Most hydrocephalus in adults is secondary and can have a definite etiology, such as subarachnoid hemorrhage. It often occurs 2-3 weeks after the onset of the disease, with headache and vomiting as the main clinical symptoms, in addition to ataxia. In severe cases, symptoms such as blurred vision and diplopia may occur. The symptoms of headache and vomiting are mostly idiosyncratic. The headache is often worse after lying down or in the morning, and may become persistent and severe as the disease progresses. Patients with hydrocephalus may also have memory loss, especially near memory loss, mental retardation, and poor calculation skills in the late stages. In children with high pressure hydrocephalus, early symptoms are mild and nutrition and development are basically normal. Their enlarged head circumference is the predominant manifestation, often appearing at the time of delivery or shortly afterwards, and will develop progressively. The child may show sparse hair, an enlarged head that makes the face relatively small, and a sunset appearance with both eyes turned downward and the lower half of the eyeballs sinking below the eyelids. In advanced stages, growth arrest, mental decline, and dementia are seen. Children with normal pressure hydrocephalus may also have symptoms of urinary incontinence, and dementia, motor disorders, and urinary incontinence are generally considered to be their triad. In general, the disease can be diagnosed based on the medical history, clinical manifestations, rapid cranial enlargement and other features.