Chapter 12 - Neurology Flashcards Preview

Pediatrics BRS > Chapter 12 - Neurology > Flashcards

Flashcards in Chapter 12 - Neurology Deck (61)
Loading flashcards...
1
Q

What is the difference between hypotonia and weakness?

A
  • hypotonia is decreased resistance to passive stretching

- weakness is decreased force generated by active muscle contraction

2
Q

What is the difference between central and peripheral hypotonia?

A
  • central is dysfunction of upper motor neurons; it more often presents with altered level of consciousness and increased DTRs
  • peripheral is dysfunction of lower motor neurons; typically presents with normal level of consciousness, diminished muscle bulk, and absent DTRs
  • both typically present with weak cry, decreased spontaneous movement, a frog-leg posture, and muscle contractures
3
Q

What history and physical exam findings are consistent with central and peripheral hypotonia?

A
  • in the history, central is often associated with neonatal seizures whereas peripheral is associated with decreased fetal movements and breech presentation
  • both tend to present with weak cry, decreased spontaneous movement, a frog-leg posture, and muscle contractures
  • central tends to present with altered level of consciousness and increased deep tendon reflexes
  • whereas peripheral generally presents with a normal level of consciousness but decreased muscle bulk and absent deep tendon reflexes
4
Q

What is the differential for central hypotonia?

A
there are acquired causes
- electrolyte abnormality
- hypoxic-ischemic injury
- sepsis or meningitis
- intracranial hemorrhage
- trauma
and congenital causes
- cerebral malformation
- chromosomal disorder like Down's or Prader-Willi
- metabolic disorders
5
Q

What is the differential diagnosis for peripheral hypotonia?

A
  • spinal muscular atrophy
  • familial dysautonomia affecting peripheral nerves
  • botulism, neonatal myasthenia, and magnesium toxicity which all impact the neuromuscular junction
  • congenital muscular dystrophy or myotonic dystrophy, metabolic myopathies like Pompe’s disease, or structural myopathies
6
Q

What does the work up for central hypotonia involve?

A
  • head CT to look for CNS injury or congenital malformation
  • serum electrolytes to rule out metabolic disorders
  • chromosomal studies
7
Q

What does the work up for peripheral hypotonia involve?

A
  • serum creatine kinase levels
  • DNA tests for spinal muscular atrophy
  • nerve conduction studies to identify myasthenic disorders
  • muscle biopsy
8
Q

Spinal Muscular Atrophy

A
  • an autosomal recessive disease leading to anterior horn cell degeneration and infiltration of microglia and astrocytes
  • caused by a mutation in the survival motor neuron gene on chromosome 5
  • the major features are peripheral hypotonia, weakness, and tongue fasciculations; patients often have a bell-shaped chest and frog-leg posture; extra ocular movements and sensory examination are normal
  • classified as type I (aka Werdnig-Hoffman disease) with an onset before 6 mo, type II with onset between 6-12mo, and type III with onset after 3 yo
  • diagnosed based on DNA testing
  • treatment is supportive
  • death is within the first year, during adolescence, or in adulthood based on the type, and death is typically due to respiratory failure
9
Q

What is the most common hereditary neuromuscular disorder?

A

Duchenne muscular dystrophy

10
Q

Infantile Botulism

A
  • a peripheral hypotonic disorder characterized by bulbar weakness and paralysis during the first year of life, secondary to ingestion of C. botulinum spores
  • spores classically contaminate honey and go on to produce a toxin which prevents presynaptic release of acetylcholine
  • constipation is classically the first symptom; neurologic symptoms typically follow and include weak cry and suck, loss of previously obtained motor milestones, ophthalmoplegia, and hyporeflexia; the paralysis is symmetric and descending
  • diagnosed based on identification of the toxin o bacteria in the stool and an incremental response during high-frequency EMG stimulation
  • treatment is mostly supportive but botulism immune globulin is available; antibiotics are contraindicated and may worsen the clinical course
  • recovery is expected by may take weeks or months
11
Q

Congenital Myotonic Dystrophy

A
  • a disorder that presents in the newborn period with weakness and peripheral hypotonia before progressing to myotonia
  • it is an autosomal dominant trinucleotide repeat disorder affecting a gene on chromosome 19, which is transmitted primarily by an affected mother
  • patients often have a history of polyhydramnios secondary to a poor swallow as well as decreased fetal movements
  • at birth patients have feeding and respiratory problems as well as facial diplegia, peripheral hypotonia, and arthrogryposis
  • myotonic facies, ptosis, a stiff straight smile, and an inability to release the grip after hand-shaking present in adulthood
  • course may be complicated by mental retardation, cataracts, cardiac arrhythmias, and infertility
  • diagnosed according to DNA testing
  • treatment is supportive and the prognosis is poor as many die from respiratory failure or all survivors have mental retardation with an IQ between 50-65
12
Q

Hydrocephalus

A
  • increased CSF under pressure
  • classified as non-communicating due to obstruction or communicating due to increased production or reduced absorption
  • can be congenital, likely due to chiari type II, Dandy-Walker malformation, or congenital aqueductal stenosis, which are all obstructive
  • or it can be acquired via intraventricular hemorrhage, bacterial meningitis (reduces absorption), or brain tumors (increases production)
  • presents with increasing head circumference, large fontanelles, prominent scalp veins, and “sunset sign” (downward deviation of eyes caused by an enlarged third ventricle pressing on the upward gaze center in the midbrain) in those with open cranial sutures
  • presents with headache, n/v, unilateral sixth nerve palsy, papilledema, and brisk DTRs in older children with closed sutures
  • requires urgent head CT and placement of a ventriculoperitoneal shunt
13
Q

Define “spina bifida” and “neural tube defect”.

A
  • spina bifida is any failure of bone fusion in the posterior midline of the vertebral column
  • neural tube defect is a term that includes all forms of failure of neural tube closure from anencephaly to sacral meningocele
14
Q

What are spina bifida occult, meningocele, and myelomeningocele?

A
  • spina bifida occult is a vertebral cleft without herniation of any neural or meningeal tissue
  • meningocele is a herniation of the meninges only, usually without any associated neural deficits
  • meningomyelocele is a herniation of the meninges and spinal cord tissue, resulting in neural deficits
15
Q

Neural tube defects have the highest and lowest incidence in which countries?

A
  • highest in Ireland

- lowest in Japan

16
Q

What is used to prevent neural tube defects?

A

prenatal folic acid supplementation

17
Q

What teratogens are known to cause spina bifida?

A
  • valproate is the leading example

- others include phenytoin, colchicine, vincristine, azathioprine, and methotrexate (which affect folic acid metabolism)

18
Q

Describe the presentation of meningocele and meningomyelocele.

A
  • bother present with a fluctuant midline mass filled with CSF and/or spinal cord tissue
  • since meningoceles are filled only with CSF, they can be transilluminated
  • unlike meningoceles, meningomyeloceles often have associated neurologic deficits which depend on the levell of the lesion but range from paraplegia to bladder and bowel incontinence
19
Q

Meningomyelocele

A
  • a form of spina bifida and neural tube deficit in which there is herniation meningeal and neural tissue
  • teratogens which may lead to this defect include valproate, phenytoin, colchicine, vincristine, azathioprine, and methotrexate while prevention relies on folic acid supplementation
  • presents as a midline, fluctuant mass with neurologic deficits depending on the level of the lesion
  • most are associated with a chair type II malformation and hydrocephalus; some are associated with cervical hydrosyringomyelia, defects in neuronal migration and genesis of the corpus callosum, orthopedic problems, or GU defects
  • diagnosed based on elevated AFP in the amniotic fluid and maternal serum; fetal sonography is also highly sensitive
  • requires urgent surgical repair within 24 hours to reduce the risk of infection or trauma to the exposed tissue
20
Q

What is cervical hydrosyringomyelia?

A

an accumulation of fluid within the central spinal cord canal and within the cord itself

21
Q

What are the most common causes of coma in pediatrics?

A
  • in children younger than 5yo, non accidental trauma and near-drowning are the most common causes
  • in older children drug overdose and accidental head injury are most common
22
Q

When assessing an individual in a coma, what are the most important goals?

A
  • determine the depth of coma
  • identify neurologic signs that may indicate the site or cause of the coma
  • monitor the patients recovery and ensure stability
23
Q

CSF or blood draining from the nose or auditory canal is indicative of what?

A

a basilar skull fracture

24
Q

What do the following motor responses indicate about a comatose patient:

  • flaccidity or no movement
  • decerebrate posturing
  • decorticate posturing
  • asymmetric responses
A
  • flaccidity or no movement: severe spinal or brainstem injury
  • decerebrate posturing: indicates subcortical injury
  • decorticate posturing: indicates bilateral cortical injury
  • asymmetric responses: suggests hemispheric injury
25
Q

What are decerebrate and decorticate posturing?

A
  • decerebrate is extension of the arms and legs, indicative of subcortical injury
  • decorticate is flexion of the arms and extension of the legs, indicative of bilateral cortical injury in a comatose patient
26
Q

What do the following respiratory states indicate about a comatose patients:

  • hypoventilation
  • hyperventilation
  • Cheyne-Stokes breathing
  • apneustic breathing
  • ataxic or agonal breathing
A
  • hypoventilation: opiate or sedative overdose
  • hyperventilation: metabolic acidosis
  • Cheyne-Stokes breathing: bilateral cortical injury
  • apneustic breathing: pontine damage
  • ataxic or agonal breathing: medullary injury and impending brain death
27
Q

What does pupillary size and reactivity suggest about a comatose patient?

A
  • unilateral, non dilated, nonreactive pupil suggests uncal herniation
  • bilateral, dilated, and nonreactive pupils suggest irreversible brainstem injury
  • bilateral constricted reactive pupils suggests opiate ingestion or pontine injury
28
Q

What is Cheyne-Stokes breathing?

A

alternating apneas and hyperapneas, suggestive of bilateral cortical injury

29
Q

What is apneustic breathing?

A

pausing at full inspiration, indicative of pontine damage

30
Q

What is ataxic or agonal breathing?

A

irregular respirations with no particular pattern, indicating medullary injury and impending brain death

31
Q

What is the oculocephalic maneuver and caloric irrigation?

A
  • the oculocephalic maneuver involves turning a comatose patient’s head; the eyes should look straight ahead and then slowly drift back to midline because of the vestibular apparatus is intact
  • however, if the brainstem is injured, head movement does not evoke any eye movement
  • when the oculocephalic maneuver is abnormal, the next step is caloric irrigation
  • it involves angling the head at thirty degrees and irrigating each auditory canal with ice water; a normal response involves eye deviation to the irrigated side and an abnormal response is suggestive of pontine injury
32
Q

What does the work up for a comatose patient involve?

A
  • assign them a score non the Glasgow coma scale
  • do a head and neck exam, check motor response, respiratory response, pupillary size and reactivity, and other brainstem responses like the oculocephlic maneuver and caloric irrigation
  • check glucose immediately in all patients
  • get a urine toxicology screen, serum electrolytes, metabolic panel, and head CT
  • do an LP if the CT scan is negative to rule out meningoencephalitis
  • do an EEG even if the patient has no history of clinical seizures
33
Q

Define epilepsy.

A

the occurrence of two or more spontaneous seizures

34
Q

Define status epilepticus.

A

a seizure lasting more than 5 minutes during which the patient does not regain consciousness

35
Q

Describe how a febrile seizures are classified.

A

they can be partial in which one hemisphere is involved
- a simple partial seizures is one in which consciousness is not impaired
- a complex partial seizure is one in which there is a loss of consciousness
generalized in which both hemispheres are involved
- these are classified according to the symptoms as tonic-clonic, tonic, clonic, myoclonic, absence, or atonic

36
Q

What is unique about the generalized tonic-clonic seizure type?

A
  • the most common generalized seizure in children
  • there is increased thoracic and abdominal muscle tone followed by clonic movements of the arms and legs as the eyes roll upward
  • there is incontinence and decreased consciousness
  • patients experience a post-octal state of variable duration
37
Q

Describe an absence seizure.

A
  • a brief staring spell without loss of posture and only minor motor manifestations which may include eye blinking or mouthing movements
  • these generally last less than 15 seconds and there is no post-ictal state
38
Q

How is status epilepticus treated?

A

with a short-acting benzodiazepine like lorazepam or diazepam followed by a loading dose of phenobarbital or phenytoin

39
Q

What is the preferred treatment for:

  • status epilepticus
  • generalized epilepsy
  • absence epilepsy
  • partial epilepsy
A
  • status epilepticus: short-acting benzodiazepine like lorazepam or diazepam followed by a loading dose of phenobarbital or phenytoin
  • generalized epilepsy: valproate or phenobarbital
  • absence epilepsy: ethosuximide
  • partial epilepsy: carbamazepine or phenytoin
40
Q

Which seizure types are most amenable to surgical treatment?

A

those which are medically intractable and have an identifiable origin in the temporal lobe

41
Q

What are two alternative treatments for seizures outside of medical therapy and surgical resection?

A
  • vagal nerve stimulators

- ketogenic diets

42
Q

Febriles Seizures

A
  • occur in children ages 6-60 months and are benign
  • there is a hereditary component
  • usually occur on the first day of a febrile illness
  • typically when fever is greater than 38 celsius
  • tend to be developmentally normal and often have a positive history for febrile seizures; diagnosis is based on history, a normal neuron exam, and exclusion of any CNS infection
  • may be the initiating event for epilepsy but the risk for epilepsy is low
  • 50% risk of a second occurrence if the first was before age 12 months and 30% if after
  • can be simple or complex depending on if they are generalized/partial, more or less than 15 minutes, and occur more than once in 24 hours
  • most are generalized (simple)
  • can be treated with aggressive antipyretics during subsequent febrile illness; if they become frequent and recurrent, abortive treatment with rectal diazepam is an option
43
Q

Infantile Spasms (aka West Syndrome)

A
  • an epileptic syndrome with onset between 3-8 months of age
  • most often caused by tuberous sclerosis, but PKU, hypoxic-ischemic injury, intraventricular hemorrhage, meningitis, and encephalitis are also possible causes
  • presents as brief, myoclonic jerks consisting of sudden arm extension or head and trunk flexion, which last 1-2 seconds and occur in clusters of 5-10 over the course of 3-5 minutes
  • EEG shows a characteristic hypsarrhthmia pattern, which is a highly disorganized pattern of high amplitude spikes and waves occurring in both cerebral hemispheres
  • ACTH IM for 4-6 weeks is the preferred treatment but valproate is second-line and vigabatrin is the most effective drug for cases caused by tuberous sclerosis
  • the prognosis is poor as most develop moderate-to-severe mental retardation
44
Q

Absence Epilepsy of Childhood

A
  • an autosomal dominant epileptic syndrome with onset between 5-9 years old
  • presents as absence seizures lasting 5-10 seconds, which occur tens or hundreds of times per day and are often accompanied by automatisms such as eye blinking or incomprehensible utterances
  • there is no loss of posture, urinary incontinence, or post-ictal state
  • the diagnosis is made based on generalized 3Hz spike and wave discharges arising from both hemispheres
  • the preferred treatment is ethosuximide followed by valproate
  • the prognosis is good as seizures usually resolve by adolescence without cognitive impairment
45
Q

Benign Rolandic Epilepsy

A
  • an autosomal dominant epileptic syndrome of nocturnal partial seizures with secondary generalization
  • presents at 3-13 years of age
  • seizures occur in the early morning hours with oral-buccal manifestation (moaning, grunting, or pooling saliva) followed by spread to the face and arm before becoming a tonic-clonic generalized seizure
  • diagnosed based on characteristic biphasic spike and sharp wave disturbance in the mid-temporal and central regions on EEG
  • preferred treatment is valproate and the prognosis is excellent as seizures typically remit spontaneously during adolescence without consequence
46
Q

What are primary and secondary intracranial headaches?

A
  • primary are caused by a primary dysfunction of neurons or muscles (e.g. migraines or tension headaches)
  • secondary are caused by increased intracranial pressure or meningeal irritation (e.g. hydrocephalus or meningitis)
47
Q

What are local and systemic, extracranial causes of headache in peditratics?

A
  • local: otitis media, refractive error or glaucoma, sinusitis, toothache or abscess, TMJ dysfunction
  • systemic: anemia, depression, hypoglycemia, hypertension, psychogenic, carbon monoxide poisoning
48
Q

What kind of headaches are worse in the morning?

A

those resulting from increased intracranial pressure

49
Q

What kind of headaches are worse toward the end of the day?

A

tension headaches

50
Q

Migraine Headache

A
  • a type of primary intracranial headache and the most common cause of headaches in pediatrics
  • they have an autosomal dominant component and are caused by changes in cerebral blood flow elicited by serotonin, substance P, and vasoactive intestinal peptide
  • they are prolonged (> 1 hour), unilateral, throbbing, and associated with nausea, vomiting, or visual changes; the most often start in the supraorbital area and radiate to the occiput; they are often accompanied by photo- or phonophobia
  • auras, if present, are most commonly transient visual changes or unilateral paresthesias or weakness
  • they are sometimes associated with focal neurologic signs: ophthalmoplegic migraines are associated unilateral ptosis or cranial nerve III palsy while basilar artery migraines are associated with preceding vertigo, tinnitus, ataxia, or dysarthria
  • sleep often improves symptoms but sumatriptan, a selective 5-Ht agonist, is the primary abortive treatment and propanol is the drug of choice for prophylaxis
51
Q

Tension Headaches

A
  • rarely seen in children, especially those under 7 yo
  • they are bifrontal or diffuse headaches described as dull or aching and increase in intensity throughout the day
  • they are associated with muscle contraction, particularly of the temporalis, master, or trapezius
  • there is no associated vomiting, visual changes, or paresthesia
  • best treated with reassurance, pain control using NSAIDs, and stress reduction
52
Q

Cluster Headaches

A
  • an extremely rare headache type in children
  • described as a unilateral frontal or facial pain accompanied by conjunctival erythema, lacrimation, and nasal congestion, usually lasting less than thirty minutes
  • they may recur several times in a day and then not occur again for weeks or months
  • abortive therapy includes oxygen or sumatriptan and prophylaxis involves CCBs or valproate
53
Q

Describe a “cerebellar gait”.

A

children have an insteady, wide-based stance with irregular steps, often veering to one side or the other

54
Q

Name five conditions which may mimic ataxia but are not cerebellar in nature.

A
  • weakness, as in Guillain-Barre, can lead to an unsteady gait
  • encephalopathy may decrease one’s level of consciousness, affecting gait
  • gait may be affected by a seizure or post-ictal state
  • vision problems may mimic an unsteady gait
  • vertigo from migraines, acute labyrinthitis, or brainstem tumors
55
Q

Acute Cerebellar Ataxia of Childhood

A
  • an unsteady gait secondary to a presumed autoimmune or post-infectious cause
  • it usually follows a viral illness by 2-3 weeks and the proposed mechanism is through immune complex deposition in the cerebellum
  • it is the most common cause of ataxia in children and has a typical onset between 18 months and 7 years old
  • presents with truncal ataxia, slurred speech, and nystagmus without fever
  • it is a diagnosis of exclusion and urgent neuroimaging is necessary in all patients with suspected cerebellar ataxia
  • treatment is supportive and complete resolution can be expected in 2-3 months
56
Q

Guillain-Barre Syndrome

A
  • a demyelinating polyneuritis, which affects the ventral spinal roots and peripheral myelinated nerve
  • occurs due to cross-reactivity and a cell-mediated immune response that damages Schwann cell membranes
  • it most commonly follows an infection with C. jejuni, which causes a prodromal gastroenteritis
  • results in symmetric, ascending muscle weakness or paralysis beginning in the lower extremities; may also see autonomic dysregulation or sensory abnormalities
  • a lumbar puncture shows albuminocytologic dissociation (increased CSF protein without elevated cell count), EMG demonstrates decreased nerve conduction velocity, and a spiral MRI is used to exclude a compressive spinal cord lesion
  • treatment is aimed at maintaining respiration as well as administration of IVIG and plasmapheresis to remove anti-myelin antibodies
57
Q

Sydenham Chorea

A
  • a self-limited autoimmune disorder associated with rheumatic fever, presenting with chorea and emotional lability
  • it occurs as a result of antibodies that cross-react with antigens on group A beta-hemolytic strep and basal ganglia cells
  • it usually follows strep pharyngitis by 2-7 months and presents with chorea, jerky or indistinct speech, chameleon tongue (unable to sustain protrusion), emotional lability, choleric hand, and milkmaid’s grip; gait and cognition are unaffected
  • diagnosis is based on evidence of rheumatic fever and exclusion of other causes; may see an elevated ASO or anti-DNase B titer
  • treatment involves haloperidol, valproate, or phenobarbital
  • may last up to 2 years, but most patients recover
58
Q

Tourette Syndrome

A
  • a chronic movement disorder which presents with at least one motor and one phonic tic before the age of 18, which is present for at least one year
  • associated with learning disability, ADHD, and OCD
  • it is a clinical diagnosis
  • pimozide is the drug of choice because of it’s minimal risk for extrapyramidal side effects; clonidine is an alternative therapy
  • in either case, tics tend to decrease in adulthood
59
Q

What is the difference between a tic and a habit?

A

habits are situation-dependent and are under voluntary control whereas tics are brief-stereotypical behaviors initiated by an unconscious urge

60
Q

Duchenne Muscular Dystrophy

A
  • an X-linked myopathy characterized by myofiber degeneration, which is more severe than Becker’s
  • caused by a deletion in the dystrophin gene, which produces a cytoskeletal protein that associates with actin; it’s absence causes weakness and rupture of the plasma membrane, leading to injury and degeneration of muscle fibers
  • onset of symptoms is between 2 to 5 years old and begins with a slow, progressive weakness first affecting the legs; likely to see pseudo hypertrophy of the caves, Gower’s sign, and possibly mild cognitive impairment
  • death is due to involvement of cardiac and respiratory muscles
  • biopsy reveals degeneration of muscle fibers and replacement with fibroblasts and lipid droplets
  • labs demonstrate elevated CK levels, EMG shows small polyphasic muscle potentials with normal nerve conductions, diminished dystrophin levels are seen on western blot, and DNA testing confirms the diagnosis
  • oral steroids can improve strength transiently but the overall prognosis is poor
61
Q

Myasthenia Gravis

A
  • a disease characterized by autoantibodies against the post-synaptic ACh receptor at the neuromuscular junction and inhibit activation
  • can be neonatal which is transient and due to transplacental transfer of antibodies, or it can be the juvenile form which presents in childhood
  • presents with muscle weakness, particularly affecting the eyes, that worsens with use and improves with rest; ptosis and diplopia are classic signs
  • associated with thymus hyperplasia or thymoma, and in these cases a thymectomy improves the symptoms of myasthenia gravis
  • an edrophonium test can be used for diagnosis and to determine if functional decline during treatment is due to too big or too small a dose of long-acting acetylcholinesterase inhibitors
  • additionally EMG shows a decremental response to low-frequency repetitive nerve stimulation
  • neonatal myasthenia requires only symptomatic treatment until it is resolved; juvenile is treated with pyridostigmine but corticosteroids and plasmapheresis are second-line therapies