tension pneumocephalus

Post
traumatic unilateral tension pneumocephalus. Axial image of the skull shows a large pocket of air along the right frontal region causing compression of the right frontal lobe.
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Post
traumatic unilateral tension pneumocephalus. Coronal image of the skull shows half and half density - half density of air and other half showing brain parenchyma.
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Post
traumatic unilateral tension pneumocephalus. Sagittal image of the brain shows the extent of compression of the right frontal lobe due to a large pocket of air. Few foci of air can also be seen along the falx.
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Post
traumatic unilateral tension pneumocephalus. Scout CT image of the skull shows diffuse hypoattenuation over the right side of the skull- depicting the region of pneumocephalusChitrangada Singh, Department of Radiology, Dr.D.Y.Patil Hospital and Research Centre, Navi Mumbai India
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Post-traumatic
tension pneumocephalus: CT findings. Intensely hypoattenuating area in the anterior portion of the cranial vault and adjacent fracture.
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Post-traumatic
tension pneumocephalus: CT findings. Multiple cranial vault fractures.
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Post-traumatic
tension pneumocephalus: CT findings. Bilateral subdural pneumocephalus (the ""Mount Fuji sign"").
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Post-traumatic
tension pneumocephalus: CT findings. Subdural pneumocephalus, brain oedema, scattered air bubbles.
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Post-traumatic
tension pneumocephalus: CT findings. Axial image in lower level shows subdural and subarachnoid air.
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Post-traumatic
tension pneumocephalus: CT findings. Subarachnoid haemorrhage in the left cerebral hemisphere.
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Radiopaedia • CC-by-nc-sa 3.0 • de

Tension pneumocephalus is a neurosurgical emergency that occurs when subdural air causes a mass-effect over the underlying brain parenchyma, often from a ball-valve mechanism causing one-way entry of air into the subdural space .

Clinical presentation

Tension pneumocephalus has a varied clinical presentation :

  • severe restlessness
  • deteriorating consciousness
  • focal neurological deficits
  • cardiac arrest

Pathology

There are numerous etiologies :

  • trauma with leakage of cerebrospinal fluid
  • recent neurosurgery (e.g. the complication risk is reported to be 2.5% after chronic subdural hematoma evacuation)
  • tumors of the paranasal sinuses
  • infections
  • use of nitrous oxide as an anesthetic agent (NO dissolves into blood and enters the subdural space, expanding the pre-existing gaseous volume)

Irrespective of the mechanism, the increased pressure leads to extra-axial mass effect and compression of the frontal lobes . The presence of air between the frontal tips suggests that the pressure of the air is at least greater than that of the surface tension of cerebrospinal fluid between the frontal lobes .

Radiographic features

Initially, subdural air compresses the frontal lobes resulting in the peaking sign is present, before the frontal lobes become separated in a characteristic appearance, aptly termed the Mount Fuji sign .

An additional reported sign of tension pneumocephalus is the presence of multiple small air bubbles in the subarachnoid space. This has been referred to as the air bubble sign .

These features are, however, not pathognomonic for tension pneumocephalus and can be seen in patients with normal intracranial pressures. Regardless of the exact pattern of intracranial gas, clinical deterioration is the key indicator for surgical intervention.

Treatment and prognosis

Tension pneumocephalus is a neurosurgical emergency .  Treatment is with surgical decompression .

Siehe auch:
Assoziationen und Differentialdiagnosen zu Spannungs-Pneumocephalus:
Pneumocephalus
 
Wikipedia • CC BY-SA 3.0
Fuji-Zeichen
Spannungs-Pneumocephalus
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posttraumatischer
Spannungs-Pneumocephalus
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