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Clinicopathological case: rapid cognitive decline in an older man
  1. Shona Scott1,
  2. Jeremy Chataway2,
  3. Jon Stone1,
  4. Colin Smith3,
  5. Richard Davenport1
  1. 1Department of Clinical Neurosciences, Western General Hospital, Edinburgh, UK
  2. 2National Hospital for Neurology and Neurosurgery, Queen Square, University College Foundation NHS Trust, London, UK
  3. 3Department of Neuropathology, Western General Hospital, Edinburgh, UK
  1. Correspondence to Dr Shona Scott, Department of Clinical Neurosciences, Western General Hospital, Crewe Road, Edinburgh EH4 2XU, UK; Shonamscott{at}nhs.net

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History

An 83-year-old man presented as an emergency with rapidly emerging confusion and visual hallucinations. His family had noted mild cognitive symptoms for a year or two, but he was living independently, and had recently enjoyed a family celebration.

He was in good health and his medical history included angina and a cholecystectomy and transurethral prostatectomy. Eight years previously, his General Practitioner had noted an isolated episode when he awoke confused, making ‘out of context’ comments about money to his wife. A CT scan of head was reported as mildly atrophic for age, and he was referred to a psychogeriatrician, but he was never assessed as he recovered fully after this isolated episode. He was on no regular medication at the time of this admission.

On assessment, his Abbreviated Mental Test was 9/10 with a normal neurological examination. The following day he appeared more confused and agitated, and was treated with lorazepam and haloperidol. Two days later he was transferred for rehabilitation, with a diagnosis of delirium, possibly due to infection (see table 1 for a summary of investigations).

Table 1

Summary of investigations

On the rehabilitation ward, he was ‘drowsy and disorientated in time and place’. He had two falls over the next few days. On the fifth day of his admission, he became hypotensive with atrial fibrillation and a rapid ventricular rate. A neurologist saw him the following day, noting dysarthria with slurred, nasal speech. His conscious level and degree of confusion fluctuated, and on day 9 there were some myoclonic jerks. Later that day he was transferred to the regional Neurosciences unit for further assessment, including MR scan of brain. Imaging was postponed, however, as his airway was unsafe and soon after transfer, his airway safety deteriorated further, and he was intubated and ventilated (it was reasoned that although his prognosis was probably poor, there was no diagnosis). Further investigations were undertaken. He was given a single course of high-dose intravenous methylprednisolone, without effect. After discussion with the family, it was decided to extubate him, and he died 24 hours later, on day 20 after admission to hospital. A limited postmortem was performed.

Discussion by Dr Jeremy Chataway

I was hoping for a white matter case, perhaps mitochondrial encephalopathy with lactic acidosis and stroke-like episodes, vanishing white matter disease or a leukodystrophy1—but it's not to be! This is about an 83-year-old gentleman who presented to the emergency department and was a bit confused, had a normal CT head scan, then died within 3 weeks. He was well in the period leading up to admission.

So I thought I would introduce a Sherlock Holmes theme because Conan Doyle was of course born in Edinburgh and attended Edinburgh Medical School. He began writing when no patients came to his practice and eventually after several moves set up an ophthalmology practice near Baker Street—but again nobody came so he kept writing. The rest is history and so you will see an astute almost Holmesian approach to this CPC!Gregory (Scotland Yard detective); Is there any point to which you wish to draw my attention?Sherlock Holmes; The curious incident of the dog in the night-timeGregory; The dog did nothing in the night-timeSherlock Holmes; That was the curious incident.The Adventures of Silver Blaze. Sir Arthur Conan Doyle 1893So eliminate all other factors and the one that remains must be the truthA Study in Scarlett. Sir Arthur Conan Doyle 1897

And there are undeniable similarities between Professor Moriarty and Dr Richard Davenport, the organiser of this course. “I'm going to break you Holmes, I'm going to bring off right under your nose the most incredible crime of the century, and you'll never suspect it until it's too late. That will be the end of you Mr. Sherlock Holmes. And when I’ve beaten and ruined you then I can retire in peace. I'd like to retire; crime no longer amuses me. I'd like to devote my remaining years to abstract science”.However, we must proceed with the case.

His deterioration was rapid with visual hallucinations on a background of mild cognitive symptoms for a couple of years. He had fairly standard general medical complaints: heart disease, prostate problems and gastrointestinal disturbance and he was not on any medication.

Mild cognitive impairment

First we will explore mild cognitive impairment and why and how that could be important. Mild cognitive impairment is a function of age, but it can be on a spectrum that may progress to Alzheimer's disease. It is defined as a memory complaint when other aspects of cognitive function are within normal limits and activities of daily living are maintained. In patients with mild cognitive impairment the rate of development of Alzheimer's disease is about 12% per year compared with about 2% per year in controls without mild cognitive impairment.2

Visual hallucinations

There are several conditions that cause visual hallucinations so maybe the answer lies here. Table 2 summarises some of the terms used to describe visual hallucinations/distortions and lists conditions that may cause visual hallucinations.

Table 2

Different types of visual hallucination/disturbance and conditions that may cause visual hallucinations3

Further analysis

Initially he had a normal neurological examination and an Abbreviated Mental Test of 9/10, but became confused and agitated requiring lorazepam and haloperidol. A few days later he was hypotensive with deranged electrolytes and atrial fibrillation, and then became comatose requiring intubation. Was this neurological disease or evidence of a more systemic illness? The only neurological-sounding symptom was nasal speech but there were no other signs. There were myoclonic jerks (day 9), raising the possibility of prion disease, but it could also be metabolic derangement or infection.

Coma

Consciousness requires arousal and awareness and depends on a functioning ascending reticular activating system and the cerebral cortex.4 Box 1 provides the features that distinguish encephalopathy and encephalitis. In addition to structural causes of coma there are many others including metabolic derangement, seizures and infection.

Box 1

Criteria for diagnosing encephalopathy and encephalitis5

Encephalopathy

  • Symptoms persisting at least 24 hours

  • Depressed or altered level of consciousness including:

    • – Lethargy or

    • – Extreme irritability or

    • – Significant change in personality or behaviour and

    • – No other cause found

Encephalitis (Infectious or Autoimmune)

  • Encephalopathy+two or more of

    • – Pyrexia >37.5°C

    • – Seizure(s)

    • – Focal neurological findings

    • – Cerebrospinal fluid pleocytosis (>5 × 109/L)

    • – Characteristic abnormal findings on neuroimaging (CT or MRI)

Identifying the cause of coma

Once general medical causes of coma have been excluded then primary neurological causes should be considered, either central or peripheral. Patients might have both neurological and non-neurological causes either simultaneously or sequentially. In addition, there are important causes of encephalopathy not to overlook:

  1. Wernicke's encephalopathy (triad of ophthalmoplegia, encephalopathy and gait ataxia): alcohol consumption may be denied or hyperemesis of pregnancy overlooked. The lesions of chronic Wernicke's encephalopathy occur in a characteristic, symmetrical distribution in structures surrounding the aqueduct and the third and fourth ventricles. It typically causes atrophy of the mammillary bodies and dorsomedial thalami. Always remember that dextrose given before thiamine replacement may precipitate Wernicke's encephalopathy. Confusion is the most common symptom of Wernicke's encephalopathy, followed by staggering gait and ocular problems but lethargy or coma may be the only symptom.

  2. Drugs; prescription drugs for example, neuroleptic malignant syndrome, as well as illicit drugs

  3. Trauma; isodense or hidden subdurals6

  4. Common systemic infection can cause coma but rarer infections such as endocarditis or HIV can present as coma. Be alert to relevant infectious causes in the returning traveller (eg, malaria).

  5. Respiratory and metabolic derangements include pulmonary causes (obstructive sleep apnoea, hypercapnia, hypoxia and carbon monoxide poisoning); renal (uraemia and haemolytic uraemic syndrome); hepatic (acute liver failure or hepatic encephalopathy); haematological (thrombotic thrombocytopenic purpura, lupus anticoagulant syndrome); and endocrine (diabetic ketoacidosis or hypoglycaemia, hypothyroidism, hypercalcaemia, hyponatraemia, Hashimoto's encephalopathy).

More rare causes of coma, easily forgotten, include Addison's disease (when the sodium may not be that low), insulinoma, phaeochromocytoma and non-CNS malignancy. Pseudo-coma due to psychogenic causes may occasionally catch out even the most experienced.

In this case no medical cause was found: blood tests were normal, the chest X-ray showed signs of pneumonia but only as his condition deteriorated, and urine was sterile. Therefore, it is likely to be a primary neurological cause of coma. A clue may be the bilateral subdural hygromas seen on MR, not evident on CT. However, we would normally discount hygromas as a cause of pathology, although they are occasionally seen in conditions such as CNS lymphoma. In this case, I conclude that the imaging is unremarkable, and not offering diagnostic clues. As well as unremarkable imaging, the cerebrospinal fluid (CSF) and other blood tests were all within normal limits.Stay with me here. Sherlock says it is a capital mistake to theorize before you have all the evidence. It biases the judgement

Rapidly progressive dementias

Delirium should be considered in all patients presenting with acute fluctuating mental states such as disturbed attention, disorganised thinking and altered level of consciousness. Rapidly progressive dementias are defined as dementias that evolve over days to weeks or subacutely over months.7 Analysis from the five largest case series of rapidly progressive dementias identified 675 patients, with a cause established in 95% of cases. Over half of the cases were accounted for by Creutzfeldt-Jakob disease (58%), neurodegenerative conditions (eg, Alzheimer's disease 22%), with up to 19% being attributed to treatable causes (Wernicke's encephalopathy, B12 deficiency and toxic/metabolic deficiencies).7

Our patient was noted to have visual hallucinations, which may suggest a neurodegenerative condition. Table 4 summarises the neurodegenerative conditions that cause rapidly progressive dementias but most of these are non-starters here as the duration from mild cognitive impairment to coma and death was so short. Alzheimer's dementia is unlikely to be this rapid unless his decline had been begun earlier than his family realised, nor would it fit with motor neurone disease or corticobasal degeneration syndrome, but prion disease is possible (and of course we are at the home of prion disease). Creutzfeldt-Jakob disease can be extremely quick and deterioration to death within 25 days has been reported but a more typical duration would be 6–18 months.7 Antemortem diagnosis of prion disease can be difficult and is based on MRI (classically showing cortical ribboning, basal ganglia and thalamus hyperintensity on diffusion-weighted imaging and fluid-attenuated inversion recovery), electroencephalogram (generalised slowing and periodic polyspike-wave complexes and sharp waves that may not become apparent until late in the disease) and CSF analysis (normal or minimally raised white cell count, total tau protein concentration elevated to >1200 pg/mL, protein 14.3.3 positive on Western blot. S100b may have a role in supporting a diagnosis if the clinical suspicion of Creutzfeldt-Jakob disease is high. Real-time quaking-induced conversion is currently being developed as an accurate premortem diagnostic test).

Table 4

Causes of rapidly progressive dementias7

CNS infections

Could this be infection? A review of admissions to a neurological intensive care found that the most common primary cause was infection.8 Herpes simplex virus accounts for about 10% of the viral encephalitides.8 Negative investigations for herpes simplex do not completely exclude the diagnosis but should be considered a ‘red flag’ to prompt further investigation for other infectious causes such as varicella-zoster virus, Epstein-Barr virus, cytomegalovirus, measles, rubella, arborvirus, enterovirus, tuberculosis, fungal, parasitic (toxoplasma and malaria), rickettsia, listeria and cryptococcus. Non-infectious causes should also be considered including Creutzfeldt-Jakob disease, paraneoplastic and inflammatory conditions such as Behçet's. The normal CSF and brain imaging count against an infectious cause and, on balance, I am discounting an infectious cause.

Vascular

Vascular causes such as stroke, venous sinus thrombosis and subarachnoid haemorrhage are unlikely particularly in the context of normal imaging and progressive symptoms, but vasculitis is a background contender. However, I would expect to see some abnormalities on the brain imaging and perhaps CSF.

Paraneoplastic and neoplastic syndromes

Another consideration would be a paraneoplastic syndrome9 typically associated with small cell lung cancer, breast cancer or germ cell tumours, and of course paraneoplastic syndromes can precede detectable tumours by months, sometimes years. Central paraneoplastic syndromes, such as cerebellar degeneration, are often associated with lung cancer. Peripheral paraneoplastic syndromes such as Lambert-Eaton myasthenic syndrome also occur. A central paraneoplastic brainstem encephalomyelitis would be high on my differential diagnosis and although serum antineuronal antibodies were negative, it may be one that has not been tested. However, we would normally expect the brain imaging to show abnormalities, particularly around the medial temporal lobes, but this is not always the case. The entirely normal CSF would be against a diagnosis of paraneoplastic encephalitis as we normally expect a lymphocytosis, oligoclonal bands or a raised protein. Primary CNS malignancy such as lymphoma should also be considered.

Autoimmune disease

A further thought would be autoimmune encephalitis10 as the patient was confused and rapidly deteriorated to coma with few localising signs. However, the autoantibody screen was negative and therefore this is unlikely, but again it could be an autoantibody that has not been tested. Imaging can be normal in about 40% of autoimmune encephalitis, so do not discount it as a diagnosis solely on normal imaging findings.

As Sherlock would say in ‘The Sign of Four’ (1890):What seems strange to you is only so because you do not follow my train of thought or observe the facts upon which large inferences may depend.

Peripheral nervous system causes including the neuromuscular junction

Disorders of the peripheral nervous system such as acute polyneuropathies, or of the neuromuscular junction such as myasthenia gravis, or drugs and toxins can lead to coma. The absence of focal signs on examination, including the normal reflexes, strongly points away from peripheral causes including acute inflammatory demyelinating polyradiculoneuropathy. However, the team did check serum anti-acetylcholine receptor and anti-muscle-specific kinase antibodies, which would suggest that they had suspicions of a peripheral cause. On balance, the lack of signs would argue against the peripheral nervous system as the primary site of pathology. This case therefore must have a central nervous system cause.

Cardiac and respiratory diagnoses

Were his new cardiac signs (atrial fibrillation) a clue to the diagnosis? We know of neurological causes of cardiac signs following subarachnoid haemorrhage and ischaemic stroke. Could endocarditis be the cause all along? Probably not and I think atrial fibrillation was more of a reflection that he was old and ill with pneumonia.

As Sherlock would say:Eliminate the impossible, whatever remains however improbable must be the truth.

So two likely candidates remain:

  1. Paraneoplastic—the 3-week time course to death would be possible; however, the negative antineuronal screen and the normal CSF would count against this diagnosis.

  2. Prion disease: sporadic Creutzfeldt-Jakob disease but the speed seems a little quick although if we go back to the history it may be longer as he had an episode of nocturnal confusion and some cognitive change.

Jeremy Chataway's diagnosis

Prion disease—a home from home. ‘There is nothing new under the sun: it's all been done before’.

Questions from the audience

Q: How much alcohol did he consume?

RD: His alcohol history was modest.

Q: Did you consider dementia with Lewy bodies, as it can have an aggressive course?

JC: Normally you would expect it to be initially reversible rather than this relentless aggressive decline into coma. He was given an antipsychotic and it's possible that accelerated his decline.

Q: Would you expect to see fluctuations in prion disease?

JC: No, but the fluctuations could be explained by superadded infection such as pneumonia.

Q: Would you expect to see some signs in prion disease?

JC: He was drowsy and dysarthric and by the time he was ventilated it would be difficult to identify signs or progression of signs. Myoclonus was noted.

Q: What was the nature of the visual hallucinations?

JS: He was wandering in a confused, aggressive and agitated state, and his hallucinosis appeared to involve people and objects. This occurred within 12 hours of admission and was severe enough that the admitting team treated him with haloperidol and lorazepam.

Q: Was there a history of sleep disturbance prior to admission?

RD: This was not specifically asked about—I assume you are wondering about REM sleep behavioural disorder as the harbinger of an α-synucleinopathy?

Q: Is it possible for this to be autoimmune encephalitis with normal imaging and CSF?

RD: Yes, all things are possible, although as Dr Chataway has identified, it would be unusual with all the tests being normal, as in this case.

Audience diagnoses

Half the audience agreed with a prion disease diagnosis; paraneoplasia found much less favour.

JS: A final comment prior to the denouement: the family were keen for the case to be presented and discussed at this CPC as a learning point. They felt haloperidol was the cause of his rapid decline and were keen for a pathological diagnosis. We are grateful them for allowing us to present this CPC.

Pathology review by Dr Colin Smith

Consent for a limited postmortem was obtained. Macroscopically the brain was a normal weight with mild symmetrical frontotemporal atrophy evident. Microscopic examination of a number of brain regions using standard H&E stains identified significant cerebrovascular disease affecting the large leptomeningeal vessels with prominent, widespread atherosclerosis but no acute thrombus. In addition, small vessel arteriolosclerosis was noted in a number of regions with some white matter rarefaction but no lacunar infarcts.

Neuritic plaques and neurofibrillary tangles were obvious in the entorhinal cortex on H&E stain, and highlighted by β-amyloid and tau immunohistochemistry. There was no evidence of spongiform encephalopathy, but there were Lewy bodies in the substantia nigra, with clear loss of pigmented neurones and extraneuronal pigment. α-Synuclein staining highlighted neuronal inclusions within the substantia nigra, along with Lewy neurites (abnormal parenchymal threads) (figure 1). There was also striking and typical α-synuclein pathology in the dorsal vagus nucleus (figure 2), and there were cortical Lewy bodies (figure 3). In the occipital region there was cerebral amyloid angiopathy, but not in other brain areas. This was mainly in the leptomeningeal and only occasionally the parenchymal vessels.

Figure 1

α-Synuclein positive intraneuronal inclusions and Lewy threads within the substantia nigra (α-synuclein immunohistochemistry ×40).

Figure 2

Dorsal motor vagus nucleus α-synuclein pathology, with both intraneuronal inclusions and threads (α-synuclein immunohistochemistry ×10).

Figure 3

Cortical Lewy bodies within the cingulate gyrus, highlighted with α-synuclein immunohistochemistry (α-synuclein immunohistochemistry ×20).

In terms of staging of the Lewy body disease, which can be done using the either the Braak11 or consortium guidelines,12 this is at least Braak stage V as the cingulate gyrus was involved and this would equate to the neocortical stage of Lewy body disease using consortium guidelines. For Alzheimer's disease-associated pathology, we can also use Braak staging for the neurofibrillary pathology and more recent guidelines also bring in amyloid with comments on Lewy body pathology. The Alzheimer's disease pathology here is Braak stage I–II.

Main pathological findings

The final pathological diagnosis is therefore diffuse Lewy body disease Braak stage V; Alzheimer's pathology Braak stage I–II; and cerebrovascular disease in the form of large vessel atherosclerosis, small vessel arteriolosclerosis and occipital cerebral amyloid angiopathy. This is on a background of pneumonia and hypoxaemia causing brain hypoperfusion and led to the more widespread changes seen.

Comments

JC: Was it the combination of antipsychotics and systemic infection that resulted in his rapid decline?

JS: A background of cerebrovascular disease and infection may explain the explosive onset and both are likely to have accelerated the process. Exposure to antipsychotics may have played a part as well, although he did not develop the typical dramatic parkinsonism that is often the consequence of antipsychotic use in dementia with Lewy bodies.

Q: So clinically was this dementia with Lewy bodies or Alzheimer's dementia?

CS: We frequently see Braak stage I–II Alzheimer's pathology in patients who were said to be cognitively normal. However we never see Braak stage V dementia with Lewy bodies in patients without clinical signs of Lewy body disease. The aim of the McKeith consortium approach was to help answer this question with regard to the relative importance of either pathology as a cause of death. This was a neocortical case and therefore the predominant pathology.

RD: Clinically we can retrospectively acknowledge the rapid onset and visual hallucinosis as consistent with a diagnosis of dementia with Lewy bodies, and this is now supported by the pathology.

Q: What are we attributing the myoclonus to?

RD: It is not an uncommon finding in end stage cognitive disease.

Q: Had he died of, say, a heart attack 1 month prior to this presentation, would the brain pathology have been the same?

CS: Yes, the clinical picture was very rapid but the pathology would have been present before his decline.

Final clinicopathological diagnosis

Dementia with Lewy bodies.

Dementia with Lewy bodies

Lewy bodies are named after Frederick Lewy who in 1912 described abnormal intracytoplasmic inclusions in a patient with Parkinson's disease; cortical Lewy bodies were finally linked with a dementia in 1961.13 Currently, it is estimated that dementia affects 7% of people over the age of 65 years and 30% of those older than 80 years.14 Dementia with Lewy bodies is the second most common degenerative dementia accounting for 10%–20% of cases at postmortem.14 ,15 If a patient has a progressive cognitive decline within a year of onset of motor parkinsonism then this is considered to be dementia with Lewy bodies,13 although it is likely that this and Parkinson's disease-associated dementia form a continuum.

The main differential diagnoses of dementia with Lewy bodies are Alzheimer's dementia, Parkinson's disease-associated dementia, atypical Parkinson's disease syndromes such as progressive supranuclear palsy or cortico-basal degeneration syndrome, and Creutzfeldt-Jakob disease.13 In Parkinson's disease, the Lewy bodies are subcortical and the progression of Lewy body pathology is usually in a caudal to rostral direction, that is, from nigra to limbic regions and finally to the neocortex.16 In contrast, dementia with Lewy bodies shows a more generalised distribution.14 They often have a poor response to levodopa, and they can be acutely sensitive to even small doses of neuroleptic drugs.17

Lewy body pathology

Lewy bodies are inclusion bodies containing mainly α-synuclein and are probably markers of neuronal distress. They are common in the ageing brain and are associated with neurodegenerative conditions,16 but the role of Lewy bodies in disease is not straightforward. A longitudinal community-based clinical-pathological study of 872 subjects found 157 subjects with Lewy bodies in the substantia nigra, limbic and neocortical regions. Of these 157 patients, 103 (66%) had a pathological diagnosis of Alzheimer's dementia but only half had detectable dementia at death and one third of people without Lewy body pathology had shown signs of dementia prior to death. However, Lewy body pathology of the neocortical type was associated with increased odds of dementia and a more rapid decline in all cognitive domains, and limbic-type Lewy body pathology was associated with poor visuospatial skills.16 Not all patients with pathologically defined dementia with Lewy bodies are clinically demented.

Dementia with Lewy bodies should be suspected in older people with mild memory impairment and visual hallucinations but an early feature may be recurrent periods of confusion.13 ,14 ,17 Typically the episodic confusion is on a background of progressive cognitive deterioration with the fluctuations mainly being of inattention and alertness. Psychiatric manifestations occur early in the disease with visual hallucinations, delusions, apathy and anxiety being the most common.13 Hallucinations are usually vivid, colourful, three-dimensional and are generally mute images of animate objects. They are recurrent and well formed, comprising small animals, people or children. Misperceptions such as mistaking carpet and wallpaper patterns for snakes is common.3 ,13 ,14 Visual hallucinations are associated with lower cortical acetylcholine levels and consequently may respond well to cholinesterase inhibitors. Dizziness, presyncope, syncope and falls due to orthostatic hypotension or carotid sinus hypersensitivity are important other early symptoms that may support the clinical diagnosis. In addition, there may be prominent REM sleep behavioural disorder.16

Rapidly progressive dementia with Lewy bodies

Typically dementia with Lewy bodies has a progressive course with mean duration from symptom onset to death of 5–8 years.18 However, some cases show rapid disease progression to death within 3–18 months of symptom onset.18 The diagnosis in patients with rapid cognitive decline can be extremely difficult because the neurological symptoms are non-specific and the investigations unremarkable. Delirium at symptom onset may be a marker of rapidly progressive dementia with Lewy bodies, but there is no identified biological substrate to predict which patients will have a rapidly progressive course.

A review of cases from a neurological tissue bank in Spain identified 83 pathologically confirmed cases of dementia with Lewy bodies (36 with a clinical diagnosis of Parkinson's disease with or without dementia and 47 with a clinical picture of dementia with Lewy bodies).18 Of these 83 patients, six had a symptom onset to death of <18 months (four male:two female, mean age onset 72.5 years). Of these six, two were noted to have auditory hallucinations, four had mild Parkinsonism and three recurrent falls. Three patients initially presented with an acute confusional state requiring emergency hospital admission. Two of these three patients had mild cognitive symptoms for several months prior to onset and all had well-formed visual hallucinations and structured delusions. Action and spontaneous myoclonus occurred in three patients and two had a significant deterioration after starting antipsychotics. MR scans of brain showed moderate atrophy but no cortical or basal ganglia abnormalities. The pathological findings were diffuse Lewy body in all patients with four cases with neocortical-diffuse pathology and two showed limbic-type pathology. There were no atypical findings in terms of extension or severity of Lewy bodies or other pathology. Five of the cases had coexisting Alzheimer-type pathology (Braak stage II–VI), four had mild amyloid angiopathy and one had small vessel pathology.18

Neuroleptic sensitivity

Up to 60% of demented patients in hospital receive antipsychotic medications.17 Patients with dementia with Lewy bodies may be particularly at risk of prolonged or permanent cognitive decline following surgery or exposure to antipsychotic medication.7 Severe neuroleptic sensitivity is characterised by sudden onset sedation, increased confusion, immobility and muscle rigidity, and 30%–50% of patients with dementia with Lewy bodies experience severe reactions even at low doses, which can be fatal within days to weeks.13 ,15

Significant striatal α-synuclein pathology and neuronal loss or dysfunction within the putamen may provide the pathophysiological reason for neuroleptic sensitivity in patients with dementia with Lewy bodies and related parkinsonism conditions.15 A prospective study of patients exposed to antipsychotic medication included 15 patients with dementia with Lewy bodies; eight of the 15 (53%) patients experienced severe neuroleptic sensitivity. In another series of 20 demented patients with dementia with Lewy bodies who died in hospital, 80% (16/20) received antipsychotic medication, and of these 81% (13/16) showed severe sensitivity to these medications and in seven (54%), the reaction appeared to precipitate their terminal decline.13 However, a history of neuroleptic tolerance is compatible with a diagnosis of dementia with Lewy bodies.19

Conclusion

Rapidly progressive dementias can be difficult to diagnose as there may be few localising features and delirium is often suspected.19 Families may not have appreciated the proceeding progressive mild cognitive impairment and initial cognitive fluctuations are discounted or forgotten about, as they are often short-lived with a seemingly good recovery. Dementia with Lewy bodies typically has a slower course and may therefore be overlooked as a cause of rapidly progressive dementia.

Key points

  • Rapid cognitive decline can be hard to diagnose when there are few localizing signs, but there is a specific differential.

  • Investigations in rapid cognitive decline are often uninformative.

  • Dementia with Lewy bodies can present alarmingly acutely.

  • Exposure to antipsychotic medications may cause deterioration in patients with dementia with Lewy bodies.

References

View Abstract

Footnotes

  • This case was presented at the 36th Edinburgh Advanced Neurology Course 2014.

  • Contributors SS took primary responsibility in writing this article and undertook a literature review. JC provided the critical appraisal of the case and CS provided the pathology and pathological discussion. JS and RD contributed towards writing the article.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed. This paper was reviewed by Simon Mead, London, UK.

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