Dementia with Lewy bodies: The emerging role of primary care

ABSTRACT

Introduction: Dementia with Lewy bodies (DLB) is an under recognized but frequent subtype of dementia. Misdiagnosis and delays in referral from primary care are common when compared to other forms of dementia.

Case: We present a case of a 63-year-old man who was eventually diagnosed with DLB three and a half years after his initial presentation.

Discussion: Core features of DLB such as hallucinations, Parkinsonism and fluctuating levels of cognition need to be recognized in primary care as being part of the DLB phenotype. DLB is a complex and debilitating neurodegenerative disorder often requiring multidisciplinary support to enable affected individuals to live well in the community. Carers of DLB patients often develop higher levels of subjective burden compared to carers of patients with other forms of dementia; this needs to be recognized and managed appropriately. There is limited research into the role of primary care physicians in DLB. Efforts should be made to reduce delays in identification.

Conclusion: Primary care has an important role in identifying those who are at risk for DLB and in referring these patients timely to the appropriate specialist. Adequate management of these patients in the community might reduce the burden associated with the DLB phenotype.

Keywords:

• Cognitive disorders and dementia
• diagnosis/diagnostic research
• health education

KEY MESSAGE

• Dementia with Lewy bodies (DLB) is under recognized and sometimes misdiagnosed despite accounting for 10–20% of new dementia referrals.

• Primary care physicians have an increasingly important role in suspecting and subsequently managing these complex patients.

• Further research into DLB in primary care would be advantageous to both patients and carers.

Introduction

Dementia with Lewy bodies (DLB) accounts for 10–20% of new dementia referrals (1,2). Despite this, DLB remains under-diagnosed with more than 50% of cases missed (3); DLB can be misdiagnosed as other forms of dementia including Alzheimer’s disease (AD) as it shares similar clinical and pathological features (4). DLB caregivers often struggle for long periods before an accurate diagnosis is made, and DLB patients often have worse quality of life compared to those with AD (5). It is estimated that by the year 2020, three million people in Europe will be affected by DLB if no effective treatment is offered (6).

DLB is a difficult condition to diagnose, particularly as the signs and symptoms may not be initially obvious as ‘dementia illness’ (7). Consequently, primary care physicians may initially struggle to refer these patients to appropriate services as their presentation with atypical symptoms of dementia may lead to referral to non-specialist services, for example, falls assessment services or geriatrics.

As with all cases of dementia, timely diagnosis remains a key priority to allow DLB patients and their carers earlier, and more timely access to services and allow them to live well in the community. Primary care physicians have a vital role in ensuring that an appropriate secondary care referral is made. In the short-term, timely diagnosis ensures access to pharmacological and psychosocial interventions, as these patients often respond well to cholinesterase inhibitors (8,9). A timely diagnosis of DLB also ensures the avoidance of inappropriate use of neuroleptic medications use by primary and secondary clinicians, which can have potentially serious and deleterious effects on these patients (10). In the longer term, the use of cholinesterase inhibitors can delay nursing home placement (11) and thus earlier treatment may have significant social impact. Earlier diagnosis also allows families and caregivers time to plan for future care and ensure preventative measures are in place e.g. in the home environment to reduce the morbidity associated with recurrent falls for patients with DLB. We highlight a case report, which demonstrates the inherent difficulties that primary care physicians face when presented with a patient suspected of having DLB.

Case

A 63-year-old man initially presented to his primary care physician with headaches, memory loss and possibly some personality changes (apathetic but anxious) according to his wife. He had no objective memory loss on brief cognitive assessment and he was therefore referred urgently to a neurology specialist to exclude a frontal brain tumour. A CT scan of the brain was found to be normal, and he was discharged from secondary care. He was seen again by his primary care physician and treated for depression and while his mood lifted, his subjective memory loss worsened over the next nine months. At this point, he was referred to a memory clinic, where he was diagnosed with possible mild cognitive impairment. It was noted however that he was too anxious and tremulous during the assessment to make a definitive diagnosis. He was given a one-year review appointment. A further review by his primary care physician six months later found that he had now developed ‘complex partial seizures’ associated with strange visual disturbances in the form of migraine-like hallucinations. He was referred to a neurologist with epilepsy expertise whilst the memory clinic was asked to expedite his review appointment. While waiting for both referrals, the patient experienced ‘drop attacks’ and falls and was referred to geriatrics by another primary care physician who had seen him separately. He was eventually reviewed in the memory clinic that resulted in further neuroimaging and in-depth neurocognitive assessment by a psychologist. He was eventually diagnosed with DLB dementia 42 months after his initial presentation.

Discussion

The case report describes an individual with memory deficits associated with some suggestive features (depression, falls, and transient loss of consciousness) of DLB. It also highlights both the diagnostic uncertainty (and subsequent multiple referrals) and delay in diagnosis associated with the condition. However, primary care physicians are faced with difficulties in not only the initial recognition and referral of suspected DLB cases (as demonstrated in the case above) but also in ongoing management post diagnosis to ensure their wellbeing in the community.

When to suspect a case of dementia with Lewy bodies

Diagnosis of individuals with DLB is usually made at secondary care level. However, primary care physicians need to be aware of some of the features of DLB to ensure that it is not missed as part of the differential diagnosis on presentation. Revised criteria have been published to guide the clinical diagnosis of DLB (Table 1) (12).

Table 1. Revised criteria for the clinical diagnosis of dementia with Lewy bodies. Adapted and based on McKeith et al. (12).

Central features^a	Core features^b	Suggestive features^c	Supportive features^d
Dementia defined as progressive cognitive decline of sufficient magnitude to interfere with normal social or occupational function.	Fluctuating cognition disorder	Rapid eye movement sleep behaviour	Falls and syncopal episodes
Prominent or persistent memory impairment may not necessarily occur in the early stages but is usually evident with progression.	Recurrent visual hallucinations	Severe neuroleptic sensitivity	Transient, unexplained loss of consciousness
Deficits on tests of attention, executive function, and visuospatial ability may be especially prominent.	Spontaneous features of Parkinsonism emission tomography imaging	Low dopamine transporter uptake in basal ganglia demonstrated by single-photon emission computed tomography or positron	Severe autonomic dysfunction, e.g., orthostatic hypotension, urinary incontinenceHallucinations in non-visual modalitiesSystematic delusionsDepressionRelative preservation of medial temporal lobe structures on imaging (CT or MRI)Preservation of medial temporal lobe structures on CT/MRI scanLow uptake meta-iodobenzylguanidine myocardial scintigraphySlow wave activity on EEG with temporal lobe transient sharp waves

A diagnosis of DLB is less likely if there is evidence of cerebrovascular disease on imaging, any other physical illness or neurological disorder or if Parkinsonism appears in severe dementia.

^aEssential for possible or probable DLB.

^bTwo core features are needed for probable DLB, one for possible DLB.

^cDiagnosis of DLB can also be made if there is ≥ 1 suggestive feature is present in addition to ≥ 1 core feature. If there are only suggestive features then possible DLB can be diagnosed.

^dCommon at presentation but no diagnostic specificity.

CT, computed tomography; MRI, magnetic resonance imaging.

Probable DLB can be diagnosed if the following criteria are met:

1. The presence of dementia AND two of the three core features.

2. The presence of dementia AND at least one suggestive feature with one core feature.

Possible DLB is diagnosed in the presence of dementia AND at least one core feature OR at least one suggestive feature.

Although supportive features lack diagnostic specificity, they are commonly present in patients with DLB and suspicions may be aroused in the community if a patient fits the criteria for dementia and has supportive features (Table 1) of DLB. Few caregivers and family members know to report these non-cognitive symptoms and ascribe these symptoms to other reasons. In primary care, the history is the key in arousing suspicion of DLB. Table 2 highlights some aspects in the history that are often associated with DLB. It is, therefore, important to ensure these features are sought for in those arousing suspicion of dementia, as patients presenting with the combination of any of these features should be referred on to memory clinic services.

Table 2. History arousing suspicion for dementia with Lewy bodies.

1.	History of repeated unexplained falls.
2.	History of tremor/loss of facial expression/slowed movements.
3.	History of shouting out/active movements during sleep which might raise the suspicion of rapid eye movement sleep behaviour disorder.
4.	History of anosmia—often predates the occurrence of DLB by many years.
5.	Long standing constipation and postural blood pressure problems can also be a feature.
6.	Unexplained mild/subtle visual disturbances e.g. presence/passage hallucinations, illusions, problems with intermittent double vision.
7.	Recurrent history of unexplained delirium.

It should be noted that Parkinson’s disease dementia (PDD) is closely related to DLB with dementia developing in up to 80% of Parkinson’s disease (PD) patients over time (13). This can lead to confusion as to whether a presentation is PDD or DLB. However, a ‘one-year rule’ is used to separate PDD from DLB where the onset of dementia within 12 months of Parkinsonism qualifying as DLB. If Parkinsonism is present for more than 12 months before dementia is diagnosed, then it is termed PDD. PDD and DLB are considered together as Lewy body dementias (LBD) and they probably represent different points on a Lewy body disease spectrum as they share common clinical features.

What are the diagnostic difficulties associated with DLB?

It is estimated that DLB accounts for around 1 in 25 of all diagnosed dementia cases in the community (14). Difficulties encountered in primary care diagnosis of dementia as a whole include atypical or non-specific presentations, the presence of co-morbid features and visuoperceptual features (15). There are many factors that may delay timely diagnosis in primary care. From the patient’s and caregiver’s perspective there can be a misinterpretation or denial of symptoms (for fear of stigmatism) and also a fear of institutionalization once a diagnosis has been made (16). Older patients can often present with many co-morbid conditions, which further limits the time required in primary care consultations to make a diagnosis of dementia. DLB itself shares clinical features with more widely recognizable diseases such as the dementia phenotype of AD, the motor phenotype of PD and the psychotic and behavioural disturbances of psychiatric aetiology. Referrals are subsequently made to other specialties where a diagnosis of DLB is not suspected leading to a delay in diagnosis and treatment (17,18).

Management of DLB patients in the community post-diagnosis

Managing DLB patients in the community is often a complex process. It is important that primary care physicians are well educated in DLB so that they can educate patients and caregivers on the symptoms, expectations and progression of the disease as well as instigate anticipatory care for future needs. Behavioural and psychological symptoms of dementia (BPSD) are well-known sources of caregiver burden (19). All BPSD tend to worsen over the course of disease.

In the community, the primary care physician will be asked to manage some of the more non-cognitive aspects of the disease. DLB patients are prone to repeated falls and syncope, transient, unexplained loss of consciousness as well as severe autonomic dysfunction leading to urinary incontinence and constipation. This can also lead to higher mortality than those with AD of similar severity due to greater functional impairment (20). Simple measures can often be adopted to prevent this from occurring in the community. For example, falls secondary to orthostatic hypotension can be managed with hydration, salt intake, avoidance of prolonged immobility, compression stockings, environmental adaptations and review of current medication.

Management of carers of DLB patients in the community post-diagnosis

Caregivers often develop higher levels of subjective burden than AD carers (2). There tends to be a lack of information available for the care of people with DLB when compared to AD or other forms of dementia and DLB caregivers may feel isolated or unsure about whether their care is appropriate or correct. This is highlighted by the fact that DLB caregivers are less likely to engage with services than caregivers of people with more typical dementia diagnoses (2). Resources such as the Lewy Body Society (http://lewybody.org) or the Lewy Body Association (http://www.lbda.org) can be valuable sources of information for ongoing support.

Future practice and research

In practice, there may be an ongoing need to increase physician’s knowledge of DLB to assist in early referral to secondary care. There may also be a need for increased awareness of regional and national support services that can benefit both the carer and care recipient. This can help alleviate some of the isolation that DLB carers feel and increase their usage of appropriate services to assist them in the care of the patient with DLB. There is also a need to strengthen and further develop the transition from primary to secondary care specialists. It has been found that the chance of referrals being made was higher in GPs who felt that there was a greater readiness among specialists to accept patients for the diagnosis of dementia (21).

Currently, there is little DLB research in primary care. A first step could be to evaluate the experience of patients diagnosed with DLB when compared to other forms of dementia such as AD to assess the key differences in their diagnostic pathway. Second, we need to highlight the experience of primary care physicians in in both diagnosis and ongoing management of DLB. For example, assessing whether practical guidelines in managing specific symptoms (depression, preventing falls, visual hallucinations, etc.) would be useful.

Conclusion

DLB is underdiagnosed but it is important to consider this dementia phenotype amongst the differential for the primary care physician when assessing patients with cognitive impairment. There is the potential for misdiagnosis due to vague signs and symptoms. Primary care has a central role in raising the suspicion DLB and appropriate referral when indicated.

Declaration of interest

The authors report no potential conflicts of interest. The authors alone are responsible for the writing and content of this paper.