A 27-year-old man with Hodgkin's disease was admitted to a hospital due to cough and fever of 5 days duration. Approximately one month later the patient had a generalized seizure with loss of consciousness for about 15 minutes. He was alert upon admission to a hospital several hours later. However, his left arm and leg were weak and he had intermittent twitching of both sides of his face. Two days later he became unresponsive and his temperature ranged from 38.9°C to 40.0°C. His breathing became irregular and a tracheotomy was performed. Blood and urine cultures were negative for microorganisms. Five days after admission to the hospital, the patient had another generalized seizure and died several hours later. At autopsy, multiple soft hemorrhagic areas were noted in frontal, temporal, and parietal lobes. The image shows what was observed on a section of necrotic brain tissue underlying the cortex of the meninges. Objects seen in the sections ranged in size from 25 to 35 micrometers. What is your diagnosis? Based on what criteria?

Figure A

Show Answer

Answer to Case #88

This was a case of fatal granulomatous amoebic encephalitis (GAE) caused by Acanthamoeba spp. Diagnostic features shown included:

• the presence of both trophozoites (blue arrows, Figure A) and cysts (gray arrow, Figure A). Naegleria does not produce cysts in the human host.
• the presence of large nuclei with big, heavy staining karyosomes in the trophozoites.
• the typical wrinkled cyst wall as seen in Acanthamoeba spp.

Figure A

More on: Free-living Amoebic Infections