Transcript Pathophysiology Secondary Injury

LSUHSC New Orleans
Department of Neurosurgery
Neurosurgical Emergencies
Frank Culicchia MD
Department of Neurosurgery
LSUHSC New Orleans
LSUHSC New Orleans
Department of Neurosurgery
Symptoms and Signs of
Elevated ICP
 Triad
 Headache, nausea, vomiting
 Cranial nerve palsies
 Papilledema
 Vital sign changes
 Cushing’s
 Arterial hypertension and bradycardia
 Respiratory changes
LSUHSC New Orleans
Department of Neurosurgery
Papilledema
 Swelling of the optic nerve
head with engorgement of
the retinal veins
 May be accompanied by
hemorrhages into the nerve
and adjacent retina
 Presence almost always
indicates raised intracranial
pressure.
LSUHSC New Orleans
Department of Neurosurgery
Pathophysiology
Secondary Injury
Increased intracranial pressure
 Severity of injury tends to increase due to heightened ICP,
especially if pressure exceeds 40 mm Hg (remember CPP)
 Increased pressure also can lead to cerebral hypoxia,
cerebral ischemia, cerebral edema, hydrocephalus, and
brain herniation
 Monro-Kellie doctorine
 In 1783 Alexander Monro deduced that the cranium was a "rigid
box" filled with a "nearly incompressible brain" and that its total
volume tends to remain constant. The doctrine states that any
increase in the volume of the cranial contents (e.g. brain, blood or
cerebrospinal fluid), will elevate intracranial pressure. Further, if
one of these three elements increase in volume, it must occur at
the expense of volume of the other two elements. In 1824 George
Kellie confirmed many of Monro's early observations.
LSUHSC New Orleans
Department of Neurosurgery
Cerebral Perfusion Pressure
 CPP= MABP-ICP
 Normal approximately 55
 Children tolerate lower CPP than elderly
LSUHSC New Orleans
Department of Neurosurgery
Pathophysiology
Secondary Injury
 Monro-Kellie Doctrine (modified)
 v.intracranial (constant) = v.brain + v.CSF + v.blood +
v.mass lesion
 Normally: brain 80%, CSF 10%, Blood 10%
 Temperature, MABP, CPP, positioning, resistance,
etc.
LSUHSC New Orleans
Department of Neurosurgery
Pathophysiology
Secondary Injury
 Cerebral Edema
 caused by effects of neurochemical
transmitters and by increased ICP
 Disruption of the blood brain barrier, with
impairment of vasomotor autoregulation
leading to dilatation of cerebral blood vessels
 Types of cerebral edema
 Vasogenic
 Cytotoxic
 Transependymal
LSUHSC New Orleans
Department of Neurosurgery
Cerebral Autoregulation
LSUHSC New Orleans
Department of Neurosurgery
Assessment of Autoregulatory
Reserve
LSUHSC New Orleans
Department of Neurosurgery
Pathophysiology
Secondary Injury
Brain Herniation
 Supratentorial herniation is due to direct mechanical
compression by an accumulating mass or to increased
intracranial pressure
 3 types of supratentorial herniation are recognized
 Subfalcine herniation: The cingulate gyrus of the frontal lobe is
pushed beneath the falx cerebri when an expanding mass
lesion causes a medial shift of the ipsilateral hemisphere. This is
the most common type of herniation
 Central transtentorial herniation: characterized by
displacement of the basal nuclei and cerebral hemispheres
downward while the diencephalon and adjacent midbrain
are pushed through the tentorial notch
 Uncal herniation: displacement of the medial edge of the
uncus and the hippocampal gyrus medially and over the
ipsilateral edge of the tentorium cerebelli foramen, causing
compression of the midbrain, while the ipsilateral or
contralateral third nerve may be stretched or compressed
LSUHSC New Orleans
Department of Neurosurgery
Pathophysiology
Secondary Injury
Cerebellar Herniation
 infratentorial herniation in which the tonsil of the
cerebellum is pushed through the foramen magnum
and compresses the medulla, leading to
bradycardia and respiratory arrest
LSUHSC New Orleans
Department of Neurosurgery
Pathophysiology
Secondary Injury
 Hydrocephalus
 communicating type is more common which
frequently is due to the presence of blood
products causing obstruction to flow of the
cerebral spinal fluid (CSF) in the subarachnoid
space and absorption of CSF through the
arachnoid villi
 noncommunicating type of hydrocephalus
often caused by blood clot obstruction of CSF
flow at the interventricular foramen, third
ventricle, cerebral aqueduct, or fourth ventricle
LSUHSC New Orleans
Department of Neurosurgery
Management of Elevated ICP:
Interventions
 Airway/ventilator
support
 Hypothermia
 Maintain adequate
CPP
 Neuromuscular
blockade
 Osmotic diuresis
 Hypertonic saline
 Sedation/analgesia
 Barbiturate coma
 Glycemic control
 CSF drainage
 Craniectomy
LSUHSC New Orleans
Department of Neurosurgery
Therapeutic Modalities for
Reduction of ICP
LSUHSC New Orleans
Department of Neurosurgery
CNS Infections
 Meningitis
 Abcess
 Brain
 Spinal cord
 Subdural
 Epidural
 Encephalitis
LSUHSC New Orleans
Department of Neurosurgery
CNS Infections: Signs and
Symptoms
 Meningismus
 Nuchal rigidity
 Headache
 Photophobia
 Fever
 Lethargy
LSUHSC New Orleans
Department of Neurosurgery
CNS Infections: Cause
 Bacterial
 Viral
 Fungal
 Parasites
 Prions
LSUHSC New Orleans
Department of Neurosurgery
CNS Infections:
Pathophysiology
 Hematogenous
 Originate from infection elsewhere in the body
 Respiratory
 Endocarditis
 Direct extension
 Sinus infections
 Osteomyelitis
 Trauma or surgery
LSUHSC New Orleans
Department of Neurosurgery
Meningitis
 Viral meningitis causes milder symptoms, requires
no specific treatment, and resolves without
complications
 Bacterial meningitis is a very serious disease and
may result in a learning disability, hearing loss,
permanent brain damage, and even death
 Viral infections are 2-3 times more common.
LSUHSC New Orleans
Department of Neurosurgery
Meningitis
 Overall incidence of bacterial meningitis in US is
estimated to be more than 400 per 100,000
newborn babies, and 1-10 cases per 100,000 adults
per year, or 25,000 cases yearly
 Approximately two-thirds of all cases are in children
 Usually occurs in isolated cases without epidemics
 More common in males than females
 More likely in late winter and early spring
LSUHSC New Orleans
Department of Neurosurgery
Meningitis
 Three types of bacteria are the most common causes of
meningitis in all age groups except newborns:
 Streptococcus pneumonia (causing pneumococcal
meningitis)
 Neisseria meningitidis (causing meningococcal meningitis)
 Haemophilus influenza type b (Hib)
 Hib vaccine as part of routine pediatric immunization has
significantly reduced the occurrence of serious Hib
disease
 Newborns are usually infected with coliform (bacteria in
the gut, contracted at birth) such as Escherichia coli or
Listeria and Group B Strep
LSUHSC New Orleans
Department of Neurosurgery
Brain Abcess
LSUHSC New Orleans
Department of Neurosurgery
Types of Primary TBI
 Skull fracture
 vault or basilar
 hematoma, cranial nerve damage, and increased
brain injury
 compound vs. simple; open vs. depressed
LSUHSC New Orleans
Department of Neurosurgery
Depressed Skull Fracture
LSUHSC New Orleans
Department of Neurosurgery
Depressed Skull Fracture
LSUHSC New Orleans
Department of Neurosurgery
Depressed Skull Fracture
LSUHSC New Orleans
Department of Neurosurgery
Depressed Skull Fracture
LSUHSC New Orleans
Department of Neurosurgery
Types of Primary TBI
 Intracranial Hemorrhages
 Epidural hematoma
 impact loading to the skull with associated laceration of
the dural arteries or veins, often by fractured bones and
sometimes by diploic veins in the skull's marrow
 most common, a tear in the middle meningeal artery
causes this type of hematoma. When hematoma occurs
from laceration of an artery, blood collection can cause
rapid neurologic deterioration
 Subdural hematoma
 tends to occur in patients with injuries to the cortical
veins or pial artery in severe TBI, with associated mortality
rate approximately 60-80%
LSUHSC New Orleans
Department of Neurosurgery
Acute Subdural Hematoma
LSUHSC New Orleans
Department of Neurosurgery
Acute Subdural Hematoma
LSUHSC New Orleans
Department of Neurosurgery
Acute Subdural Hematoma
LSUHSC New Orleans
Department of Neurosurgery
Acute Subdural Hematoma
LSUHSC New Orleans
Department of Neurosurgery
Epidural Hematoma
LSUHSC New Orleans
Department of Neurosurgery
Epidural Hematoma
LSUHSC New Orleans
Department of Neurosurgery
Epidural Hematoma