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Tension pneumocephalus

Tension pneumocephalus

Tension pneumocephalus showing the Mount Fuji sign
Tension pneumocephalus showing the Mount Fuji sign

Presenting Complaint:  Head injury, bleeding from ears 24hrs
The patient is a 52 year old man who suffered blunt trauma to his head when the a log fell from a loaded truck hitting him on the head and knocked him out unconcious He was immediately rushed to a nearby hospital where upon review he was referred to   Komfo Anokye Hospital for futher management treatment.
Examination : breathing spontaneously with symmetric chest moment.  Neck was was immobilized with hard cervical collar
GCS 7/15  prior  to endotracheal intubation. BP 150/90mmhg pulse 80bpm RR 20cpm RBS 5.1mm/l
Respiratory Examination: air entry adequate bilateral  with vesicular breath sounds ,no crepitus or deformity of chest wall palpated
Cardiovascular system: stable vitals. No obvious external bleeding points noted. Focused abdominal ultrasound for trauma ( FAST) was negative.
Gastrointestinal system : no relevant finding noted
Musculoskeletal system : no deformity of extremities noted
Central nervous system : no seizure documented after injury and during admission.  Both pupils were slightly dilated and responded sluggishly to light . Dried blood in ear and nostrils seen
Diagnosis : Severe head injury r/o base of skull fracture
Initial management :
Cuffed endotracheal intubation
Antiseizure prophylaxis:  I.V phenytoin 100mg
Hypertonic saline 3% to treat cerebral oedema
IV antibiotic prohylaxis
Head end of bed elevated to 30 deg with neck in neutral position
Investigation : Head CT scan showed free bteewn the frontal lobes and the frantal bones. There were few collections seen intraparenchymal areas of the brain
Diagnosis of tension pneumocephalus secondary to base of skull fracture. Patient was prepared for emergency Burr hole craniotomy
Operative detail :
Under geneneral anaesthesia with cuffed endotracheal intubation and in supine position. Head was draped routinely . 3cm scalp incision made on the right anterior parietal bone . Cruciate incison made in the dura to get access to the trapped air. Size 24 Foleys catheter introduced into subdural space and used to aspirate much of the air evident as bubbles when aspirated through saline. Wound closed routinely over closed drain.
Postoperative period : patient recovered fully after anaesthesia had worn off. GCS improved to 15/15.
Speech was normal  but he had difficulty  hearing difficulty more in the left than the right. He could hear only if spoken to in an unacceptably loud voice
He was discharged on post operative day 5 with consult to the ENT department
Pneumocephalus, which is abnormal presence of air in the cranial cavity, could follow many conditions, commonest being head trauma, then tumors, infections, as well as post surgical procedures of the head. Rarely, it could develop in the scuba diver or spontaneously. In anaesthesia practice it may follow nitrous oxide use especially if it is not discontinued before dura closure, lumbar puncture, spinal/epiddural anaesthesia, positive pressure ventilation , and hyperbaric oxygen therapy . Other contributing factors for the development of pneumocephalus include head position, duration of surgery, hydrocephalus, intraoperative osmotherapy, hyperventilation, and continuous CSF drainage via lumbar drain .
The presence of intracranial air is an indication of an open fracture or a fracture line extending into a sinus. The air collection may be located in the extradural, subdural, subarachnoid, intraventricular, and intracerebral spaces. Intracerebral and intraventricular pneumocephalus occurs when there are tears in the dura and arachnoid layers. Also for the intraventricular pneumocephalus, fulminating, often fatal, intracrannial sepsis may develop.
Basically, two theories have been proposed as the mechanism by which pneumocephalus develop. The first is a ball valve mechanism by Dandy , which describes a uni-directional air movement from the outside into the cranial cavity which then gets trapped. The second one is the soda bottle theory proposed by Horowitz ). This postulated that negative intracranial pressure occur as a result of excessive CSF loss, draining into distensible spinal space, or just draining by a normal physiological mechanism like Valsalva manouvre. In this illustrated case of tension pneumocephalus due to basal skull fracture, both mechanisms could significantly be responsible. The diagnosis of tension pneumocephalus is difficult, as the symptoms and mechanism of injury mimic those associated with intracranial hemorrhage It should however be suspected in neurological deterioration in head injured patients as one of the secondary effects of the trauma. Clinical presentation includes headaches, nausea and vomiting, seizures, dizziness, and depressed neurological status. A significant amount of pneumocephalus can also simulate a space-occupying lesion (9). When pneumocephalus is suspected, CT can play a vital role in determining the precise location of the gas collection, its relationship to the basal skull fracture site or air sinuses, whether the air bubbles were single or multiple , and the amount of mass effect on the brain.  It is also evident on plain skull x-rays and this is important in centres where CT and/or MRI scans are not available. A common feature on the CT scan is the Mount Fuji sign, described by a group of Japanese neurosurgeons in which the two frontal poles are surrounded and separated by air . The other usual finding on CT scan is the presence of multiple small air bubbles scattered through several cisterns (“air bubble sign”)
Pneumocephalus rarely need surgical intervention except when it is associated with significant neurological deficit and supported with features of tension Pneumocephalus. When indicated, the management involves closing the causative breech in the cerebral integuments but surgical intervention should be done if the CSF leak persists for more than a week. Small volumes of air <2mls are frequent in head injury and usually resolve without treatment. Large volumes however indicate the possibility of a persistent open communication that requires neuroimaging and possibility of surgical correction. Avoidance of contributing factors, high index of suspicion, and confirmation with neuroimaging are important in attenuating mortality and morbidity. Supplemental oxygen increases the rate of absorption of Pneumocephalus . Injuries associated with a pneumatocele or a single intracranial air bubble, have a good prognosis, as do frontobasal lesions. Injuries associated with multiple air bubbles have a bad prognosis .
When indicated surgery can be done as open or endoscopic repair . This case further illustrates the importance of neuroimaging in making accurate diagnosis to offer adequate treatment. Early diagnosis and timely appropriate intervention will reduce morbidity and unnecessary mortality from a case as this.
Presented by : Dr Richard Ametih Resident, general surgery during neurosurgery rotation
Special thanks to :
Dr Frank Nketiah , Resident , neurosurgery
Dr Vowotor , Consultant neurosurgeon
Dr Kwabena Danso , House officer
Miss Adwoa Yeboah , Medical student


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