Hypotension

Definition

Hypotension is defined as a state of abnormally diminished blood pressure. The normal blood pressure is 120/80 mmHg and a slight drop or elevation is seen at different times in the day. Blood pressure equal to or below 90/60 mmHg is considered as hypotension. Prolonged hypotension may not present with obvious symptoms except at times of increased physical activity.  A sudden drop in blood pressure, however, leads to prominent symptoms. The condition causes insufficient blood supply to the body including organs such as kidneys, heart and brain. Severely low blood pressure occurs in ‘shock’ which is a life threatening condition.

Symptoms

The symptoms of hypotension varies depending on the severity of the condition. Lightheadedness is by far the most common symptom in even mild cases. It progressively gets worse into dizziness and even fainting as the blood pressure continues to drop. It is usually accompanied by shortness of breath and rapid breathing as the body attempts to increase blood oxygenation. Typically the heart also beats faster (tachycardia) in an attempt to stabilize the blood pressure.

Other symptoms of hypotension includes :

  • Blurred vision
  • Difficulty concentrating
  • Confusion
  • Paleness of the skin
  • Palpitations
  • Irregular heartbeats (arrhythmia)
  • Nausea and sometimes vomiting

In some cases the hypotension can occur with changes in body position .This is known as postural or orthostatic hypotension. The condition is characterized by sudden drop in blood pressure on change in positions such as suddenly standing up from lying or sitting position. The pressure quickly comes back to normal within minutes.

Causes

Hypotension can develop due to various factors. Decrease in the volume of blood can be a primary cause of hypotension. The loss of the blood volume could be due to hemorrhage, fluid loss due to diarrhea and severe starvation. Cardiac problems which may lead to hypotension include congestive cardiac failure, cardiac arrhythmias and myocardial infarction.

Drugs used to treat hypertension (high blood pressure) such as beta blocker and diuretics can also lead to development of hypotension. Alcohol in excess quantity, anti-depressant and anti-anxiety medications also contribute to the drop in blood pressure. Hormonal changes and endocrine disorders can also lead to lowered blood pressure.

Widening of blood vessels is known as vasodilation and it leads to decreased resistance to blood flow and decreased blood pressure. Vasodilation can be caused by sepsis, brain injuries or drugs such as calcium channel blockers.

Treatment

The treatment of hypotension comprises of treating the underlying cause. Generally hypotension is transient and does not require any long term treatment. Postural hypotension can be treated by additional salt, water and electrolyte intake in the diet. Increase intake of beverages containing caffeine is also advised but in moderation.

In patients with hypotension associated with shock, emergency medical treatment is indicated as the condition is life threatening. The blood volume needs to be restored to normal levels. Blood transfusions and intravenous fluids are recommended in such conditions.

Hypotension caused by sepsis is treated with fluids and antibiotic medications. In cases with hypotension due to severe dehydration, electrolytes and fluids are given by intravenous route. Mild cases with dehydration can be treated with oral electrolytes and fluids.

Hypotension which developed as a side effect of medication is treated by substituting the medicines with suitable alternatives.

 

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