Blood pressure disorders during Parkinson's disease

Blood pressure disorders are highly prevalent in the course of Parkinson's disease (PD). They relate to autonomic failure and are frequently associated with orthostatic hypotension, postprandial hypotension and supine hypertension. Supine hypertension, which may concern up to 50% of patients with PD and autonomic failure, is driven by residual sympathetic activity and changes in sensitivity of vascular adrenergic receptors. It can also be induced or worsened by antihypotensive drugs. Even if little data is available, a set of arguments suggests that supine hypertension sometimes requires treatment. This review will focus on recent data on the pathophysiology and the management of supine hypertension in the context of its association with orthostatic hypotension.

Blood Pressure Disorder

You've probably heard that high blood pressure is a problem. So what about low blood pressure?

Blood pressure is the force of your blood pushing against the walls of your arteries. Each time your heart beats, it pumps out blood into the arteries. Your blood pressure is highest when your heart beats, pumping the blood. This is called systolic pressure. When your heart is at rest, between beats, your blood pressure falls. This is the diastolic pressure. Your blood pressure reading uses these two numbers. Both are important. Usually they're written one above or before the other, such as 120/80. If your blood pressure reading is 90/60 or lower, you have low blood pressure.

Some people have low blood pressure all the time. They have no symptoms and their low readings are normal for them. In other people, blood pressure drops below normal because of some event or medical condition. Some people may experience symptoms of low pressure when standing up too quickly. Low blood pressure is a problem only if it causes dizziness, fainting or in extreme cases, shock.

Different Types of Blood Pressure Disorders

There are different types of blood pressure disorders. About 95 percent of people with high blood pressure have what is known as essential hypertension, which is really a fancy way of saying that it just happens, and we don't know why. The other five percent of cases have secondary hypertension, where there is an identifiable, and usually correctable, cause. The most common type of secondary hypertension is renovascular hypertension, in which a narrowing of the artery to one or both kidneys occurs.

It is thought that hypertension is the end result of a number of different factors which make the blood pressure go up, and it is probable that different mechanisms are important in different individuals. This may explain why a particular type of treatment may work very well in one person, but not at all in another. The types of essential hypertension are:

White coat hypertension: Blood pressure is only high in a doctor's office. It can be detected by measuring the blood pressure over a period of 24 hours using a technique called ambulatory monitoring. This involves wearing a blood pressure monitor that can take readings while you are going about your normal daily activities, typically every 15 minutes.

People with white coat hypertension are not necessarily nervous or neurotic, and they may look and feel quite calm while in the doctor's office. It is generally thought that they do not need to take medications for their blood pressure, and that they are at relatively low risk of heart disease and stroke. It is, however, very important that they continue to have their pressure checked (by self-monitoring, for example) on a regular basis.

White coat hypertension occurs in about 20 percent of hypertensive patients. It is more common in women than in men, and it's surprisingly common in older people. One study found that 40 percent of hypertensives over the age of 65 had white coat hypertension.

Systolic hypertension: A high systolic, but normal diastolic pressure (a reading of 170/80 mm Hg would be typical). It's caused by an age-related loss of elasticity of the major arteries, and is mainly seen in people over the age of 65.

Malignant hypertension: An acute emergency requiring immediate treatment in hospital. Whatever the underlying cause, when the blood pressure reaches a certain level for a sufficient length of time it sets off a vicious cycle of damage to the heart, brain, and kidneys, resulting in further elevation of the pressure. Not surprisingly, if untreated, it can be rapidly fatal.

Labile hypertension: Although this term is quite commonly used, it doesn't have much meaning. 'Labile' means variable, and just about everyone with hypertension has 'lablie hypertension.' It has also been used to refer to people whose blood pressure is sometimes normal and sometimes high, also called Borderline hypertension

Borderline hypertension: This is a blood pressure level which is in the 'gray zone' between normal and high (for example, someone with an average pressure of about 140/90 mmHg).

Pulmonary hypertension: High blood pressure in the pulmonary circulation (the arteries which go to the lungs). The blood pressure in the arms and the rest of the body is normal or low. It is quite different from essential hypertension, and is usually a consequence of disease of the lungs or heart.

Acclerated hypertension: Severe hypertension of recent origin, which may lead to malignant hypertension.

Secondary hypertension: Hypertension which arises from an identifiable disorder of an organ in the body which, if corrected, cures or greatly improves the hypertension. Examples are a narrowing of one of the arteries to the kidneys (renovascualar hypertension), or a tumor of an adrenal gland.

Renovascular hypertension: Hypertension caused by one or more narrowed renal arteries.

Pseudohypertension: In the elderly with very rigid arteries, the blood pressure cuff may not be able to compress the artery, so a falsely high blood pressure reading is obtained.