Tuesday, December 15, 2009

Head injury - part 3

Management of mild head injury (GCS 14-15)

Most of the occasions, patients with mild head injury, after history and examination, and a period of observation, will be allowed to be discharge after following criterias met :


                                   Battle's sign

a) Full GCS score (15/15)
b) No focal neurological deficits
c) Accompanied by a responsible adult
d) Not under influence of any drugs/alcohol
e) Verbal/Written advice about the injury given


Racoon's Sign


Statement e) means : Advice regarding any worsening of symptoms, such as persistent headahce not relieved by analgesia, severe vomiting, blurring of vision, diplopia, weakness/numbness of limbs have been given verbally or written.

Sometimes, for patients with mild head injury, decision of whether to perform CT brain or not can be a big headahce. However, here are the NICE guidelines regarding indications of CT brain in patients with mild head injury :

a) GCS is <13 at any point
b) GCS is 13-14 at 2 hours time
c) Evidence of focal neurological deficit
d) Suspicion of open, comminuted, depressed, or basal skull fracture
e) Vomiting > 1 episode
f) Seizures

Urgent indication

a) Age > 65 years old
b) Evidence of coagulopathy (liver disease, blood dyscarias, warfarin, anti-platelet medications)
c) Dangerous mechanism of head injury (CT within 8 hrs)
d) Antegrade amnesia > 30 mins (CT within 8 hrs)

Management of moderate/severe head injury

First of all, resuscitation and primary survery.
After stabilising cervical spine at 3 fixation point, start primary surveying.
Remember that normalising the patient's oxygenation and circulation is more important than getting a CT done! This is to prevent secondary brain injury

After primary survey, you've made a diagnosis of moderate/severe head injury, the next step is CT brain, to detect any intracranial hematoma, or any skull fractures, soft tissue injuries, or any mild intracerebral contusion.
For intubated patients, it's recommended that you've asked for CT cervical spine.

Before ariving at the hospital, some conservative management can be given for raised ICP, which includes :

a) Reversed tredelenburg : Raised head upto 20-30 degrees
b) Check if the cervical collar is too tight (may obstruct venous drainage from brain)
c) If there's pupillary dilatation (may be due to acute raised ICP), 0.5mg/kg 20% IV mannitol can be given.

Medical management of severe head injury

Severe head injury is preferably managed in a neurointensive care unit.
ICP can be monitored by passing a catheter into the frontal horn of the lateral ventricle (2 finger breadth from the blurred hole, behind the hairline)
Raise the patient's head for about 20-30 degrees

Protect the patient's airway!
For those with traumatic brain injury and coma, they are more prone to aspiration.
Preferably intubate the patient, and provide high flow oxygen. (Prevent hypoxia)

Make sure that the cervical collar is not too tight.

Cerebral vasculatures are very sensitive to the PCo2 level. When there's a rise in PCo2 level, the cerebral vasculatures dilates, and elevates the ICP. In contrast, when there's a fall in PCo2 level, cerebral vasculature constricts.

Hence, you must try to maintain the PCo2 level in between 4.5-5kPa.
Some experienced anesthetist may induce hyperventilation in patients to cause temporary reduction in ICP by reducing the PCo2 level.

Sedative given, either with or without muscle relaxant.
Mannitol/Frusemide given to reduce cerebral edema.
Patient is prone for hyponatremia or other electrolyte imbalance -> correct it
Avoid pyrexia, as it'll cause undesirable increase in the brain metabolic activity.
Barbiturates eg: thiopentone sodium is given to reduce ICP and brain metabolic rate.
Prophylactic anticonvulsant given.

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