Organic brain syndrome

  • Definition

    Organic brain syndrome (OBS) is a general term used to describe decreased mental function due to a medical disease, other than a psychiatric illness. It is often used synonymously (but incorrectly) with dementia.

    Alternative Names

    OBS; Organic mental disorder (OMS); Chronic organic brain syndrome

    Causes, incidence, and risk factors

    Disorders associated with OBS include:

    • Brain injury caused by trauma
      • Bleeding into the brain (intracerebral hemorrhage)
      • Bleeding into the space around the brain (subarachnoid hemorrhage)
      • Blood clot inside the skull causing pressure on brain (subdural hematoma)
      • Concussion
    • Breathing conditions
      • Low oxygen in the body (hypoxia)
      • High carbon dioxide levels in the body (hypercapnia)
    • Cardiovascular disorders
      • Abnormal heart rhythm (arrhythmias)
      • Brain injury due to high blood pressure (hypertensive brain injury)
      • Dementia due to many strokes (multi-infarct dementia)
      • Heart infections (endocarditis, myocarditis)
      • Stroke
      • Transient ischemic attack (TIA)
    • Degenerative disorders
      • Alzheimer's disease (also called senile dementia, Alzheimer's type)
      • Creutzfeldt-Jacob disease
      • Diffuse Lewy Body disease
      • Huntington's disease
      • Multiple sclerosis
      • Normal pressure hydrocephalus
      • Parkinson's disease
      • Pick's disease
    • Dementia due to metabolic causes
    • Drug and alcohol-related conditions
      • Alcohol withdrawal state
      • Intoxication from drug or alcohol use
      • Wernicke-Korsakoff syndrome (a long-term effect of excessive alcohol consumption or malnutrition)
      • Withdrawal from drugs (especially sedative-hypnotics and corticosteroids)
    • Infections
      • Any sudden onset (acute) or long-term (chronic) infection
      • Blood poisoning (septicemia)
      • Brain infection (encephalitis)
      • Meningitis (infection of the lining of the brain and spinal cord)
    • Other medical disorders
      • Cancer
      • Kidney disease
      • Liver disease
      • Thyroid disease (high or low)
      • Vitamin deficiency (B1, B12, or folate)

    Other conditions that may mimic organic brain syndrome include:

    • Depression
    • Neurosis
    • Psychosis