Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
The dementia in treatable conditions may be reversible or partially reversible, even if the underlying disease or damage is not. However, readers should note that if underlying brain damage is extensive or severe, these causes may be classified as irreversible by the individual's physician(s).
Head injury: This refers to brain damage from accidents, such as motor vehicle wrecks and falls; from assaults, such as gunshot wounds or beatings; or from activities such as boxing without protective gear. The resulting damage of brain cells can lead to dementia.
Normal pressure hydrocephalus: The brain floats in a clear fluid called cerebrospinal fluid. This fluid also fills internal spaces in the brain called cerebral ventricles. If too much fluid collects outside the brain, it causes hydrocephalus. This condition raises the fluid pressure inside the skull and compresses brain tissue from outside. It may cause severe damage and death. If fluid builds up in the ventricles, the fluid pressure remains normal ("normal pressure hydrocephalus"), but brain tissue is compressed from within.
Simple hydrocephalus: Simple hydrocephalus may cause typical dementia symptoms or lead to coma. In normal pressure hydrocephalus, people have trouble walking and become incontinent (unable to control urination) at the same time they start to lose mental functions, such as memory. If normal pressure hydrocephalus is diagnosed early, the internal fluid pressure may be decreased by putting in a shunt. This can stop the dementia, the gait problems, and the incontinence from getting worse.
Brain tumors: Tumors can cause dementia symptoms in a number of ways. A tumor can press on structures within the brain such as the hypothalamus or pituitary gland, which control hormone secretion. They can also press directly on brain cells, damaging them. Treating the tumor, either medically or surgically, can reverse the symptoms in some cases.
Toxic exposure: People who work around solvents or heavy metal dust and fumes (lead especially) without adequate protective equipment may develop dementia from the damage these substances can cause to brain cells. Some exposures can be treated, and avoiding further exposure can prevent further damage.
Metabolic disorders: Diseases of the liver, pancreas, or kidneys can lead to dementia by disrupting the balances of salts (for example, sodium and calcium) and other chemicals (like low glucose levels) in the blood. Often, these changes occur rapidly and affect the person's level of consciousness. This is called delirium. Although the person with delirium, like the person with dementia, cannot think well or remember, treatment of the underlying disease may fully reverse the condition. If the underlying disease persists, however, brain cells may die, and the person will have dementia.
Hormone disorders: Disorders of hormone-secreting and hormone-regulating organs such as the thyroid gland, the parathyroid glands, the pituitary gland, or the adrenal glands can lead to hormone imbalances, which can cause dementia if not corrected.
Poor oxygenation (hypoxia): People who do not have enough oxygen in their blood may develop dementia because the blood brings oxygen to the brain cells, and brain cells need oxygen to live. The most common causes of hypoxia are lung diseases such as emphysema or pneumonia. These limit oxygen intake or transfer of oxygen from the airways of the lungs to the blood. Cigarette smoking is a frequent cause of emphysema. It can worsen hypoxic brain damage by damaging the lungs and also by increasing the levels of carbon monoxide in the blood. Heart disease leading to congestive heart failure may also lower the amount of oxygen in the blood. Sudden, severe hypoxia may also cause brain damage and symptoms of dementia. Sudden hypoxia may occur if someone is comatose or has to be resuscitated.
Drug reactions, overuse, or abuse: Some drugs can cause temporary problems with memory and concentration as side effects in elderly people. Misuse of prescription drugs over time, whether intentional or accidental, can cause dementia. The most common culprits are sleeping pills and tranquilizers. Other drugs that cause dry mouth, constipation, and sedation ("anticholinergic side effects") may cause dementia or dementia symptoms. Illegal drugs, especially cocaine (which affects circulation and may cause small strokes) and heroin (which is very anticholinergic) may also cause dementia, especially in high doses, if taken for long periods, or in older people. The withdrawal of the drug usually reverses the symptoms.
Nutritional deficiencies: Deficiencies of certain nutrients, especially B vitamins such as low levels of vitamin B12, can cause dementia if not corrected.
Chronic alcoholism: Dementia in people with chronic alcoholism is believed to result from other complications such as liver disease and nutritional deficiencies.
Delirium, dementia, amnesia, and certain other alterations in cognition are subsumed under more general terms such as mental status change (MSC), acute confusional state (ACS), or organic brain syndrome (OBS).