Diagnosis:
Neuropsychological/Psychometric testing
Or Clinical features
The underlying etiology is determined by a combination of clinical features, neuropsychological testing, imaging and laboratory testing
Clinical features:
This is an acquired persistent disorder where there is an impairment of the content of consciousness (intellectual function) with compromise in at least 2, e.g.:
- Memory
- Language i.e. aphasia
- Visuospatial skills e.g. apraxia, agnosia, navigation
- Executive function e.g. impaired abstraction, planning, judgment, reasoning etc.
- +impairment in functional independence
- Or pathology evidence of dementia
Severe dementia:
- MMSE score below 15 (or <10)
- or a clinical dementia rating CDR of 2 or higher
Differential Diagnosis:
- Don’t misdiagnose dementia in a patient who is really depressed a.k.a. pseudodementia
- Reversible causes are: thyroid dysfunction, B12 deficiency, intracranial mass, normal pressure hydrocephalus
Screening:
No single tests is satisfactory
MMSE, mini-mental state examination:
- If 21-23, suggests mild dementia. +LR= 9
- If <15 or <10, severe dementia
- If 24-26, do further testing
- If >26, suggests dementia is unlikely. –LR= 0.1
- When monitoring, a change of 4 is considered significant.
Abbreviated mental test AMT:
- If <6, suggests dementia
Investigations to consider:
Bloods:
- FBC: macrocytic anemia, infection
- ESR: chronic infection, vasculitis
- Complete metabolic panel, Ca++ +phosphate +albumin: hypercalcemia
- Glucose: a cause of delirium, diabetes as a risk factor
- Cholesterol +triglycerides
- TFT: hypothyroidism
- B12 & Folate levels & blood smear: vitamin B12 deficiency
- Liver enzymes: early hepatic encephalopathy
- Syphilis serology: VDRL, FTA-abs
- HIV serology: AIDS dementia complex
- Vasculitis screen: ESR, CRP, ANA screen, ENA panel (anti- dsDNA, anti-Sm, anti-RNP, SSA, SSB, anti-Jo-1, antitopoisomerase ‘formerly anti Scl-70’, antinucleolar, anticentromere), ANCA (c-ANCA, p-ANCA), Complement C3, C4 and CH50
- Ceruloplasmin, Copper: Wilson’s disease
- HIV serology: AIDS dementia complex
- PTH: Hyperparathyroidism
- Short ACTH stimulation test: screening for Addison’s disease
ECG: evaluation of cardiac disease
CXR: paraneoplastic & metastatic
CT:
- Normal pressure hydrocephalus
- Chronic subdural hematoma
- Neoplastic disease (orbitofrontal meningioma, Glioblastoma), multiinfarct dementia
Polysomnogram: obstructive sleep apnea
MRI:
- Normal pressure hydrocephalus
- Chronic subdural hematoma
- Neoplastic disease (orbitofrontal meningioma), multiinfarct dementia, leukoareosis on MRI in Binswanger’s disease, hippocampal atrophy in alzheimer’s, lymphoma
- CJD findings
EEG
MRI
Lumbar puncture:
- TB meningitis, cryptococcal meningitis, vasculitis, protein 14-3-3 in CJD, lymphoma,
Thrombophilia screen
Neuropsychological/Psychometric testing: localises affected areas
Screening for Cushing’s disease
Serum toxicology
Urine toxicology
Urine heavy metals
EEG: CJD or nonconvulsive seizures
If is early onset & positive family Hx. genotype for APP PS1 & PS2 mutations
PET Scan
SPECT Scan
Apolipoprotein E
Brain and meningeal biopsy: CJD or vasculitis, various dementias
Monitor:
Regular review for cataract & glaucoma
Regular review for cognitive state
MMSE: a change of 4 is considered significant
Assess nutrition, hydration & skin care
Treatment:
General measures:
- Influenza vaccination
- Address hydration, nutrition, skin care, cataract & glaucoma, risk of falls
- Avoid: Benzodiazepines as they worsen disinhibition & confusion
- Social: very important
- Education of family & carers
- Reality orientation: reinforce name, date, place & time when speaking to the patient
- Respite for carers
- Day hospital attendance
- Involve occupational therapy
- Involving a community psychiatric nurse
- See if they are eligible for benefits
- Address type of accommodation
- Recommend support from voluntary organisations
Specific Management for underlying cause