A normal adult is considered to have increased cranial pressure if it exceeds 1,96 kPa (200 mmH2O). Intracranial hypertension can be caused by intracranial occupational lesions, intracranial infectious diseases, cranioencephalic injury, cerebral hypoxia, etc. The diagnosis of increased intracranial pressure can be generally established when the typical “three main signs” of headache, vomiting and optic papilledema are present, and a thorough history and neurological examination should be conducted. For intracranial diseases without typical clinical manifestations of increased intracranial pressure, some focal symptoms and signs, such as rapidly increasing head circumference in infants, progressive headache, epilepsy, progressive sensorimotor disorders, hearing and visual impairment in adults, suggest the possible presence of intracranial occupying lesions. The following tests can help to clarify the diagnosis and differential diagnosis as early as possible. 1. General examination including three major routine tests, sputum exfoliation cell examination, coagulation function related tests, serological examination (carcinoembryonic antigen, acid phosphatase methemoglobin, lactate dehydrogenase alkaline phosphatase, chorionic gonadotropin, etc.), as well as frontal and lateral X-ray chest examination, liver B-mode ultrasonography, and gastric and intestinal endoscopy or bronchial endoscopy if necessary. If superficial lymph nodes are found to be enlarged, biopsy can be done and sent to pathology in order to find out whether the primary tumor exists and the scope and type of invasion. 2.Other auxiliary examinations Computed tomography (CT), magnetic resonance imaging (MRI) and digital subtraction (DSA) are the most important examinations to determine the metastatic tumor in the brain and the localization of the lesion. MRI can be observed at various levels and different parameters (T1, T2, proton density) can be used to improve the detection of abnormal images and have certain ability to identify the nature of the lesion. DSA can show clear images of blood vessels in the brain, and metastatic tumors can form tumor coloring images due to rich blood supply, which is helpful to understand the direction of blood vessels in the brain or changes such as disconnection, and can also provide information for choosing treatment. Regular examination of CT and MRI is helpful for timely comparison and observation and early detection of brain metastases. 3.Lumbar puncture Retrieve cerebrospinal fluid for routine and pathological cytological examination. Centrifugal sedimentation or the use of filters can improve the positive rate, however, repeated examination is often required; if necessary, send bacterial culture and related virological examination. Funduscopic examination should be performed before lumbar puncture, and for those with optic disc edema, the puncture should be slow and the retention of cerebrospinal fluid should be low, and for safety reasons, dehydration treatment can be performed first.