Dizziness is the sensation of feeling light-headed, off-balance or unsteady on your feet, while vertigo is characterized by a feeling that you or the environment around you is spinning. According to Merck.com, the brain, circulatory system, nerves, inner ear, eyes, muscles and joints work together to maintain balance, so problems with any of these structures can cause dizziness or vertigo.
Disruption in Blood Flow to the Head
A drop in blood pressure, dehydration due to illness, low blood sugar, allergies, hyperventilation and anxiety disorders can all interfere with the normal circulation of blood to the brain and cause dizziness or light-headedness, according to the National Institutes of Health. Heart arrhythmias, structural problems with heart valves, deterioration of heart muscle and/or blockages in the arteries supplying the heart with blood are more serious possible causes of dizziness that require prompt medical evaluation.
Inner Ear Problems
Vestibular, or inner ear, problems can cause a sensation of floating, dizziness or unsteadiness, hearing loss, a persistent ringing or buzzing, and a heavy head, according to the Mayo Clinic. One underlying cause of inner ear problems is an acoustic neuroma, a growth that forms on the nerve that runs from the inner ear to the brain.
Meniere’s disease, a condition characterized by excess fluid in the inner ear, is a known cause of vertigo, as is acute vestibular neuronitis, an inflammation of the inner ear that causes severe dizziness and nausea and vomiting.
Benign paroxysmal positional vertigo is another cause of vertigo that occurs in response to a change in position of the head. When an individual lies down, sits up or otherwise alters the normal upright positioning of the head, otoconia--small crystals made of calcium carbonate--drift into canals within the inner ear and cause a spinning sensation.
Merck.com reports that certain medications can also adversely affect the inner ear and lead to vertigo. Some of these medications include aspirin, chemotherapy drugs such as cisplatin, certain antibiotics and the diuretic furosemide. Excessive consumption of alcohol, sedatives and anti-seizure medication can also cause dizziness.
Sensory Disturbances
Changes in vision caused by cataracts, recent eye surgery or new glasses can cause dizziness, according to Merck.com. Damage to the nervous system can also disturb the senses and contribute to a loss of balance. For example, peripheral neuropathy--nerve damage and loss of sensation in the legs, feet, arms or hands--and diseases that affect the nervous system such as Parkinson’s disease can also cause dizziness.
Musculoskeletal Disorders and Other Diseases
According to Merck.com, musculoskeletal disorders affecting the body’s muscles, joints and nerves--for example, osteoarthritis and rheumatoid arthritis--can cause muscle weakness and deterioration of weight-bearing joints, making it more likely for people to lose their balance and feel unsteady on their feet.
In rare instances, symptoms of dizziness or vertigo may be caused by a serious underlying medical disorder. According to the National Institutes of Health, some of these disorders may include a brain tumor or bleed in the brain, stroke, seizures or multiple sclerosis.
