John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.
Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
How is low blood pressure diagnosed and evaluated?
In some individuals, particularly relatively healthy ones, symptoms of weakness, dizziness, and fainting raise the suspicion of low blood pressure. In others, an event often associated with low blood pressure, for example a heart attack has occurred to cause the symptoms.
Measuring blood pressure, in both the lying (supine) and standing positions usually is the first step in diagnosing low blood pressure. In patients with symptomatic low blood pressure, there often is a marked drop in blood pressure upon standing, and patients may even develop orthostatic symptoms. The heart rate often increases greatly. Once low blood pressure has been identified as the cause of symptoms, the goal is to identify the cause of the low blood pressure. Sometimes the causes are readily apparent (such as loss of blood due to trauma, or sudden shock after receiving x-ray dyes containing iodine). At other times, the cause may be identified by testing:
Electrocardiograms (EKG) can detect abnormally slow or rapid heart beats,
pericarditis, and heart muscle damage from either
previous heart attacks or a reduced
supply of blood to the heart muscle that has not yet caused a heart attack.
Holter monitor recordings are used to diagnose intermittent episodes of abnormal heart rhythms. If abnormal rhythms occur intermittently, a standard EKG
performed at the time of a visit to the doctor's office may not show the
abnormal rhythm. A Holter monitor is a continuous recording of the heart's
rhythm for 24 hours that often is used to chart and diagnose intermittent episodes of
bradycardia or tachycardia.
Patient-activated event recorder. If the episodes of bradycardia or tachycardia are
infrequent, a 24-hour Holter recording may not capture these sporadic
episodes. In this situation, a patient can wear a patient-activated event
recorder for up to four weeks. The patient presses a button to start the
recording when he or she senses the onset of an abnormal heart rhythm or
symptoms possibly caused by low blood pressure. The doctor then analyzes the recordings
at a later date to identify the abnormal episodes.
examinations of the structures and motion of the heart using ultrasound.
Echocardiograms can detect pericardial fluid due to pericarditis, the extent
of heart muscle damage from heart attacks, diseases of the heart valves, and rare tumors of the heart.
Tilt-Table tests are used to evaluate patients suspected of having postural
hypotension or syncope due to
abnormal function of the autonomic nerves. During a
tilt-table test, the patient lies on an
examining table with an intravenous infusion administered while the heart rate and
blood pressure are monitored. The table then is tilted upright for 15 minutes
to 45 minutes. Heart rate and blood pressure are monitored every few minutes.
The purpose of the test is to try to reproduce postural hypotension.
a doctor may administer epinephrine (Adrenalin, Isuprel) intravenously to induce postural hypotension.