An 82-year-old man is found unresponsive by his neighbor. The patient lives alone in his suburban home. When the neighbor went to check on him, the patient was on the floor and not answering any questions. His medical history is unknown. On arrival of emergency medical services, the patient is obtunded and responds only to painful stimuli. Supportive measures are begun, including endotracheal intubation, but the patient dies en route to the hospital. Autopsy reveals extensive atherosclerotic disease involving the coronary and internal carotid arteries. Histopathologic examination of the brain in the right middle cerebral artery territory shows neurons with intensely eosinophilic cytoplasm and nuclear fragmentation. Based on these findings, this patient's cerebral injury most likely occurred approximately how long ago?

Question

An 82-year-old man is found unresponsive by his neighbor.  The patient lives alone in his suburban home.  When the neighbor went to check on him, the patient was on the floor and not answering any questions.  His medical history is unknown.  On arrival of emergency medical services, the patient is obtunded and responds only to painful stimuli.  Supportive measures are begun, including endotracheal intubation, but the patient dies en route to the hospital.  Autopsy reveals extensive atherosclerotic disease involving the coronary and internal carotid arteries.  Histopathologic examination of the brain in the right middle cerebral artery territory shows neurons with intensely eosinophilic cytoplasm and nuclear fragmentation.  Based on these findings, this patient's cerebral injury most likely occurred approximately how long ago?

Quizplus · Accepted Answer

11ec160b_39c9_2f55_9249_654771826a00_MD0001_00 This patient was found unconscious, in rapid hemodynamic decline, an unknown amount of time after an inciting cardiovascular event. The autopsy demonstrates histopathologic evidence of ischemic stroke caused by widespread atherosclerosis. Sustained interruption in blood circulation to branches of the internal carotid arteries (eg, middle cerebral artery) can lead to tissue hypoxia and irreversible cellular injury with characteristic microscopic and macroscopic changes. Specific findings vary with time but follow a predictable course. Red neurons are typically seen 12-24 hours after irreversible ischemic injury and are characterized by intense eosinophilic staining of the cytoplasm due to dissolution of Nissl bodies (basophilic granules consisting of rough endoplasmic reticulum and ribosomes). The nuclei also become pyknotic (eg, shrunken and deeply basophilic) and undergo fragmentation (karyorrhexis). After about a day, the tissue damage promotes neutrophil infiltration, followed by macrophage/microglial recruitment a few days later. (Choice A) There is typically little change in the microscopic or macroscopic appearance of brain tissue <1 hour after irreversible ischemic injury. (Choice C) At 1-2 weeks, there will be robust phagocytosis of neuron and myelin breakdown products by activated macrophages/microglia. Around this time, astrocytes start proliferating with the development of a network of cytoplasmic extensions (reactive gliosis), and new vessels are formed in the periphery of the necrotic area. (Choices D and E) Several months to years after brain infarction, the necrotic area appears as a cystic cavity surrounded by a wall of dense fibers formed by astrocytic processes (glial scar). Educational objective: Inadequate blood supply to the brain (eg, arterial thrombosis or embolism) leads to ischemic stroke. The first microscopic changes are typically seen 12-24 hours after irreversible ischemic injury and include intense eosinophilic staining of the neuronal cytoplasm (red neurons) and nuclear fragmentation. __________ References: Histopathological changes in acute ischemic stroke. (http://www.ncbi.nlm.nih.gov/pubmed/19690757)

An 82-Year-Old Man Is Found Unresponsive by His Neighbor