NEUROPATHOLOGICAL FINDINGS IN THE BRAIN OF QUINLAN,KAREN,ANN - THE ROLE OF THE THALAMUS IN THE PERSISTENT VEGETATIVE STATE

Background. Karen Ann Quinlan had a cardiopulmonary arrest in 1975 and died 10 years later, having never regained consciousness. Her story p rompted a national debate about the appropriateness of life-sustaining treatment in patients who are in a persistent vegetative state and le d to the development of medicolegal guidelines for the care of such pa tients. This report describes the neuropathologic features of Quinlan' s brain. Methods. The entire brain and spinal cord were systematically sampled for histologic examination. The brain stem and central cerebr um were embedded en bloc and serially sectioned. Three-dimensional com puter reconstructions helped visualize the topographic features of the lesions. Results. Contrary to expectation, the most severe damage was not in the cerebral cortex but in the thalamus, and the brain stem wa s relatively intact. The neuropathological findings included extensive bilateral thalamic scarring, bilateral cortical scars primarily in th e occipital pole and parasagittal parieto-occipital region, and bilate ral damage to cerebellar and focal-basal-ganglia regions. The brain st em and basal forebrain and the hypothalamic components of the ascendin g arousal systems and brain-stem regions critical to cardiac and respi ratory control were undamaged. The lesions were consistent with hypoxi a-ischemia after the cardiopulmonary arrest. Conclusions. Although the neuropathological findings in the case of Karen Ann Quinlan were comp lex, the disproportionately severe damage in the thalamus as compared with the cerebral cortex supports the hypothesis that the thalamus is critical for cognition and awareness and may be less essential for aro usal.