Transcript Dr L Downie - Grampian Dementia Care

Direct Access to Imaging for Dementia
Diagnosis in Primary Care
Dr. Linda Downie, Cuminestown Medical Practice 2014
DIAGNOSIS OF DEMENTIA IN PRIMARY CARE
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The SIGN guidelines define dementia as:
‘A generic term indicating a loss of intellectual functions including memory, significant deterioration in the
ability to carry out day-to-day activities, and often, changes in social behaviour.’
As the population ages and becomes better informed about dementia the prevalence of people
diagnosed with the condition will continue to rise. As things stand the diagnosis of dementia is made by
Older Adult Psychiatrists however much of the ongoing management of the condition is already being
done by Primary Care.
The Integrated Care Pathway for Dementia paves the way for competent GP’s to confidently make the
initial diagnosis and instigate the appropriate treatments and supports. Much of what is required is
already done in Primary Care however there are some barriers that can be identified to overcome.
SIGN guideline 86 Feb 2006 summarises its recommendations on imaging in the diagnosis of dementia
as:
Structural imaging should ideally form part of the diagnostic workup of patients with suspected dementia.
SPECT may be used in combination with CT to aid the differential diagnosis of dementia when the
diagnosis is in doubt.
NICE Clinical Guideline 42 Nov 2006 recommends:
Structural imaging should be used in the assessment of people with suspected dementia to exclude other
cerebral pathologies and to help establish the subtype diagnosis. Magnetic resonance imaging (MRI) is the
preferred modality to assist with early diagnosis and detect subcortical vascular changes, although
computed tomography (CT) scanning could be used. Specialist advice should be taken when interpreting
scans in people with learning disabilities.
Perfusion hexamethylpropyleneamine oxime (HMPAO) single-photon emission computed tomography
(SPECT) should be used to help differentiate Alzheimer’s disease, vascular dementia and frontotemporal
dementia if the diagnosis is in doubt. People with Down’s syndrome may show SPECT abnormalities
throughout life that resemble those in Alzheimer’s disease, so this test is not helpful in this group.
A further meeting was arranged to discuss the logistics of direct access to imaging from Primary care
with Dr Alison Murray, Consultant Neuroradiologist, Dr Essem and Dr Lawrie, Consultants in Older
Adult Psychiatry, GP, CPN and a representative from Alzheimer's Scotland. Dr Alison Haddow has also
been involved. It was recognised that imaging alone cannot diagnose dementia, it is a clinical diagnosis
based on persisting acquired cognitive deficits in more than one area of cognition interfering with
activities of daily living. Some signs can be seen which indicative of dementia but these can vary widely
with the actual level of cognitive decline and are influenced by numerous factors such as level of
cognitive reserve and pre-morbid IQ. However as imaging plays an important role in the diagnostic
process as recognised by both SIGN and NICE guidelines it is necessary to enable access to appropriate
imaging by the appropriate professional at the appropriate time.
SPECT CT as a combination procedure is easier on patients as it only involves one visit to the scanner
and the radiation dose is the same as having a SPECT and CT scan. In the age range for patients
receiving this test for this indication the risk of the exposure to this level of radiation causing a future
cancer is probably negligible. Possible dementia indicators can be picked up slightly earlier on SPECT
CT than CT alone. There is no limitation to who can receive SPECT based on renal function or allergies
as iodine is not used in the injection.
CT alone without SPECT is a shorter, less expensive procedure that does not involve any injected
substance. It will exclude other cerebral pathologies causing cognitive impairment and established
changes consistent with Vascular, Alzheimer’s and Fronto-Temporal dementia can be identified.
In Aberdeen CT or CT SPECT are the commonly used scanning modalities for dementia diagnosis. MRI
is unfeasible as our available scanners are already at capacity for essential investigations. Professor
Murray confirmed that CT and CT SPECT provide all of the necessary information to exclude other
cerebral pathologies and establish the subtype diagnosis (with the exception of Lewy Body Disease in
the absence of Parkinsonism which if clinically suspected would require a specific type of scan using
radioactive dopamine).
As part of a working group that comprised of GP’s, Older Adult Psychiatrists, a CPN ,
a District Nurse, social work and a representative from Alzheimer’s Scotland we
identified where in the pathway potential barriers lay.
Dr Lawrie and Dr Essem discussed that they most frequently rely on CT scans for their clinical practice
and that in some cases they were happy to make clinical diagnosis without the need for a scan and that
in cases where clinical management would not be altered regardless of the result a scan would not be
indicated. Professor Murray indicated that in her experience some of the Psychiatrists did have a
preference for requesting CT SPECT for diagnostic purposes.
The format of reporting scans was also discussed and it was raised that for the scan results to be useful
and accessible to GP’s who may only have to interpret a couple of scans a year that a clear indication of
the dementia subtype(s) related to the changes seen would be very helpful. Dr Murray proposed a
reporting template for the radiologists to use to allow clear interpretation of results by GP’s.
Following our discussions it was recognised that there is potential for change to the current system
and that this could be evaluated for its health economic benefits, both with regards to enabling the new
pathway and future planning for the expected increase in diagnosis of dementia with the changing
population demographics towards an older cohort of patients. We have met with Paul McNamee from
the health economic department for guidance on properly evaluating our process.
Next Steps
This is an ongoing project and the next step will involve identifying GP practices who have engaged
with the dementia scholarship to have access to either CT or CT SPECT for their new diagnosis of
dementia and comparing scans and patient outcomes with data from practices which have not yet
engaged and will continue for the present time with the current system for dementia assessment
through secondary care. Colleagues will be invited to participate in this over the next few months and
we are applying for research funding.
The 3 area’s highlighted were:
1.Lack of ability of GP’s to directly refer for imaging
2.Grampian Joint Formulary states anticholinesterase inhibitors to be initiated by
specialists in dementia
3.Currently post-diagnostic support is accessed through secondary care team
referral.
For the purposes of this project I have concentrated on access to imaging although
discussions are ongoing regarding the other area’s.
Learning Points
Participating in the dementia scholarship has given me much greater confidence in dealing with
patients with dementia and their potential complications. I have an in depth understanding of the
issues surrounding the diagnosis and management of dementia and through this have made contacts
with Psychiatry, Radiology, Health Economics and 3rd Sector colleagues.