NPPA and ablepharon macrostomia syndrome: Hackett et al. proposed that hypoxemia-induced activation of peripheral chemoreceptors might increase extracellular water by upregulating circulating antidiuretic hormone (ADH) levels, thus promoting BBB permeability and increasing the ICP to cause AMS symptoms.209 Other studies also suggested that acute hypoxia elevated circulating ADH and aldosterone205,210 and decreased atrial natriuretic peptide (ANP),211 potentially contributing to anti-diuresis and fluid retention.