A17. Examination of the unconscious patient

From greek.doctor
  • Differentiate between cardiac, metabolic, and neurological causes
    • Most unconscious patients have underlying cardiac or metabolic problem; neurologic cause of unconsciousness is rare
    • Cardiac causes of unconsciousness
      • Most common
      • Suspicious features
        • Low heart rate
        • Low blood pressure
        • Abnormal ECG
    • Endogenous metabolic causes of unconsciousness
      • Etiology
        • Metabolic acidosis
        • Hypoglycaemia
        • Hyperglycaemic crisis
        • Hepatic encephalopathy
        • Uraemia
        • Hypercapnia
      • Suspicious features
        • Abnormal blood sugar
        • Kussmaul breathing (quick and deep)
        • Abnormal odour of breath
        • Hypotonia
        • Hyporeflexia
    • Exogenous metabolic causes of unconsciousness (intoxication)
      • Etiology
        • Opioids
        • Benzodiazepines
        • Alcohol
      • Suspicious features
        • Drugs or needles around the patient
        • Needle marks on the patient’s arms
        • Slow, superficial breathing
        • Extreme miosis (pinpoint pupils)
        • Low blood pressure
    • Neurological causes of unconsciousness
      • Etiology
        • Brainstem lesion (of the ascending reticular activating system)
          • Increased ICP -> foramen magnum herniation
          • Brainstem stroke
          • Trauma
        • Bilateral thalamus lesion
          • There’s a relatively frequent malformation where both thalami receive blood from same artery -> prone to bilateral ischaemia
        • Bilateral frontal lobe lesion
      • Suspicious features
        • Abnormal pupillary light reflex
          • Unilateral dilated fixed pupil – CN III palsy
          • Bilateral dilated fixed pupils – tectal lesion or atropine
          • Midpoint fixed pupils – midbrain lesion
          • Pinpoint fixed pupils – pons lesion, opioids
          • Small reactive pupils – thalamus lesion or metabolic
        • Abnormal conjugation
          • Conjugated and deviated eyes (deviate ipsilateral to cortical lesion)
          • Dysconjugated eyes (brainstem or CN III, IV, VI lesion)
          • Skew deviation (brainstem lesion)
        • High blood pressure
          • Increased ICP -> Cushing reflex
        • Decorticate posturing
          • Flexed elbows, adducted arms, flexed fingers and wrists
          • Indicates damage above the red nucleus, e.g. rostral midbrain, thalamus, internal capsule, hemispheres
        • Decerebrate posturing
          • Upper and lower extremities extended and internally rotated
          • Indicates damage below the red nucleus, e.g. caudal midbrain or pons
        • Absent oculocephalic reflex (brainstem lesion) (see topic 3)
        • Absent corneal reflex
        • Absent cough reflex (lower brainstem lesion)
        • Hyperreflexia
  • History
    • From relatives or other witnesses
    • Did patient have any symptoms right before loss of consciousness?
    • Was loss of consciousness abrupt or gradual?
    • Patient’s recent health
    • Patient’s functional status
    • Previous medical history
    • Medication use
  • Examination
    • General examination
      • ABC (airways, breathing, circulation)
        • Are the airways obstructed?
        • Breathing
          • Cheyne-Stokes breathing -> brainstem lesion, heart failure
          • Slow, superficial breathing -> drugs, narcotics
          • Quick, superficial breathing -> brainstem lesion
          • Kussmaul breathing -> acidosis, hyperglycaemic crisis
        • Circulation
          • Pulse
          • Temperature
            • Hyperthermia -> infection, heat stroke
            • Hypothermia -> cold exposure, sepsis, CNS disease
          • Skin colour
          • Blood pressure
            • Hypertension -> CNS haemorrhage
            • Hypotension -> circulatory shock
      • Smell of breath
        • Alcohol, ketone bodies, liver failure, uraemia, …
      • Bruises which can suggest a fall
    • Neurological examination
      • Determine Glasgow coma scale score
        • To what degree is the patient arousable?
          • Shout to them
          • Induce pain
            • Press on the exit point of the ophthalmic nerve
            • Press on fingernail
        • Observe eye opening, movement, and verbal response
      • Examination of meningeal signs (see topic 1)
        • Only examined if cervical trauma can be excluded
        • Meningeal signs can be present in subarachnoid haemorrhage
      • Examination of cough reflex
        • By suction or inserting endotracheal tube
      • Examination of pupil and pupillary reflexes
        • Unilateral, maximally dilated
        • Bilateral, maximally dilated
        • Mid-dilated, does not react to light
        • Tiny pinpoint pupils
        • Horner syndrome (see topic 41)
      • Examination of position of eyes
        • Conjugate deviation
        • Dysconjugate deviation
        • Skew deviation
      • Examination of spontaneous eye movements
        • Downward deviation of eyes
        • Repetitive horizontal movements
      • Examination of reflex eye movements
        • Oculocephalic (doll’s eyes) reflex
        • Oculovestibular reflex
      • Examination of corneal reflex
      • Examination of muscle tone
      • Examination of fundus
        • Papilloedema
        • Haemorrhage
      • Examination of pyramidal signs