Severe hypotension is considered when blood pressure values are below 50/30 mmHg, i.e. well below the pressure considered normal.
There are multiple triggers: significant blood loss, dehydration, severe infection, severe allergic reaction, heart attack, arrhythmia or heart failure, and even a sudden change in body position. Some drugs or substances can also cause low blood pressure (alcohol, anxiolytics, antidepressants, diuretics, hypotensives).
It manifests with blurred vision, dizziness, lightheadedness, weakness, nausea or vomiting, drowsiness, chest pain, headache, palpitations and/or fainting.
The diagnosis is reached by measuring vital signs (blood pressure, heart rate, temperature, respiratory rate and/or glycemic control). It should be complemented with a detailed clinical history and in many occasions with blood analysis, blood cultures, electrocardiogram, abdomen and/or thorax x-ray and urinalysis.
It is essential to treat the cause of hypotension. If it is due to fluid loss, fluids will be replaced with intravenous serum therapy or blood transfusion; if there is active bleeding, urgent surgery may be required. If it is due to infection, treatment will be based on antibiotics. If it is due to a severe allergy (anaphylaxis), contact with the allergenic substance will be avoided and antihistamines and/or corticosteroids will be administered. More severe cases will require drugs to increase blood pressure. If the hypotension has been caused by a rapid change of position, it can be resolved by lying the affected person down and raising the legs to facilitate blood return.
In cases of more severe hypotension, call for help or go to the nearest emergency room, as low blood pressure can cause important organs such as the heart or brain to be deprived of oxygen and can have serious consequences. If the person stops breathing or stops having a pulse, cardiopulmonary resuscitation (CPR) should be started.
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