Download Pediatric Neurologic Emergencies – Maria Antonia Valencia

Pediatric Neurologic Emergencies – Maria Antonia Valencia-Moral, MD
February 12, 2010
Italicized words - audio
Lecture Outline
- Definition and Pathophysiology, Identification, Work up, Initial management of:
o Impairment of consciousness and coma
o Status epilepticus
o Acute paralysis (not discussed)
I.
-
Consciousness Definitions
2 components: awareness as a function of the higher cortical areas and awake/wakefulness as a
function of the ARAS (Ascending Reticular Activating System)
Consciousness: spontaneously occurring state of AWARENESS of self and the environment
Unconsciousness: is the opposite and may be physiologic (sleep) or pathologic (coma) which is
really the emergency situation
Categories of Impaired Consciousness
- Impairment of consciousness with activated mental status – they are awake but they are
confused
o Hallucinations
o Delusions
o Delirium
- Impairment of consciousness with reduced mental state
o Obtundation – responsive to other stimuli other than pain; lethargy - drowsy
o Stupor – responsive to pain
o Coma – is really the emergency situation, unresponsive to pain
- Impairment along the continuum of coma-vegetative state-minimally conscious state and
related conditions – persistent vegetative state/PVS
Pathophysiology
- Consciousness is the result of the interplay between the:
o Cerebral cortex
o Ascending reticular activating system
- Coma is produced by conditions causing a pathology either in:
o Bilateral cerebral cortical dysfunction – cannot be one-sided only; or there may be onesided lesion but in the presence of mass edema, the other side can also be affected
o ARAS dysfunction – brainstem tumor that can damage the ARAS even if the cerebral
cortex is intact
o Both
Figure 1. Regulation of consciousness.
Evaluation
- Clinical evaluation – ABC’s of life support – first line of support
o Airway
o Breathing
o Circulation
- Identification of cause
- History
- General physical examination
- Neurological examination
Historical Cues
Symptoms/Historical Cues
Sudden onset
Kerosene stove use or heaters
Probable Etiology
Convulsions or if post-ictal state, the patient can
recover; intracranial hemorrhage
Ingestion of a drug or toxin
Suggests elevated cranial pressure: neoplasm,
hydrocephalus, migraine syndromes
Traumatic Brain Injury: epidural, subdural,
subarachnoid
Infectious causes: meningitis, encephalitis, abscess
Inborn errors of metabolism, drug overdose,
munchausen’s syndrome by proxy
Carbon monoxide poisoning
General Physical Examination
PE findings
Probably Etiology
Preceded by sleepiness or unsteadiness
Headache
History of Trauma
Fever
Intermittent coma
Fever
Hypothermia
Tachycardia
Bradycardia
Tachypnea
Slow, irregular, periodic breathing
Hypotension
Hypertension
Infection, heat stroke
Drug intoxication
Hypovolemic shock, Tachyarrythmias
Myocardial injury, late effects of hypoxemia or
increased ICP; in Cushing reflex there is increased
ICP and to compensate, the mean arteriolar
pressure (MAP) will increase to increase cerebral
perfusion  bradypnea and bradycardia along
with hypotension
Abnormality of oxygenation, acidosis, brainstem
lesions
causing
central
neurogenic
hyperventilation
Toxic ingestion or increased ICP
Shock, adrenal insufficiency
Hypertensive encephalopathy or as a reaction to
increased ICP
3 Goals for the Initial Assessment
- To confirm the diagnostic impression from the History and PE
- To localize the level of neurologic dysfunction
- To serve as a basis for comparison of future examinations so you will know if the patient is
improving or deteriorating
5 Pathophysiologic variables:
- Mental status
- Respiratory patterns
- Pupillary sizes and reactivity
- Oculo-cephalic and oculo-vestibular responses (Doll’s eyes) – reflects the brainstem integrity
- Motor responses
Mental status
- The use of lethargy, obtundation, stupor and coma does not give much clinical significance.
- Best to describe the patient’s response to various stimuli – where Glasgow Coma Scale is
needed
- Attempts to test for higher cortical function should be made when they begin to rouse from their
coma state.
Respiratory Patterns
Respiratory pattern
Cheyne-Stokes Respiration
Central Neurogenic Respiration
Apneustic breathing
Ataxic breathing
Pattern
Crescendo-decrescendo
hyperventilation alternating with
Apneusis
Continuous rapid respiration
causing acidosis
Periodic apnea after prolonged
inspiration and expiration
Chaotic breathing – no pattern
Localization
Bilateral cerebral dysfunction or
upper diencephalic dysfunction
Midbrain dysfunction
Pontine damage
Medullary dysfunction
Ineffectual breathing
Very shallow
Depression
of
respiratory
centers; can be secondary to
drug overdose like Phenobarbital
or phenytoin
Pupillary Sizes and Reactivity
Pupillary Reaction and Size
Normal reaction
Pathology
Hemispheric lesions since papillary reaction is a
brainstem function, not the cerebral cortex; in
cortical blindness, there is a lesion in the occipital
lobe, the papillary response is normal but the
patient cannot see
Small reactive pupils
Barbiturate/narcotic intoxications
Anisocoric – very serious condition wherein the Uncal herniation
oculomotor nerve on one side is being compressed
Mid position, fixed
Midbrain lesions
Pinpoint
Pontine lesions, opiates and derivatives
intoxication
Bilaterally dilated and non-reactive – most serious Medullary pathology
condition, can be fatal since the medulla is where
the cardiac and respiratory centers are located
Oculo-cephalic (Doll’s eyes) and Oculo-vestibular (Ice-water Calorics) Responses
- To test for the patients in altered conscious state
- Brainstem tests
- Do Doll’s eye first – if no response, proceed with calorics testing
- Think of “COWS” when doing calorics: “cold means the movement of the eye is toward the
opposite side; and if it’s warm it is toward the same side” (C –old O – pposite W – warm S –
Same)
- Absence of response indicates poor prognosis – the response should be symmetric and bilateral.
- Both of these tests will determine the integrity of the brainstem
Motor Responses
- Note the symmetry of movement in patients who cannot follow commands.
Ex. Patient thrashing about all limbs – no paralysis; asymmetric movements suggest a
hemiparesis.
- Note appropriate responses to stimulus in “socially” acceptable sites like the supraorbital ridge,
sternum, and the nails.
- Note abnormal postures if present: decorticate and decerebrate posturing
- Check for DTRs and plantar responses to be able to localize the lesion.
Figure 2. Decerebrate and decorticate postures.
Glasgow Coma Scale – the most important scale to be used
Function
Eye Opening
Verbalization
Adults
Spontaneous
To Command
To Pain
None
Oriented
Disoriented
Inappropriate
Incomprehensible
Motor
None
Obeys commands
Localizes
Withdraws
Reflex flexion
Reflex extension
None
Children
Spontaneous
To sound
To pain
None
Appropriate
for age,
flexes and
follows,
social smile
Inconsolable
cry
Persistently
irritable
Restless,
lethargic
None
Spontaneous
Localizes
Withdraws
Reflex
flexion
Reflex
extension
None
Total score
The lowest score is 3 not zero.
Score
4
3
2
1
5
4
3
2
1
6
5
4
3
2
1
15
Causes of Alteration in Sensorium
- Metabolic, toxic, infectious
- Supratentorial mass lesions that compress or displace the diencephalon or brainstem
- Subtentorial mass or destructive lesions that compress or damage the ARAS
- Traumatic axonal injury that affects both cerebral hemispheres, the ARAS or their
interconnections.
Management
- Question informants thoroughly.
- ABC’s first
- Draw blood for: depending on your working diagnosis
o Culture – for infectious causes
o CBC – also for infectious cause
o Electrolytes – since these are rapidly reversible causes for coma
o Sugar - hypoglycemia
o BUN, creatinine
o Serum osmolality
o ABG
o Ammonia
o Toxic drug screen
o Liver function tests
o Coagulation profile
o Antiepileptic drug levels
- Ancillary procedures (when appropriate)
o Neuroimaging (CT scan or MRI) – usually do it for all coma patients
o Lumbar puncture - if you’re thinking of infection
o EEG – if you’re thinking if seizure
Treatment Goals
- Ensure oxygenation
- Maintain circulation
- Give glucose
- Correct acid-base and electrolyte imbalance
- Consider specific antidotes like drug overdose or dose exposure
- Reduce increased intracranial pressure: you may elevate the head up to 45° to increase jugular
venous pressure, regulate the respiration to avoid bradypnea or decrease perfusion in the brain.
Bradypnic environment tends to retain CO2 causing vasodilatation and further increase ICP. We
ventilate the patient and monitor PCO2 which should not be over 35mm; and we can also give
osmotic diuretics like mannitol.
- Stop seizures
- Treat infection
- Adjust body temperature – keep them normothermic or slightly hypothermic which is
neuroprotective
- Manage agitation
II. Status Epilepticus
Definitions:
-
Seizure: an abnormal excessive neuronal discharge arising from the brain capable of causing
alteration in function and/or behavior; it depends on what part of the brain has the condition
Convulsion: a type of seizure with a motor component
Epilepsy: recurrent unprovoked seizures (operational definition is more than two unprovoked
seizures)
Status epilepticus: a single seizure lasting at least 30 minutes or recurrent seizures lasting > 30
minutes without fully regaining consciousness between seizures
Epidemiology (Hauser 1990)
- Incidence of 41 patients per year per 100,000 population
- 50 episodes of status epilepticus per year per 100,000
- Projected that between 102,000 and 152,000 events occur in the US annually
There is a higher incidence among less than 1 year with bimodal contribution with increased incidence in
adults over 40 years.
4 Major Etiologies
- Febrile – the most common etiology for children
- Acute symptomatic encephalopathies ex. meningitis
- Remote symptomatic encephalopathies ex. HIV
- Idiopathic
- 4% are secondary to progressive CNS disease
Pathogenesis: can lead to significant morbidity and mortality
- Cellular ischemic changes begin to occur in 15-30 minutes
- Irreversible damage begins at 90-120 minutes of continuous seizures
- Damage is due to the combined effects of: hypotension, hyperthermia, hypoglycemia and
acidosis
-
The immature brain is more susceptible to seizures (higher incidence among less than 1 year
old) because the synapses are still not well-developed. But is relatively more resistant to
sequelae (higher in adults). Therefore, there is higher recovery rate and lower mortality
among children having status epilepticus.
Treatment goals
- Ensure adequate oxygenation and circulation
- Terminate clinical and electrical seizure activity as soon as possible
- Prevent seizure recurrence
- Identify and treat precipitating factors: hypoglycemia, electrolyte imbalance, low drug levels,
fever
- Prevent systemic complications
- Evaluate and treat the cause
Figure 3. Protocol for Treatment of Status Epilepticus. Every 5-10 days, you are assessing the child or the
adult. Usually the first line of treatment is benzodiazepam because they are fast-acting. But if they don’t
respond to the initial doses, long-acting convulsants are already used. There is a need to load since the
goal of treatment is to achieve therapeutic dose in lesser duration (within 24 hours); as compared to
giving a maintenance dose that will take four half-lives of the drug to maintain the therapeutic level
which will account for 20 days.
Management
- Supportive care
- Lab testing: blood glucose, blood gas, electrolytes, CBC, AED levels, cultures, toxic screens, urine
drug and metabolic screen
- Neuroimaging
- Lumbar puncture
- EEG monitoring
Morbidity and Mortality
- Common sequelae:
o Intellectual dysfunction
o Permanent neurologic deficits – usually weakness depending on what part of the brain is
affected
o Continuing recurrent seizures
- Mortality rates are higher in adults than in children
- About 5% in children – but still serious because the children have the higher probability to live so
they will also spend that whole lifetime with their seizure.