Review Question - QID 109112

This patient with Huntington’s disease is presenting with the characteristic jerky, dance-like movement known as chorea. Chorea is the result of atrophy of the caudate and putamen and leads to hydrocephalus ex vacuo.

Huntington’s disease is an autosomal dominant trinucleotide repeat disorder. In this disease, NMDA receptor binding and glutamate excitotoxicity result in neuronal death in specific regions of the brain. Importantly, neuronal death in basal ganglia structures such as the caudate and the putamen cause choreiform movements such as those seen in this patient. Caudate and putamen atrophy are specific findings in Huntington’s disease.

Incorrect Answers:
Answer 1: Huntington’s disease results in caudate atrophy rather than caudate overactivity. This decrease in function is due to neuronal degeneration.

Answer 3: Depigmentation of the substantia nigra pars compacta is seen in Parkinson's disease rather than Huntington’s disease. This due to a loss of dopaminergic neurons.

Answer 4: Atrophy of the subthalamic nucleus is often the result of a lacunar stroke. This causes sudden, flailing movements of the contralateral extremities.

Answer 5: A lesion of the cerebellar vermis would involve the midline structures, resulting in truncal ataxia with a wide-based gait and bilateral limb abnormalities. Huntington’s disease does not characteristically involve the cerebellum.

Bullet Summary:
Huntington’s disease is an autosomal dominant neurodegenerative disorder with a characteristic jerky, dance-like movement known as chorea that is a result of atrophy of the caudate and putamen.