Lightheadedness

Keeping a sense of balance requires the brain to process a variety of information received from the eyes, the nervous system, and the inner ears. If the brain is unable to process these signals, such as when the messages are contradictory, or if the sensory systems are improperly functioning, an individual may experience lightheadedness or dizziness.

Causes

Lightheadedness can be simply (and most commonly) an indication of a temporary shortage of blood or oxygen to the brain due to a drop in blood pressure, rapid dehydration from vomiting, diarrhea, or fever. Other causes are: altitude sickness, low blood sugar, hyperventilation, postural orthostatic tachycardia syndrome (increase in heart rate upon sitting up or standing), panic attacks, and anemia. It can also be a symptom of many other conditions, some of them serious, such as heart problems (including abnormal heart rhythm or heart attack), respiratory problems such as pulmonary hypertension or pulmonary embolism, and also stroke, bleeding, and shock. If any of these serious disorders are present, the individual will usually have additional symptoms such as chest pain, a feeling of a racing heart, loss of speech or a change in vision.

Many people, especially as they age, experience lightheadedness if they arise too quickly from a lying or seated position. Lightheadedness often accompanies the flu, hypoglycaemia, common cold, or allergies. Dizziness could be provoked by the use of antihistamine drugs, like levocetirizine, or by some antibiotics or SSRIs. Nicotine or tobacco products can cause lightheadedness for inexperienced users. Narcotic drugs, such as codeine, can also cause lightheadedness.