I would think sinus issues would present with pain, pressure, and mucus, possibly but not necessarily bloody....
Not necessarily. There are case reports of strange neurological symptoms with pressure changes that end up being related to anatomic anomalies in the sinuses. We published one in UHM a few years back on a diver who experienced sudden, painless vision loss at depth that resolved spontaneously on ascent, and another group published a similar case in the very next issue. We concluded that ours was related to a bony dehiscence in the sphenoid sinus after ruling out other potential causes and based on similar case reports in mountaineers and other ascents to altitude; their guy had CT scans showing it.
Best regards,
DDM