People confuse hypertension and hypotension simply because they sound similar. But, hypotension is low blood pressure and hypertension is high blood pressure.
What is Hypotension?
Hypotension is low blood pressure. The heart pumps out blood into general circulation and the vessel wall elasticity, capacity of vessels and the nerve impulses help maintain the blood pressure. When the blood pressure is very low, and the circulation is compromised, the patient is said to be in shock. Blood is the transport medium for nutrients, gases, and waste products. It carries oxygen from lungs to cells where it is used in cellular aerobic respiration. It transports carbon dioxide to the lungs to be removed from the body by exhalation. It carries nutrients from the gut to target cells where they are utilized and stored. Cells and the immediate environment hang in a delicate balance in which blood plays a vital role. A good blood supply is needed for cell survival. Without good blood supply less oxygen goes into cells; fewer nutrients go into cells and waste products accumulate in tissue. Without a good blood supply cells will die.
Causes of Low Blood Pressure: Blood pressure and heart rate are the two main variables in perfusion control. Many cardiac, pulmonary, gastrointestinal, renal, traumatic and systemic conditions can cause low blood pressure. Cardiac failure (left ventricular failure), heart rhythm abnormalities, valve disorders, myocarditis, cardiomyopathies, ischemic heart disease, pulmonary embolism, severe diarrhea and vomiting, diabetes insipidus, bleeding, shock (hypovolemic, septic, anaphylactic and neurogenic), inflammatory disorders, low serum protein and inappropriate use of drugs can lower blood pressure.
ECG, 2d echocardiogram, CKMB, ESR, CRP, serum electrolytes, viral screening, plasma renin activity, vasopressin level, ANA, ADsDNA, rheumatoid factor and serum protein may be according to the clinical judgment of the doctor.
Treating Low Blood Pressure: Administration of intravenous fluids, adrenaline, noradrenaline, dopamine infusions may be used to treat severe hypotension/shock.
What is Hypertension?
Hypertension is elevated blood pressure above norms for age and clinical status. Blood pressure usually goes up with age due to loss of elasticity of blood vessels. This is called essential hypertension. Blood pressure can go up due to specific conditions, as well.
Causes of High Blood Pressure: High serum thyroxin, cortisol, adrenaline, noradrenaline, renal failure, cardiac failure and certain drugs can cause high blood pressure. Elevation of blood pressure due to another condition is called secondary hypertension. The cause should be investigated and treated to bring the secondary high blood pressure down.
High blood pressure exerts a strain on the heart leading to heart failure, heart muscle enlargement and valve failure. High blood pressure may rupture small blood vessels inside the brain, especially, if they are congenitally weakened (arterio-venous malformation). This gives rise to hemorrhagic strokes (bleeding into the brain substance). Chronic high blood pressure also leads to renal failure.
Treating High Blood Pressure: Angiotensin receptor blockers, ACE inhibitors, xanthine, caffeine, loop diuretics, thiazides, spironolactone and ethanol promote water loss and lowers blood pressure.
High blood pressure during pregnancy is lethal for the fetus. Pregnancy induced hypertension leads to pre-eclampsia. It features high blood pressure, loss of protein in urine and swelling. Eclampsia causes fits. High blood pressure during pregnancy damages the placenta and compromises blood supply to the fetus. Therefore, in case of severe hypertension, blood pressure should be brought rapidly under control, fits should be prevented, and pregnancy may have to be terminated.
Hypertension vs Hypotension
• Hypertension is commoner than hypotension.
• Hypertension does not cause symptoms at early stages, but hypotension immediately shows symptoms.
• Hypotension features dizziness, tiredness, and blurred vision while hypertension features headache, visual halos and chest pain.
• Hypotension does not cause fits during pregnancy while hypertension does.
• Intravenous fluid and sympathomimetic treat hypotension while diuretics and vasodilators treat hypertension.