How Low Blood Pressure Is Diagnosed
According to Harvard Health Publishing, a person is considered to have hypotension or low blood pressure when their values drop 20 mmHg on the systolic range and 10 mmHg on the diastolic range.
This, of course, depends on the context, and the American Heart Association reminds us that it is only considered to be so in the presence of certain symptoms. As these don’t always appear, making a diagnosis of low blood pressure requires several tests.
Although the drop in blood pressure causes different symptoms from its counterpart, hypertension, it’s very important to find the causes that trigger it, as well as ruling out possible differential diagnoses and initiating personalized treatment. In this article, we’ll explain what you should do in order to detect it through laboratory tests and images.
Tests and methods for the diagnosis of low blood pressure
As this evidence indicates, the first thing the specialist will do during the diagnosis of low blood pressure is to measure the blood pressure along with the heart rate in various positions (upright and supine).
This is the starting point, and, from here, they will be able to determine any possible complementary examinations and tests. Keep reading and we’ll explain the whole procedure, as well as other diagnostic tests for hypotension.
Anamnesis
Anamnesis is the collection of information based on a patients’s medical history and asking them questions.
The specialist will scrutinize these findings, their possible inclusion in risk groups, the intake of medications, and the characteristics or symptoms that occur during the drop in blood pressure (for example, if it occurs after eating, exercising, or standing up).
Initial clinical evaluation
This is carried out in silence, in a room with a temperature of between 20 and 24 degrees Centigrade after the patient has been resting for 5 minutes, while trying to create a calm atmosphere. The doctor will then measure the blood pressure in intervals of 60-180 seconds, with the patient both standing up and sitting down.
The change in blood pressure levels due to positional variations is known as orthostatic hypotension. The patient can also be told to eat and then tested 20 minutes later. Postprandial hypotension occurs when the pressure drops after each meal, and so this is a practical way to diagnose it.
Stress test
Depending on their criteria, the specialist can also create different stressful situations for the diagnosis of low blood pressure. For example, they can perform a cardiac stress test, measure tension in sudden changes in position, adjust the room temperature, or give drugs that promote rapid heartbeats.
Blood tests
Studies indicate that an important part of diagnosing hypotension is to rule out catalytic conditions, such as diabetes, anemia, vitamin deficiencies, neurodegenerative diseases, and more. Some can be detected through a blood test, and so tests of this type will be carried out at the same time.
Valsalva maneuver
This is a technique in which you try to breathe with your mouth closed. In certain conditions, blood pressure can create imbalances in its standard range. In this case, sudden drops will be looked for during or after the patient has completed the test. Normally, pressure instability in this setting is due to problems in the autonomic nervous system.
Tilt table test
If, during the initial clinical evaluation, the specialist doesn’t find a definitive test that is enable to warn of a drop in blood pressure, then the tilt table technique can be used. This consists of laying the patient on a special table that can change from a vertical to a horizontal position in just a matter of seconds.
The blood pressure results will then be measured and interpreted based on the above. The patient is likely to faint during the test if the descent leads to syncope.
Electrocardiogram
This is used to detect abnormalities in the heart based on its electrical signals. It can detect, for example, irregularities of the heart rhythm, some abnormalities in its structure or the speed of the heartbeat.
Imaging tests for the diagnosis of low blood pressure
Since there are countless conditions that can cause low blood pressure, your doctor will carry out imaging tests to diagnose the most obvious ones. They will often perform an echocardiogram.
With the help of this method, detailed images of the heart are obtained through high-frequency sound waves. The test detects the condition of the heart muscle, its chambers, its pumping efficiency, and its size, among other things.
Differential diagnosis of low blood pressure
During the diagnosis, the specialist will also rule out conditions that can be confused with symptoms of hypotension. The evidence indicates that the most common are the following:
- Anemia
- Cardiac arrhythmias
- Congestive heart failure
- Myocardial infarction
- Myocarditis
- Pericarditis
- Valvular heart disease
- Venous insufficiency
- Diabetes insipidus
- Suprarrenal insufficiency
- Dehydration
- Hypothyroidism
- Consumption of drugs
- Pregnancy.
Anxiety disorders or panic attacks can also cause symptoms very similar to hypotension. As appropriate, additional testing will be carried out to completely rule out these and other conditions.
As soon as the diagnosis of low blood pressure has been confirmed, treatment will proceed. This will attack the underlying condition and be supplemented with small lifestyle changes.
Treatment can also be complemented with the intake of some drugs, the use of compression stockings, and an increase in sodium intake in the diet. However, this will always be determined in a personalized way based on the results of the tests.
- Gupta, V., & Lipsitz, L. A. Orthostatic hypotension in the elderly: diagnosis and treatment. The American journal of medicine. 2007; 120(10): 841-847.
- Lahrmann, H., Cortelli, P., Hilz, M., Mathias, C. J., Struhal, W., & Tassinari, M. EFNS guidelines on the diagnosis and management of orthostatic hypotension. European journal of neurology. 2006; 13(9): 930-936.
- Lanier, J. B., Mote, M. B., & Clay, E. C. Evaluation and management of orthostatic hypotension. American family physician. 2011; 84(5): 527-536.
- Palma, J. A., & Kaufmann, H. Epidemiology, diagnosis, and management of neurogenic orthostatic hypotension. Movement disorders clinical practice. 2017; 4(3): 298-308.
