Investigation of suspected dementia
Routine investigations that should be conducted at the first presentation include:
- Full blood count (FBC)
- Urea and electrolytes (U&E)
- Liver function test (LFT)
- Calcium
- Thyroid function tests
- Serum vitamin B12 and folate levels
- CT scan of brain without contrast
B12 deficiency, thyroid abnormalities and calcium excess can all cause symptoms like dementia.
The CT scan is useful for excluding other causes of dementia such as tumour or normal pressure hydrocephalus. A CT scan is also useful for identifying the amount of ischemic cerebro vascular disease. Recommended practice is to request a CT scan without contrast unless a tumour or vascular lesion is suspected.
At presentation it is recommended to perform a midstream urine test (MSU) if delirium is considered a possibility.
Other investigations
Other investigations that should be considered to rule out other causes e.g. delirium, depression and CVA include:
- ESR
- Chest X-ray
- Electrocardiogram (ECG)
- Lipid study
- Fasting blood sugar levels (BSL)
(An ECG will help rule out conditions that may contradict with cholinesterase inhibitor medications in the future).
Special investigations
Special investigations that can also be conducted include:
- Electroencephalogram (EEG)
- Syphilis serology or HIV
- Magnetic resonance imaging (MRI)*
- Positron emission tomography (PET)*
- Neuropsychological assessment
These investigations should not be undertaken routinely unless there are risk factors identified or clinical presentation determines the need for further testing.
* Request by a specialist is required for MRI and PET investigations so that the patient can claim the MBS rebate.