Autonomic testing in functional gastrointestinal disorders: implications of reproducible gastrointestinal complaints during tilt table testing.
BACKGROUND
The pathophysiology of functional abdominal pain (FAP) is unknown. The upright portion of a tilt table test triggers typical symptoms in certain children.


OBJECTIVE
To compare the pathophysiology and treatment response of children with FAP whose gastrointestinal symptoms (GI) were replicated (RGI) by tilt table testing (TTT) to those in whom TTT did not have this effect (NRGI).


METHODS
An IRB-approved retrospective review of the autonomic laboratory database identified all children tested for GI complaints. We compared results of TTT, Valsalva maneuver, deep breathing and the axon reflex sweat test. Overall treatment response and that specific to fludrocortisone was ranked from 1 to 5, with 1 "much worse," 3 "neutral," and 5 "much better."


RESULTS
32/76 identified children had reproducible symptoms on TTT (RGI) and 44 did not (NRGI). The RGI group was younger, had a shorter duration of symptoms, more postural tachycardia syndrome (POTS) and benefited more from fludrocortisone (73% in RGI vs. 25% in NRGI).


CONCLUSIONS
Dividing patients with FAP according to the effect of TTT on their symptoms appears to delineate 2 fundamentally different groups, with potentially different pathophysiologies and treatment responses. A prospective study is needed.
Safder
Shaista
S
Department of Pediatrics, Rainbow Babies and Children Hospital, Case medical Center, 11100 Euclid Avenue, Cleveland, OH 44106, USA. shaista.safder@uhhospitals.org
Chelimsky
Thomas C
TC
O'Riordan
Mary Ann
MA
Chelimsky
Gisela
G