Giddiness after breakfast

Hello Dr. Agar,

For a long time now, I feel very giddy about 15 minutes after breakfast. This continues for a few hours. This does not happen on the morning after a night off dialysis. I tried adjusting my dry weight but it happens even after going up 1 kg and here, I end up having symptoms of too much fluid at the end of the day. So I am not sure if it is the dry weight. I found something about “Post Prandial Hypotension” being a possibility in dialysis patients. Could this be it? Or could this be something else?


Dear Kamal

This is difficult to answer with certainty without an intimate knowledge of your dry weight, your UFR, your pre and post BPs, your weight gains, your dialysis times (duration) and treatment frequencies, your cardiac status, your ejection fraction on echo … in short, a lot of detail about your treatment schedules and individual characteristics that I do not have.

However, there IS a well-known condition known as post-prandial (after eating) hypotension (low BP) in dialysis patients … though this seems to have been reported more particularly in facility-based patients rather than home patients … where the BP falls after eating. Indeed, we discourage eating during dialysis in our facility patients … and for a hour or so after the end of dialysis until enough time has passed for circulatory equilibration to occur … just for this very reason.

When we eat (and this is a normal physiological response to the ingestion of food in any and all circumstances), there is an upswing in the amount of blood that is directed from the circulation into the 'splanchnic circulation = that rather segregated corner of our circulatory system that is directed to and supplies the gut (our multiple metres of intestine) in order to aid in absorption and carriage of absorbed nutrients to the liver and beyond.

So … eating triggers an increase in perfusion of the coeliac axis (the superior and inferior mesenteric arteries = the splanchnic circulation) … and, in simple terms, this ‘robs’ the general circulation of a slug of its circulating blood volume. This plundered volume then is, in effect, segregated from (and ‘unavailable’ to) the more general circulatory ‘pool’. As such, it is a volume that is then (1) less available for dialysis and (2) unavailable to sustain any fall in the general circulatory volume as it is reduced by UF during dialysis.

Where the UFR is high, or if the cardiac output is compromised in any way (eg: the ejection fraction is ‘iffy’), or if a patient is truly near or at dry weight at the time of eating, this sudden additional ‘loss’ of circulating volume to the splanchnic circulation can precipitate the clinical consequence of a fall in BP and make any hypovolaemic symptoms and/or volume-related effects of dialysis worse.

In effect, it can induce a ‘mini-flat’ … or make a ‘flat’ worse than it otherwise would be!

One way to test this out would be to delay breakfast - at least for 1-1.5 hrs post-dialysis - to allow for full trans-compartmental equilibration time.

Try that … and see if it works.

Could it be something else? … well, possibly, but not likely. There are other circulatory (vaso-active) hormones that are triggered by eating and that may be at play here - but I have to suspect that that is unlikely.

My guess = this is an expression of post-prandial hypotension … and the best way to avoid that is to avoid eating until post-dialysis volume equilibration has occurred.

Thanks Dr. Agar for your response. I usually have breakfast about 3 hours after closing dialysis. I have found some articles on the internet that advise eating a breakfast that is low in carbohydrates. Will try that and see. Thanks!