A 56-year-old man presents with worsening headache following a fall one week prior.
56岁男性，一周前摔倒后出现头痛，并逐渐加重。
1.There is midline shift.
中线结构有移位。
True
False
2.There is sulcal effacement.
脑沟变浅。
True
False
3.What is the most likely etiology of the above finding?
最有可能的病因是下列哪项？
Subacute epidural hematomas 亚急性期硬膜外血肿
Subacute subdural hematomas 亚急性期硬膜下血肿
Subdural effusions 硬膜下积液
Subdural empyemas 硬膜下积脓
Follow-up CT images
Bilateral burr holes are placed for drainage of the subdural hematomas. In the immediate postoperative period, the patient develops worsening headache and confusion.Follow-up images from unenhanced CT of the head are shown below.
该患者行双侧硬膜下血肿钻孔引流术，术后立即出血头痛加重伴意识模糊。复查头颅CT平扫，如下图所示。
4.There is subfalcine herniation.
该患者出血大脑镰下疝。
True
False
5.There is interhemispheric air between the tips of the frontal lobes.
双侧额叶之间顶端可见气体。
True
False
6.Which of the following imaging signs is present above?
图中表现可见下列哪种征象？
Peaking sign 山峰征
Mount Fuji sign 富士山征
Air bubble sign 小气泡征
Canyon sign
7.What is the diagnosis?
该病正确诊断是下列哪项？
Incomplete drainage of subdural hematomas 硬膜下血肿引流不完全
Expected postoperative pneumocephalus 术后颅内积气
Tension pneumocephalus 张力性气颅
Iatrogenic intracranial hemorrhage 医源性颅内出血
Obstructive hydrocephalus 梗阻性脑积水
8.What is the appropriate management for this patient?
该患者进一步需怎样处理？
Follow-up CT scan in 24 hours 24小时后复查CT
Discharge with outpatient follow-up CT in one month 出院，一个月后复查CT、门诊随访
Mannitol and observation 甘露醇 密切观察
Emergent surgical decompression 急诊手术减压
Postprocedure CT images
The patient undergoes surgical decompression of the tension pneumocephalus.Postprocedure unenhanced CT images of the head are shown below.
该患者因张力性气颅行手术减压，术后复查CT如下图所示。
9.There is persistent tension pneumocephalus.
仍有张力性气颅存在？
True
False
10.Which of the following is the most common etiology of tension pneumocephalus?
下列哪项是张力性气颅最主要的病因？
Penetrating craniofacial trauma 颅面部穿通伤
Functional endoscopic sinus surgery 鼻窦内镜检查
Burr hole drainage of subdural collections 硬膜下积液钻孔引流术
Idiopathic 自发性
选择题答案：
False
True
Subacute subdural hematomas
False
True
Mount Fuji sign
Tension pneumocephalus
Emergent surgical decompression
False
Burr hole drainage of subdural collections
Findings and Diagnosis
Findings
Initial unenhanced CT of the head: There are bilateral crescentic hypodense subdural collections, consistent with subacute subdural hematomas, in this patient with history of fall and head trauma. There is mild mass effect on the brain parenchyma with sulcal effacement. There is no midline shift or hydrocephalus.最初的头颅CT平扫示双侧硬膜下新月形低密度影，结合患者头颅外伤病史，考虑为亚急性期硬膜下血肿。脑实质占位效应明显，脑沟变浅。中线结构无移位，无脑积水。
Unenhanced CT of the head following burr hole placement: Following bilateral burr hole placement for drainage of the subdural hematomas, there is pneumocephalus, predominantly overlying the bilateral frontal lobes, with mass effect on the brain parenchyma. The pneumocephalus widens the interhemispheric fissure and causes a triangular conformation of the anterior tips of the bilateral frontal lobes, which is termed the “Mount Fuji sign” 钻孔引流术后复查头颅CT平扫可见颅内气体沿双侧额叶分布，脑实质受压。大脑纵裂增宽，双侧额叶之间顶端形成三角形样结构，即“富士山征”
Unenhanced CT of the head following decompression of pneumocephalus:The patient undergoes surgical decompression of the tension pneumocephalus. CT scan demonstrates markedly improved mass effect on the brain parenchyma and resolution of Mount Fuji sign with small amount of residual pneumocephalus and heterogeneous subdural collection along the frontal convexities. 张力性气颅手术减压后复查头颅CT示脑实质受压明显减轻，富士山征消失，仅见少量气体，及硬膜下不均匀液性密度影
Differential Diagnosis
Tension pneumocephalus 张力性气颅
Nontension pneumocephalus 非张力性气颅
DiagnosisTension pneumocephalus
张力性气颅
Discussion
Pathophysiology
Pneumocephalus caused by entry of gas into the cranial vault via a dural defect.气体通过硬脑膜的缺损进入颅内引起气颅。
Tension physiology contributes to continued increase in intracranial pressure and mass effect on brain parenchyma. Proposed mechanisms include the following:张力性气颅使颅内压不断增高，脑实质受压。其病因包括：
Ball-valve mechanism, whereby air enters the cranial cavity and is trapped.活瓣效应使气体易进入颅腔，但无法排出。
Continuous leakage of cerebrospinal fluid (CSF) leading to negative intracranial pressure, drawing in air.脑脊液持续流失，颅压降低，吸入空气。
Tension pneumocephalus most commonly occurs following drainage of subdural collections (ranging from 2.5% to 16% of cases). Other etiologies include craniofacial surgery and trauma.张力性气颅最常发生于硬膜下积液钻孔引流术后（发生率约2.5%-16%）。其他病因包括颅面部手术、外伤等。
It’s important to distinguish from nontension pneumocephalus, as tension physiology is a neurosurgical emergency.由于张力性气颅需要急诊手术处理，所以与非张力性气颅鉴别非常重要。
Untreated, tension pneumocephalus can lead to brainstem herniation and death.张力性气颅不经处理，可引起脑疝，导致死亡。
Clinical Presentation
Patients present with a nonspecific spectrum of clinical symptoms, including headache, focal neurologic deficits, confusion, and seizures.
临床症状没有特异性，主要包括：头痛、神经定位体征、意识模糊、癫痫等。
CT Feature
Mount Fuji sign refers to the characteristic appearance of the frontal lobes on axial images.横断位图像双侧额叶之间可见“富士山征”是本病的特征性表现。
Cortical veins tether the tips of the frontal lobes.双侧额叶之间顶端的皮层静脉相互牵拉。
Pneumocephalus collapses the adjacent parenchyma and widens the interhemispheric fissure, manifesting in a triangular conformation of the frontal lobe tips. Entrance of air into the interhemispheric space implies higher pressure than surface tension of cerebrospinal fluid.颅内气体压迫脑实质，使大脑纵裂增宽，双侧额叶之间形成三角形结构。气体进入双侧大脑半球之间，提示颅内压高于脑脊液压力。
Differential Diagnosis
Nontension pneumocephalus
非张力性气颅
Treatment
Emergent decompression is performed to reduce mass effect on parenchyma. Methods include needle aspiration, burr hole placement, craniotomy, and ventriculostomy.急诊手术减压，方法包括：穿刺、钻孔、开颅、脑室造口引流等。
Effective treatment is evidenced by improvement in imaging findings.术后复查CT，脑实质受压情况好转提示治疗有效。
