Alternative names  
Cerebellar ataxia; Ataxia - acute cerebellar; Cerebellitis;  Acute cerebellar ataxia

Definition
Acute cerebellar ataxia is sudden onset of muscle incoordination (ataxia), often following an infectious viral disease that attacked the brain.

Causes, incidence, and risk factors

Acute cerebellar ataxia is most common in children, especially those younger than 3 years old. It often occurs several weeks after a viral illness. Common predisposing infections include chickenpox and coxsackie viral illnesses. In adults, the most common infectious causes are Epstein-Barr virus and mycoplasma infections.

Ataxia may affect movement of the trunk (axial) or limbs. Axial ataxia is characterized by a broad-based unsteady gait (walking style). When the child is sitting, the trunk may deviate side-to-side, back-to-front, or a combination of these movements, returning to the vertical position in a jerky motion. Jerky eye movements (nystagmus) and jerky, explosive speech (dysarthria) may develop at the same time.

Limb ataxia affects the fine motor control of the hands or legs. For example, when reaching for an object, an affected person’s hand may sway back and forth.

The condition usually subsides without treatment over a period of weeks to months. Occasionally, a child will retain a persistent movement disorder or behavioral problem.

Symptoms

 
• Sudden onset jerky body (trunk) movement  
• Wide-based unsteady gait  
• Inability to walk without support  
• Jerky eye movements (nystagmus)  
• Jerky speech pattern (dysarthria)  
• Uncoordinated movements of the arms or legs

Other suggestive findings:

 
• Appears in child less than 3 years of age  
• May follow a viral infection

Signs and tests
The diagnosis of acute cerebellar ataxia is made by excluding other causes of ataxia, and by taking a history of a recent illness.

Tests may include: