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Poor Cerebral Circulation: Overview
Cerebral circulation involves a most remarkable system of supply and demand. The brain, having a cell metabolism utterly dependent on immediate availability of oxygen, and having by far the highest metabolic rate of any organ in the body, requires excellent circulatory flow in order to function.
The brain is the most active metabolic organ in the body, and also one of the most vulnerable to metabolic upset. Without significant variation between wakefulness or sleep or levels of physical/mental activity, the central nervous system uses some 15-20% of one's oxygen intake and only a slightly lesser percentage of the heart's output. Circulating blood volume within the brain at any instant is about 750 ml and remains essentially constant, although regional variations occur within the brain with change in mental activity. Virtually all of this oxygen use is for conversion of glucose to CO2. Since neural tissue has no mechanism for storage of oxygen, there is an oxygen metabolic reserve of only about 8-10 seconds. When brain cells are deprived of their blood supply, a stroke occurs. Without access to vital nutrients and oxygen, brain cells die. The effects of a stroke can vary widely depending on where it occurs in the brain, the severity of the attack, and the general health of the person. A minor stroke may not even be noticed, while a major one can cause crippling mental and physical disabilities or even death. The brain automatically regulates the blood pressure between a range of about 50 to 140 mm Hg. If pressure falls below 50mm Hg, adjustments to the vessel system cannot compensate, brain perfusion pressure also falls, and the result may be hypoxia and circulatory blockage. Pressure elevated above 140mm Hg results in increased resistance to flow in the cerebral arterial tree. Excessive pressure can overwhelm resistance, leading to elevated capillary pressure, loss of fluid to the meager tissue compartment, and brain swelling. Causes & Development
Disruptions to the brain's blood circulation include cerebral hemorrhage, thrombosis, embolism, or subarachnoid hemorrhage. These usually result from pre-existing vascular disease or congenital weakness and may be precipitated by trauma. Most commonly these problems occur in older persons. - Hemorrhage usually occurs in atherosclerotic vessels. The resulting blood clot destroys brain tissue, and the neural tissue remaining next to the clot may be softened, leading to later complications. The clot and dead tissue are removed by macrophages, and the damaged area is invaded by connective tissue and glia, often producing a fluid-filled cyst.
- Thrombosis most commonly involves formation of a clot at a site of vessel lumen constriction due to growth of atherosclerotic plates. Blockage of circulation leads to tissue softening and death, and to congestion of flow and edema in adjacent areas.
- Embolism is the blockage of a cerebral vessel by a physical object, such as a dislodged clot, air, tumor cells, infectous mass. Often the situation involves multiple embolisms, complicating the clinical picture.
- Aneurisms are the expansion of a vessel, usually an artery, and these balloons may reach a diameter of several inches. If this occurs within the cranial cavity, the displacement of neural tissue and the compression of other vessels and of cranial nerves can obviously lead to severe problems. Most arise from the middle cerebral artery or the internal carotid, and if expansion is slow enough, there may be extensive erosion of bone. Clinically there is the added danger that the weakened vessel will rupture, giving the added problems of subarachnoid hemorrhage. Treatment usually involves surgery, if the vessel is accessible. Methods include removal of the sac or reinforcing the vessel wall with muscle or connective tissue, or ensheathing or replacing the weakened vessel with plastic.
Chronic hypertension may result in vascular sclerotic lesions and lead to headache, dizziness, digestive symptoms, and even seizures. The final outcomes may include any of the problems described above. Treatment & Prevention
Treatment involves weight loss (if this is part of the problem), sodium restriction, and drugs to reduce pressure, in addition to symptomatic treatments if these do not subside. Complications
Part of the clinical problem is that by the time these symptoms manifest themselves, there may have been extensive damage.
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Signs, symptoms & indicators of Poor Cerebral Circulation:
Risk factors for Poor Cerebral Circulation:
Recommendations and treatments for Poor Cerebral Circulation:
KEY | | Weak or unproven link |  | | Strong or generally accepted link |  | | Likely to help |
GLOSSARY
Arterial (Arteries, Artery)
Blood that leaves the heart. When it leaves the right ventricle, it is venous blood; and when it leaves the left ventricle, through the aorta, it is fresh and oxygenated. After it has passed out to the capillaries and started to return, it is venous blood.
Capillary
Any of the smallest blood vessels connecting arterioles with venules and forming networks throughout the body.
Central Nervous System (CNS)
A collective term for the brain, spinal cord, their nerves, and the sensory end organs. More broadly, this can even include the
neurotransmitting hormones instigated by the CNS that control the chemical nervous system, the endocrine glands.
Chronic (Chronicity)
Usually referring to chronic illness: Illness extending over a long period of time.
Cysts (Cyst)
A closed pocket or pouch of tissue; a cyst may form within any tissue in the body and can be filled with air, fluid, pus, or other material. Cysts within the lung generally are air-filled, while cysts involving the lymph system or kidneys are fluid filled. Cysts under the skin are benign, extremely common, movable lumps. These may develop as a result of infection, clogging of sebaceous glands, developmental abnormalities or around foreign bodies.
Edema
Abnormal accumulation of fluids within tissues resulting in swelling.
Embolism
Obstruction of a vessel by an abnormal body, usually a detached blood clot.
Glucose
A sugar that is the simplest form of carbohydrate. It is commonly referred to as blood sugar. The body breaks down carbohydrates in foods into glucose, which serves as the primary fuel for the muscles and the brain.
Hemorrhage (Hemorrhaging)
Profuse blood flow.
Hg
The chemical symbol for mercury, often used to indicate pressure measurements in either inches or millimeters.
Hypertension
High blood pressure. Hypertension increases the risk of heart attack, stroke, and kidney failure because it adds to the workload of the heart, causing it to enlarge and, over time, to weaken; in addition, it may damage the walls of the arteries.
Lesion (Lesions)
Any damage to tissue structure or function; an abnormal change in body tissue caused by disease or injury. A scar is a lesion, as is cancer, a stomach ulcer or a pimple.
Lumen
Space in the interior of a tubular structure.
Macrophage (Macrophages)
An immune system cell that scavenges bacterial and other foreign material in the blood and tissues. It is a mature form of what is released from the marrow as a monocyte. A macrophage lives long, can digest much detritus, and is able to wear particles of odd food on its outer membrane. This allows T-cell and B-cell lymphocytes to taste the particle (an epitope) and form an antibody response. Further, these macrophages, traveling as monocytes, will take up permanent residence in many tissues, providing them with immunity. They line the spleen, form the cleansing Kupffer cells in the liver, make up the "dust cells" that protect the lungs, protect the synovial fluids of the joints, and form the microglial cells that provide protection to the brain and nerve tissues. Essentially the macrophages clean up messes and act as the intermediates between innate and acquired immunity.
Metabolism (Metabolic, Metabolize, Metabolizes, Metabolizing)
The chemical processes of living cells in which energy is produced in order to replace and repair tissues and maintain a healthy body. Responsible for the production of energy, biosynthesis of important substances, and degradation of various compounds. Also defined as the sum total of changes in an organism in order to achieve a balance (homeostasis): Catabolic burns up, anabolic stores and builds up; the sum of their work is metabolism.
Milliliter (mL)
0.001 or one thousandth of a liter.
Millimeter (Millimeters, mm)
A metric unit of length equaling one thousandth of a meter, or one tenth of a centimeter. There are 25.4 millimeters in one inch.
Perfusion
Usually Coronary/Myocardial perfusion: Flow of blood to the heart and/or blood vessels surrounding the heart.
Seizure (Seizures)
While there are over 40 types of seizure, most are classed as either partial seizures which occur when the excessive electrical activity in the brain is limited to one area or generalized seizures which occur when the excessive electrical activity in the brain encompasses the entire organ. Although there is a wide range of signs, they mainly include such things as falling to the ground; muscle stiffening; jerking and twitching; loss of consciousness; an empty stare; rapid chewing/blinking/breathing. Usually lasting from between a couple of seconds and several minutes, recovery may be immediate or take up to several days.
Sodium
An essential mineral that our bodies regulate and conserve. Excess sodium retention increases the fluid volume (edema) and low sodium leads to less fluid and relative dehydration. The adult body averages a total content of over 100 grams of sodium, of which a surprising one-third is in bone. A small amount of sodium does get into cell interiors, but this represents only about ten percent of the body content. The remaining 57 percent or so of the body sodium content is in the fluid immediately surrounding the cells, where it is the major cation (positive ion). The role of sodium in the extracellular fluid is maintaining osmotic equilibrium (the proper difference in ions dissolved in the fluids inside and outside the cell) and extracellular fluid volume. Sodium is also involved in nerve impulse transmission, muscle tone and nutrient transport. All of these functions are interrelated with potassium.
Stroke (Stroke-Type Event)
A sudden loss of brain function caused by a blockage or rupture of a blood vessel that supplies the brain, characterized by loss of muscular control, complete or partial loss of sensation or consciousness, dizziness, slurred speech, or other symptoms that vary with the extent and severity of the damage to the brain. The most common manifestation is some degree of paralysis, but small strokes may occur without symptoms. Usually caused by arteriosclerosis, it often results in brain damage.
Thrombosis
Formation of blood clots causing vascular obstruction.
Vascular
Relating to the blood vessels of the body. The blood vessels of the body, as a group, are referred to as the vascular system. They are composed of arteries, veins and capillaries - arteries that pass oxygen-rich blood to the tissues of the body; veins which return oxygen-depleted blood from the tissues to the lungs for oxygen; and the capillaries that are the tiniest vessels and are between the arteries and veins.
Last updated: Aug 30, 2010
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