Alternate Names: OBS; Organic mental disorder; Chronic organic brain syndrome

Causes and Risks: OBS is a common "diagnosis" of the elderly. It is not an inevitable part of aging, however. OBS is not a separate disease entity, but is a general term used to categorize physical conditions that can cause mental changes.

Disorders associated with OBS include, but are not limited to:

• Degenerative disorders:
  • Creutzfeldt-Jacob disease
  • Huntington disease
  • Multiple sclerosis
  • Normal pressure hydrocephalus
  • Pick’s disease
  • Senile dementia/Alzheimer’s type
• Cardiovascular disorders:
  • Arrhythmias -- may cause some types of OBS
  • Cardiac infections (endocarditis, myocarditis, etc.) -- may sometimes cause OBS
  • Hypertensive brain injury
  • Multi-infarct dementia
  • Stroke
  • TIA
• Trauma-induced brain injury:
  • Chronic subdural hematoma
  • Concussion
  • Intracerebral hemorrhage
  • Subarachnoid hemorrhage
• Dementia due to metabolic causes
• Respiratory conditions -- may cause or aggravate OBS
  • Hypoxia (decreased oxygen in the body)
  • Hypercapnia (increased carbon dioxide levels in the body)
• Infections
  • Any acute or chronic infection
  • Septicemia (presence in the bloodstream of toxic by-products caused by infection)
  • Meningitis
  • Encephalitis
• Drug and alcohol related conditions
  • Intoxication, drug abuse or alcohol use
  • Long-term effects of alcohol, Wernicke-Korsakoff syndrome
  • Alcohol withdrawal state
  • Withdrawal from drugs (especially sedative-hypnotics and corticosteroids)
• Parkinson’s disease

Prevention: Prevention for most of these disorders are unknown.

Symptoms: Symptoms vary with the specific disease. In general, organic brain syndromes cause varying extents of confusion, delirium (severe, short term losses of brain function), agitation, and dementia (long-term, often progressive, losses of brain function).

Signs and Tests: Testing and physical examination vary depending on the specific disorder.

Treatment: Treatment varies with the specific disorder. Many of the disorders have nonspecific treatments, primarily supportive care to assist the person in areas where brain function is lost. Medications may be needed to reduce aggressive behaviors typical of some of the conditions in this category.

Prognosis: See the specific disorder. Some disorders are acute and treatable, but many are chronic or progressive.

Complications: Loss of ability to interact or function independently is common.

Call your health care provider if "organic brain syndrome" has been diagnosed and you are uncertain of the actual, specific diagnosis.