[Three patients with transient global amnesia following an increased venous pressure: a study using 3.0 Tesla diffusion-weighted magnetic resonance imaging].

We present 3 patients with transient global amnesia (TGA). Patient 1 was a 67-year-old man who had developed TGA 5 years ago. He showed sudden onset amnesia immediately after he quarreled with his wife loudly during driving. Three-Tesla (3T) diffusion-weighted magnetic resonance imaging (DWI) taken 18 hours after onset revealed a small hyperintense signal area in the right CA1 subfield of the hippocampus. Patient 2 was a 66-year-old woman who showed sudden onset amnesia immediately after she walked for about 20 minutes holding a heavy luggage with her arms. 3T DWI taken 64 hours after onset revealed a small hyperintense signal area in the left CA1 subfield of the hippocampus. Patient 3 was a 68-year-old woman who showed sudden onset amnesia immediately after she hurriedly cleaned up her house with a cleaner. 3T DWI taken 48 hours after onset revealed small hyperintense signal areas in the left CA1 subfield and the right subiculum proper of the hippocampus. She developed TGA recurrence 6 months after the first episode of TGA. All these 3 patients had no cardiovascular diseases. Their amnesia resolved within 5-6 hours. Magnetic resonance venography (MRV) revealed hypoplasia of the left transverse sinus in Patient 1 and Patient 3, and aplasia of the left transverse sinus in Patient 2. Ultrasound studies revealed a retrograde flow component of internal jugular vein during Valsalva maneuver in Patient 2. We speculate that an increased venous pressure might have precipitated cerebral venous ischemia in the hippocampus, which is most vulnerable to ischemic insults.