The phenomenon due to orthostatic hypotension, a drop in blood pressure when moving from a lying or sitting position to standing
Blurred vision, dazed, to the point of being unable to stand. Many have happened to find themselves in these conditions when they got up abruptly from bed in the morning (perhaps because they were late), or from their desk after sitting for a long time. Why does this happen? Could this be a symptom of a health problem? Temporary fainting due to so-called orthostatic hypotension, i.e a sudden drop in blood pressure: a reduction of at least 20 mmHg in systolic blood pressure (the maximum) and/or at least 10 mmHg in diastolic blood pressure (the minimum), which occurs in the first three minutes after assuming an upright position. The consequence is that not enough blood reaches the brain. Normally, standing or sitting causes blood vessels in the legs and lower body to narrow; this way more blood reaches the heart and brain.
In general, we speak of hypotension (low blood pressure) when the maximum at rest falls below 90 mmHg (millimeters of mercury) and the minimum below 60 mmHg. One of the most common causes of the drop in blood pressure dehydration: Blood vessels cannot contract enough to send blood to where it is needed because there is not enough fluid in circulation. Even neurological disorders they can cause hypotension, in particular orthostatic hypotension: it is in fact the nerves that carry the order to the heart to beat faster (to adequately supply the brain) and to the blood vessels the input to tighten. particular the case of a 69-year-old war veteran, of which the New York Times Magazine
: the man often fainted (even with actual fainting spells) when he assumed an upright position. The doctors had hypothesized that it could depend on the severe peripheral neuropathy he was suffering from: his feet were almost totally numbbut sometimes felt burning or pins and needles.
The case of the 69-year-old from Birmingham (Alabama, USA) was not easy to solve. Every time her blood pressure dropped, her heart rate increased. Doctors therefore ruled out a neurological problem, because if the nerves can’t tell blood vessels to tighten, they can’t even tell the heart to beat faster: in neurogenic orthostatic hypotension, in fact, heart rate remains stable even when blood pressure drops. The other more frequent cause, that of dehydration: administering liquids to the patient had in fact had no effect on the disorder.
The solution to the riddle had to be sought elsewhere. A few years earlier the man had fallen into the bathtub, he had broken ribs and punctured a lung. It had been necessary to rush him to the hospital. In patients who are bedridden during their hospitalization, they can form blood clots in the veins of the legs due to forced immobility: to avoid the risk, anticoagulant therapy is generally administered. But since the 69-year-old had suffered a punctured lung, resulting in hemorrhage, he could not take blood thinners. Given the situation, the doctors had decided to insert a filter into the main vein that carries blood from the legs to the heart (the inferior vena cava) to capture any clots. Filters of this type should be removed after a few months, but in many cases this is not the case. The man had lived with the device inserted into his vein for over 15 years.
Doctors hypothesized that the filter, having captured numerous clots, blocked the entire vessel and was therefore the cause of hypotension. One element confirmed it: seven years earlier the man had undergone a CAT scan, which he had shown almost total obstruction of the vena cava. It was therefore possible that the blood, when the patient stood up, did not have the possibility of reaching the brain in adequate quantity because it was blocked by the clots gathered on the filter. Doctors decided to try: the man underwent surgery to remove the filter and place nine stents (metal retractors) in the main veins of the legs, to ensure proper blood flow. The operation was resolved: Veteran no longer suffered from dizziness, dizziness, or falls. All he has left is some numbness in his feet. The doctors who treated him admit that it is certainly a rare case, but in patients suffering from orthostatic hypotension this possibility too should be ventilated.
In general, orthostatic hypotension does not cause any problems if the pressure does not fall too much, but if the significant drop occurs, symptoms such as dizziness, blurred vision, confusion, up to loss of consciousness (syncope), due to a reduction in blood flow to the brain, which resolves quickly upon returning to the lying position. Syncope due to orthostatic hypotension, therefore, does not in itself entail consequences (unless there is a fall to the ground with trauma). In case of loss of consciousness it is important to rule out other potentially serious causes, such as a cardiac arrhythmia. Orthostatic hypotension mostly affects Older people, in which reflexes are less quick and efficient. It can also be favored by antihypertensive drugs. Therefore, when starting therapy for high blood pressure, the doctor should measure the patient’s pressure even in an upright position, in order to make a careful choice of drugs and the relative doses.
December 5, 2022 (change December 5, 2022 | 12:49 am)
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