Cyclic vomiting associated with excessive dopamine in Riley-day syndrome.

OBJECTIVE

To analyze the neurochemical profile during the recurrent attacks of nausea and vomiting in patients with Riley-day syndrome.

BACKGROUND

One of the most disabling features of patients with Riley-day syndrome are recurrent attacks of severe nausea/retching/vomiting accompanied by hypertension, tachycardia, and skin flushing, usually triggered by emotional or other stresses.

METHODS

We monitored blood pressure and heart rate and measured plasma catecholamines during typical dysautonomic crises triggered by emotionally charged situations. For comparison, measurements were repeated at follow-up after the symptoms had resolved and the patients were feeling calm and well.

RESULTS

During a typical attack, patients were hypertensive and tachycardic. In all patients, circulating levels of norepinephrine (P < 0.002) and dopamine (P < 0.007) increased significantly.

CONCLUSIONS

Activation of dopamine receptors in the chemoreceptor trigger zone may explain the cyclic nausea/retching/vomiting of patients with Riley-day syndrome.