Doctors find air pocket hidden in man's brain

A CT scan of the man's head revealed a large air cavity compressing his right frontal lobe. The condition is known as pneumocephalus.

Story highlights

  • Treatment for pneumocephalus depends on may factors, including symptoms
  • Condition commonly compresses the frontal lobe, can affect voluntary muscle movement

(CNN)Doctors treating a patient who had complained of repeatedly losing his balance made an unexpected discovery: The 84-year-old man had a 3½-inch pocket of air in his brain.

The man had been referred to the emergency room by his primary physician in Northern Ireland.
    He told his doctor about weeks of recurrent falls and three days of left-side arm and leg weakness, according to the report, published in the journal BMJ Case Reports. The patient, who is not identified in the report, did not have any visual or speech impairments and did not seem confused or have facial weakness, according to the authors.
      An MRI shows the air-filled cavity in the patient's brain.
      "The thing I was most concerned about in an elderly patient with new onset limb weakness and balance disturbance was some form of stroke," said Dr. Finlay Brown, a leading author of the report and a general practitioner in Belfast who treated the man.
      The physicians performed scans of the brain to identify any signs of bleeding or brain damage caused by blocked blood vessels, according to Brown.
      But what they found was much more unusual.

        Small benign tumor

        A computed tomography scan of the patient's brain showed a large pocket of air -- also called a pneumatocele -- in the patient's right frontal lobe that was approximately 3½ inches long.
        "We knew immediately that there was something very abnormal," Brown said. "Initially, we thought perhaps the patient hadn't disclosed having previously had some form of operation or a congenital abnormality, but ... he confirmed he hadn't."
        The air pocket was right behind the frontal sinus and above the cribriform plate, which separates the nasal cavity from the cranial cavity.
        "This was a rare presentation in this guy of a lot of air in his brain," said Dr. Alan Cohen, professor of pediatric neurosurgery at Johns Hopkins Hospital, who was not involved in the case report.
        When pneumatoceles are present in the brain, the condition is often referred to as pneumocephalus. They most commonly compress the frontal lobe, which plays a large role in voluntary muscle movement, Cohen said.
        An MRI of the man's brain also showed a small benign bone tumor, or osteoma, that had formed in the man's paranasal sinuses and was eroding through the base of the skull, causing air to leak into the cranial cavity, according to the report.

        'Inverted Coke bottle'

        "It's kind of like an inverted