Alcoholic cerebellar degeneration

Alcoholic cerebellar degeneration is a common type of acquired cerebellar ataxia characterised by chronic vermal atrophy ¹. It is a potential sequela of chronic alcohol abuse or malnutrition ². It has also been described in literature as alcohol-related cerebellar degeneration, alcohol-induced cerebellar degeneration and nutritional cerebellar degeneration ^1,2.

Epidemiology

The prevalence is estimated at 12 – 27% from autopsies ².

Risk factors are conditions predisposing to malnutrition, including chronic alcohol abuse ². Regarding alcohol use, the duration of excessive use is likely the main factor ^3-5.

Clinical presentation

Gait ataxia is the primary manifestation owing to predominant involvement of the anterosuperior cerebellar vermis. Other clinical features may also be present ²:

• Coarse tremor
• Truncal instability
• Nystagmus
• Lower limb ataxia
• Upper limb ataxia (in severe cases)

Pathology

The exact pathogenesis is yet to be elucidated, but is thought to arise from either alcohol neurotoxicity, nutritional deficiency (notably thiamine) or both ^1,6.

Despite its current name, alcohol may not necessarily be a prerequisite as similar clinicopathological findings have been described in durations of abstinence or in malnourished non-alcoholics ^2,6. It is no wonder that alternative terms have been adopted in literature.

Histologically, there is Purkinje cell loss in the cerebellar cortex accompanied by Bergmann gliosis, and a variable loss of the molecular layer and granule cells ⁷. There may also be associated neuronal loss in the dorsal inferior olivary nuclei. The underlying cerebellar white matter is otherwise preserved ⁷.

Radiographic features

CT

Findings are similar to those in MRI.

MRI

Abnormalities are best demonstrated on sagittal views of T1-weighted images ². Midline cerebellar structures are primarily involved.

Early features consist of cerebellar volume loss localised to the anterior superior vermis (lingula, central lobule, culmen, declive) and associated widening of inter-folial sulci ^2,7,8. Subsequent progression to involve the posterior inferior vermis and anterior lobes of the cerebellum can occur ⁸.

These features may occur in isolation or in the presence of other radiographic abnormalities associated with chronic alcohol use, such as those in Wernicke encephalopathy ⁷. Correlation of radiographic findings with the clinical presentation is crucial as vermian atrophy can be present in asymptomatic individuals ².

PET

FDG studies may exhibit hypometabolism in similarly affected areas of the cerebellum ⁹.

Treatment and prognosis

Treatment is targeted towards abstinence, nutritional supplementation and gait optimisation ².

Improvement varies with the degree of abstinence and dietary repletion, although gait ataxia can be persistent in severe cases ².

Differential diagnosis

Alcoholic cerebellar degeneration should be distinguished from cerebellar hypoplasia and other forms of cerebellar atrophy.