I. Conditions arising from head trauma or primary central nervous system
disease
A. Trauma
1. Intracranial hematoma (subdural, epidural, subarachnoid)
2. Cerebral contusion
3. Diffuse cerebral edema
4. Concussion
B. Seizures
1. Status epilepticus (convulsive, nonconvulsive)
2. Postictal state
C. Infection
1. Meningitis
2. Encephalitis
3. Focal infections (brain abscess, subdural empyema, epidural abscess)
D. Neoplasms
1. Tumor (edema, hemorrhage, blockage of CSF flow)
E. Vascular disease
1. Cerebral infarct (thrombotic, hemorrhagic, embolic)
2. Cerebral sinovenous thrombosis
3. Subarachnoid hemorrhage
4. Vascular malformation/aneurysm
F. Hydrocephalus
1. Obstructive (from tumor or other cause)
2. Cerebrospinal fluid shunt malfunction
II. Conditions affecting the brain diffusely
A. Vital sign abnormalities
1. Hypotension, hypertension
2. Hypothermia, hyperthermia
B. Hypoxia
1. Pulmonary disease
2. Severe anemia
3. Methemoglobinemia
4. Carbon monoxide
5. Posthypoxic encephalopathy
C. Intoxications
1. Sedative drugs: antihistamines, barbiturates, benzodiazepines, ethanol,
gamma-hydroxybutyrate (GHB) and analogs, narcotics, phenothiazines,
clonidine
2. Tricyclic and other antidepressants
3. Antipsychotics (i.e., risperidone, quetiapine, olanzapine)
4. Antiepileptics
5. Salicylates
D. Metabolic abnormalities
1. Hypoglycemia (sepsis, gastroenteritis, insulin overdose, ethanol
intoxication)
2. Hyperglycemia (diabetic ketoacidosis, hyperglycemic hyperosmolar
syndrome)
3. Metabolic acidosis
4. Metabolic alkalosis
5. Hyponatremia, hypernatremia
6. Hypocalcemia, hypercalcemia
7. Hypomagnesemia, hypermagnesemia
8. Hypophosphatemia
9. Uremia (kidney failure)
10. Liver failure
11. Acute toxic encephalopathy (Reye syndrome)
12. Inherited metabolic disorders
E. Other
1. Intussusception
2. Hemolytic uremic syndrome
3. Dehydration
4. Sepsis
5. Rheumatologic conditions (SLE, Behỗets)
6. Psychiatric conditions
TABLE 17.3
COMMON CAUSES OF COMA/ALTERED LEVEL OF
CONSCIOUSNESS
Subdural hematoma
Epidural hematoma
Cerebral edema
Postictal state
Hypotension
Posthypoxic/ischemic insult
Hypoglycemia
Toxic ingestions
Hypo- and hypernatremia
Meningitis
TABLE 17.4
LIFE-THREATENING CAUSES OF COMA/ALTERED LEVEL OF
CONSCIOUSNESS
Intracranial hemorrhage
Cerebral edema
Brain neoplasms
Cerebral infarctions
Cerebrospinal fluid shunt malfunction
Meningitis, encephalitis
Toxic ingestions
Hypotension
Hypoxia
Sepsis
Primary Central Nervous System Disorders
Trauma
Coma-producing brain lesions that result from trauma include subdural and
epidural hematomas, intraparenchymal and subarachnoid hemorrhage, penetrating
injuries, cerebral contusion, diffuse cerebral edema, and concussion (see Chapter
113 Neurotrauma ). Though most pediatric head injuries are blunt in nature and
are accompanied by a history of trauma, nonaccidental head trauma is also
common and may present with nonspecific complaints and deliberately inaccurate
histories. Patients suffering head trauma may present in a comatose state or may
be alert for variable periods after impact.
ALOC resulting from diffuse cerebral edema and diffuse axonal injury is
common in children and is less amenable to neurosurgical intervention than focal
lesions such as epidural and subdural hematomas. Characteristic loss of gray–
white interface on CT may not be visible for 12 to 24 hours after injury. When
diffuse radiographic abnormalities appear, they may resemble those produced by
hypoxic/ischemic insult.
Concussion is an inexact term for a transient alteration in normal neurologic
function after head trauma. Postconcussion syndrome is characterized by variable
combinations of physical symptoms (e.g., nausea, vomiting, dizziness, headache),
behavioral changes (e.g., irritability), sleep disturbances, and cognitive
dysfunction, with symptoms lasting weeks in some patients. Neuroimaging
studies are normal in concussion, yet patients may be ill enough to require
admission for observation, analgesia, and intravenous (IV) hydration.
Seizures
Consciousness is greatly diminished during and after periods of seizure activity.
Generalized seizure activity is readily recognizable by rhythmic motor activity
accompanying ALOC. Partial or absence seizure activity may present more subtly
with staring, tremors, eye blinking, rhythmic nodding, or other repetitive motor
activity. Seizures of all types, except absence and simple partial seizures, are
usually followed by a postictal period, during which obtunded patients gradually
regain consciousness. Patients in nonconvulsive status epilepticus may present in
coma, and if other causes have been ruled out, comatose patients should have an
electroencephalogram (EEG) performed.
The diagnostic approach toward a patient with ALOC from seizure activity
varies based on whether seizures have occurred in the past and the progression or
resolution of his or her neurologic abnormalities (see Chapter 72 Seizures ).
Posttraumatic or new focal seizures are assumed to reflect an intracranial lesion
until proven otherwise. Children taking antiepileptic medications benefit from
drug-level measurement (if available for the medication) during an observation