Neurology QOD review

• A 14-year-old boy presents to your office because the side of his face is drooping. His mother states that he complained yesterday of decreased food taste. Today, while at school, he could not use the microscope in science class because he couldn't close his left eye, and his teacher noted that his smile was crooked. Physical examination reveals no abnormalities and no vesicles in his ears. Mental status on neurologic examination is normal, pupil responses are normal, extraocular movements are full, and there is no nystagmus or reported double vision. He is unable to close his left eye or raise his left eyebrow, has decreased left-side nasolabial folds, and cannot close his mouth to puff out his cheeks.  His palate and tongue movements are normal. Motor examination reveals normal proximal and distal strength in both arms and normal regular and tandem gait.

 

Of the following, the MOST appropriate initial diagnostic procedure is

1. blood test for antistreptococcal antibodies  

2. brain magnetic resonance imaging  

3. edrophonium (Tensilon®) test  

4. no further testing  

5. noncontrast head CT

Answer D• Acute focal or generalized weakness is a medical emergency requiring a systematic

history and neurologic examination to localize the problem. For acute focal weakness, the problem can localize to the brain, brainstem, spinal cord, anterior horn cell, root, nerve, junction, or muscle. Often, the physical examination can localize the problem to one of these levels. In the case of acute unilateral facial weakness, as described for the boy in the vignette, the typical differential diagnosis is acute facial nerve palsy (ie, Bell palsy) or a more rostral disease process of the brainstem or brain (cerebrum, motor cortex) such as a stroke. The key diagnostic point for facial weakness is whether the weakness involves the entire side of the face or the face below the forehead. A 7th nerve palsy affects all the innervated muscles, weakening or paralyzing the entire hemi-face from forehead to chin. A lesion above the facial nerve nucleus typically weakens the face below the forehead.

The boy described in the vignette has full left-sided facial weakness, including the muscles in his forehead. Such findings localize to the facial nerve, and in this clinical setting, neuroimaging is not revealing. Accordingly, no further testing is required. When the examination localizes a problem involving facial weakness to the brain or brainstem, brain magnetic resonance imaging (MRI) or, if MRI is not available quickly, noncontrast head computed tomography should be obtained.

• Facial weakness due to an acute brain process, such as a left middle cerebral artery stroke, usually presents with involvement of both the contralateral right face and the right hand. The brainstem, specifically the pons, is the source of the facial nerve, and brainstem diseases can produce full hemi-facial weakness. However, due to the close proximity of other brainstem nuclei, a brainstem lesion affecting the left face also should affect other functions, including the left 6th nerve, which abducts the left eye. Often, sensory and motor findings on the opposite side of the body, the so-called "crossed signs," indicate brainstem disease.

The edrophonium/Tensilon® test involves administration of this acetylcholinesterase inhibitor to increase acetylcholine at the neuromuscular junction and reverse weakness. The test is used for diagnosis of myasthenia gravis. Myasthenia gravis typically produces bilateral fatiguing weakness, particularly ptosis, as well as weakness in other cranial nerves or generalized weakness.

Facial nerve palsy can be caused by a variety of infectious agents, but no specific diagnostic testing is indicated in most cases. Assessment of antistreptococcal antibodies is not helpful because streptococci do not cause facial nerve palsy. However, in regions where Lyme disease is endemic or exposure is possible, testing for Lyme disease may be indicated.

The American Academy of Neurology practice parameter states that oral steroids probably are beneficial and acyclovir possibly is beneficial for treatment of facial nerve palsy. Pediatric studies and reviews have concluded that evidence is insufficient to recommend steroids for children. However, many clinicians recommend administering a short course of oral prednisone for Bell palsy.

During the health supervision visit for a healthy 4-month-old boy, you note that his head circumference is 46 cm (>98th percentile) and his length and weight are at the 50th percentile. He has mild frontal bossing and widely split cranial sutures. The fontanelle is flat. Arm and leg movements, tone, and reflexes are normal. In reviewing prior growth parameters, you note that his head circumference was at the 75th percentile at birth and the 90th percentile at 2 months.Of the following, the MOST helpful next diagnostic procedure is

1. electroencephalography

2. head ultrasonography

3. lumbar puncture with manometry

4. plain radiography of the skull

5. three-dimensional head CT scan

Answer B

• The boy described in the vignette is healthy, with no abnormalities of neurodevelopment, and his neurologic examination reveals no changes in mental status or evidence of focal brain abnormalities or increased intracranial pressure. However, assuming measurements are accurate, he has steadily crossed head circumference percentiles since birth. Neuroimaging is important to determine the reason for his crossing of percentiles. The differential diagnosis includes hydrocephalus, arachnoid cyst, parenchymal brain lesions, subdural hematomas, and neurodegenerative diseases. Although the most helpful high-resolution image in this case is brain magnetic resonance imaging, sedation usually is required for such imaging in a child of this age. In contrast, head ultrasonography through the fontanelle can be performed quickly and with less risk and cost because sedation is not needed. The results can be used in planning referral to neurosurgery or neurology. Some conditions, such as an arachnoid cyst, may not require urgent intervention, and observation suffices, with magnetic resonance imaging scheduled for a later date.

Because the child does not have seizures, electroencephalography is not indicated. Lumbar puncture to rule out elevated intracranial pressure is not needed because the sutures are open. Therefore, in a chronic process, pressure will not rise to a level that is dangerous or requires measurement. Studies of bone are not helpful. Radiography of the skull will not provide information that affects management. Three-dimensional computed tomography scan is helpful for assessing craniosynostosis if the child's head shape is abnormal and fused ridges at the cranial sutures are palpable.

• A 4-year-old boy presents to the emergency department with balance problems. He had been previously healthy, but his walking has worsened progressively for the past 2 days, with staggering and lurching. On physical examination, the boy is cooperative and alert. His muscles are not tender, and his joints are not red, swollen, or tender. His vision seems functionally normal, but there is end-gaze nystagmus in all directions. When sitting independently, his head and trunk bob. His strength appears normal, and his reflexes are normal. When asked to stand with his hands outstretched, a symmetric tremor is evident and worsens as he approaches the target on finger-to-nose testing. His gait is broad-based. A urine toxicology screen reveals normal results. Brain magnetic resonance imaging shows no tumors or other gray or white matter lesions. Lumbar puncture shows 3 white blood cells, 2 red blood cells, protein of 20.0 g/dL, and glucose of 50.0 mg/dL (2.8 mmol/L).

Of the following, you are MOST likely to advise the child's mother that

1. IV steroids significantly reduce recurrence risk

2. neuroblastoma is a common cause of these symptoms

3. repeat lumbar puncture is needed in 2 days

4. symptoms may resolve in weeks to months

5. symptoms usually resolve after antibiotics

Answer D

• A child who experiences subacute-onset gait or balance problems should be evaluated thoroughly in the emergency department based initially on localization obtained through careful examination. The differential diagnosis includes structural and immunologically mediated diseases that can be life-threatening or cause permanent neurologic injury. The bilateral symptoms with completely normal mental status and no somnolence described for the boy in the vignette makes a cerebral cause less likely. The lateral end-gaze nystagmus, tremor on hand activation and finger-to-nose testing, trunk bobbing (titubation), and broad-based gait localize the problem to the cerebellum (Item C118). The subacute onset of such symptoms strongly suggests acute cerebellar ataxia, which usually is acquired after infection or immunization. Because this is a self-limited, monophasic illness, the mother can be advised that the symptoms should resolve in weeks to months.

A repeat lumbar puncture in a few days is not likely to clarify the diagnosis. Otitis media does not cause nystagmus and ataxia, and antibiotics are not indicated (unless there is a concurrent bacterial infection). The recurrence risk for acute cerebellar ataxia is low, and it is unknown whether steroids reduce the risk further. Although clinical trials are not available to guide management, due in part to the low incidence of this condition, many clinicians empirically treat with a short course of high-dose steroids to reduce the duration of illness.

• Although the time course makes a structural cerebellar or brainstem lesion unlikely for this patient, ordering the magnetic resonance imaging is reasonable because children in this age group may present with cerebellar and brainstem neoplasms such as astrocytomas, pontine gliomas, primitive neuroectodermal tumors (medulloblastomas), or ependymomas. Rarely, such a presentation may be associated with Guillain-Barré syndrome. Therefore, specialty consultation is advised.

For children presenting with acute ataxia, the clinician should be especially vigilant for the possibility of neuroblastoma presenting as opsoclonus myoclonus ataxia syndrome. Case series have shown that children who have opsoclonus myoclonus often are misdiagnosed initially as having acute cerebellar ataxia. Because distinguishing these diagnoses clinically is challenging, specialty consultation is advisable.

American Board of Pediatrics Content Specification:Know the prognosis of childhood cerebellar ataxia

• A 2-year-old boy is brought to the emergency department because he has been having episodes in which his arms and legs become stiff, his head turns to the side, and his jaw becomes clenched. The episodes, which occurred in the past hour, last for 30 seconds and resolve spontaneously. After the episodes, he is fussy but awake and alert. His mother reports that earlier today he had fallen off the bed but subsequently acted normally. He is otherwise healthy and takes no medications. His maternal grandmother has type 2 diabetes and gastroesophageal reflux, and his mother suffers from an anxiety disorder. On physical examination, his heart rate is 140 beats/min, respiratory rate is 24 breaths/min, blood pressure is 100/60 mm Hg, and oxygen saturation is 98%. All of his other physical findings are within normal parameters.

Of the following, the MOST likely cause of this child's signs and symptoms is

1. epidural hematoma

2. glyburide ingestion

3. lorazepam ingestion

4. metoclopramide ingestion

5. new-onset seizure disorder

Answer D

• The child described in the vignette is exhibiting signs of an acute dystonic reaction, one of many neurologic manifestations that can result from toxic ingestions. Acute dystonia is a well-recognized adverse effect of metoclopramide as well as typical and atypical antipsychotic medications. Glyburide, an oral hypoglycemic agent, may cause sedation and seizures related to hypoglycemia, and lorazepam, a benzodiazepine, causes sedation and coma in overdose. An epidural hematoma is likely to cause sedation and focal motor deficits. Finally, although differentiating an acute dystonic reaction from a seizure may be challenging, the stereotypical muscular activity and lack of unresponsiveness during the episodes reported for this boy are hallmarks of acute dystonia.

• More than 50% of all poisonings reported to the American Association of Poison Control Centers involve children younger than 5 years of age, and although most of these exposures are not serious, those that result in neurologic toxicity frequently require medical intervention. Common neurologic signs and symptoms following significant toxic exposures include seizures, coma, acute dystonia, ataxia, and muscular abnormalities (Item C16). These neurologic effects may be related to a direct effect on the central or peripheral nervous system or to resultant metabolic abnormalities (eg, hypoglycemia, acidosis).

• A 10-year-old boy presents to the emergency department with a 2-day history of progressive difficulty with speech and coordination. On physical examination, the restless but otherwise quiet child has a normal mental status and eye movements. His speech is slurred, and he cannot maintain tongue protrusion without an in-and-out darting movement. Continuous flowing and jerky movements occur when he holds his hands outstretched or overhead (Item Q134). Although his grip is strong, he cannot maintain it well because of irregular hand and arm movements. He had a sore throat and fever 2 months ago. You diagnose chorea.

Of the following, the MOST effective treatment for suppressing the chorea for this boy is

1. carbamazepine

2. clonazepam

3. haloperidol

4. penicillin

5. trihexyphenidyl

Answer C

• The restless, continuous, involuntary movements that are irregular in direction and amplitude described for the boy in the vignette represent classic chorea. He also has the classic "milk-maid's grip" and "darting tongue" signs, in which a simple motor command cannot be maintained due to choreic intrusions or involuntary relaxations (Item C134). The most common form is poststreptococcal, immune-mediated chorea, that is, Sydenham chorea. The prior sore throat and fever reported for the boy may have been an undiagnosed group A beta-hemolytic streptococcal infection. This possibility should be evaluated with blood testing for two antistreptococcal antibodies: antistreptolysin O and anti-DNAse B. Other diagnostic possibilities include chorea associated with systemic lupus erythematosus, antiphospholipid antibody syndrome, or hyperthyroidism.

Haloperidol is a dopamine receptor-blocking agent that also is referred to as a neuroleptic. This high-potency antipsychotic can suppress chorea effectively, but the incidence of adverse effects is high. Fortunately, Sydenham chorea usually is self-limited and a low dose is generally helpful. Other antipsychotics (fluphenazine or risperidone) or dopamine-depleting agents (tetrabenazine) also may be used. Because of the diagnostic complexity and therapeutic considerations, the boy should receive prompt specialty consultation with a neurologist or a movement disorder specialist.

Carbamazepine is an anticonvulsant. It does not treat chorea and occasionally may induce it. Valproic acid, another anticonvulsant, sometimes is used to suppress chorea but probably is less effective than haloperidol. Penicillin is indicated for secondary prevention among patients who have rheumatic fever, even with chorea as the sole manifestation. However, penicillin does not treat the chorea. Clonazepam is a benzodiazepine that may be helpful, but sedating doses often are required for efficacy. Trihexyphenidyl is an anticholinergic medication that may reduce dystonia, but it tends to worsen the symptoms of Sydenham chorea.

• During the health supervision visit for a 6-week-old boy, his father expresses concern that his son "doesn't look like" his other children. Growth parameters are normal except for a head circumference of 35.5 cm (less than the 5th percentile). On physical examination, you note that the infant does not appear to fixate or track your face visually. There is "slip through" on vertical suspension and "draping over" on horizontal suspension. Deep tendon reflexes are brisk. Moro reflex is present and brisk.

Of the following, the MOST likely cause of this infant's hypotonia is

1. anterior horn cell disease

2. congenital brain malformation

3. congenital myasthenic syndrome

4. congenital myopathy

5. spinal cord disease

Answer B

• The diagnostic process for a "floppy" infant involves the same thinking process as for acute weakness, with the primary difference being the urgency. Chronic generalized hypotonia at a health supervision visit does not require emergency evaluation unless there is difficulty breathing. The first step is to try to determine the responsible neurologic level, based on history and physical examination. The brain, brainstem, spinal cord, anterior horn cell, root, nerve, junction, and muscle should be considered systematically in each case.

Three findings for the child described in the vignette localize his problem, at least in part, to the cerebrum. First, and most importantly, the head circumference of this 6-week-old is essentially that of a newborn. It is important to determine by reviewing prior measurements whether head growth has arrested or the microcephaly was present at birth. Second, the infant is not tracking visually. Because this could be an eyeball or brainstem problem, it is important to assess the red reflex, pupil reactions, and vestibular ocular reflex (manually move the head briskly but gently to each side and determine if the eyes move the expected, opposite direction). In the presence of microcephaly, cortical visual processing problems are more likely than eye or brainstem problems. Finally, the infant's reflexes are brisk, which is usually indicative of brain pathology. Absent reflexes point to a peripheral nervous system problem. The compilation of these findings suggests that the most likely cause is a congenital brain malformation.

Spinal cord lesions can cause weakness and hypotonia caudal to the level of the lesion, but they do not result in a small head or poor visual tracking. Similarly, spinal muscular atrophy/anterior horn cell disease, congenital myasthenia (neuromuscular junction dysfunction), or congenital myopathies would not account for this symptom complex.

• A 17-year-old girl presents with complaints of recurring headaches that are becoming more frequent. She was diagnosed with migraine headaches 2 years ago. Previously she had an average of one migraine per month, but she now has one per week. She has no double vision, vomiting, or awakening from sleep with headaches. Headaches can occur at any time of day, are throbbing and bifrontal, and are associated with nausea and phonophobia. They are relieved by nonsteroidal anti-inflammatory drugs and by lying down in the dark. They rarely last more than 4 hours. The adolescent and her mother are concerned that the increased headache frequency could be due to a brain tumor or aneurysm.

Of the following, the MOST appropriate next step is

1. brain MRA to rule out aneurysm

2. brain MRI to rule out brain tumor

3. head CT with contrast to rule out brain tumor

4. LP with manometry to rule out elevated ICP

5. perform no diagnostic testing at this time

Answer E

• When evaluating a child who has a headache, the first decision point is whether to perform medical diagnostic testing, particularly neuroimaging such as head computed tomography (CT) scan or brain magnetic resonance imaging (MRI). This decision is based on an assessment of the likelihood of a primary headache (eg, migraine, tension, cluster) or a secondary headache (due to disease). Primary headaches are painful paroxysmal events occurring in isolation or, more commonly, as part of a chronic, recurring pain disorder. No underlying lesion is causing the pain. Most children, adolescents, and adults presenting to the primary care physician with headache, including the girl described in the vignette, have primary headaches, and no medical diagnostic testing is needed as part of validated standard of care. The advantages and disadvantages of neurodiagnostic tests for a variety of conditions are noted in (Item C6).

A family history of aneurysms may increase the risk for aneurysms (and anxiety), but it is not an indication for neuroimaging testing for aneurysms in a patient younger than age 30 years. However, because cigarette smoking increases the risk for aneurysmal rupture, this is a good opportunity to remind families about the dangers of smoking.

Most brain tumors are sporadic primary tumors or metastatic, not familial, and, therefore, a family history of brain tumors is not an indication for neuroimaging in most cases. In the absence of symptoms and signs of elevated intracranial pressure or meningitis, lumbar puncture is not needed.

• Imaging studies (CT scan, MRI, and occasionally magnetic resonance angiography), sometimes followed by lumbar puncture with manometry, are indicated when there is suspicion of intracranial disease (eg, tumor, aneurysm) or other medical processes, particularly processes that increase intracranial pressure. Symptoms that may herald the presence of secondary headache include pain awakening from sleep, pain relieved by vomiting, and pain increased by the Valsalva maneuver. Additional symptoms such as new binocular double vision, any focal numbness or weakness, or loss of coordination should prompt an investigation. Secondary headaches are more likely in the presence of abnormal signs such as papilledema, acquired (new) ocular malalignment with double vision, stiff neck, limb weakness, or ataxia.

American Board of Pediatrics Content Specification(s): Know the values and limitations of ancillary neurodiagnostic tests in the evaluation of a headache

• A 14-year-old boy who was diagnosed with migraines at age 11 presents to the emergency department with a severe migraine. For the past 2 months, he has had two to three such headaches per week. His mother asks about using stronger pain medications. You are concerned about the possible complications of medication overuse.

Of the following, the class of abortive medications that is MOST likely to induce chronic headaches is

1. caffeine-containing medications

2. isometheptene compounds

3. nonsteroidal anti-inflammatory drugs

4. opiates

5. triptans

Answer D

• Opiates and barbiturates are more likely than caffeine-containing medications, isometheptene compounds, nonsteroidal anti-inflammatory drugs (NSAIDs), or triptans to cause chronic headaches due to overuse of medications. Medication overuse headache is the third most common type of chronic headache after migraine and tension headache. Most often, it results from NSAID use because NSAIDs are the most widely used agents for headaches. However, the probability of medication overuse headache is higher with opiates.

Medication withdrawal headache is a huge public health problem and a factor involved in chronic daily headache for many adolescents. The only effective treatment is withdrawal of the medication. Although less common than with opiates, medication overuse headache may occur with over-the-counter analgesics, triptans, ergotamines, and combination analgesics with caffeine.

Other well-known complications of medications used to treat headache include constipation with opiates, tolerance with benzodiazepines, and gastrointestinal distress with NSAIDs.

• A 12-year-old girl presents to the emergency department with back pain. She had been practicing flips on her backyard trampoline with parental supervision and landed awkwardly. Within 1 hour of presentation, she complains of an inability to move her legs and numbness in both legs. On physical examination, she has normal upper limb strength but reduced strength of both legs. You suspect a spinal cord injury.

Of the following, the additional clinical finding that is most suggestive of an acute spinal cord injury in this girl is

1. ankle clonus

2. dermatomal band of sensory loss in the trunk

3. hyperalgesia of the soles of the feet

4. hyporeflexia at the knees

5. positive Romberg sign

Answer D• The girl described in the vignette has sustained a spinal cord contusion from the fall. The back

pain and combination of numbness and weakness in both legs but not arms localizes the problem to the spinal cord. In the short term after the injury, reflexes typically are diminished, even though this is an "upper motor neuron" lesion, above the anterior horn cell/motor neurons exiting the cord. Therefore, hyporeflexia at the knees would be expected. Upper motor neuron signs of a positive Babinski response (upgoing toes), ankle clonus, hyperreflexia, and spasticity all may occur in days or weeks if there has been permanent damage to the spinal cord, but these would not be present acutely.

Sensory symptoms and physical examination findings may be helpful in this setting to localize the lesion along sensory pathways: skin, nerve, root, spinal cord, thalamus, and cortex. Among the potential positive findings are tingling or shooting pains, and negative findings may include loss of pain/temperature or vibration/proprioception in predictable body distributions. A complete spinal cord lesion results in loss of sensation of all modalities, from the toes up to a dermatomal level in the trunk 1 to 2 roots below the level of top of the cord lesion.

A dermatomal band of sensory loss would be expected for injury of a single nerve exiting the cord, not a problem intrinsic to the cord. Hyperalgesia, or increased sensitivity to pain, results from damage to peripheral nerves.

• A Romberg test is performed by having a patient stand with feet together, touching each other, and the examiner standing next to the patient. With eyes open, vision, proprioception, and vestibular systems combine to allow the patient to maintain balance. The visual system allows a patient to compensate for a mild proprioceptive or vestibular deficit. When the eyes close, characteristic swaying and loss of balance may occur. This positive Romberg sign may occur in spinal cord lesions when there is a loss of posterior column/proprioceptive pathways. This test cannot be performed or interpreted accurately when there is leg weakness, as in the girl in the vignette.

American Board of Pediatrics Content Specification(s): Recognize the clinical manifestations of an acute spinal cord lesion

A 13-year-old girl has had 5 days of unremitting headache that is relieved by vomiting but not sleep and 1 day of double vision. She was previously healthy and has no history of migraine headaches, but she was treated for otitis media 6 weeks ago. Findings on physical examination are normal except for some tenderness over her left mastoid. On neurologic examination, you note normal mental status and normally reactive pupils and vision but florid papilledema. She cannot abduct her right eye fully and has subjective double vision with both eyes open looking to the right but not looking to the left or with either eye covered. Facial sensation and movements are normally symmetric, and the rest of the findings are normal. Head computed tomography scan yields normal results.

Of the following, the diagnostic test or procedure that is MOST likely to be helpful is

1. brain magnetic resonance imaging

2. cerebral angiography

3. lumbar puncture with manometry

4. ocular nerve sheath fenestration

5. serum vitamin A measurement

Answer C•

The girl described in the vignette has unremitting head pain that improves transiently after vomiting but not sleep. In addition, she has a new symptom of double vision when looking to the right, not left, an acquired ocular malalignment consistent with a right 6th nerve palsy. The lack of facial weakness or facial sensory loss suggests that this symptom comes from outside of the brainstem. Funduscopic examination reveals bilateral papilledema. This complex of symptoms is characteristic of raised intracranial pressure due to pseudotumor cerebri. Diagnosis and treatment are needed to reduce pain and prevent visual loss.

An urgent head computed tomography (CT) scan in the emergency department showed normal findings. This rules out hydrocephalus or a mass lesion but does not rule out elevated intracranial pressure. The most helpful procedure to determine this finding is a lumbar puncture with manometry. Manometry pressure measurement should be obtained with the child in the lateral decubitus position, with legs relaxed. A pressure greater than 20 cm H2O confirms the clinical impression of elevated intracranial pressure and relieves the pressure. The pressure often remains low for several days because cerebrospinal fluid drains into the soft tissues around the lumbar puncture site. Cerebrospinal fluid studies should include assessment of protein, glucose, and cell count. Bacterial, fungal, and Mycobacterium tuberculosis studies as well as cytology for malignancy may be indicated in some cases.

• The differential diagnosis of pseudotumor cerebri includes complications of obesity; adverse effects of medications such as minocycline, isotretinoin, or steroids; hypervitaminosis A; venous sinus thrombosis; anemia; renal failure; and hypercalcemia.

The recent history of otitis media and current pain over the mastoid described for the girl are consistent with mastoiditis. The cause for her pseudotumor was venous sinus thrombosis. This may be apparent on head CT scan, but magnetic resonance imaging (MRI) with contrast and with venography is more sensitive for detection than head CT or routine MRI.

Cerebral angiography typically is used to characterize arterial vascular pathology. However, this invasive procedure is undertaken infrequently because of improvements in magnetic resonance angiography. Ocular nerve sheath fenestration is performed occasionally as a longer term treatment for refractory pseudotumor cerebri to reduce pressure on the eyes and preserve vision. Serum vitamin A measurement is reasonable after lumbar puncture as part of the evaluation for causes of intracranial hypertension.

American Board of Pediatrics Content Specification(s): Recognize the physical characteristics of a headache due to increased intracranial pressure

• A 10-year-old previously healthy girl presents with subacute low back pain. In the past 24 hours, she had "pins and needles" tingling in her left leg and subsequently her right leg. Six hours after the onset of the tingling, she was unable to void urine. On physical examination, the girl is not somnolent or confused, but she has flaccid weakness in the legs, absent reflexes in the legs, a sensory level in the lower back at T9-10, diminished sensation in the feet to pinprick and vibration, and reduced rectal tone.

Of the following, the MOST appropriate next diagnostic test is

1. brain MRI with contrast

2. computed tomography scan of the spine

3. electroencephalography

4. lumbar puncture

5. spinal MRI with contrast

• Answer E• The symptom complex of escalating back pain, leg numbness, leg weakness, and urinary

retention described for the girl in the vignette mandates urgent evaluation. The loss of leg strength and rectal tone as well as a sensory level documented on the physical examination are pathognomonic for a spinal cord lesion. Emergency imaging of the spine with magnetic resonance imaging (MRI) is warranted

Computed tomography scan of the spine is appropriate for detecting lesions in bone, but it is less sensitive than MRI, particularly for intramedullary (intracord) processes. MRI is the preferred imaging modality for inflammatory conditions such as infectious/postinfectious/inflammatory myopathies; vascular conditions such as strokes, hematomas, vascular malformations; neoplasms; and trauma. If an inflammatory lesion is seen, brain MRI with contrast should be obtained to look for demyelination in brain, cerebellum, brainstem, and optic nerves.

A problem in the brain, specifically hydrocephalus, can cause leg weakness, but it would not cause a sensory loss at and below a dermatomal level. Therefore, imaging of the head is not needed initially and likely would be helpful only if a demyelinating spinal lesion is identified on MRI. Lumbar puncture is not indicated initially and could cause problems for this child. Because the problem clearly localizes to the spine, it is necessary to identify a structural problem in the spine first. If there is a mass lesion in the spinal cord, shifting of the cord could cause more extensive problems. Electroencephalography would not be helpful for this patient because the symptoms and signs are not consistent with a seizure disorder.

• An 8-year-old girl who has intellectual disability and dysmorphic facial features presents to the emergency department with reduced alertness of 24 hours' duration. For the past hour, she has been crying inconsolably and holding her head. At triage she makes poor eye contact and is banging her head. Physical examination of the irritable child reveals dysmorphic features and abnormal head shape. On eye examination, her pupils are equally reactive and appear normally aligned. It is unclear whether her neck is supple, due to a lack of cooperation, but she has a subcutaneous tube connected to a shunt bulb over her right parietal skull.

Of the following, the MOST appropriate next step is to

1. insert a needle into the shunt bulb

2. order brain MRI with contrast

3. order head CT without contrast

4. order stat electroencephalography

5. perform a lumbar puncture

• Answer C• The girl described in the vignette is manifesting symptoms of elevated intracranial pressure,

including head pain and, ominously, mental status changes. The most likely cause for her problems is a malfunction of her ventriculoperitoneal shunt, resulting in acute hydrocephalus. The diagnostic modality of choice is head computed tomography (CT) scan, which should be obtained emergently, along with a routine radiographic shunt series to assess for disconnections in tubing.

Brain magnetic resonance imaging is less available than CT scan, requires more time for study completion, and involves a greater need for sedation in an agitated patient. Moreover, in this clinical setting, if there is hydrocephalus, it should be readily apparent on CT scan.

Electroencephalography is not necessary emergently. Although nonconvulsive status epilepticus could explain mental status changes, this condition typically would not produce the pain syndrome this child is experiencing.

In the setting of elevated intracranial pressure, it is important to determine initially if an intracranial mass lesion is present. Such a lesion may be a contraindication to the use of lumbar puncture. Withdrawing fluid through the shunt generally is not performed as an initial intervention before obtaining radiologic confirmation of the shunt malfunction.

American Board of Pediatrics Content Specification(s): Recognize the signs and symptoms of shunt malfunction in hydrocephalus

• A 14-year-old girl has had 3 days of new, unremitting headache associated with vomiting and awakening from sleep and 1 day of double vision. Physical examination reveals normal visual acuity in each eye, normal pupillary responses in each eye, subjective diplopia when looking to the left, and incomplete abduction of the left eye. Funduscopic examination reveals bilateral papilledema (Item Q166). Noncontrast head computed tomography scan yields normal results.

Of the following, the MOST likely diagnosis is

1. brain tumor in the posterior fossa

2. communicating hydrocephalus

3. complicated migraine

4. optic neuritis

5. pseudotumor cerebri

• Answer E• The girl described in the vignette has a headache due to elevated intracranial

pressure. The most likely diagnoses when the history strongly supports elevated intracranial pressure and the neurologic examination shows bilateral papilledema and a 6th nerve palsy are either a space-occupying process such as a brain tumor or hydrocephalus or pseudotumor cerebri. Normal findings on head computed tomography scan generally exclude space-occupying processes sufficient to cause such signs and symptoms, including hydrocephalus and a posterior fossa (cerebellum, brainstem) tumor. Accordingly, the most likely diagnosis is pseudotumor cerebri.

• Complicated migraines are diagnoses of exclusion. Essentially, these are migraines accompanied by strokelike symptoms that may present with visual complaints, but more commonly they present with loss of strength on one side of the body or even aphasia. They do not present with papilledema.

• Optic neuritis, or inflammation of the optic nerve, typically is painful, especially with eye movement; is unilateral; and causes loss of central visual acuity. The girl in the vignette has normal visual acuity, which is often the case in pseudotumor. In optic neuritis, papillitis, which can look like papilledema, may be seen

• The first goal in assessing a new complaint of headache is to determine whether the headache is due to an intracranial disease process, also known as a secondary headache, or is a paroxysmal event related to an idiopathic headache disorder such as migraine or tension headache, also known as a primary headache.

• Because many secondary headaches produce pain related to elevations in intracranial pressure, symptoms in the history that are consistent with this should be elicited, including:

• 1. Pain worse when recumbent• 2. Pain awakening from sleep or noted prominently on morning awakening• 3. Pain resulting in vomiting, with subsequent temporary relief of pain• 4. Pain worse with Valsalva maneuvers such as bowel movements or coughing• 5. Pain unlike prior headache pains• 6. Pain that has been unremitting/gradually increasing as opposed to typical waxing and

waning in chronic, nonprogressive primary headache disorders• The constellation of symptoms described for this girl raises these concerns and should

prompt a careful general and neurologic examination.• Two eye signs also should be sought carefully in the presence of a new headache. The

first is oculomotor paralysis. The subjective double vision looking laterally indicates a new acquired ocular malalignment. This can localize to the brainstem, but this patient has no other neighboring brainstem findings, such as facial weakness, suggesting that the brainstem is not involved. In the setting of high intracranial pressure headache, this can be a "false localizing sign"; that is, the brainstem is not involved, although the finding does indicate brain pathology: raised intracranial pressure. The second sign is the funduscopic examination finding of papilledema. The funduscopic examination finding of blurred margins of the optic disc (ie, papilledema) provides important confirmation of this clinical impression and warrants urgent neuroimaging.

• For this girl, head computed tomography (CT) scan should be performed in the emergency department. Although head CT scan is less sensitive than magnetic resonance imaging for some important intracranial lesions, including posterior fossa tumors, it can exclude hydrocephalus or any posterior fossa lesions sufficiently large to produce headache by inducing hydrocephalus. Head CT scan in pseudotumor cerebri or idiopathic intracranial hypertension yields normal results. The diagnosis is confirmed by lumbar puncture showing elevated pressure, greater than 20 cm, on manometry.

• When pseudotumor has been diagnosed, a thorough search should be undertaken for the cause. Two common causes are obesity and use of oral acne medications such as minocycline. Neurology referral is recommended. The major long-term risk is permanent visual loss. At the time of presentation, subjective visual acuity may be normal, as might be results of bedside testing. However, careful perimetry testing by the ophthalmologist may show an enlarged blind spot. Left untreated, these may enlarge further and become permanent.

• American Board of Pediatrics Content Specification(s): • Know the importance of decreased vision in papilledema• Recognize the significance of papilledema

• A 22-month-old boy presents with irritability and broad-based gait. In addition, he has mild tremor of the trunk and jerky movements of his limbs, particularly when excited or upset. His mother noted some "funny" movements of his eyes yesterday that she described as "bobbing." Notable findings on neurologic examination include irritability, poor cooperation, full extraocular movements with no nystagmus, normal face and tongue movements, general tremulousness, jerky limb and trunk movements, and broad-based, lurching gait. Brain magnetic resonance imaging and cerebrospinal fluid studies yield normal results.

Of the following, the test that is MOST likely to be useful in establishing the diagnosis is

1. alpha-fetoprotein measurement

2. electroencephalography

3. frataxin gene testing

4. serum ceruloplasmin & urinary copper levels

5. urinary vanillylmandelic acid & homovanillic acid

• Answer E• The diagnostic key for the boy described in the vignette is clinical recognition that he has

opsoclonus myoclonus ataxia syndrome. One possible cause is neuroblastoma, a tumor that can trigger an autoimmune response, leading to the paraneoplastic opsoclonus myoclonus syndrome. There is no characteristic antibody test for this diagnosis, but the tumor may produce high quantities of catecholamines, which can be identified in urine. Therefore, measurement of vanillylmandelic acid and homovanillic acid in the urine is the most useful test for helping to establish the diagnosis.The symptoms of encephalopathy, with irritability and changes in motor control affecting hands (tremor), gait, and balance, are ominous, and the differential diagnosis is relatively broad. Anatomic localization of the gait problems and tremor with behavioral change could be localized to the central nervous system above the spinal cord, possibly the cerebellum and brainstem. The appropriate initial test, brain magnetic resonance imaging, was obtained, and findings were normal/nondiagnostic. Therefore, cerebrospinal fluid studies for infection/inflammation were appropriately obtained.The differential diagnosis of this clinical presentation includes two inflammatory conditions: opsoclonus myoclonus ataxia syndrome and acute cerebellar ataxia. These can be very difficult diagnoses to distinguish, particularly because opsoclonus can be transient and clinicians may not recognize opsoclonus versus nystagmus. Moreover, the multifocal and truncal myoclonus of opsoclonus myoclonus ataxia syndrome visually resembles truncal ataxia of acute cerebellar ataxia. Urgent neurology consultation is advisable.

• Alpha-fetoprotein (AFP) is an important blood test to consider for a young child who has chronic progressive choreoathetosis or ataxia. Elevated AFP values are present in toddlers presenting with ataxia due to ataxia telangiectasia (AT), a condition in which neurologic symptoms are present several years before telangiectasias emerge. The extreme irritability exhibited by the child in the vignette is not characteristic of AT. Moreover, the time course of his symptoms is subacute, over days, whereas AT and other degenerative diseases typically progress over months or years.

Electroencephalography (EEG) provides information about the physiology of the cerebral cortex that usually aids in epilepsy syndrome diagnosis and occasionally to diagnose the cause of an encephalopathy or to help determine if myoclonus has a cerebral cortical origin. It is unlikely to be helpful in this case because there are no paroxysmal events under consideration, and EEG is not useful for diagnosing causes of ataxic gait.

Frataxin gene testing is used to confirm the diagnosis of Friedreich ataxia, a degenerative disease that presents after age 5 years with progressive gait ataxia, distal sensory loss, and muscle wasting. Serum ceruloplasmin and urinary copper testing are used in diagnosing Wilson disease. Neurologic manifestations of Wilson disease, including dysarthria, dystonia, tremor, and mood disorder, do not present until after the age of 5 years.

American Board of Pediatrics Content Specification(s): Understand that urinary catecholamine excretion is increased in most patients with a neuroblastoma and that tests of urine for VMA and VHA are appropriate screening tests for the tumor

A 15-year-old boy presents to the emergency department after an apparent seizure. He had a sudden arrest of normal activity at school, with posturing on the left side, eye deviation, and loss of consciousness for about 1 minute, followed by confusion. On physical examination, he is fully oriented and answers questions appropriately. He is afebrile. Results of cranial nerve examination, motor examination, and gait evaluation are normal.

Of the following, the procedure that is MOST likely to establish the cause of the seizure is

1. brain MRI with contrast

2. electroencephalography

3. lumbar puncture

4. noncontrast head CT

5. urine toxicology screen

Answer: A

• The boy described in the vignette has had a first unprovoked seizure. The semiology of the seizure included some focality, with posturing on the left side, indicating that this was likely a focal, or partial, seizure. In the emergency department, after resolution of the postictal confusion, his mental status and neurologic examination results are normal.

The most important diagnostic test for determining the cause of one or more focal-onset seizures is a brain magnetic resonance imaging (MRI) with contrast. Although head computed tomography (CT) scan often is the initial neuroimaging performed in the emergency department, MRI is more sensitive to lesions that can be missed on CT scan (Item C70). Rather than duplicating costly neuroimaging studies, if the child is clinically healthy and the parents are reliable, the clinician may safely defer an emergent head CT scan and schedule the more sensitive brain MRI as a follow-up test.

Urine toxicology screening should be considered in the emergency department after a first unprovoked seizure, but the lack of confusion or encephalopathy reported for the boy combined with his rapid return to a normal mental status argues against a drug-induced seizure.

A lumbar puncture should be obtained in a child who has a partial seizure, fever, and confusion to evaluate for encephalitides, particularly herpes encephalitis. Because this adolescent is afebrile and has a clear sensorium, cerebrospinal fluid studies and urgent neuroimaging need not be obtained.

Electroencephalography (EEG) can be helpful for determining an epilepsy syndrome diagnosis. For example, juvenile myoclonic epilepsy can present at this age and is characterized by myoclonus, generalized tonic-clonic seizures, and sometimes absence seizures, with generalized epileptiform discharges on EEG. However, epilepsy is a clinical diagnosis made after two unprovoked seizures. In the setting of a single focal seizure, the initial emphasis should be on determining whether a treatable focal lesion caused the seizure, for which EEG is unlikely to be helpful.

Item C70

• Illustration of the enhanced diagnostic sensitivity of MRI scan compared with CT scan. Noncontrast CT (left) and MRI (right) for the boy described in the vignette. Although the CT scan shows no abnormality, MRI demonstrates a signal change in the right cerebral hemisphere consistent with a low-grade glioma.