Symmetrical necrosis in the gray matter of the brainstem and spinal cord. Two adult cases of anoxic encephalopathy]

We describe distinctive necrosis in the brainstem of two adult patients of anoxic encephalopathy. The patients were a 75-year-old man and an 82-year-old woman, who were resuscitated after cardiac arrest that lasted about 20 minutes and artificially ventilated. The first patient remained comatose without recovery of brainstem reflexes and had persistent hypotension requiring continuous infusion of catecholamine until death that occurred two weeks after the onset of illness. In the second patient, her general circulation recovered on the next day resuscitation, and traces of brainstem reflexes reappeared thereafter, while her consciousness was severely disturbed throughout the three weeks' clinical course. Both of the patients failed to regain spontaneous respiration and required the ventilatory support. On general autopsy, the first patient had small cell carcinoma of the lung with metastasis to the pleura, hilar lymph nodes and liver. In the second patient, an old myocardial infarction and pneumothorax were found. The neuropathological findings in the two patients were similar, varying only in their severity, except for the presence of the degenerative changes compatible with those of progressive supranuclear palsy in the second patient. There were laminar necrosis in the cerebral cortex and severe ischemic changes in the basal ganglia, thalamus and cerebellum. The cerebral white matter, however, exhibited only myelin pallor without apparent destruction. There was no herniation in the brain. In the first patient, fresh hemorrhages were noted in the bilateral globus pallidus. In the brainstem, symmetrical necrosis was present exclusively in the gray matter: the superior and inferior colliculi, periaqueductal gray matter, substantia nigra and the several cranial nuclei including the spinal nucleus of the trigeminal nerve, solitary and vestibular nuclei. In the second patient the symmetrical necrotic foci were also found in the substantia gelatinosa of the lower lumbar and sacral cords which were available for examination. Around these sharply demarcated necrotic lesions of the brainstem and spinal cord were there rarefaction and pronounced astrogliosis. Unlike the cases of neonates or infants, symmetrical necrosis in the brainstem has been reported to be exceptional in adult patients of anoxic encephalopathy. Now that the medical technology of resuscitation is well advanced, the adult patients exhibiting the pathology presented here may be encountered more frequently than previously thought.