The management of head injury has been based on the concept of primary and secondary brain injury. The primary brain injury was defined as the irreversible pathology sustained at the time of the trauma, whereas the secondary brain injury has been considered the subsequent or progressive brain damage that occurs due to an evolving pathology following the injury. It has been the general contention that the primary injury is irreversible, and management should be directed at preventing or treating secondary pathology (such as cerebral swelling, hydrocephalus and intracerebral haematoma).

However, it is now clear that some of the biochemical events associated with what was considered irreversible brain injury are potentially preventable, or even reversible if treatment is instituted early enough. The distinction between primary and secondary injury has become blurred, and the terms, whilst useful concepts, are now becoming obsolete.

Most head injuries result from blunt trauma, as distinct from a penetrating wound of the skull and brain caused by missiles or sharp objects. The pathological processes involved in a head injury are:

• direct trauma

• cerebral contusion

• intracerebral shearing

• cerebral swelling (oedema)

• intracranial haemorrhage

• hydrocephalus.

Direct trauma. Although penetrating injuries produce most of their damage by direct trauma to the brain this is not the case with blunt injuries, in which the energy from the impact has a more widespread effect.

Cerebral contusion. This may occur locally under the position of the impact (coup injury) although it usually occurs more severely at a distance from the area of impact as a result of a ‘contre-coup’ injury. As the brain is mobile within the cranial cavity the sudden acceleration/deceleration force will result in the opposite ‘poles’ of the brain being jammed against the cranial vault. A sudden blow to the back of the head will cause the temporal lobes to slide across the floor of the middle cranial fossa and the frontal lobes across the floor of the anterior cranial fossa, causing contusion on the undersurface of those lobes and to the temporal and frontal poles of the brain as they strike the sphenoid ridge and frontal bones, respectively.

Cerebral contusion consists of lacerated haemorrhagic brain, and a ‘burst temporal lobe’ may result when the temporal pole has been severely injured.

Shearing forces. Intracerebral shearing forces occur as a result of the differential brain movement following blunt trauma, frequently in conjunction with a contre-coup type of injury. The rotational acceleration following injury will cause shear forces that result in petechial haemorrhages (particularly in the upper brainstem, cerebrum and corpus callosum), and tearing of axons and myelin sheaths (Diffuse Axonal Injury-DAI). The early pathological changes consist of retraction balls or microglial stars, and if the patient lives for a number of months before death then widespread degeneration of myelin will be apparent at postmortem.

Cerebral swelling. This occurs following trauma, either in a focal pattern around an intracerebral haematoma or diffusely throughout the cerebrum and/or cerebellum. The nature of the pathological processes are not clearly understood but involve a disturbance of vasomotor tone causing vasodilatation and cerebral oedema. In addition, cerebral contusion and petechial haemorrhages will contribute to the brain swelling.

Intracranial haemorrhage. Intracranial haemorrhage may be:

.intraventicular

.subarachnoid

• intracerebral

• subdural

• extradural.

(See other posts for full details)

Hydrocephalus. This occurs infrequently in the early stages after a head injury. It may be due to obstruction of the 4th ventricle by blood, swelling in the posterior fossa, or the result of a traumatic subarachnoid haemorrhage causing obstruction to the absorption of CSF and resulting in a communicating hydrocephalus. This latter type of hydrocephalus is an uncommon, but important, cause of delayed neurological deterioration either in the weeks following the head injury or some years later.

Concussion

Concussion involves an instantaneous loss of consciousness as a result of trauma. The term ‘concussion’ was introduced by Pare and is derived from the Latin ‘concutere’ which means to shake. In 1941 Denny-Brown and Russell showed that concussion was produced by a blow on the cranium when it was free to move and subsequent studies showed that the acceleration/deceleration of the head resulted in shear strains, contre-coup injury, petechial and punctate haemorrhages throughout the brainstem, cerebral hemispheres and corpus callosum, and neuronal injury, the extent depending on the force of the impact. The term concussion is not strictly defined with respect to the severity of the injury.

However, a minimum criterion is that the patient will have had a period of amnesia. The retrograde amnesia of most cerebral concussion is usually short term, lasting less than 1 day. The initial retrograde amnesia may extend over a much longer period but it gradually shrinks down. A more reliable assessment of the severity of the head injury is the post-traumatic amnesia. If the amnesia following the head injury lasts more than 1 day then the concussion is regarded as being severe.

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Cranial Nerves Injury

The cranial nerves may be injured as a result of either direct trauma by the skull fracture, movement of the brain, or cerebral swelling.

The 1^st (olfactory) nerves. These are the most commonly affected and this may be as a result of either a fracture through the anterior cranial fossa, directly affecting the tracts, or tearing of the delicate nerve rootlets passing through the cribriform plate caused by the sudden brain movement, particularly from a blow to the back of the head. The features are parosmia or anosmia.

The 8th (vestibullocochlear)nerve. Damage to this nerve is often associated with a fracture of the petrous temporal bone. Deafness may be conductive, due to a haemotympanum, or sensorineural as a result of injury to the inner ear or to the nerve itself. Vertigo and nystagmus are due to vestibular nerve or end-organ damage and usually resolve within a few months of the injury.

Facial(7^th nerve) paralysis. This is usually associated with a fracture through the petrous temporal bone, although this may only be evident on a high-resolution CT scan using the bone ‘window’. It may be either immediate, as a result of direct compression of the nerve, or delayed, due to bleeding and/or swelling around the nerve. The features include deviation of the mouth to the normal side, flattening of the nasolabial fold, drooling of the eyelids, loss of eyebrows, etc.

The 6th (abduscens) cranial nerve. This has a long course from the brainstem to its entry into Dorello’s canal and the nerve is easily damaged by torsion or herniation of the brain. Affected individuals present with lateral gaze palsy.

The 3^rd (occulomotor) nerve. This may also be damaged by direct trauma or by brain herniation, the herniated uncus of the temporal lobe either impinging on the midbrain or directly stretching the nerve. Occulomotor nerve palsy causes ptosis with the eye deviated “down and out”.

The 2^nd (optic) nerve. This is infrequently injured by direct trauma.

Skull fractures

Trauma may result in skull fractures which may be open/closed or linear/depressed. See skull fractures for further details.

Scalp lacerations

The extent of the scalp laceration does not necessarily indicate the degree of trauma to the underlying brain.

Other injuries

The most common associated injuries are to the chest, cervical spine, skeletal and cardiovascular systems. Many individuals with associated high cervical cord injuries do not survive long enough as to reach hospitals.

Broad-spectrum agents are used initially, while specific drugs are commenced as soon as results of CSF analysis are available.

The use of corticosteroids in the management of bacterial meningitis is controversial. While some studies have documented its benefits, especially reduction in hearing impairment, others have not found it so useful. If dexamethazone is to be used, it needs to be started before, or along with the first dose of antibiotics to reduce the patient’s inflammatory response.

The definite diagnosis of bacterial meningitis is based on the findings of cerebrovascular fluid (CSF) examination. The CSF is obtained from lumbar puncture. The usual picture is pleocytosis with cell count over 1,000 cells per mm3 (with polymorphonuclear cells predominating), hypoglycorrhagia with glucose under 30 mg per dL and elevated protein usually over 200 mg per dL. Gram staining and microscopy may reveal the causative organism.

Differential Diagnosis
◦ Systemic Lupus Erythematosus and other connective tissue diseases
◦ Drug-induced meningitis
◦ Tumours
◦ Epidermoid & Parasitic cysts

“I do agree that the Democrats have been intellectually lazy in failing to take the core ideals of the Democratic Party and adapting them to circumstances…. It’s not just a matter of sticking in a quote from the Bible into a stock speech.”

“There has yet to be a serious conversation about health care on the floor of the United States Senate.”

“…as parents, we need to find the time and the energy to step in and find ways to help our kids love reading. We can read to them, talk to them about what they’re reading and make time for this by turning off the TV ourselves. Libraries can help parents with this. Knowing the constraints we face from busy schedules and a TV culture, we need to think outside the box here - to dream big like we always have in America.
Right now, children come home from their first doctor’s appointment with an extra bottle of formula. But imagine if they came home with their first library card or their first copy of Goodnight Moon? What if it was as easy to get a book as it is to rent a DVD or pick up McDonalds? What if instead of a toy in every Happy Meal, there was a book? What if there were portable libraries that rolled through parks and playgrounds like ice cream trucks? Or kiosks in stores where you could borrow books?
What if during the summer, when kids often lose much of the reading progress they’ve made during the year, every child had a list of books they had to read and talk about and an invitation to a summer reading club at the local library? Libraries have a special role to play in our knowledge economy.” — June 27, 2005 Speech to the American Library Association

We are one people, all of us pledging allegiance to the stars and stripes, all of us defending the United States of America. In the end, that’s what this election is about. Do we participate in a politics of cynicism or do we participate in a politics of hope?

John Kerry calls on us to hope. John Edwards calls on us to hope.
I’m not talking about blind optimism here - the almost willful ignorance that thinks unemployment will go away if we just don’t think about it, or the health care crisis will solve itself if we just ignore it. That’s not what I’m talking about. I’m talking about something more substantial.
It’s the hope of slaves sitting around a fire singing freedom songs. The hope of immigrants setting out for distant shores.

The hope of a young naval lieutenant bravely patrolling the Mekong Delta.
The hope of a millworker’s son who dares to defy the odds.

The hope of a skinny kid with a funny name who believes that America has a place for him, too.
Hope in the face of difficulty. Hope in the face of uncertainty. The audacity of hope!

In the end, that is God’s greatest gift to us, the bedrock of this nation. A belief in things not seen. A belief that there are better days ahead.

I believe that we can give our middle class relief and provide working families with a road to opportunity.

I believe we can provide jobs to the jobless, homes to the homeless, and reclaim young people in cities across America from violence and despair.

I believe that we have a righteous wind at our backs and that as we stand on the crossroads of history, we can make the right choices, and meet the challenges that face us.

America! Tonight, if you feel the same energy that I do, if you feel the same urgency that I do, if you feel the same passion I do, if you feel the same hopefulness that I do — if we do what we must do, then I have no doubts that all across the country, from Florida to Oregon, from Washington to Maine, the people will rise up in November, and John Kerry will be sworn in as president, and John Edwards will be sworn in as vice president, and this country will reclaim its promise, and out of this long political darkness a brighter day will come.

Thank you very much everybody. God bless you. Thank you.

Thank you, and God bless America.

Neonatal period: Escherichia coli, group B streptococci (S. agalactiae), and L. monocytogenes.

Ages 2 months to 5 years: H. influenzae

Above 5 years: S. pneumoniae and N. meningitidis.

In addition to the age of the patient, another factor that determines the causative pathogens is the presence of immunosuppression. In immunosuppressed patients, the most frequent pathogens include L. monocytogenes (especially in patients with cell-mediated immunity deficiency), S. pneumoniae (in patients with humoral immunity deficiency), and P. aeruginosa, enteric gram-negative bacilli, and S. aureus (in neutropenic patients).

Now even as we speak, there are those who are preparing to divide us, the spin masters, the negative ad peddlers who embrace the politics of anything goes.

Well, I say to them tonight, there is not a liberal America and a conservative America — there is the United States of America. There is not a Black America and a White America and Latino America and Asian America — there’s the United States of America.

The pundits, the pundits like to slice-and-dice our country into Red States and Blue States; Red States for Republicans, Blue States for Democrats.

But I’ve got news for them, too:
We worship an awesome God in the Blue States, and we don’t like federal agents poking around in our libraries in the Red States.
We coach Little League in the Blue States and yes, we’ve got some gay friends in the Red States.

There are patriots who opposed the war in Iraq and there are patriots who supported the war in Iraq.