Thread by @MedinaRiojaMD

Dementia with Lewy Bodies:

Part 2️⃣ Biomarkers
🧠💊⚕️

#Neuro #Neurotwitter #Teaching #Education

#NotEverythingIsMemory

#Dementia

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Introduction

What is a biomarker? 🏷🧪️

"A characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention." 🩸🧠

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Introduction

What is the use of biomarkers? 🧠

Diagnostic tool🪓

Tool for staging the disease 🥼

Indicator of prognosis📡

Predic or monitor of clinical response to an intervention🚨

Remember: "tools"should aid clinicians, not be the source of all truth.

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⚠️⚠️Disclaimer

The following thread will present a few Imaging and other biomarkers that can help aid the diagnosis of DLB.
There are some fluid biomarkers which their role in routine clinical diagnosis is yet to be established. Those will not be mentioned today.

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MRI 🏥

Insular atrophy? Useful in pro-DLB? ( 🔵 arrow)

🦪Relative preservation of medial temporal lobe ( vs AD)

🧠

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DAT-Scan

"Reduced DAT binding suggests nigrostriatal degeneration."

Useful in DLB vs AD DDx, not between "degenerative parkinsoninsm-syndromes".

NC: normal cognition.

🦪Check the asymmetry

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SPECT/PET

🦪🏝️Sign

Hypometabolism in the lateral occipital cortex and precuneus with relatively spared metabolism in the posterior cingulate (🟡 arrows) and medial temporal lobe (🔴 arrow)

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MIBG 🧠

Abnormal (low uptake) 123Iodine-MIBG myocardiac scintigraphy🤔

🦪Also seen in PD and PDD

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Polysomnography🥱

REM without atonia, gold standard to make the diagnosis of RBD. 😴💤

🦪 RBD NOT ESPECIFIC OF DLB

A: normal
B: REM without atonia

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EEG 🧠⚡

Prominent posterior slow-wave activity with periodic fluctuations in the
pre-α/θ range

A: px with AD
B: px with DLB

🔵 Arrow = Frontal intermittent rhythmic delta activity

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Want a summary?
🤔

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Here is the summary!

Biomarkers are only helpful in the proper clinical context. Without suggestive symptoms, the result is difficult to interpret and the usefulness fades away. ⚠️🚨

I hope you have enjoyed this thread!

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Sources:
1.- Clin Pharmacol Ther. 2001 Mar;69(3):89-95.
doi: 10.1067/mcp.2001.11398
2.- Int J Mol Sci. 2022 Jun 7;23(12):6371. doi: 10.3390/ijms23126371
3.- J Neurol. 2022 Feb;269(2):639-653. doi: 10.1007/s00415-021-10402-2

Sources:
4.- Neurology. 2017 Jul 4;89(1):88-100.
doi: 10.1212/WNL.0000000000004058
5.- Front Aging Neurosci. 2018 Jul 3;10:190. doi: 10.3389/fnagi.2018.00190