lightheaded

[knotical]

Sent this email to DAN, but since the weekend might delay their response I'm posting here also:

On 07 April, approximately one hour after completing a pool session with students, I experienced lightheadedness without dizziness. The light-headedness lasted 24 hours. No syncope, but I mostly stayed seated or lying down. The pool session was unremarkable with perhaps 10 ascents from 10 feet.

On 11 May, starting approximately one hour after completing a shorter pool session, I experienced three brief periods of lightheadedness, each lasting about 5 minutes, over a span of about an hour. The pool session was unremarkable with perhaps 4 ascents from 10 feet.

Any thoughts about cause/mechanism? Any recommendations?

thank you

[DandyDon]

More info about your age, known physical issues and those of your parents might help those qualified here. I'll be reading...

[knotical]

Thanks, Don. I'm 67. Annually my doctor tells me I'm in excellent health, based on clinical and lab results. I've been taking well-tolerated medication for years for BPH, a hiatal hernia, and osteopenia.

My father died at 86 of myocardial infarction. He had suffered from Alzheimer's. My mother died at 90 of myocardial infarction. She had well-controlled hypertension. My blood pressure has always been on the low side of normal.

After my first incident, neither my doctor nor I attributed the episode to the pool session. He suspected a possible arrhythmia and I was to capture it on an EKG if it recurred. The second incident resolved before I reached a clinic.

DAN's response was that light-headed is too non-specific and that they would send me a list of local dive physicians, which I am awaiting.

But mainly I'm trying to figure out if there is some physiological mechanism whereby such exposure to pressure changes could trigger a delayed lightheadedness.

[Duke Dive Medicine]

Knotical,
A few questions:
1. Does this only happen after you dive, or does it occur at other times as well; for example, after exerting yourself or standing up from a sitting or lying position?
2. Do you notice any other symptoms with the lightheadedness, for example, palpitations, "skipped" heartbeats, a sensation of your heart pounding in your chest, sweating, cool skin, nausea, or any pain in the chest or arms?
3. You said that your blood pressure runs "low normal". Can you define low normal?
4. On the two days that you noticed the symptoms, did you reduce your fluid intake so you wouldn't have to pee in the pool?
5. Can you list the specific medications and doses that you are taking?

[knotical]

1. I've experienced the "head rush" of standing up too quickly occasionally over the years. It has always gone away almost immediately if I sit down then stand up more gradually. These are the first two times it has not resolved quickly.

2. The only other symptom was a very minor "headache". It was bilateral and similar to the feeling of a tight muscle, in both my neck and around the skull. It went away on its own quickly both times.
The first time my pulse was slightly elevated. The second time, it seemed normal. I always have a hard time finding my own pulse, so I can't say with confidence whether there were any abnormalities.

3. 100/70, typically. Occasionally a bit lower. Seldom higher than 110/75.

4. Not consciously. I always keep a water bottle poolside to avoid dehydration.

5. tamsulosin, 0.4 mg, daily
lansoprazole, 30 mg daily
risedronate, 35 mg, weekly
fexofenadine, 180 mg daily, seasonally
I don't think my prescriptions have been changed for 10 years or so.


Thank you !

[Bubbletrubble]

Duke Dive Medicine asks some good questions, particularly the one regarding orthostatic hypotension. It appears that you have a family history of heart disease and high blood pressure.

FYI, lightheadedness is a side effect of one class of meds used to treat BPH (alpha blockers).
Alpha blockers block the alpha-adrenergic receptors in the prostate and in blood vessels, in addition to other particular areas of the body. Alpha-adrenergic antagonism causes smooth muscle relaxation.
In most cases, alpha blockers used to treat BPH are selective for the alpha-1a receptor which is expressed in the prostate. Alpha-1b receptors are more highly expressed in the blood vessels.

FWIW, tamsulosin (Flomax) is a commonly prescribed alpha blocker with alpha-1a selectivity for patients with BPH.

I'd be suspicious of an issue with your BPH med if you are taking an alpha blocker and either the dose was increased or metabolism of the drug in your body changed (for whatever reason).

This information may or may not be helpful in figuring out what made you lightheaded. A good cardiovascular exam might be in order. Some patients with intermittent CV symptoms might benefit from around-the-clock outside-the-hospital Holter monitoring.

[Duke Dive Medicine]

Bubbletrubble makes some great points. The tamsulosin can cause orthostatic hypotension but I wonder why, if that's what it is, it would only happen after diving. I was thinking Holter monitor myself and I think his suggestion to see a cardiologist is a good one.

[knotical]

Thank you all. I'll share this thread with my primary.

My dosages have not changed since '05 or before. That's based on the oldest slip of paper I found in the back of my file.

I'm curious if anyone sees a possible mechanism linking the small pressure changes and my symptoms. I still recognize the possibility of coincidence, but ...

[Duke Dive Medicine]

I'm curious if anyone sees a possible mechanism linking the small pressure changes and my symptoms. I still recognize the possibility of coincidence, but ...

I can't think of one. Immersion itself causes fluid redistribution which could exacerbate underlying cardiac problems; the time course of the symptoms is a bit unusual, though. If you had bad breathing gas you'd know it right away. It doesn't sound like it's related to the inner ear. "Lightheadedness" typically implies impaired circulation, at least to me. I'd reiterate the recommendation to see a cardiologist, especially considering your age and family history.

[Bubbletrubble]

Bubbletrubble makes some great points. The tamsulosin can cause orthostatic hypotension but I wonder why, if that's what it is, it would only happen after diving. I was thinking Holter monitor myself and I think his suggestion to see a cardiologist is a good one.

I was thinking along the lines that the OP was relatively horizontal while in the water and then proceeded to stand up upon exiting the water. I'd say that's consistent with orthostatic hypotension. It still doesn't explain why the OP is experiencing this now and not before. Presumably, he was diving fairly regularly over the past few years.

A cardiologist might be able to get to the bottom of this.