal adversive (from the mesial frontal lobe).

Question 11

An 8-year-old boy presents with:

A history of focal, unremitting seizures occurring on the left side of the body
Progressive hemiparesis on the left side
Diminished intelligence
New hemianopia
Atrophy of the right hemisphere on MRI
What syndrome does this child most likely have?

Answer 11

Rasmussen syndrome
Explanation
Rasmussen syndrome (chronic focal encephalitis) is believed to be an immunologic process involving one hemisphere of the brain. About 70% have a history of infectious or inflammatory illness themselves or in a family member. The disease is not fatal but deteriorates to a stable, often devastating, neurologic deficit. A modified hemispherectomy or focal cortical excision usually improves symptoms markedly and is the recommended treatment.

Question 12

As a single risk factor, what is the most common cause of ischemic strokes in children?

Answer 12

Answer
Sickle cell disease
Explanation
Sickle cell disease is responsible for nearly 10% of pediatric strokes. Genotype SS has the highest incidence of stroke among the sickle hemoglobinopathies. Congenital heart disease is the second most common risk factor for pediatric ischemic strokes.

Question 13

A 5-year-old suffers a fall and develops bilateral orbital ecchymoses with appearance of otorrhea.

Where is the skull fracture most likely located?

Answer 13

Basilar skull area
Explanation
Bilateral orbital ecchymoses (“raccoon eyes” or black eyes) indicates a fracture at the base of the skull. Such a fracture also might be indicated by posterior auricular ecchymoses (Battle sign) and tympanic membrane discoloration if the petrous bone of the middle fossa is involved. Otorrhea and rhinorrhea also point to this location.

Question 14

A 10-year-old boy has the following recurrent seizure episodes:

Morning myoclonic jerking
Generalized tonic-clonic seizures occurring just after awakening or during sleep
Normal intelligence
Family history of similar seizures
What condition causes the type of seizure he is having

Answer 14

Juvenile myoclonic epilepsy (JME)
Explanation
JME is a subtype of generalized epilepsy. This is usually a lifelong condition. Seizures increase with sleep deprivation, stress, or alcohol use.

Question 15

A woman undergoes a prenatal ultrasound at ∼ 32 weeks of gestation. The brain of the fetus shows widely separated frontal horns, with the 3rd ventricle being very high between the lateral ventricles. The mother admits to using cocaine during the pregnancy.

What is the diagnosis?

Answer 15

Answer
Agenesis of the corpus callosum
Explanation
Agenesis of the corpus callosum is one of the > 25 neuronal migration disorders. It can be inherited as an X-linked dominant (e.g., Aicardi syndrome), recessive, or autosomal dominant trait. Recently, maternal cocaine use has been linked to this condition. Agenesis of the corpus callosum occurs in a wide variety of disorders, with similar severity variations. Some are asymptomatic and have normal intelligence, while others have severe intellectual disability and seizures (particularly infantile spasms in Aicardi syndrome).

Question 16

A White female newborn presents in the delivery room with:

Large parts of the cranium missing, including the frontal and parietal bones
Missing forebrain
Facial and eye abnormalities
Prenatally, the mother had elevated serum levels of α-fetoprotein.

What is the diagnosis?

Answer 16

Answer
Anencephaly
Explanation
Anencephaly occurs when the anterior neural tube fails to close. It has an incidence of ~ 1/10,000 live births and is invariably lethal. Girls and Caucasians are more commonly affected. Failure of closure of the posterior neural tube results in myelomeningocele.

Question 17

What is the treatment for juvenile myasthenia gravis?

Answer 17

Answer
Oral anticholinesterase medications; possibly immunosuppression, thymectomy, plasmapheresis or IV immunoglobulin (IVIG)
Explanation
Treat with oral anticholinesterase medications (e.g., pyridostigmine); these increase the concentration of acetylcholine at the receptor site, and can result in muscarinic (e.g., abdominal cramping, diarrhea, salivation) and nicotinic (e.g., fasciculations, muscle cramping) side effects. Most patients require immunosuppression at some point as well. Thymectomy induces remission in as many as 50–60%. Finally, plasmapheresis or IVIG is beneficial for short-term amelioration of worsening symptoms.

Question 18

A 16-year-old boy presents with:

Unilateral retroorbital pain that feels “like an ice pick”
Ipsilateral lacrimation, eye redness, and nasal congestion
Headache that has occurred at the same time of the day for the last 3 days
What is the best acute treatment for this boy?

Answer 18

Oxygen
Explanation
This boy is suffering from cluster headaches. The 1st line treatment options for cluster headaches include oxygen therapy and triptans. Cluster headaches are rare in children < 10 years of age but become increasingly common between 10 and 20 years of age. Boys are affected much more than girls (3:1 to 4:1). They present with daily attacks that commonly occur at the same hour each day. The pain is strictly unilateral; severe; and is supraorbital, retroorbital, or temporal in location. Ipsilateral autonomic symptoms, like those in our example, are common.

Question 19

An infant is born with a severe seizure disorder that begins at birth. A CT scan of the head shows a brain without cerebral convolutions and with a poorly formed sylvian fissure.

What is the diagnosis?

Answer 19

Lissencephaly (agyria)
Explanation
Lissencephaly is characterized by a smooth cerebral surface with a thickened cortical mantle of the brain. It lacks cerebral folds (gyri) and grooves (sulci) and has a poorly formed sylvian fissure. Lissencephaly is caused by a defect in the neuronal migration during weeks 12–24 of gestation. It is associated with several disorders, especially isolated lissencephaly sequence, Miller-Dieker syndrome, and Walker-Warburg syndrome. These children have severe psychomotor impairment, seizures, poor feeding, recurrent pneumonia, and shortened lifespans; they rarely reach 10 years of age.

Question 20

A 5-month-old infant presents with:

Constipation
Generalized weakness
Decreased ability to suck
Poor gag reflexes
Loss of deep-tendon reflexes
Facial diplegia
Lack of pupillary response to light
Ptosis
What is the likely diagnosis?

Answer 20

Answer
Botulism
Explanation
Botulism is due to the effects of Clostridium botulinum toxin. The toxin affects the presynaptic mechanisms that release acetylcholine in response to nerve stimulation. In the past, outbreaks occurred in infants who were given honey at young ages. Most cases of infant botulism are probably due to the ingestion of environmental dust contaminated with C. botulinum spores. The symptoms described here are classic for an infant.

Question 21

A child presents with an ischemic stroke.

If a prothrombotic factor is responsible, what is the likely abnormality?

Answer 21

Answer
Acquired antiphospholipid antibody
Explanation
About 1/3 of children with ischemic stroke have an abnormality in prothrombotic factors. One of the most frequent disorders of this type is an acquired antiphospholipid antibody—especially anticardiolipin antibody and lupus anticoagulant.

Question 22

A 5-year-old asymptomatic girl presents as a new patient for a routine visit to your practice. On physical examination, you note a tuft of hair in the midline of her lower back.

What abnormality does this suggest?

Answer 22

Spina bifida occulta
Explanation
Spina bifida occulta is very common (∼ 10% of the population) and rarely causes any problems. It can be associated with syrinx or tethered cord. It is a midline defect of the vertebral bodies without protrusion of the spinal cord or meninges. Most patients are asymptomatic and have no neurologic signs. Some cases present with patches of hair, lipoma, skin-color changes, or a dermal sinus. MRI provides the most thorough evaluation of the defect and is helpful to ensure no spinal cord anomaly (e.g., tethered cord).

Question 23

A 7-year-old girl has a seizure that presents with:

Loss of consciousness
Unresponsiveness
Automatism consisting of repetitive lip smacking
She reports a hallucination before her seizure with intense fear of a monster beside her in the room but does not have recollection of the seizure itself.
Postictally, she is aggressive and angry toward her mother.
What type of seizure did this child experience?

Answer 23

Focal seizure with impaired awareness
Explanation
Focal seizures with impaired awareness (a.k.a. focal seizures with impaired consciousness and formerly called complex partial seizures) have variable symptoms but usually include alterations in consciousness, unresponsiveness, and automatisms. Automatisms are repetitive, purposeless, undirected, and inappropriate motor activities. Commonly, they include repetitive lip smacking, swallowing, chewing, or fidgeting of the fingers or hands. Prior to the seizure, an aura is common, which can include hallucinations. Postictally, these children may act aggressively or angrily to objects or persons that are in their way; this does not occur as a manifestation of the seizure itself.

Question 24

A 4-year-old boy presents with:

Frequent falling
Waddling gait
Toe walking
Calf muscle pseudohypertrophy
Positive Gowers sign—using arms to climb up the legs when rising from a seated position on the floor
Elevated CK
What is the diagnosis?

Answer 24

Duchenne muscular dystrophy (DMD)
Explanation
DMD is the most common form of muscular dystrophy. It is X-linked recessive and therefore only occurs in boys. Affected boys commonly lose the ability to walk by 12 years of age.

Question 25

A full-term infant presents with focal seizures on the 2nd day of life. The infant has a neonatal cerebral infarction.

In what arterial distribution do most neonatal cerebral infarctions occur?

Answer 25

Answer
Middle cerebral artery
Explanation
Neonatal cerebral infarction is estimated to occur in 1/4,000 infants. Most are embolic and occur in the distribution of the left middle cerebral artery. The placenta appears to be the source for some of these emboli. The most common presentation for infants with neonatal cerebral infarction is focal seizures within the first few days of life

Question 26

A newborn is noted to have a herniation of meninges through a defect in the posterior vertebral arches. The spinal cord itself is normal. The area is well covered with skin.

What is the diagnosis?

Answer 26

Answer
Meningocele
Explanation
A meningocele is the rarest of the 3 types of spina bifida. It is a herniation of the meninges alone (not the spinal cord) through a defect in the posterior vertebral arches. Most meningoceles are well covered with skin and pose no urgent problem. Delay surgery for those patients with completely normal neurologic exams and complete full-thickness skin covering the meningocele. Technically, the surgery is easier when the child is larger and the skin is less fragile. Children with CSF leaking through the meningocele or with incomplete skin covering need immediate surgical correction due to the risk of meningitis.

Question 27

A 7-year-old girl is experiencing recurrent episodes with these characteristics:

10- to 20-second lapses in awareness
Amnesia during the episodes
Episodes have abrupt onset and ending—sometimes occurring in the middle of conversation.
Flickering of the eyelids is common.
Occasionally, she stares or has eye rolling.
EEG shows a 3-Hz generalized spike and wave discharge.
What type of seizure is she having?

Answer 27

Answer
Absence seizure (petit mal seizure)
Explanation
Absence seizures are classically characterized as described in the vignette. Atypical absence seizures may also have brief jerks of the eyelids and limbs, transient change in postural tone (increase or decrease), pupillary dilation, skin-color changes, and tachycardia. Absence seizures are not associated with auras, hallucinations, or postictal abnormalities. Do not confuse absence seizures with focal seizures, which last longer (generally > 30 seconds), have auras, and include slow return to consciousness.

Question 28

A 2-year-old child with history of infantile spasms has gradually developed the following findings:

Severe tonic seizures and generalized tonic-clonic seizures
Intellectual disability
An EEG shows generalized, bilateral synchronous, sharp wave and slow wave complexes, occurring in a repetitive fashion in long runs at ~ 2 Hz.

What syndrome does this child likely have?

Answer 28

Lennox-Gastaut syndrome
Explanation
Lennox-Gastaut syndrome refers to a varied group of symptoms with multiple seizure types, intellectual disability, and the characteristic EEG pattern described in the vignette. 25–40% have a history of infantile spasms.

Question 29

A 3-year-old girl with a recent varicella infection presents to the emergency department with acute onset of gait unsteadiness. Evaluation shows:

Hypotonia
Tremor
Horizontal nystagmus
Dysarthria
Severe ataxia
Sensory exam is normal.
Deep-tendon reflexes are normal.
CSF is normal, except for 15 lymphocytes/µL.
What is the most likely diagnosis?

Answer 29

Acute cerebellar ataxia of childhood (a.k.a. acute cerebellitis)
Explanation
Acute cerebellar ataxia of childhood occurs most commonly in children between 1 and 3 years of age (although it can also be seen up to ~ 6 years of age). Its onset is abrupt, and about 50% of affected children have a recent history of URI or viral GI illness. These viruses can include varicella, rubeola, mumps, rubella, echoviruses, EBV, and influenza. Some bacterial infections, such as group A Streptococcus and Salmonella, also have been implicated.

Question 30

A 3-year-old boy has the following type of seizure:

1 second in duration
Abrupt, bilateral, symmetric muscle contraction
He fell to the ground during the seizure.
No loss of consciousness
What type of seizure did he have?

Answer 30

Answer
Myoclonic seizure
Explanation
Myoclonic seizures have the characteristics described in the scenario. These seizures can be isolated, or they can occur with absence attacks. In brief attacks, consciousness may be maintained. Myoclonic seizures can be associated with generalized epilepsy or with progressive neurodegenerative genetic diseases.

Question 31

A newborn presents in the delivery room with herniation of the brain and its coverings through a skull defect in the occipital region.

What is the diagnosis?

Answer 31

Answer
Encephalocele
Explanation
An encephalocele is a neural tube defect in which a skull defect causes herniation of the brain, its coverings, or both. 75% of the time, it is in the occipital region. In the U.S., it occurs with a frequency of ~ 1/10,000 live births. Males and females are equally affected

Question 32

A 2-year-old boy falls from a 2-story house and hits his head on the ground. Skull x-rays indicate a linear skull fracture.

Where are skull fractures most commonly located?

Answer 32

Parietal area
Explanation
More than 80% of skull fractures are simple linear or diastatic fractures; the parietal area is the most common location. Diastatic fractures typically involve the lambdoid suture.

Question 33

A 3-year-old otherwise healthy boy presents with:

Fever of 104.9°F (40.5°C)
10 minutes of generalized tonic-clonic seizure
Examination reveals a well-looking child who is tired, but is otherwise unremarkable with absence of meningeal signs.
Evaluation of the family history shows that his father had one seizure as a child.
What is the diagnosis?

Answer 33

Answer
Febrile seizure
Explanation
Febrile seizures are very common. (2–5% of children experience at least 1 febrile seizure before 5 years of age.) This is a simple febrile seizure because the child is otherwise healthy, the seizure is triggered by a fever, lasts < 15 minutes, is nonfocal, and did not recur. ~ 40% of those affected have at least one 1st or 2nd degree relative with a history of febrile seizures

Question 34

After a difficult labor, a newborn presents with:

Paralysis of the flexors and extensors of the forearm and intrinsic muscles of the right hand
Sensory loss on the ulnar side of the right hand
What is the most likely diagnosis?

Answer 34

Déjerine-Klumpke palsy (a.k.a. Klumpke palsy)
Explanation
In contrast to upper brachial plexus injuries, lower brachial plexus injuries (C8–T1) show more sensory (ulnar side of the hand) and vasomotor involvement, with paralysis of the flexors and extensors of the forearm and intrinsic muscles of the hand. If the 1st thoracic root is involved, Horner syndrome is likely. Injury occurring with Horner syndrome has a worse long-term motor outcome

Question 35

A 13-year-old girl presents with:

Worsening muscle weakness that is exacerbated by repetitive muscle use
Ocular muscle weakness and ptosis
What is the most likely diagnosis?

Answer 35

Juvenile myasthenia gravis
Explanation
Myasthenia gravis is rare in children. Juvenile myasthenia gravis is an acquired autoimmune disorder and affects girls more than boys, usually after 10 years of age. 80–90% of affected children have circulating autoantibodies to acetylcholine receptors (AChR-Ab). The disease progresses gradually, with worsening muscle weakness, fatigability, and respiratory compromise. Muscle weakness is exacerbated by repetitive muscle use. Ocular muscles are involved, resulting in ptosis and ophthalmoplegia

Question 36

After a difficult labor, a newborn presents with:

A sagging left shoulder
A left arm that hangs limp in internal rotation with a flexed wrist
Absent left biceps tendon reflex
Normal sensory examination
What is the most likely diagnosis?

Answer 36

Answer
Erb palsy
Explanation
Birth trauma is the most common cause of peripheral nerve injury, with the upper brachial plexus the most frequently injured. When nerve roots of CN 5, CN 6, and occasionally CN 7 are involved, it is referred to as Erb palsy (a.k.a. Erb paralysis, Duchenne-Erb palsy). Infants present with the findings described here, known as the “waiter’s tip position.” Symptoms are due to paralysis of the supinator, deltoid, biceps, brachioradialis, and extensor carpi radialis muscles

Question 37

A 14-year-old girl with history of Campylobacter diarrhea presents with:

Progressive weakness that began distally in her legs, with paralysis moving upward toward her lower abdomen
Lost tendon reflexes in lower extremities
Sensory examination intact, except for possible diminution of vibratory sensation
CSF showing elevated protein with a normal cell count
What is the diagnosis?

Answer 37

Answer
Guillain-Barré syndrome
Explanation
Guillain-Barré syndrome (GBS) classically is associated with preceding infections, especially Campylobacter, Mycoplasma, or Epstein-Barr virus. GBS can be differentiated from transverse myelitis because patients with GBS do not have a sensory level. In those with GBS, CSF shows cytoalbuminologic dissociation with elevated protein levels as high as 100–150 mg/dL with a WBC < 10 cells/μL.

Question 38

A child with sickle cell disease has a history of chronic, occlusive cerebrovascular disease. On cerebral angiography, the patient is found to have extensive collateral vessels, resulting from prior occlusions of arteries around the circle of Willis.

What is the name of the anomaly seen on cerebral angiography?

Answer 38

Answer
Moyamoya
Explanation
Moyamoya, a Japanese term meaning “puff of smoke,” refers to the extensive collateral vessels occurring around the circle of Willis as seen on cerebral angiography. Moyamoya can be seen as a primary disease, or secondary to vasculopathy from sickle cell disease, neurofibromatosis Type 1, trisomy 21, and cranial irradiation

Question 39

A 12-month-old presents for evaluation. He was born weighing 1,200 grams, and he has a history of intraventricular hemorrhage and subsequent development of periventricular leukomalacia. He also has the following upper motor neuron signs:

Weakness
Spastic diplegia (legs with more spasticity than his arms)
Hypertonicity with contractures
Hyperreflexia with clonus
Extensor plantar response
Which type of cerebral palsy does he most likely have?

Answer 39

Answer
Spastic cerebral palsy (CP)
Explanation
Of the 5 types of CP, spastic is the most common, occurring in 70% of cases. Spastic CP presents with upper motor neuron signs, including weakness, hypertonicity with contractures, and hyperreflexia with clonus. Know this: Because spastic CP involves upper motor neuron signs, abnormal reflexes (such as extensor plantar response) are typically seen in these children. Spastic diplegia most commonly presents in preterm infants with a history of intraventricular hemorrhage and subsequent periventricular leukomalacia; hence its association with low-birth-weight infants.

Question 40

A 3-month-old girl presents with:

Hypotonia and weakness that is symmetric and with more proximal muscle involvement
Legs more affected than arms
Difficulty feeding
Tongue fasciculations
No sensory deficits
What is the most likely diagnosis?

Answer 40

Answer
Spinal muscular atrophy Type 1 (SMA1), a.k.a. Werdnig-Hoffmann disease or severe infantile SMA
Explanation
SMA is the 2nd most common lethal AR disorder (cystic fibrosis is 1st). SMA1 (a.k.a. Werdnig-Hoffmann disease or severe infantile SMA) is the most severe of the spinal muscular atrophies. Most patients die by 2 years of age from respiratory failure. Proximal muscle weakness with tongue fasciculations are the classic buzzwords to remember in this diagnosis. New disease modifying gene therapies make early diagnosis critically important.

Question 41

An infant is born to a mother who took valproic acid during her 1st trimester. The infant has:

A lumbosacral defect that involves the nerve roots, spinal cord meninges, vertebral bodies, and skin
Flaccid paralysis of the lower extremities
No deep-tendon reflexes of the lower extremities
Lack of response to touch or pain in the lower extremities
Bilateral clubfoot
What 2 abnormalities will this infant most likely develop?

Answer 41

Hydrocephalus and Chiari malformation Type II
Explanation
This child has a myelomeningocele, the most severe type of spina bifida. 80–85% of children with a myelomeningocele will develop hydrocephalus in addition to a Chiari malformation Type II. Type II is the most common form of Chiari malformation and occurs when the 4th ventricle, cerebellar vermis, and lower medulla are pushed down below the level of the foramen magnum. With a Chiari malformation Type I, the cerebellar tonsils are pushed down below the level of the foramen magnum. In Chiari malformation Type III, the cerebellum herniates (creating an encephalocele) through a cervical spina bifida defect.

Question 42

An infant is born to a mother who took valproic acid during her 1st trimester. The infant has:

A lumbosacral defect that involves the nerve roots, spinal cord meninges, vertebral bodies, and skin
Flaccid paralysis of the lower extremities
No deep-tendon reflexes of the lower extremities
Lack of response to touch or pain in the lower extremities
Bilateral clubfoot
What is the diagnosis?

Answer 42

An infant is born to a mother who took valproic acid during her 1st trimester. The infant has:

A lumbosacral defect that involves the nerve roots, spinal cord meninges, vertebral bodies, and skin
Flaccid paralysis of the lower extremities
No deep-tendon reflexes of the lower extremities
Lack of response to touch or pain in the lower extremities
Bilateral clubfoot
What is the diagnosis?

Question 43

A 3-month-old girl presents with:

Hypotonia
Symmetric proximal muscle weakness
Difficulty feeding
Tongue fasciculations
What is the diagnosis, and what gene carries this anomaly?

Answer 43

Spinal muscular atrophy Type 1 (SMA1; a.k.a. Werdnig-Hoffmann disease); SMN1 gene on chromosome 5q13
Explanation
SMA1 presents before 6 months of age with the listed symptoms. In particular, if you see tongue fasciculations in a child this age in a question, look for SMA as an answer! SMA is the 2nd most common lethal AR disorder; cystic fibrosis is 1st. Gene mutation screening allows diagnosis of 95% of SMA cases; the defect is in the SMN1 gene found on chromosome 5q13. New disease modifying gene therapies make early diagnosis critically important.

Question 44

A 9-month-old presents with increased lethargy. The grandmother brought in the child because she is worried that the child may have been abused. She notes that she has witnessed the mother shaking the child vigorously in the past.

Which type of intracranial bleed should you be concerned about in this child?

Answer 44

Subdural hematoma
Explanation
Abusive head trauma (formerly shaken baby syndrome) is responsible for some chronic subdural hematomas. Subdural empyema, which is a complication of bacterial meningitis, also presents as a chronic subdural collection.

Question 45

A 10-year-old boy presents with initial severe back pain that radiates to the front. This is then followed by:

Rapidly progressive paraparesis
Loss of sphincter tone
Loss of pain and temperature sensations below the level of T7
What is the most likely diagnosis?

Answer 45

Answer
Transverse myelitis
Explanation
Transverse myelitis refers to segmental spinal cord disease, with both motor and sensory abnormalities at and below the level of the lesion. Most lesions occur at the thoracic cord level. MRI may be helpful in showing intramedullary signal change.

Question 46

A 10-year-old girl was seen by an outlying emergency department and was given an IM intragluteal injection of penicillin for presumed streptococcal pharyngitis. Over the next few hours, she develops the following symptoms:

Loss of left leg flexion
Flail foot drop on the left
Absence of ankle jerk reflex on the left
Sensory loss below the left knee, except the medial portion is intact
What is the likely diagnosis?

Answer 46

Answer
Sciatic nerve injury
Explanation
Sciatic nerve injection injuries occur during IM injections. IM injections during infancy are contraindicated in the intragluteal area and should be done with extreme caution in older children. Most patients are managed conservatively with pain control and physiotherapy. Consider surgery in infants and in patients with severe deficits not improving in 3 months

Question 47

Hypoactive or absent deep-tendon reflexes
Ataxia
Corticospinal tract dysfunction
Impaired vibratory and proprioceptive function
Hypertrophic cardiomyopathy
Diabetes mellitus
Name the disorder with these findings.

Answer 47

Friedreich ataxia
Explanation
Friedreich ataxia is transmitted as an AR disorder and maps to chromosome 9. It occurs in about 1/30,000 to 1/50,000 in the White population

Question 48

A 17-year-old girl presents with:

Optic neuritis
Oculomotor disturbance
Incoordination of her upper extremities, with dropping of objects
Sensory deficits
CSF shows an increase in IgG and oligoclonal bands.
MRI shows areas of active demyelination as well as evidence of prior demyelination
What is the most likely diagnosis?

Answer 48

Answer
Multiple sclerosis (MS)
Explanation
MS is rare in childhood; only 5% of all patients with MS had symptom onset before 10 years of age. Most pediatric cases present in adolescence. The CSF and MRI findings are classic. Look for this in an adolescent girl with visual changes and motor disturbances.

Question 49

A 5-year-old boy falls from a 25-foot tree and hits his head. Initially, he is unconscious. He regains consciousness and appears to be doing better. After several hours, however, he worsens. He loses consciousness and develops focal neurologic signs. He has a dilated pupil that has progressed to cranial nerve 3 palsy and a contralateral hemiplegia.

What is the most likely etiology of these findings?

Answer 49

Answer
Epidural hematoma
Explanation
An epidural hematoma happens when bleeding occurs between the skull and the dura. It occurs most commonly with a temporal bone fracture, which causes a tear of the middle meningeal artery or, more frequently in children, a tear in the bridging veins or dural sinuses. Epidural hematomas of arterial origin can grow rapidly and acutely raise intracranial pressure, which results in hypertension, bradycardia, and a progressive decline in mental status. This can occur after a lucid interval. Treatment is surgical intervention. Untreated, mortality is ~ 100%