Low Blood Pressure - Causes

What causes low blood pressure?

Low blood pressure can be caused by sudden changes of position (orthostatic hypotension), blood volume redistribution in response to eating (postprandial hypotension), abnormal brain signaling (neurally mediated hypotension), and conditions that cause shock. Medications, heart disease, pregnancy, bedrest, malnutrition, and other health conditions can also contribute to low blood pressure.

Cardiovascular causes of low blood pressure

Low blood pressure may be caused by cardiovascular conditions including:

Bradycardia (slow heart rate)
Heart failure (deterioration of the heart’s ability to pump blood)
Heart valve disease
Hypotension

Other causes of low blood pressure

Low blood pressure can also be caused by other diseases, disorders or conditions including:

Alcohol use
Anemia
Certain medications, including ACE inhibitors, angiotensin receptor blockers, beta blockers, calcium channel blockers, diuretics, erectile dysfunction drugs, narcotics, nitrates, some antianxiety medications, some antidepressants, and some anti-Parkinson’s drugs
Endocrine diseases, such as Addison’s disease (deceased production of hormones by the adrenal glands), diabetes (chronic disease that affects your body’s ability to use sugar for energy), hypothyroidism (underactive thyroid), or parathyroid disease
Extended bedrest
Hypovolemia (decreased blood volume)
Malnutrition
Pregnancy

Serious or life-threatening causes of low blood pressure

In some cases, low blood pressure may be a symptom of a serious or life-threatening condition that should be immediately evaluated in an emergency setting. These include:

Anaphylaxis (life-threatening allergic reaction)
Arrhythmia (irregular heart rhythm)
Extensive burns
Head injury
Hemorrhage or internal bleeding
Hypovolemic shock
Myocardial infarction (heart attack)
Poisoning
Septic shock (shock due to a life-threatening bacterial blood infection)

Questions for diagnosing the cause of low blood pressure

To diagnose your condition, your doctor or licensed health care practitioner will ask you several questions related to your low blood pressure including:

When did you first notice your low blood pressure?
What seems to bring it on?
Does anything make it improve?
Do you have any other symptoms?
Do you have any other medical problems?
What medications are you taking?
Do you drink alcohol or use any illicit drugs?

What are the potential complications of low blood pressure?

Because low blood pressure can be due to serious diseases, failure to seek treatment can result in serious complications and permanent damage. Once the underlying cause is diagnosed, it is important for you to follow the treatment plan that you and your health care professional design specifically for you to reduce the risk of potential complications including:

Brain damage
Heart disease
Injury due to fainting
Kidney damage
Loss of strength
Shock
Stroke

References:

Hypotension. PubMed Health. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004536/. Accessed May 24, 2011.

Low blood pressure. American Heart Association. http://www.heart.org/HEARTORG/Conditions/HighBloodPressure...re_UCM_301785_Article.jsp. Accessed May 24, 2011.

INTRODUCTION

What is low blood pressure?

Blood pressure is the measure of pressure of the blood inside arteries when your heart pumps (systolic pressure) and when it is at rest (diastolic pressure). Although there are thresholds for defining high blood pressure, or hypertension, there are no specific thresholds for defining low blood pressure, or hypot... Read more about low blood pressure introduction

SYMPTOMS

What other symptoms might occur with low blood pressure?

Low blood pressure may accompany other symptoms that vary depending on the underlying disease, disorder or condition. Symptoms that frequently affect the cardiovascular system may also involve other body systems.... Read more about low blood pressure symptoms