The neurologic examination of the comatose patient should include standard tests of eye opening, responsiveness to verbal and tactile stimuli, and deep tendon reflexes as well as the more specialized examinations described in this section Any focal (unilateral) abnormal finding is always significant because it may indicate a structural CNS lesion Abnormal findings on neurologic examination reflect the underlying pathologic condition causing coma and may allow localization of a lesion within the brain Patients with ALOC benefit from quantification of their impairment using standard measurements, allowing evaluation and documentation of patients’ changing neurologic status over time The effect of medical interventions may then be more easily assessed The use of accepted scoring systems also facilitates communication with consultants such as neurologists and neurosurgeons In addition, many outcome measures of neurologically injured patients rely on scales used to assess neurologic function The most widely used measurement of consciousness is the Glasgow Coma Scale (GCS) shown in Table 17.1 Patients are graded on three areas of neurologic function: Eye opening, motor response, and verbal responsiveness A GCS score of is the minimum score possible and represents complete unresponsiveness; a GCS score of 15 indicates a fully alert patient Pupillary responses provide the most direct window to the brain of a comatose patient A unilaterally enlarging pupil (greater than mm) that becomes progressively less reactive to light indicates either progressive displacement of the midbrain or medial temporal lobe, or downward displacement of the upper brainstem Bilateral enlarged and unreactive (“blown”) pupils indicate profound CNS dysfunction and are most commonly seen with posttraumatic increases in ICP Nontraumatic conditions affecting the brain diffusely usually spare pupillary responses Exceptions include maximal constriction of pinpoint pupils caused by opiate intoxication and minimal constriction of widely dilated pupils caused by intoxication with anticholinergic agents Other ocular signs noted in patients with depressed consciousness are the roving side-to-side conjugate eye movements seen in lighter stages of metabolic coma Persistent conjugate deviation of the eyes to one side may be caused by focal seizure activity, its resultant postictal state, or focal lesions within the brain Ongoing seizure activity is usually apparent because of the jerking ocular movements present but nonconvulsive status may present with coma only Most structural brainstem lesions abolish conjugate eye movements, but it is rare for a metabolic disorder to so Deepening ALOC may also be measured by the reduction and loss of spontaneous blinking, then loss of blinking caused by touching the eyelashes, and finally loss of blink with corneal touch Both eyes should be tested to detect asymmetry Limb movement and postural changes seen in comatose patients include the bilateral restless movements of the limbs of patients in light coma Unilateral jerking muscular movements may indicate focal seizure activity or generalized convulsions in a patient with hemiparesis Decerebrate rigidity refers to stiff extension of limbs with internal rotation of the arms and plantar flexion of the feet It is not a posture that is held constantly; it usually occurs intermittently in patients with midbrain compression, cerebellar lesions, or metabolic disorders Decorticate rigidity, when arms are held in flexion and adduction and legs are extended, indicates CNS dysfunction at a higher anatomic level, usually in cerebral white matter or internal capsule and thalamus Signs of meningeal irritation include Kernig sign, resistance to bent knee extension with the hip in 90 degrees flexion, and Brudzinski sign, involuntary knee and hip flexion with passive neck flexion In infants, meningeal irritation may be manifest as paradoxic irritability, in which picking up the baby to soothe results in pain and worsening crying The abnormal breathing pattern most commonly seen in comatose patients is Cheyne–Stokes respirations, where intervals of waxing and waning hyperpnea alternate with short periods of apnea Other abnormal breathing patterns that occur with brainstem lesions include central neurogenic hyperventilation, which can produce respiratory alkalosis, and apneustic breathing, in which a 2- to 3second pause occurs during each full inspiration Laboratory and Radiologic Studies Immediate bedside glucose, sodium, blood gas, and hemoglobin determination should be performed on every patient with nontraumatic ALOC Other laboratory tests indicated for evaluation of coma in the absence of trauma include electrolytes, blood urea nitrogen, creatinine, blood gas, hemoglobin, hematocrit, osmolality, ammonia, and antiepileptic levels Toxicologic screening of both blood and urine should be obtained in patients with ALOC of unknown origin A noncontrast CT scan of the brain can reveal many causes of coma, such as cerebral edema, hydrocephalus, malignancy, hematomas, and abscesses Infarction, thrombosis, and inflammatory conditions may require the addition of contrast or the use of magnetic resonance imaging Vital Sign Abnormalities Evaluation and treatment of airway, breathing, and circulatory compromise always take precedence in the child with ALOC Both airway patency and respiratory effort may be compromised by decreased mental status and may result in hypoxia and/or hypercarbia The former may be readily measured using pulse oximetry, although values will be inaccurate if a toxic hemoglobinopathy, such as methemoglobinemia or carboxyhemoglobinemia, is present The adequacy of ventilation can be assessed clinically with a stethoscope and can be quantified by continuously monitoring end-tidal CO2 (see Chapter 21 Cyanosis ) Arterial blood gas analysis with co-oximetry is useful to quantify respiratory and acid–base status and to identify altered hemoglobin states The numerical definition of hypotension varies with age, but pallor and evidence of poor peripheral perfusion, with prolonged capillary refill time, is recognizable even before placement of a sphygmomanometer cuff Immediate administration of IV crystalloid therapy starting with 20 mL/kg of normal saline or lactated Ringer solution is indicated, followed by additional boluses and vasopressors if needed Of the empiric antidotal therapies often used in adults, only glucose (0.25 to 0.5 g/kg) is routinely administered to children An empiric trial of naloxone (0.1 mg/kg, max mg/dose) is sometimes justified, whereas flumazenil and thiamine are given only for specific indications (see Chapter 102 Toxicologic Emergencies ) Severe hypertension is less easily discerned on physical examination If confirmed in more than one extremity, antihypertensives should be administered via the IV route (see Chapters 37 Hypertension and 100 Renal and Electrolyte Emergencies ) Mental status should improve after blood pressure is lowered to high normal levels Patients in hypertensive crises are at risk for hemorrhagic stroke and should be evaluated with a head CT scan if they are neurologically abnormal after blood pressure lowering Hypertension in the comatose patient after traumatic injury may represent a physiologic response to increased ICP to allow maintenance of cerebral perfusion pressure by raising mean arterial pressure In this context, elevated blood pressure should not be lowered with antihypertensives; treatment instead should be aimed at decreasing ICP Hypothermia and hyperthermia are readily recognized once a core (rectal) temperature less than 35°C or greater than 41°C is obtained The mental status of these patients should begin to improve as body temperature approaches the normal range A significant percentage of patients with abnormal core temperatures have drowned, fallen through ice, or were engaged in sporting activities in extreme environments or without adequate hydration Adolescents with hypothermia may have associated ethanol toxicity Head trauma, hypoxia, and/or cervical spine injury may be present in these patients History of Head Trauma The patient with deeply depressed consciousness (GCS score less than 9) after head trauma is presumed to have increased ICP until proven otherwise Rapid sequence intubation is indicated to protect the airway and to maintain effective ventilation Cervical spine injury should be assumed and cervical immobilization maintained at all times An emergent noncontrast brain CT scan should be obtained and neurosurgery consulted Elevation of the head of the bed to 30 degrees and maintenance of the midline position of the head are simple nonpharmacologic maneuvers to try to reduce ICP In cases when immediate but necessary neurosurgical intervention is not possible for intracranial hemorrhage (e.g., extended transport time) or in cases of diffuse cerebral edema, 3% saline or mannitol may be helpful to treat elevated ICP History of Seizures The patient with ALOC in the absence of trauma should be evaluated for recent seizure activity with current postictal state (see Chapters 72 Seizures and 97 Neurologic Emergencies ) A history of previous seizures, witnessed convulsive activity, and ALOC consistent with previous postictal periods are valuable clues to this etiology of coma Ongoing seizure activity may be revealed by the presence of muscular twitching, increased tonicity, nystagmus, or eyelid fluttering Patients with subtle or completely nonconvulsive forms of status epilepticus may exhibit tachycardia but may require an EEG to diagnose The mental status examination of the postictal patient should gradually improve over several hours Although temporary focal neurologic deficits (e.g., Todd paralysis) may follow seizures, they must be presumed to indicate the presence of focal CNS lesions until proven otherwise The evaluation of neurologically depressed patients with seizures varies based on the patient’s history, type of seizure, and presence or absence of fever Patients with a history of seizures should have serum antiepileptic concentrations measured and be observed until they approach their neurologic baseline Children who have had a simple febrile seizure (see Chapter 72 Seizures ) should return to their baseline state soon, usually within hour Those who remain lethargic or irritable past this point (especially after antipyretic administration) should be suspected of having meningitis and are candidates for lumbar puncture Patients with new-onset generalized seizures who are afebrile warrant additional evaluation Depending on recent history (e.g., vomiting or diarrhea), it may be advisable to check serum electrolytes or a toxicologic screen Depending on local resources and practice, patients with newly diagnosed afebrile seizures