Question explored with the scientific record
Conversation so far
- 1 is nausea in long covid considered a PEM + a private exchange
- 2 so what is nausea when i walk too fast or move to actively + a private exchange
- 3 PEM in long covid
- 4 exertion intolerance more than the classic delayed crash. so wha is the solution?
- 5 autonomic testing. a lying standing bp test was normal
- 6 what is autonomic dysfunction.
- 7 autonomic dysfunction. what does a tets look like and who does it?
Answered on this page ↓
autonomic dysfunction. what does a tets look like and who does it?
A tilt-table test is a 10 to 45 minute stand-up stress test of your blood pressure and heart rate. It is run by a neurologist or cardiologist with an autonomic lab, not a general clinic.
You lie flat, strapped to a table that tilts you upright while heart rate and blood pressure are tracked beat to beat [3]. The standard version lasts 10 minutes; a 45-minute version caught far more orthostatic intolerance than the short one, with sensitivity rising from 0.31 to 0.59 [1]. That is the honest weakness: a short tilt misses a lot of real cases.
The rest of the battery maps the other loops. Deep breathing and a Valsalva maneuver (bearing down) test the heart-rate reflexes [1][3]. A sweat test (QSART) checks the small nerves that control sweating, and it matched skin biopsy about 70% of the time when positive [1][2]. Skin biopsy counts nerve fibers directly [1].
| Test | What it measures | Who runs it |
|---|---|---|
| Head-up tilt | BP and HR on standing [3] | Autonomic lab (neuro/cardio) |
| Valsalva, deep breathing | Heart-rate reflexes [3] | Autonomic lab |
| QSART sweat test | Small nerve fibers [1] | Autonomic lab |
| Skin biopsy | Nerve fiber density [1] | Neurology/dermatology |
One caution: in migraine patients, the lab tests and skin biopsy did not separate those with symptoms from those without, though small fiber damage was common in both [1]. A normal result does not clear you.
My call: ask for a prolonged tilt and the full battery at a dedicated autonomic lab, because the short test under-detects. Confidence: moderate.
Sources used 3
-
Autonomic Dysfunction among Migraineurs with and without Complaints of Orthostatic Intolerance: Evidence for Small Fiber Nerve Damage
In adult migraineurs, prolonged 45-minute head-up tilt detected orthostatic intolerance more often in those with symptoms than without, but small fiber neuropathy was common in both groups.
DOI: 10.30756/ahmj.2021.06.01 -
Orthostatic intolerance and autonomic dysfunction following bariatric surgery: A retrospective study and review of the literature
This retrospective study investigates the prevalence of orthostatic intolerance and autonomic dysfunction in 14 patients following bariatric surgery, revealing significant autonomic testing results and suggesting a higher incidence of these complications than previously recogniz…
DOI: 10.1016/j.autneu.2016.05.003 -
Autonomic dysfunction in patients with orthostatic dizziness
Autonomic dysfunction underpins orthostatic dizziness, and combined autonomic testing (head-up tilt, Valsalva maneuvers, beat-to-beat BP/HR monitoring) helps distinguish neurogenic from nonneurogenic orthostatic hypotension and characterize postural tachycardia syndrome, guiding…
DOI: 10.14253/acn.2023.25.1.27