Be on the lookout for Harlequin ... known as a wily character, this disorder can be tricky to diagnose and determine an underlying cause

About a third of patients also had pupillary abnormalities and abnormal reflexes ... consistent with Ross syndrome 👁️ 🔨

Post surgical patients looked similar to other patients other than onset.

Other than where a causes was suspected (patient with cancer) imaging was rarely useful.

Over 26 yrs, 51 patients presented with Harlequin.

🔹median age 52
🔹76% women

Causes:
▶️17 % occurred as post-op complications

⏯️Other causes included: neoplasm, MS, trauma, small fiber neuropathy, pure autonomic failure, autoimmune

⏭️ causes was deemed idiopathic in 37%

Sympathetics to the face:

🧠 Descending from the hypothalamus
⬇️intermediolateral cell column of the SC
⤴️second order neurons exit T1-T3 to the stellate ganglion
⬆️ third order neurons form a plexus around carotids to face 🙂‍↕️

Damage anywhere along this pathway can lead to Harlequin

First, what is Harlequin syndrome?

Unilateral facial anhidrosis leads to contralateral flushing and hyperhidrosis. While the flushed side is often concerning to the patient- the problem is the anhidrotic side which leads to compensatory sweating😓

TST: 🟣 sweating 🟡 is anhidrosis

In Clinical Autonomic Research:

pubmed.ncbi.nlm.nih.gov/40721556/

5/ Three Actionable Takeaways from Dr. Block’s summary of our conversation:

2. Well-being initiatives must go beyond surface-level fixes: Yoga and mindfulness have value, but true solutions require structural changes like reducing unnecessary tasks and fostering social connections.

Thanks, Paul! Yes, the natural history paper is fantastic.

PAF is fascinating. I also think we are missing so many patients... since there are no motor or cognitive features, they never get to neurology

This 'pure' group is important.

It's a #synucleinopathy with autonomic involvement and many have central involvement (RBD) yet don't develop motor or cognitive impairment leading to #MSA #PD or #DLB

And many thanks to my amazing colleagues & mentors @MayoClinicNeuro

Timeline was interesting with most symptoms clustering around OH onset.

Median time to development of DEB was 7 years after OH but note the variability

In patients that remain PAF, most developed widespread autonomic failure... bladder, bowels, sexual and thermoregulatory dysfunction.

Dream enactment behavior was documented in 52% - likely an undercount due to the study timeline for PAF diagnosis (1998-2012)

Let's dive in...

In our cohort of 202 PAF patients with over a year to follow-up, 65 % remain PAF. We called patients to assess for symptom timeline and phenoconversion.

This was a follow-up to our study focused on risk factors for phenoconversion.

pubmed.ncbi.nlm.nih.gov/32546656/

PAF is defined by neurogenic OH. For many, the term PAF means a prodromal state to a synucleinopathy with motor or cognitive impairment.

PAF➡️ MSA
PAF➡️DLB or PD

Yet many studies have shown the majority remain PAF.

So what is their natural history?
link.springer.com/article/10.1...

Her birth was at the start of WWI and WWII altered her professional career by leading to training in neurology with van Boegart. She later served her Belgian community through multidisciplinary neurologic care.

Interesting to see the eponym persist #historyofmedicine

Louis-Bar was interesting. Despite a very productive start to an academic career and training under Ludo van Bogaert, she was seemingly an outcast from the scientific community.

An honor to work with the legend Dr. Wijdicks on the review of Janice Nimura's book on the Blackwell sisters

hekint.org/2021/07/15/b...

Great work, Jeff!