Low Blood Pressure (Hypotension): Causes

Pathogenesis (development of disease)

The cause of primary (essential) hypotension is not known. It is a regulatory disorder of the circulatory system on a constitutional basis – mostly affecting leptosome (narrow-bodied) patients and women. Secondary hypotension is caused by diseases, medications and also immobility. Orthostatic hypotension also falls under this term. This occurs as a result of a shift of blood to the venous system of the legs and intestinal tract (digestive organs) that takes place when the patient stands up. This results in a temporary decrease in the supply of oxygen to the brain.

Etiology (causes) of primary hypotension

Biographic CausesParticularly commonly affected by hypotension (low blood pressure) are:

  • Age
    • Older people
    • Adolescents in growth spurt
  • Tall, slender people – so-called leptosome physique.
  • Pregnant

Behavioral causes

  • Consumption of stimulants
    • Alcohol – (woman: > 20 g/day; man: > 30 g/day).
  • Drug use
    • Opiates or opioids (alfentanil, apomorphine, buprenorphine, codeine, dihydrocodeine, fentanyl, hydromorphone, loperamide, morphine, methadone, nalbuphine, naloxone, naltrexone, oxycodone, pentazocine, pethidine, piritramide, remifentanil, sufentanil, tapentadol, tilidine, tramadol)
  • Physical activity
    • Lack of physical activity

Causes related to disease

  • Eating disorders associated with underweight

Etiology (causes) of secondary hypotension

Endocrine hypotension

  • Adrenogenital syndrome (AGS) – autosomal recessive inherited metabolic disorder characterized by disorders of hormone synthesis in the adrenal cortex. These disorders lead to a deficiency of aldosterone and cortisol.
  • Bartter syndrome – very rare genetic metabolic disorder with autosomal dominant or autosomal recessive or X-linked recessive inheritance; defect of tubular transport proteins; hyperaldosteronism (disease states associated with increased secretion of aldosterone), hypokalemia (potassium deficiency) and low blood pressure.
  • Addison’s disease – adrenal insufficiency.

Cardiovascular hypotension

  • Accretio pericardi and concretio pericardi – adhesions of the pericardium to the pleura as a result of pericarditis.
  • Aortic arch syndrome, carotid sinus syndromeCardiac arrhythmias – e.g. paroxysmal tachycardia – seizure-like cardiac arrhythmia with increased heart rate above 100/min.
  • Aortic stenosis – narrowing of the aorta or aortic valve.
  • Heart failure (cardiac insufficiency)
  • Mitral stenosis – narrowing of the mitral valve stenosis.
  • Myocardial infarction (heart attack)
  • Postprandial hypotension (systolic blood pressure drop of at least 20 mmHg for a period of at least 30 minutes within two hours of food intake; elderly survivors after intensive care unit stay)

Neurogenic hypotension

  • After sympathectomy – removal of the sympathetic border cord.
  • After administration of antihypertensive drugs, e.g., diuretics, beta-blockers, ACE inhibitors, etc.
  • Shy-Drager syndrome – progressive degenerative disease of the central nervous system, which is associated with hypotension when the body is upright.

Hypovolemic hypotension due to blood or plasma loss.

  • In burns, accidents, inflammation.
  • Vomiting, diarrhea, extreme sweating, not drinking enough.
  • In shock – decrease in the amount of circulating blood.

Medication

Orthostatic hypotension occurs as a result of a shift of blood to the legs and viscera that occurs when standing up. This causes a lack of blood flow to the brain, which leads to an undersupply of oxygen and, as a result, the symptoms previously described.This form of hypotension often occurs in very slim, younger women and after prolonged immobilization. Similarly, infections or hormonal dysfunction can lead to orthostatic hypotension.