More on Autonomic Dysfunction following Covid-19

I’ve previously discussed about how frequent POTS can be in children and adolescents following Covid-19, and the importance of treating it even in adolescents and pre-adolescents. We have published studies showing POTS (which is a form of dysautonomia) is more frequent in children with long covid compared with controls, and how this can be managed.

Recent studies are confirming our findings.

An international cohort included 526 adults with LC aged 20–65 years who previously completed baseline evaluations of LC symptoms, autonomic symptom burden, and quality of life. A subset of individuals completed a 10-min active stand test.

A total of 71.9% of participants with LC had a Composite Autonomic Symptom Score-31 (COMPASS-31) score ≥ 20, suggestive of moderate-to-severe autonomic dysfunction. The median symptom duration was 36 [30–40] months, and 37.5% of participants could no longer work or had to drop out of school due to their illness. In addition, 40.5% of individuals with autonomic dysfunction were newly diagnosed with POTS, representing 33% of the total LC cohort. Female sex and joint hypermobility were associated with an increased risk of autonomic dysfunction.

The authors concluded that evidence of chronic moderate-to-severe autonomic dysfunction was seen in most participants with LC in our cohort and was significantly associated with reduced quality of life and functional disability. POTS was the most common post-COVID autonomic diagnosis.

Importantly, POTS and Dysautonomia have practical (negative) implications on patients. As shown in this review, Cerebral blood flow (CBF) is vital for delivering oxygen and nutrients to the brain. Many forms of orthostatic intolerance (OI) involve impaired regulation of CBF in the upright posture, which results in disabling symptoms that decrease quality of life. Because CBF is not easy to measure, rises in heart rate or drops in blood pressure are used as proxies for abnormal CBF. These result in diagnoses such as postural orthostatic tachycardia syndrome and orthostatic hypotension. However, in many other OI syndromes such as myalgic encephalomyelitis/chronic fatigue syndrome and long COVID, heart rate and blood pressure are frequently normal despite significant drops in CBF. This often leads to the incorrect conclusion that there is nothing hemodynamically abnormal in these patients and thus no explanation or treatment is needed. In this review, the authors examined the literature studying CBF dysfunction in various syndromes with OI and evaluate methods of measuring CBF including transcranial Doppler ultrasound, extracranial cerebral blood flow ultrasound, near infrared spectroscopy, and wearable devices.

adapted from previous paper

In addition, a more invasive (because requires radiation exposure) to measure CBF is through SPECT. In this study, Abnormal CBF was seen in 61% but did not differ by POTS triggers. The regions with the lowest mean z-scores were the lateral prefrontal and sensorimotor cortices. Hierarchal regression analyses found number of brain regions with abnormal CBF, autonomic and gastric symptoms to account for 51% of variances in health utility. Cerebral hypoperfusion is prevalent in those with POTS and cognitive dysfunction even whilst supine, contributing to reduced quality of life.

This means that the impact of multiple brain hypoperfusion episodes on brain function and health, including aging, need to be urgently addressed!