Thalamic Anatomy and Pathology (Continued)

The thalamic perforating arteries may also hemorrhage. This often produces a thalamic syndrome similar to ischemic infarction. However, as the hemorrhage grows it may press downward on the midbrain, causing impairment of consciousness or a cluster of eye movement problems known as Parinaud syndrome. In Parinaud syndrome there is loss of pupillary light reflexes, upgaze, and vergence eye movements due to pressure on the pretectal area and dorsal midbrain.

The thalamus is also characteristically involved in fatal familial insomnia, a prion disorder that causes rapid onset of dementia, ataxia, and brainstem dysfunction, including almost complete inability to sleep in some cases. However, the pathology involves the cerebral cortex and brainstem as well, and it is difficult to determine how much of the symptomatology is due to the thalamic degeneration. Eastern equine encephalitis also preferentially involves the thalamus and basal ganglia.

Only gold members can continue reading. Log In or Register to continue