Coma

Basics

Description

  • Light coma:
    • Responds to noxious stimuli
  • Deep coma:
    • Does not respond to pain
  • Unresponsiveness:
    • Loss of either arousability or cognition:
      • Loss of arousal
      • Arousal is primarily a brainstem function
      • Impairment of the reticular activating system
      • Loss of cognition
      • Requires dysfunction of both cerebral hemispheres
    • Stupor:
      • Deep sleep, although not unconsciousness
      • Exhibits little or no spontaneous activity
      • Awaken with stimuli
      • Little motor or verbal activity once aroused
  • Obtundation:
    • Mental blunting with mild or moderate reduction in alertness
  • Delirium:
    • Floridly abnormal mental status
    • Irritability
    • Motor restlessness
    • Transient hallucinations
    • Disorientation
    • Delusions
  • Clouding of consciousness:
    • Disturbance of consciousness
    • Impaired capacity to think clearly or perceive, respond to, and remember current stimuli

Etiology

  • Diffuse brain dysfunction (69%):
    • Lack of nutrients:
      • Hypoglycemia
      • Hypoxia
    • Poisoning:
      • Ethanol
      • Isopropyl alcohol
      • Ethylene glycol
      • Methanol
      • Salicylates
      • Sedative-hypnotics
      • Narcotics
      • Anticonvulsants
      • Isoniazid
      • Heavy metals
      • Opiates
      • Benzodiazepines
      • Anticholinergics
      • Lithium
      • Phencyclidine
      • Cyanide
      • Carbon monoxide
      • Isoniazid
    • Infection:
      • Bacterial/tuberculous/syphilitic meningitis
      • Encephalitis
      • Falciparum meningitis
      • Typhoid fever
      • Rabies
    • Endocrine disorders:
      • Myxedema coma
      • Thyrotoxicosis
      • Addison disease
      • Cushing disease
      • Pheochromocytoma
    • Metabolic disorders:
      • Hepatic encephalopathy
      • Uremia
      • Porphyria
      • Wernicke encephalopathy
      • Aminoacidemia
      • Reye syndrome
      • Hypercapnia
    • Electrolyte disorders:
      • Hypernatremia, hyponatremia
      • Hypercalcemia, hypocalcemia
      • Hypermagnesemia, hypomagnesemia
      • Hypophosphatemia
      • Acidosis, alkalosis
    • Temperature regulation:
      • Hypothermia
      • Heat stroke
      • Neuroleptic malignant syndrome
      • Malignant hyperthermia
    • Uremia
    • Postictal state, status epilepticus
    • Psychiatric
    • Shock
    • Fat embolism
    • Hypertensive encephalopathy
  • Supratentorial lesions (19%):
    • Hemorrhage (15%):
      • Intraparenchymal hemorrhage
      • Epidural hematoma
      • Subdural hematoma
      • Subarachnoid hemorrhage
    • Infarction (2%):
      • Thrombotic arterial occlusion
      • Embolic arterial occlusion
      • Venous occlusion
    • Tumor or abscess (2%):
      • Hydrocephalus
      • Herniation
      • Hemorrhage from erosion into adjacent blood vessels
  • Subtentorial lesions (12%):
    • Infarction
    • Hemorrhage
    • Tumor
    • Basilar migraine
    • Brainstem demyelination

Pregnancy Considerations
Eclampsia

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