Hallucinations are a common symptom in dementia. Some hallucinations are caused by the dementia-causing disease itself, sometimes by medications and sometimes by other conditions. Hallucinations can occur in almost anyone under the right circumstances. Elderly patients with dementia are much more susceptible to additional neurological insults than a healthy person.
Hallucinations Caused by Dementia
Visual hallucinations are prominent in Lewy body dementia and can be the first symptom of the disease. As explained by MayoClinic.com, this is a type of dementia that shares some aspects of both Parkinson's and Alzheimer's. A study published in "Psychosomatics" states that about one quarter of patients with Alzheimer's suffer from hallucinations. According to "Harrison's Principles of Internal Medicine," hallucinations in Lewy body dementia as well as in Alzheimer's may be linked to a deficiency in the neurotransmitter acetylcholine.
Other Medical Conditions
Elderly people in general are prone to hallucinations when medically ill. Dementia exacerbates this tendency. Patients with dementia who are hospitalized for treatment of any medical condition are very sensitive to changes in the environment, such as the level of lighting and noise, and also to isolation. Typically the elderly patient is seen picking at nonexistent things in the air. Also common are hallucinations of little animals walking along the walls. Urinary tract infections and pneumonia are common causes for delirium, a condition that includes confusion and hallucinations. Metabolic disturbances such as low or elevated blood sugar and low or elevated blood sodium can also lead to hallucinations. Strokes, meningitis and seizures are among the neurological conditions that can complicate dementia and cause hallucinations.
Medications
Medications that increase dopamine in the brain, used in the treatment of Parkinson's disease, can cause hallucinations. Many commonly used medications for a variety of conditions can cause hallucinations in a patient with dementia. Examples include benzodiazepines such as diazepam or lorazepam and narcotics such as morphine. Alcohol intoxication and withdrawal can cause hallucinations. And this should always be kept in mind as a possible cause, since with enough determination, an alcoholic patient with dementia might be able to obtain alcohol even in a nursing home.
References
- "Psychosomatics"; Delusions and Hallucinations in Alzheimer's Disease: Review of the Brain Decade; Medhat Bassiony and Constantine Lyketsos; October 2003
- "Harrison's Principles of Internal Medicine"; Anthony Fauci et al.; 2008
- MayoClinic.com: Lewy Body Dementia
