Unveiling the Possibility of Subclinically Present Congenital Hydrocephalus Triggered by Thalamic Hemorrhage in Late-onset Years: A Case Report.

Congenital hydrocephalus manifesting in old age is exceptionally rare. We present a case of hydrocephalus in an older woman, where congenital hydrocephalus was suggested following a thalamic hemorrhage. A woman in her 90s gradually developed gait and cognitive impairments. Eight months before her admission, she suffered a thalamic hemorrhage, after which she became bedridden and was transferred to our hospital following impaired consciousness from asphyxiation. Upon admission, her Japan Coma Scale score was 200. A head computed tomography scan revealed significant ventricular enlargement. A tap test was conducted to diagnose normal pressure hydrocephalus, resulting in a slight improvement in her Japan Coma Scale score to 20. Consequently, a ventriculoperitoneal shunt was performed. Two weeks after the ventriculoperitoneal shunt, her consciousness improved to a Japan Coma Scale score of 2, and she resumed oral intake. Two months after the surgery, head magnetic resonance imaging revealed tetraventriculomegaly, an open aqueduct, a wide foramen of Magendie, and a large cisterna magna. These findings raised the suspicion of previously undetected congenital hydrocephalus, exacerbated by panventriculomegaly with a wide foramen of Magendie and a large cisterna magna, revealed after the thalamic hemorrhage. At the final evaluation, she required only minimal assistance with oral intake, showing significant improvement not only compared with her condition before the ventriculoperitoneal shunt procedure but also to her state before the thalamic hemorrhage.