head_injury_adult
head injury in the adult patient
introduction
the far majority of patients with minor head injury do NOT develop serious intracranial complications
nevertheless, there are high risk patients (eg. those on
anticoagulants) and high risk trauma which substantially increase the risk of such bleeds and for these patients, CT scan is almost mandatory (see below for indications).
when considering a CT brain, also consider whether a CT
cervical spine is warranted at the same time.
in patients with brain injury after trauma, 7-20% will have Cx spine injury
in particular, elderly patients who have fallen over and hit their head have a high risk of C2 fractures and should have a low threshold for CT scan of cervical spine if they had complained of neck pain at any stage after the fall or if they have neck tenderness.
patients deemed safe for discharge home should be discharged with a carer who is given a
patient information sheet so they know what to look out for, how to manage concussion and when to bring the patient back if there is deterioration or warning signs.
one should avoid using
aspirin (acetylsalicylic acid) as an analgesic for headache in such patients due to the theoretical risk of potential for increased bleeding
patients should not be allowed self-discharge as a duty of care if they are significantly cognitively impaired (eg. intoxicated) and at risk, particularly if they have no suitable carer to keep an eye on them.
intracranial injuries
initial brief loss of consciousness (LOC)
concussion
impaired cognitive, emotional, memory, sleep &/or behavioural function (+/- headache, vomits, impaired balance, tinnitus) following head injury
post-traumatic amnesia, in which events following the injury cannot be recalled, is a hallmark of concussion
the neural damage involved in causing concussion is NOT detectable on CT scan or MRI and is thought to be a milder form of diffuse axonal injury
~90% resolve within 10 days
it appears resting of the brain is helpful in allowing early resolution
risk factors for delayed recovery include:
age > 55yrs
previous head injury
substance abuse
depression
stress
other major injuries
premature return to work may not only prolong the impairment, but the impairment may result in occupational accidents from the impaired judgement or skills.
post-concussion syndrome:
second impact syndrome
multiple episodes may lead to either:
diffuse axonal injury (DAI)
usually results from acceleration injury due to traumatic rotation of the head causing mechanical forces to act on the long axons leading to axonal structural failure.
the usual cause for persistent impaired consciousness
the deeper the white matter lesion, the more profound and persistent the impairment of consciousness
this is present on post-mortem in 30-40% of those with traumatic brain injury who die
this injury is not visible on CT scan but requires MRI
DAI and younger age may contribute to an increased risk of developing
dysautonomia
85% result from bleeding from the middle meningeal artery
often associated with a “lucid interval” until the mass effect compromises the brainstem and consciousness falls.
convex on CT scan
may require emergency neurosurgical drainage to prevent death
subdural haematoma
intraventricular haemorrhage
an indicator of severe brain injury and may result in post-traumatic hydrocephalus and require emergent placement of an intraventricular catheter or a
V-P shunt if chronic hydrocephalus develops
Duret haemorrhages
small punctate hemorrhages that are often caused by arteriole stretching during either primary injury, or secondarily due to transtentorial herniation
commonly lethal when they occur in the brainstem
secondary injuries
following head injury for a period of days, the brain is especially vulnerable to changes in intracranial pressure, blood flow, and anoxia
ischaemia
cerebral oedema
raised inctracranial pressure (ICP)
vasospasm
infection
seizures
hydrocephalus
hypoxic insult
hypercapnia
metabolic insults from deranged metabolic states eg. hyperglycaemia, hyponatraemia, etc.
role of CT brain in head injury
helps exclude acute haemorrhage such as extradural (epidural), subdural and intraventricular bleeds as well as intracerebral bleeds
helps define anatomic location of lesions although posterior fossa tends to be poorly depicted
demonstrates mass effect and midline shift, and evidence of uncal herniation
helps identify skull fractures although depressed fractures at the vertex can be difficult to see
sensitive in detecting intracranial air indicating penetrating injury
sensitive in detecting foreign bodies
NOT sensitive for concussion which is a clinical diagnosis, nor is it sensitive for cerebral contusions in the early phases
NOT sensitive for detecting diffuse axonal injury (DAI) nor tiny haemorrhages such as Duret haemorrhages
indications for CT brain in adults with head injury
NICE 2014: scan within 1 hour
NICE 2014: scan within 8hrs if
older indications
decreased GCS or falling GCS
penetrating injury
clinical evidence of fracture base of skull - CSF rhinorrhoea, haemotympanum, Battle's sign, or racoon eyes, etc.
drug or alcohol intoxication
-
persistent vomiting
seizures
increasing headache
suspected depressed skull fracture
some
2) would also consider CT scan if either:
references
head_injury_adult.txt · Last modified: 2020/05/25 11:09 by gary1