ESSENTIALS OF DIAGNOSIS
Abnormal motor responses to stimuli
Abnormal respiratory patterns
Abnormal pupillary responses
Abnormal eye movements
Stupor and coma are reduced states of alertness that differ from syncope in being sustained and from sleep in being less easily reversed. They are clinically defined in terms of response to stimulation, and because terms such as lethargy, obtundation, stupor, and coma are not rigorously defined, an examiner should record both the minimal stimulus that produces a response (eg, voice, passive movement, pain) and the response itself (eg, groaning, purposeful movement, extensor posturing, no response).
Delirium refers to severe inattentiveness, altered mental content, and sometimes hyperactivity. Delirium can presage or alternate with stupor or coma.
Consciousness requires both arousal and mental content. Coma can be caused by any lesion—structural or metabolic—that disrupts the brainstem reticular activating system, the cerebral hemispheres to which it projects, or both. The causes of coma are usefully divided into supra- and infratentorial structural lesions and diffuse or metabolic disorders. By concentrating the neurologic examination on motor responses to stimuli, respirations, pupils, and eye movements, the clinician can usually identify which type of lesion is present.
A. Initial Examination and Immediate Interventions
The examination begins with the detection and treatment of any immediate life-threatening condition (eg, hemorrhage, airway obstruction, hypotension, or cardiac arrhythmia). Finger-stick glucose is obtained, and if in doubt, 50% dextrose (plus thiamine and multivitamins) is given intravenously. Thiamine (and other multivitamins) is given with the glucose to prevent precipitation of Wernicke-Korsakoff syndrome. If opioid overdose is a possibility, naloxone is administered. If trauma is suspected, injury to internal organs or the neck must be considered.
Examination includes skin, nails, and mucous membranes (cyanosis, pallor, cherry redness, jaundice, petechiae, decubiti, uremic frost, dry myxedema, hypo- or hyperpigmentation, signs of trauma), breath (acetone, alcohol), and fundi (papilledema, hypertensive or diabetic retinopathy, Roth spots, subhyaloid hemorrhage). Fever might reflect infection or heat stroke. Hypothermia might indicate cold exposure, hypothyroidism, hypoglycemia, or sepsis. Urinary or fecal incontinence might signify an unwitnessed seizure. The scalp should be palpated for signs of trauma and the ears and nose examined for blood or cerebrospinal fluid. Resistance to passive neck flexion suggests meningitis or subarachnoid hemorrhage; resistance in all directions suggests bone or joint disease, including fracture.
C. Neurologic Examination
Inspection identifies limb position and spontaneous movements, either voluntary or involuntary (eg, seizure or myoclonus). Patients sometimes display spontaneous involuntary movements such as facial grimacing, jaw gyrations, tongue protrusions, and complex repetitive limb movements that defy ready interpretation. Asymmetric movements or postures can signify either hemiparesis or focal seizures. Asymmetry of muscle tone suggests a structural lesion, but ...