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Introduction to Dementia

Dementia is a chronic or progressive condition, usually of cognitive function. For example, memory loss and reduced thinking skills. It can affect memory, thinking, orientation, comprehension, numeracy, learning, language and judgement, but not consciousness. Cognitive impairment is usually accompanied by a decline in emotional control, social behaviour and motivation. Dementia is an umbrella term for memory loss and other mental abilities that significantly affect daily life. Dementia is caused by damage to brain cells and there are many different types of dementia, for example Alzheimer's disease, Vascular dementia, Lewy body dementias, Parkinson's disease, Frontotemporal dementia, Huntington's disease, HIV-associated dementia, Creutzfeldt-Jakob disease, Alcohol-related dementia. The dividing line between the different types of dementia is unclear and mixed types of dementia can exist. Alzheimer's disease, on the other hand, is the most common type of dementia, accounting for approximately 60-70% of dementia cases.

 

NIA-AA CORE CLINICAL DIAGNOSTIC CRITERIA FOR ALL-CAUSE DEMENTIA.

The patient has cognitive or behavioural symptoms that:

1. interferes with the ability to perform work or daily activities

2. decreases from previous levels of functioning and performance

3. cannot be explained by delirium or major mental disorder

 

The detection and diagnosis of cognitive impairment is made by:

1. a history taken from the patient and an informed person

2. an objective cognitive assessment, such as a "mental status examination or neuropsychological test

 

Cognitive or behavioural disorders involve at least two of the following areas:

1. impaired ability to acquire and remember new information

2. impaired ability to reason, judge and process complex tasks

3. impaired visuospatial ability

4. impaired language function

5. changes in personality, behaviour or demeanour

 

Clinical manifestations of Alzheimer's disease

In the absence of sudden changes in cognition or function, it is almost imperceptible. The most common clinical manifestation is amnesia, characterised by progressive memory loss of recent events. Patients often have difficulty remembering recent conversations, dates, things to do, etc. The cognitive decline is gradual over the course of the disease. Behavioural impairment may occur in the moderate stage. Near total dependence on others for daily care and loss of function are common in the late stages.

 

Cognitive Symptoms

Ø  Memory loss (poor recall and losing items)

Ø  Aphasia (circumlocution and anomia)

Ø  Apraxia

Ø  Agnosia

Ø  Disorientation (impaired perception of time and unable to recognize familiar people)

Ø  Impaired executive function

 

Neuropsychiatric Symptoms

Ø  Depression, psychotic symptoms (hallucinations and delusions)

Ø  Behavioral disturbances (physical and verbal aggression, motor hyperactivity, uncooperativeness, wandering, repetitive mannerisms and activities, and combativeness)

 

Functional Symptoms

Ø  Inability to care for self

²  Dressing

²  Bathing

²  Toileting

²  Eating

²  Difficulty walking

 

The Minimum Mental State Examination (MMSE) is a 30-point assessment tool for Alzheimer's disease, which classifies Alzheimer's disease into three levels: mild, moderate and severe.

Mild is an MMSE score of 26-21, which means that the person has difficulty remembering recent events. The ability to manage finances, prepare food and carry out other household activities is reduced. May get lost when driving or walking. Begin to withdraw from difficult tasks or give up hobbies and may refuse to remember problems.

Moderate is an MMSE score of 20-10, meaning the person needs assistance with activities of daily living. Often disoriented in terms of time. Recollection of recent events is severely impaired, some details of past life and the names of family and friends may be forgotten, and functioning may vary from day to day. Patients often have problems recognising and losing the ability to drive safely. Agitation, paranoia and delusions are common.

Severe is an MMSE score of 9-0, meaning that the person has lost the ability to speak, walk and eat. Incontinence. Care is required 24 hours a day, 7 days a week.

 

Treatment goals for Alzheimer's disease

1. to treat symptomatic cognitive impairment to maintain the patient's function for as long as possible.

2. to manage psychiatric and behavioural sequelae.

 

Medication for Alzheimer's disease

Acetylcholinesterase inhibitors (AChEIs) have been shown to be beneficial in the early and ongoing treatment of Alzheimer's disease by delaying the progression of cognitive decline, possibly improving quality of life, and are the mainstay of treatment for Alzheimer's disease. Acetylcholinesterase inhibitors increase the level of the neurotransmitter acetylcholine in neuronal synapses, thereby enhancing cholinergic activity in the affected brain regions. In moderate to severe cases, the addition of methylphenidate may be beneficial. This approach can be followed to maintain maximum cognitive and motor activity in daily life. The most common adverse reactions associated with the use of AChEI are nausea, anorexia and diarrhoea. Serious adverse side effects include bradycardia, atrioventricular block and syncope. Gastrointestinal side effects can be reduced by taking with food.

 

FDA approved drug for Alzheimer's disease treatment

MEDICATION	INDICATION	DOSE RANGE	ADVERSE EFFECTS
Donepezil	Mild-to-moderate	ü  5–10 mg once daily at bedtime ü  Effective dose: 5–10 mg daily	Bradycardia or heart block, syncope, nausea, diarrhea, insomnia, vomiting, muscle cramps, fatigue, anorexia
Donepezil (available as generic donepezil in 10-mg tablets or Aricept in 10- or 23-mg tablets)	Moderate-to-severe	ü  10 mg once daily at bedtime ü  Effective dose: 10 or 23 mg daily	Bradycardia or heart block, nausea, diarrhea, insomnia, vomiting, muscle cramps, fatigue, anorexia
Galantamine (available as generic galantamine, galantamine ER, Razadyne, or Razadyne ER)	Mild-to-moderate	Immediate-Release Tablets or Oral Solution: ü  4–12 mg twice daily Extended-Release Capsules: ü  8–24 mg once daily	headache, decreased appetite, weight loss
Rivastigmine (available as generic rivastigmine capsules or Exelon capsules, oral solution, or transdermal patch)	Mild-to-moderate	Capsules or Oral Solution: ü  1.5–6 mg twice daily Patch: ü  Effective dose: 9.5 mg/24 h	Nausea, vomiting, anorexia, dyspepsia, weakness
Memantine (available as generic memantine tablets or Namenda tablets or oral solution)	Moderate-to-severe	Tablets or Oral Solution: ü  10 mg twice daily	Dizziness, headache, confusion, constipation
Memantine extended release (available as Namenda XR)	Moderate-to-severe	ü  Patients on memantine 10 mg twice daily may be switched to Namenda XR 28 mg daily the day following the last dose of 10-mg memantine ü  Effective dose: 28 mg daily	Headache, diarrhea, dizziness
Namzaric (memantine HCl ER and donepezil HCl) capsules	Moderate-to-severe	ü  Once patient stabilized on a daily dose of memantine ER (10 mg twice daily or 28 mg ER once daily) and donepezil 10 mg daily may switch to Namzaric 28-/10-mg capsule once a day in the evening	Headache, diarrhea, dizziness, anorexia, vomiting, nausea, ecchymosis

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reference:

Hazzard's Geriatric Medicine and Gerontology, 7e.

Pharmacotherapy: A Pathophysiologic Approach, 11e.

WHO.