10.3

• Brain injuries produced by blows that do not penetrate the skull are called closed-head TBIs.
• Contusions are closed-head TBIs that involve damage to the cerebral circulatory system. Such damage produces internal hemorrhaging, which in turn produces a localized collection of blood in the brain—in other words, a bruised brain.
• This occur when the brain slams against the inside of the skull.

  Contusion
• Blood from such injuries can accumulate in the subdural space—the space between the dura mater and arachnoid membrane—and severely distort the surrounding neural tissue. Such a “puddle” of blood is known as a subdural hematoma.
• The space between the dura mater and arachnoid membrane.

  Subdural space
• True or False: Contusions frequently occur on the side of the brain opposite the side struck by a blow.

  True
• Contusions frequently occur on the side of the brain opposite the side struck by a blow. The reason for such so-called contrecoup injuries is that the blow causes the brain to strike the inside of the skull on the other side of the head.
• When there is a disturbance of consciousness following a blow to the head and there is no evidence of a contusion or other structural damage, the diagnosis is mild TBI (mTBI).
• Why is mTBI no longer called the concussion?

  It was associated with the mistaken assumption that its effects involved no long-term damage
• True or False: Substantial evidence that the effects of mTBIs can last many years and that the effects of repeated mTBIs can accumulate.

  True
• Chronic traumatic encephalopathy are common for individuals who have experienced repeated mTBIs such as boxers, rugby players, American football players.
• An invasion of the brain by microorganisms is a brain infection, and the resulting inflammation is called encephalitis.
• An invasion of the brain by microorganisms is a brain infection, and the resulting inflammation is called encephalitis.
• two common types of brain infections:

  bacterial infections and viral infections
• When bacteria infect the brain, they often lead to the formation of cerebral abscesses — pockets of pus in the brain.
• inflammation of the meninges

  meningitis
• Bacteria are also the major cause of meningitis (inflammation of the meninges), which is fatal in 30 percent of adults.
• Syphilis bacteria are passed from infected to noninfected individuals through contact with genital sores. The infecting bacteria then go into a dormant stage for several years before they become virulent and attack many parts of the body, including the brain.
• The syndrome of mental illness and dementia that results from a syphilitic infection is called general paresis.
• two types of viral infections of the nervous system:

  • those that have a particular affinity for neural tissue
  • those that attack neural tissue but have no greater affinity for it than for other tissues.