We describe clinical and laboratory findings in 35 patients tested positive for SARS-CoV-2 by reverse transcriptase-polymerase chain reaction on nasopharyngeal swab experiencing one or multiple syncope at disease onset. Clinical neurologic and cardiologic examination, and electrocardiographic findings were normal. Chest computed tomography showed findings consistent with interstitial pneumonia. Arterial blood gas analysis showed low pO
2
, pCO
2
, and ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO
2
/FiO
2
) indicating hypocapnic hypoxemia. Patients who presented with syncope showed significantly lower heart rate as compared to 68 SARS-CoV-2 positive that did not. Such poorer than expected compensatory heart rate increase may have led to syncope based on individual susceptibility.
We speculate that SARS-CoV-2 could have caused angiotensin-converting enzyme-2 (ACE2) receptor internalization in the nucleus of the solitary tract and other midbrain nuclei, impairing baroreflex and chemoreceptor response, and inhibiting the compensatory tachycardia during acute hypocapnic hypoxemia.
Introduction Subcutaneous sumatriptan, a 5HT1B/1D agonist, is the most effective drug in cluster headache acute treatment. About 25% of the patients do not respond to subcutaneous sumatriptan; the reasons for this are unknown. In this study, we compare clinical characteristics of cluster headache patients responding and non-responding to subcutaneous sumatriptan. Methods We retrospectively investigated the clinical records of 277 cluster headache patients. Patients reporting repeated satisfactory response to subcutaneous sumatriptan within 15 minutes were considered responders. Results Of 206 cluster headache patients who had used subcutaneous sumatriptan (mean age 45.6, 16% females, 48% chronic), 91% were responders, and 9% non-responders. Compared to responders, non-responders had longer and more frequent attacks: 60 (median; IQR 38–90) vs. 100 (60–120) minutes ( p = 0.028), 4 (2.5–5) vs. 3 (2–4) attacks/day ( p = 0.024). No other difference was found. Conclusions In cluster headache attacks with long duration and high frequency, pain mechanisms not involving 5HT1B/1D receptors may play a more relevant role.
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