Damage, degeneration or loss of nerve cells in the part of your brain that controls muscle coordination (cerebellum), results in ataxia. Your cerebellum comprises two pingpong-ball-sized portions of folded tissue situated at the base of your brain near your brainstem.
The right side of your cerebellum controls coordination on the right side of your body; the left side of your cerebellum controls coordination on the left.
Diseases that damage the spinal cord and peripheral nerves that connect your cerebellum to your muscles also can cause ataxia. Ataxia causes include:
Head trauma. Damage to your brain or spinal cord from a blow to your head, such as might occur in a car accident can cause acute cerebellar ataxia, which comes on suddenly.
Stroke. When the blood supply to a part of your brain is interrupted or severely reduced, depriving brain tissue of oxygen and nutrients, brain cells die.
Cerebral palsy. This is a general term for a group of disorders caused by damage to a child's brain during early development - before, during or shortly after birth - that affects the child's ability to coordinate body movements.
Autoimmune diseases. Multiple sclerosis, sarcoidosis, celiac disease and other autoimmune conditions can cause ataxia.
Infections. Ataxia can be an uncommon complication of chickenpox and other viral infections. It might appear in the healing stages of the infection and last for days or weeks. Normally, the ataxia resolves over time.
Paraneoplastic syndromes. These are rare, degenerative disorders triggered by your immune system's response to a cancerous tumor (neoplasm), most commonly from lung, ovarian, breast or lymphatic cancer. Ataxia can appear months or years before the cancer is diagnosed.
Tumor. A growth on the brain, cancerous (malignant) or noncancerous (benign), can damage the cerebellum.
Toxic reaction. Ataxia is a potential side effect of certain medications, especially barbiturates, such as phenobarbital; sedatives, such as benzodiazepines; and some types of chemotherapy. These are important to identify because the effects are often reversible.
Also, some medications you take can cause problems as you age, so you might need to reduce your dose or discontinue the medication.
Alcohol and drug intoxication; heavy metal poisoning, such as from lead or mercury; and solvent poisoning, such as from paint thinner, also can cause ataxia.
Vitamin E, vitamin B-12 or thiamine deficiency. Not getting enough of these nutrients,because of the inability to absorb enough, alcohol abuse or other reasons, can lead to ataxia.