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Pneumocephalus

What is Causing This Man’s Persistent Headaches and Nausea Post-Sinus Surgery?

Ahad Qazizada, MD 

Volume 55 - Issue 6 - June 2015

A 77-year-old male presented to the hospital complaining of persistent headaches and nausea for 2 days. He said his pain intensity was a 7 out of 10, and his head was throbbing in the right frontal area. He reported no visual changes, neck pain, vomiting, chills, fever, rhinorrhea, or epistaxis. 

The patient underwent bilateral endoscopic maxillary antrostomy and ethmoidectomy, as well as nasal septal reconstruction and inferior turbinate reduction with microdebrider 5 days prior.

The right nasal pack had dislodged spontaneously 2 days after the operation, and the left pack was removed by an ear, nose, and throat (ENT) specialist. The next morning, the patient experienced a headache in the right frontal area. 

He took the postprocedure pain medication prescribed by the ENT, but the medication did not help.

History

The patient has a history of chronic obstructive pulmonary disease, a 60-pack-year smoking habit that he quit a few months prior, and benign prostate hypertrophy.

His past surgical history includes right hip and bilateral knee replacement, cervical spine surgery, and appendectomy.

Physical Examination

On arrival to the hospital, the patient was normotensive with a respiratory rate of 18 beats per minute and adequate oxygen saturation on room air. Eyes demonstrated normal extra ocular movement and normal pupillary response, no drainage from either nostril anteriorly, no sinus pressure or tenderness, no proptoses or chemosis, no drainage down the back of throat, no neck rigidity, or adenopathy. Lung and cardiovascular exam were normal; no abnormal neurologic finding was noted either. 

Laboratory Tests 

A complete blood count and comprehensive metabolic panel were within normal limits, except for slight leukocytosis at 12.6 x 109/L (neutrophil 84.5%, lymphocyte 7.5%, monocyte 6.5%, eosinophil 1.0%, basophil 0.5%). Urinalysis and coagulation panels were normal. 

A CT of the brain was ordered (Figure). 

Answer: Pneumocephalus post-sinus surgery

The patient was diagnosed with pneumocephalus post-sinus surgery. Clinically, the patient does not have signs of meningitis, no gross midline shift on CT, and no evidence of intracranial bleed. The patient admitted for observation; ENT and neurosurgery were consulted. A supplemental oxygen was provided nasally to enhance reabsorption of air. The patient’s head was elevated and pain management was provided. An incentive spirometry was used to minimize the likelihood of pneumonia given his underlying COPD. A daily CT was repeated, which showed that the right frontal cereberal convexicity pneumocephalus was gradually decreasing. The patient was discharged on fourth day and was asked to follow-up with the ENT.

Discussion

Pneumocephalus was first described by Lecat in 1741,1 and later in an autopsy report of a patient who sustained head trauma in 1866,2 and in another autopsy report of a patient with chronic ethmoid sinusitis in 1884.2 The latter report was remarkable because it was the first to demonstrate the presence of intracranial air during life as well as the first to advance a mechanism for intracranial air. The term pneumocephalus however, was not officially introduced into medical vernacular until 1914.2

Pneumocephalus, which translates to “air inside the head,” implies a compromise in the craniodural barrier of the presence of gas, which forms an infection inside the cranial vault. This breach in the craniodural barrier is most commonly associated with traumatic fractures of the sinuses, skull base, cranial vault, or mastoid air cells. As much as 2 ml of air is required for pneumocephalus to be visible on x-rays, but as little as 0.5 ml can be detected with a CT.3 Depending on the route of entry, air can be seen in intraventricular, brain parenchymal, subarachnoid, or subdural space. Intracranial air that produces a mass effect is known as tension pneumocephalus.

Etiology. Numerous case reports on pneumocephalus in the literature in recent years demonstrate a wide range of etiologies. In one study of 295 pneumocephalus cases, 73.9% of incidents were caused by trauma, 12.9% neoplasm, 8.8% infection, 3.7% post-operative, and 0.6% idiopathic.4

Presentation. Patients with clinically significant pneumocephalus may present with nausea, vomiting, fever, headache, confusion, agitation, syncope, lethargy, speech changes, aphasia, vision changes, seizure, paresis/hemiparesis, ataxia, and rhinorrhea.1-5 The evaluation of such patients should focus on signs of infection, level of consciousness, pupillary response, eye movements, and motor responses.6

Treatment. The review of case reports in the literature indicates that in the majority of cases, pneumocephalus is treated expectantly.7-8 Conservative medical management of pneumocephalus includes bed rest, analgesia, elevating the head, avoiding coughing, sneezing, and nose-blowing, and the Valsalva maneuver. Additional recommendations include the use of laxatives to decrease intra-abdominal pressure during bowel movements and supplemental oxygen therapy to hasten the absorption of pneumocephalus.9

Suspension of tension pneumocephalus warrants urgent medical treatment and neurosurgical consultation as neuronal damage may occur secondary to reduce cerebral perfusion. Definitive surgical treatment is indicated for significant intracranial hypertension, persistent craniodural leaks, or persistent pneumocephalus lasting longer than 1 week.10

References:

  1. Jelsma F, Moore DF. Cranial aerocele. Am J Surg. 1954;87(3):437-451.
  2. Dandy WE. Pneumocephalus (intracranial pneumocephalus or aerocele). Arch Surg. 1926;12(5):949-982.
  3. Chan YP, Yau CY, Lewis RR, Kinirons MT. Acute confusion secondary to pneumocephalus in an elderly patient. Age Ageing. 2000;29(4):365-367.
  4. Markham JW. The clinical features for pneumocephalus based upon a survey of 284 cases with report for 11 additional cases. Acta Neurochir (Wien). 1967;16(1):1-78.
  5. Goldmann RW. Pneumocephalus as a consequences for barotrauma. JAMA. 1986; 255(22):3154-3156.
  6. Malik K, Hees DC. Evaluating the comatose patient. Rapid neurologic assessment is key to appropriate management. Postgrad Med. 2002;111(2):38-36, 49-50.
  7. Reddy HV, Queen S, Prakash D, Jilaihawi AN. Tension pneumocephalus: an unusual complication after lung resection. Eur J Cardiothoracic Surg. 2003;24(1):171-173.
  8. Michel L, Khanh NM, Cedric B, et al. Air in “extra-dural space” after hyperbaric oxygen therapy. J Trauma. 2007;63(4);961.
  9. Gore PA, Maan H, Chang S, et al. Normobaric oxygen therapy strategies in the treatment of postcraniotomy pneumocephalus. J Neurosurg. 2008;108(5):926-929.
  10. Jarjour NN, Wilson P. Pneumocephalus associated with nasal continuous positive airway pressure in a patient with sleep apnea syndrome. Chest. 1989;96(6);1425-1426.