Pearls & Oysters: Paroxysmal Exercise-Induced Dyskinesias Due to Pyruvate Dehydrogenase Deficiency 2023 de Gusmao et al

Abstract

Paroxysmal exercise-induced movement disorders may be caused by energy metabolism disorders, such as Glut 1 deficiency, pyruvate dehydrogenase deficiency or mitochondrial respiratory chain disorders. A 4-year-old boy with a history of febrile seizures presented with paroxysmal dystonia, triggered by exercise, or occurring at rest. Additional investigations demonstrated pallidal hyperintensities on brain MRI and low CSF glucose. Pyruvate and lactate were elevated. The clinical presentation, combined with neuroimaging abnormalities and biochemical profile (the lactate/pyruvate ratio) were clues to pyruvate dehydrogenase deficiency, a treatable metabolic disorder with neurological presentations.

Open access, https://n.neurology.org/content/early/2023/02/20/WNL.0000000000207142

 

High fives all round that team. For interest, the FLAIR hyperintensity in the globi pallidi is non-specific and can be seen in a number of metabolic conditions and toxin exposures. Classically carbon monoxide affects those same parts of the basal ganglia symmetrically, while methanol tends to affect the putamina, which are just outside the bright arrowed bits shown in this case.



These sorts of mitochondrial disorders can cause lots of damaging effects in the brain and there are quite a number of different types. MRIs try to give a steer to the metabolic neurologists based on the pattern of brain involvement. This is sometimes helpful for the geneticists when targeting the likely candidates.

This case is an example of the sorts of conditions that Jo's colleague would be seeing that is so different to the reversible/non-destructive type picture in ME/CFS, where MRIs look "within normal limits" based on our current understanding*.

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*"Normal" findings of perivascular spaces and choroid plexus calcification may turn out to be more important than we've given them credit for. Further studies pending.

 

I have paroxysmal dyskinesia and over the years there have been a few other ME patients who have said it is part of their disease. Official descriptions say that some patients while identical in presentation have a psychologically induced version which is diagnosed by taking a holistic view of the patient so guess what my neurologist said. Out the door, abandoned. Though one doctor asked how long I had had choreoathetosis so that is as close as I have got to empathy.

I became friendly with an MS sufferer who had the same problem and it was a relief to be able to talk to her and joke about things like giving my husband a black eye and having little kids wave back!

She was told that people can have a mild inherited problem but a major neurological disease makes it worse, though that was about 20 years ago so thinking may have changed

It is embarrassing and exhausting. Looking at descriptions I have the kinesegenic form mostly with some nonkinesegenic episodes but the worst symptoms are usually after too much exertion. Baclofen and gabapentin tone down the movements a bit and my GP is willing to prescribe them.

Recently came across a paper about cases being caused by a reactivation of HHV6 which could provide a link to ME.

I have so many of these weird symptoms it annoys me that fatigue is all that is taken into account especially when other things are so disabling and may give clues to how ME works.