Why is my B/P around 18 points higher in my left arm than my right?

sunshine08,

Thanks for your posted question.  It is not unusual to have different blood pressure readings in the arms.  As you mentioned, this difference may be as much as 5 - 10 mm in normal adults. 

There can be several reasons for a significant difference.  One major cause is vascular disease in which the blood flow is being restricted to the arm with the lower pressure.  This could be from a blockage within the artery from build-up of fatty deposits, or could be a constriction around the blood vessel by muscle or bone (such as a cervical, or extra, rib).  Local factors in each arm may also be the cause of the discrepancy, affecting the blood pressure measurement process (muscle, vascular variation).

Though vascular disease (blockages) are less likely in people your age, this is something that should be brought to your doctor's attention and discussed.  Knowing your history and physicial findings, he is the best person to determine whether further evaluation is warranted, and how to go about investigating this further.

I also note that you are checking your own pressure.  The technique you're using may also affect your readings.  In automatic machines, correct placement of the cuff and location of the stethescope device is essential.  If you are listening yourself with a stethescope, this could also influence your readings.  Many doctors feel that patients cannot get a true reading by listening with a stethescope because they can sense the reading earlier and later.  Their pulse is actually felt and then interpreted as a sound.  Sounds a bit complex, but true.

So, again, discuss this with your physician.  I hope this information has been useful.

Martin Cane, M.D.