[Hematoma of the head of the caudate nucleus]

We studied five patients with cerebral hemorrhage limited to the head of the caudate nucleus. This rare localization represents 11% of central nuclei hemorrhages. This entity has various clinical expressions; some are similar to a subarachnoid hemorrhage, others show the same manifestations associated with hemiparesis and neuropsychological findings, while still in others, the neuropsychological syndrome with speech, behaviour or memory disturbances predominates. Recovery depends on the patient's previous clinical status and on the presence of associated lesions at the time of hemorrhage. Typical warning signs, like headache, are often absent in the elderly and debilitated. Meningismus is explained by the intraventricular extension of the hemorrhage. Motor deficit, usually moderate, is probably due to impairment of the anterior portion of the posterior arm of the internal capsule. Destruction of the head of the left caudate nucleus, which is part of the circuit causing "subcortical aphasias", is responsible for non specific speech disturbances, that are however remarkably rich in semantic paraphasias. These dysfunctions could be caused by a "cortical diaschisis" as suggested by SPECT analysis. Memory dysfunction as a result of caudate lesion is questioned. However confusion and behavioural disturbances, like preservations, transitory mutism and self neglect, seem characteristic. As shown by cerebral blood flow (CBF) studies, these disturbances might represent a frontal dysfunction caused by the interruption of the dorso-latero-prefrontal and orbito-frontal circuits. When the hemorrhage extends beyond the head of the caudate nucleus, behavioural changes occur due to the involvement of neighbouring structures such as the thalamus, internal capsule, temporal lobe and nucleus accumbens. Caudate hemorrhages occur mostly in the elderly, often with long-standing arterial hypertension causing lesions of the lenticulo-striate arteries. Severe stenosis or complete occlusion of the middle cerebral artery with a fragile anastomotic circuit or angiopathies in younger individuals (particularly Asiatics: moyamoya disease) are less frequent, but they should be considered and investigated by arteriography. Vascular malformations are a rare cause and a relationship with amyloid angiopathy can only be suspected.