The mammillary bodies are involved in all cases. Involvement of the medial dorsal nuclei of the thalamus is responsible for the memory defect. The walls of the third ventricle are also involved. In full-blown WKS, all these structures are involved. In less severe cases, some may be spared.
Thiamine pyrophosphate is important for carbohydrate metabolism.
It acts as a coenzyme in the decarboxylation of pyruvic acid to acetaldehyde and acetate. These stores can be depleted in alcoholic malnourished patients. Alcohol, in particular, displaces more nutritious foods from the diet, adds carbohydrates that use up thiamine, and impairs the absorption of vitamins. Therefore, vitamin B1 supplementation is mandatory for patients even remotely at risk. It causes ataxia of stance and gait with relative sparing of the arms.