Diagnostic hallmarks of POTS identified

By Joanna Lyford, Senior medwireNews Reporter

US researchers have identified a constellation of symptoms that are associated with a diagnosis of postural tachycardia syndrome (POTS) in adolescent patients with headache.

Hallmark symptoms of the condition included new-onset motion sickness, dizziness as a headache trigger, and orthostatic headaches.

The findings are reported in Headache by Geoffrey Heyer (Nationwide Children's Hospital, Columbus, Ohio) and come from a study involving 70 patients aged 11-19 years who suffered from headaches and lightheadedness.

All patients completed a standard tilt-table test. In all, 37 (53%) patients met diagnostic criteria for POTS, defined as a sustained increase in heart rate of at least 30 beats per minute or an increase in total heart rate of at least 120 beats per minute, together with orthostatic symptoms that corresponded with heart rate changes and resolved with recumbency.

Among the 33 patients without POTS, two had a normal tilt-table test and 31 had syncope.

Heyer's group assessed the frequency of 13 symptoms in patients with and without POTS. Three symptoms - new-onset or worsening motion sickness, lightheadedness/dizziness preceding or triggering headache, and orthostatic headache - were significantly more frequent in the POTS group.

Two further symptoms - vertigo and evening exacerbation of headache - were also more frequent in the POTS patients, although the difference was of marginal statistical significance.

The most strongly predictive symptom for POTS was orthostatic headache, defined as a headache that occurs with standing and resolves with recumbency. This symptom had a sensitivity of 89.2%, specificity of 78.8%, positive predictive value of 82.5%, and negative predictive value of 86.7%.

Dizziness preceding or triggering a headache was the next strongest predictor, with a sensitivity of 78.4%, specificity of 78.8%, positive predictive value of 80.6%, and negative predictive value of 76.5%.

Finally, new-onset or worsening of prior motion sickness had a sensitivity of 54.1%, specificity of 81.8%, positive predictive value of 76.9%, and negative predictive value of 61.4%.

Commenting on their findings, Heyer et al note that POTS is a heterogeneous disorder with several different pathophysiological mechanisms leading to a common clinical presentation.

They conclude: "While no single clinical symptom or headache type reliably establishes the POTS diagnosis, several symptoms can help to distinguish the POTS patient in an adolescent headache population."

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