Dementia

    By Kottapurath Kunjumoideen MD

Introduction
Dementia is the loss of intellectual abilities like memory, judgment and abstract thinking previously attained, now which is severe enough to interfere with social or occupational functioning. Memory deficit is the most important feature of dementia. Language, calculating abilities, judgment of a situation, problem solving abilities are lost. Dementia affects 3-11% of the community dwelling adults who are more than 65 years of age. Risk factors for dementia are advanced age, family history of dementia and apolipoprotein E-4 allele.

How are dementias classified?
Dementia can be caused by variety of conditions. They are classified into reversible and irreversible dementias. Reversible dementia constitutes 10-20% of all dementias and they can be cured or at least partially treated, if the basic underlying problem is solved.

Causes of remediable (reversible) dementias:

• Intoxications:
• Medications like Alfamethyldopa, digitalis, lithium, beta blockers, alpraxolam, clonazepam, opiates, and antihistamines
• Substance abuse including alcohol
• Heavy metals like lead, mercury and arsenic
• Infection of the central nervous system:
• Chronic bacterial meningitis or partially treated meningitis
• Neurosyphilis in AIDS patients.
• Chronic infections like tuberculous meningitis
• Herpes encephalitis
• AIDS dementia complex: This is the most frequent neurological complication of AIDS
• Metabolic/Nutritional:
• Hypo/hyperthyroidism
• Hypo/ hyperglycemia
• Parathyroid disease
• Hypopituitarism
• Calcium abnormalities
• Cushing's disease
• Porphyria
• Uremia
• Wilson's disease
• Vitamin B 1 deficiency can cause Wernicke's encephalopathy and then Korsakoff's demetia
• Vitamin B12 deficiency
• Folate deficiency usually results from poor dietary intake, frequently facilitated by alcoholism. May produce irritability, memory loss, personality changes. It is reversible if corrected early.
• Structural and neoplastic:
• Hydrocephalus including obstructive and normal pressure hydrocephalus
• Subdural hematomas especially chronic
• Gliomas
• Meningeal carcinomatosis.
• Vascular:
• Hypertension produces multi infarct dementia
• CNS vasculitis
• Hypoperfusion- cardiac disorders

Causes of Non-remediable dementias:

• Alzheimer's disease: This accounts for 50% of the dementias
• Pick's disease
• Fronto temporal atrophy without picks bodies
• Lewy body disease
• Spinocerebellar degeneration
• Parkinson's disease
• Hungtington's chorea
• Inflammatory conditions like multiple sclerosis, lupus erythematosis, sarcoidosis, Sjogren's syndrome
• Infectious disease with slow virus causes Creutzfeldt-Jakob disease
• Binswanger' s disease
• Delayed effect after brain irradiation
• Hypoxic encephalopathy
• Traumatic- after severe head injury

What symptoms does the patient with dementia have?
Initially there will be lack of interest in work. Forgetfulness is the earliest symptom. Patient can't remember the names properly. Difficulty in handling money and calculation becomes evident. The patient may repeatedly ask the same question, failing to retain the answers. Then he may no longer able to think about a problem or discuss about it. Unreasonable anger, easy crying and aggressiveness may be there. Frequent change in mood becomes evident. There will be difficulty in using a telephone, dressing or walking. The patient has difficulty in speaking. He substitutes words (paraphasia) and sometimes repeats the same sentences (echolalia). In later stages there will be difficulty in walking.

How do you diagnose dementia?
The history is the most important and must be taken from a reliable relative. The time when the symptoms started and how it started must be asked. Systemic diseases, history of trauma, surgery, psychiatric illness, alcohol abuse, exposure to occupational toxins should be ruled out. History of Urinary incontinence and gait disturbance should be asked.

Mini-mental state exam (MMSE) is the most widely used test to screen the cognitive impairment. Diagnosis is mainly based on clinical examination. Brain biopsy should be done for chronic conditions like slow virus disease. Patients with focal disease should undergo MRI and if there is a lesion in MRI, should undergo biopsy

Tests to be done are:

• Complete blood count
• Renal profile
• Thyroid function
• B12
• Folate
• Urine analysis
• CT brain

Optional tests include (done wherever necessary)

• MRI (to rule out structural causes)
• Liver function test
• Heavy metal screening
• ESR
• Antinuclear antibodies (to rule out lupus)
• VDRL
• EEG
• Spinal tap with CSF study.
• HIV titer (to rule out AIDS dementia complex)

What are the treatments available for dementia?
Patients with remediable causes of dementia like hypothyroidism, normal pressure hydrocephalus, chronic subdural hematoma should be treated accordingly after consultation with the treating physician. For Alzheimer's disease drugs like rivastigmine are available which gives some improvement. Sedatives can be given for aggressiveness. Patient requires support from the family and friends. He should be taken care 24 hours because he may be disoriented and wander aimlessly.

Did you know?
Dementia is the loss of intellectual abilities like memory, judgment and abstract thinking previously attained, now which is severe enough to interfere with social or occupational functioning. Memory deficit is the most important feature of dementia. Language, calculating abilities, judgment of a situation, problem solving abilities are lost.