Simple blood pressure test could diagnose fibromyalgia

A study has found that the standard blood pressure test used in every doctor's office could be used as a diagnostic test for fibromyalgia syndrome.

Everybody has had a blood pressure test at the doctor's office. The doctor or nurse straps a cuff to your upper arm and then inflates it until it stops the blood flow in a large artery. Then, the air in the cuff is slowly released, and the doctor/nurse listens with a stethoscope. When the blood starts to pulse through the artery, it makes a sound. Sounds continue to be heard until pressure in the artery is higher than the pressure in the cuff.

While the person conducting the test listens with the stethoscope, they take down two readings from a pressure gauge. The instrument used for the test is called a sphygmomanometer (SFIG'mo-mah-NOM'eh-ter) and comprises the inflatable cuff and pressure gauge. The two readings indicate the systolic and diastolic blood pressure. Systolic pressure is the pressure of the blood flow when the heart beats (the pressure when the first sound is heard). Diastolic pressure is the pressure between heartbeats (the pressure when the last sound is heard). Blood pressure is measured in millimeters of mercury, which is abbreviated mm Hg and the healthy range is typically said to be 100-140 mm Hg for systolic and 60-100 mm Hg for diastolic.

Now, a large proportion of the population undoubtedly find the whole procedure a little uncomfortable.Having your arm squeezed until the blood stops isn't the most pleasant experience one can have, you may even feel a little woozy at the prospect. That said, most people are able to suffer the discomfort for a few moments and the test is taken with no problems. It turns out however, that when it comes to fibromyalgia patients, the majority of them experience not only discomfort, but genuine pain when they undergo the blood pressure test. Health care workers noticed that fibromyalgia patients complained of pain and discomfort a lot more often whilst undergoing the test than did the general population and patients with other conditions. This led a group of researchers to investigate whether the standard blood pressure test (Sphygmomanometry) might actually be used as a test to diagnose fibromyalgia.

The researchers published the results of their study, 'Sphygmomanometry-Evoked Allodynia - A Simple Bedside Test Indicative of Fibromyalgia: A Multicenter Developmental Study', in the December 2006 issue of the Journal of Clinical Rheumatology.

The research team studied 20 fibromyalgia patients, 20 rheumatoid arthritis (RA) patients, 20 osteoarthritis (OA) patients and 20 healthy individuals in each of three separate public rheumatology outpatient services. This is what is referred to as a 'multicenter study'. Participants are studied in multiple locations simultaneously, using the exact same testing methods. This approach increases the significance of any findings, should the results from each location agree with each other. In this study, each participant was asked to answer the question, “When I take your blood pressure, tell me if the cuff’s pressure brings forth pain.”

The results from the study indicated that 69% of fibromyalgia patients experienced 'sphygmomanometry-evoked allodynia', the tongue-twister medical term for pain caused by the blood pressure test. In contrast, only 10 percent of OA patients, five percent of RA patients and two percent of healthy individuals reported experiencing any pain. The study also found that the average blood pressure at which fibromyalgia patients felt pain was lower than the other three groups. Further to this, the researchers found that there was a correlation between the severity of a patients fibromyalgia and the blood pressure value at which pain was first experienced. The more the severe the fibromyalgia, the lower the blood pressure at which the pain developed. The severity of a participants fibromyalgia was determined by a combination of the Fibromyalgia Impact Questionnaire (FIQ) score, number of tender points, and the FIQ visual analog scales for pain intensity and fatigue, currently the main diagnostic tests for the condition.

The researchers conclude that their study demonstrates a strong association between pain experienced during blood pressure testing and the diagnosis of fibromyalgia. They also highlight the fact that sphygmomanometry is a simple test and a universally standard clinical procedure that may be useful in recognizing fibromyalgia patients. Based on the results of this study, the researchers suggest looking for other indicators of fibromyalgia in anyone who has sphygmomanometry-evoked allodynia.

If doctors take notice of this new research it could dramatically reduce the number of people with fibromyalgia who are being misdiagnosed due to the lack of a definitive laboratory test, and a lack of knowledge on the part of health professionals. Fibromyalgia is currently diagnosed based on the presence of 11 'tender points' in various locations around the body. When pressure is applied to these points a fibromyalgia patient will feel pain. To confuse the issue, a group of experts on the condition have come to the consensus view that an individual may have fewer than the 11 tender points and still be considered to be suffering from fibromyalgia and treated accordingly. Undoubtedly the use of the blood pressure test will not replace the current diagnostic criteria for fibromyalgia but it does offer the often confused family doctor another way to check for the condition or confirm a diagnosis. The fact that the equipment is already present in every doctor's office and the test is part of a regular check-up means there is no reason not to use it to screen for fibromyalgia. Now, when a patient complains of pain during a blood pressure test, a doctor will know to suspect fibromyalgia.