Circulation: If your brain does not get enough blood flow, you feel lightheaded. Almost everyone has experienced this on occasion when standing up quickly from a lying-down position. But some people have light-headedness from poor circulation on a frequent or chronic basis. This could be caused by arteriosclerosis or hardening of the arteries, and it is commonly seen in patients who have high blood pressure, diabetes, or high levels of blood fats (cholesterol). It is sometimes seen in patients with inadequate cardiac (heart) function, hypoglycemia (low blood sugar), or anemia (low iron).
Certain drugs also decrease the blood flow to the brain, especially stimulants such as nicotine and caffeine. Excess salt in the diet also leads to poor circulation. Sometimes circulation is impaired by spasms in the arteries caused by emotional stress, anxiety, and tension.
If the inner ear fails to receive enough blood flow, the more specific type of dizziness vertigo occurs. The inner ear is very sensitive to minor alterations of blood flow and all of the causes mentioned for poor circulation to the brain also apply specifically to the inner ear.
Neurological diseases: A number of diseases of the nerves can affect balance, such as multiple sclerosis, syphilis, tumors, etc. These are uncommon causes, but your doctor may perform certain tests to evaluate these.
Anxiety: Anxiety can be a cause of dizziness and lightheadedness. Unconscious overbreathing (hyperventilation) can be experienced as overt panic, or just mild dizziness with tingling in the hands, feet, or face. Instruction on correct breathing technique may be required.
Vertigo: An unpleasant sensation of the world rotating, usually associated with nausea and vomiting. Vertigo usually is due to an issue with the inner ear. The common causes of vertigo are (in order):
Benign Positional Vertigo: Vertigo is experienced after a change in head position such as lying down, turning in bed, looking up, or stooping. It lasts about 30 seconds and ceases when the head is still. It is due to a dislodged otololith crystal entering one of the semicircular balance canals. It can last for days, weeks, or months. The Epley "repositioning" treatment by an otolaryngologist is usually curative. BPV is the commonest cause of dizziness after (even a mild) head injury.
Meniere's disease: An inner ear disorder with attacks of vertigo (lasting hours), nausea, or vomiting, and tinnitus (loud noise) in the ear, which often feels blocked or full. There is usually a decrease in hearing as well.
Migraine: Some individuals with a prior classical migraine headache history can experience vertigo attacks similar to Meniere's disease. Usually there is an accompanying headache, but can also occur without the headache.
Infection: Viruses can attack the inner ear, but usually its nerve connections to the brain, causing acute vertigo (lasting days) without hearing loss (termed vestibular neuronitis). However, a bacterial infection such as mastoiditis that extends into the inner ear can completely destroy both the hearing and equilibrium function of that ear, called labyrinthitis.
Injury: A skull fracture that damages the inner ear produces a profound and incapacitating vertigo with nausea and hearing loss. The dizziness will last for several weeks and slowly improve as the other (normal) side takes over. BPV commonly occurs after head injury.
Allergy: Some people experience dizziness and/or vertigo attacks when they are exposed to foods or airborne particles (such as dust, molds, pollens, dander, etc.) to which they are allergic.
