the key to the diagnosis is a good history and physical examination. the health care practitioner will want to know the circumstances that are associated with the symptoms of lightheadedness or passing out since the patient is unlikely to have taken their blood pressure and checked their pulse rate in the midst of the episode. the symptoms tend to be transient and resolve quickly. should there be concern that the vital signs will change with position the health care practitioner will take the blood pressure in both lying and standing positions and look for changes. according to the american academy of neurology the formal diagnosis of orthostatic hypotension requires a 20mm drop in systolic blood pressure or a 10mm drop in diastolic blood pressure within three minutes of standing. often there is an associated increase in the heart rate especially if dehydration or bleeding is the cause (if the patient is taking a beta blocker the heart rate may not be able to respond with an increase). blood tests may be ordered to look for the underlying cause. these may include a red blood cell count (complete blood count or cbc) to access for anemia or bleeding. electrolytes may be checked especially if there has been a history of fluid loss through vomiting or diarrhea since sodium and potassium abnormalities may be an issue. kidney function may be assessed. if the physical examination reveals concern about the heart an electrocardiogram (ekg) may be done to evaluate electrical conduction and heart rhythm. an echocardiogram or ultrasound of the heart may be ordered to evaluate the heart valves and assess the function of the heart muscle. a stress test may be considered if there is concern about coronary artery disease. a heads-up tilt table test may be ordered if the symptoms of orthostatic hypotension continue to recur but it has been difficult to document abnormalities in blood pressure readings. during the test the patient is strapped flat on a table and as the table gradually is tilted to a 70 or 80 degree angle continuous blood pressure and heart rate readings are taken. the patient may be left on the table for more than 10 minutes to look for the delayed changes seen in postural orthostatic tachycardia syndrome. for many patients the diagnosis may be made based upon the history and physical examination and no further testing may be needed.
how is orthostatic hypotension diagnosed?