Herniation: Compartment Syndrome of the Head Connie Chen, MD Neurology Consultants of Dallas

Goals Understand Understand Recognize Recognize Treat Treat

Theory Compartment = skull contents Compartment = skull contents Fixed volume: Fixed volume: Brain (80%), blood (10%), csf (10%) Brain (80%), blood (10%), csf (10%) Stable pressure: CPP=MAP-ICP Stable pressure: CPP=MAP-ICP

Theory Autoregulation of increased intracranial pressure (cough/valsalva): Autoregulation of increased intracranial pressure (cough/valsalva): Increased ICP Increased ICP Increase MAP Increase MAP Compartment’s goal: Maintain CPP!! Compartment’s goal: Maintain CPP!!

Another look Perfusion of a compartment: Perfusion of a compartment: CPP= MAP- ICP CPP= MAP- ICP If MAP cannot increase: Increased ICP = Decreased CPP Increased ICP = Decreased CPP Decreased CPP = Tissue ischemia Decreased CPP = Tissue ischemia Tissue ischemia = Edema Tissue ischemia = Edema

Another look Edema = Further increased ICP Edema = Further increased ICP Further decreased CPP = Tissue death Further decreased CPP = Tissue death

What Else? Monro-Kellie doctrine: Monro-Kellie doctrine: - Skull is a fixed volume - increase in one volume leads to decrease in others. Brain> blood, csf

What Else? Increased ICP (via increased volume) Increased ICP (via increased volume) Displace blood/csf Displace blood/csf **Displace brain** !!!! **Displace brain** !!!!

Theory Increased ICP via increased volume Displaces blood, CSF, then brain & Reduces CPP causing brain ischemia

Recognize Looking at a Head CT is not recognition Looking at a Head CT is not recognition

Recognize Displaced brain will cause neurologic signs Displaced brain will cause neurologic signs

Signs Where does displaced brain go? Where does displaced brain go? Side to side: subfalcine Side to side: subfalcine Side to bottom: uncal (transtentorial) Side to bottom: uncal (transtentorial) Top to bottom: central tentorial Top to bottom: central tentorial Bottom to top: “upward” Bottom to top: “upward” Bottom thru the “hole”: tonsillar Bottom thru the “hole”: tonsillar falx tentorium foramen magnum

Signs Subfalcine Subfalcine ACA compression: contralateral leg paresis ACA compression: contralateral leg paresis Somnolence Somnolence Uncal (transtentorial) Uncal (transtentorial) Anisocoria to “blown pupil” Anisocoria to “blown pupil” Midbrain and PCA compression: Midbrain and PCA compression: Somnolence, Somnolence, Contralateral hemiparesis, occipital infarct Contralateral hemiparesis, occipital infarct Decerebrate posturing (extensor) Decerebrate posturing (extensor) midbrain

Signs Central tentorial Central tentorial Somnolence/coma Somnolence/coma Bilaterally “blown” pupils Bilaterally “blown” pupils Decorticate/decerebrate posturing Decorticate/decerebrate posturing Bilateral midbrain, PCA compression Bilateral midbrain, PCA compression Upward (rare) Upward (rare) Midbrain compression Midbrain compression “Blown” pupils “Blown” pupils Somnolence/coma Somnolence/coma midbrain

Signs Tonsillar Tonsillar Somnolence Somnolence Quadriparesis Quadriparesis Cardiac arrythmias Cardiac arrythmias Respiratory failure Respiratory failure midbrain medulla Foramen magnum

More Signs Vital sign changes (brainstem is being crushed): Vital sign changes (brainstem is being crushed): “Cushing Reflex” : Bradycardia/hypertension Bradycardia/hypertension respiratory change Somnolence/Coma Somnolence/Coma EXAMINE PT: pupils, pupils, pupils EXAMINE PT: pupils, pupils, pupils

Pupils? Blown pupils: (large unreactive) Blown pupils: (large unreactive) Not medication unless ophthalmology came Not medication unless ophthalmology came Or if under GENERAL anesthesia Or if under GENERAL anesthesia Compression of midbrain Compression of midbrain Pinpoint pupils: (small unreactive) Pinpoint pupils: (small unreactive) Often caused by medication (benzo’s, opiates) Often caused by medication (benzo’s, opiates) Also from pontine damage Also from pontine damage

Pupils? Anisocoria: Anisocoria: Sometimes normal or surgical Sometimes normal or surgical Sometimes meds: nebulizer Sometimes meds: nebulizer Compression of CN III Compression of CN III Irregular: Irregular: Surgical Surgical Ongoing ischemia: “cat eye” Ongoing ischemia: “cat eye”

Exam Summary Vital sign change is LATE Vital sign change is LATE Early exam change- somnolence Early exam change- somnolence Pupil change- anisocoria or less reactive Pupil change- anisocoria or less reactive Very late change: comatose, dilated pupils, posturing Very late change: comatose, dilated pupils, posturing

Treatment Head CT is not a treatment

Treatment Herniation = Brain CODE Herniation = Brain CODE Stabilize your pt first: ABC’s, then BCB Stabilize your pt first: ABC’s, then BCB Then conduct “secondary survey” Then conduct “secondary survey”

Treatment Control your compartment (BCB) Control your compartment (BCB) Blood Blood CSF CSF Brain Brain

Blood Allow outflow: Allow outflow: Cut the tape off of the neck Cut the tape off of the neck Head midline Head midline Head of bed at 45 degrees Head of bed at 45 degrees Constrict blood vessels: Constrict blood vessels: Hyperventilate: BAG! Hyperventilate: BAG! Goal is pH change- not pCO2 Goal is pH change- not pCO2

CSF Drain CSF Drain CSF Intraventricular catheter placement Intraventricular catheter placement Spinal CSF removal will let you herniate faster Spinal CSF removal will let you herniate faster

Brain Steroids only work on tumors

Brain Shrink Shrink Hyperosmolar agents: mannitol, hypertonic saline Hyperosmolar agents: mannitol, hypertonic saline Doses? Bolus vs infusion. Doses? Bolus vs infusion. Cut Cut Surgical removal Surgical removal Shut down Shut down Neuroanesthetic agents: propofol, thiopental Neuroanesthetic agents: propofol, thiopental

How Long? Hyperosmolar agents and hyperventilation lasts 6 hours at best.

Then what? Your pt is better Your pt is better Your pt is not better Your pt is not better

Then what? Head CT verifies your diagnosis and identifies the problem

Release Release the compartment : “pop the top” Release the compartment : “pop the top” Early vs. late Early vs. late

Case 60 yo wm s/p acute right MCA stroke 60 yo wm s/p acute right MCA stroke

Case 4 days later 4 days later Pt becomes somnolent but arousable Pt becomes somnolent but arousable There’s new anisocoria There’s new anisocoria Plan? Plan?

Case 12 hours later 12 hours later Not arousable- comatose Not arousable- comatose Still anisocoria, right pupil stops reacting Still anisocoria, right pupil stops reacting Plan? Plan?

Case Other options?

Summary Look outside your “box” Look outside your “box” Herniation is reversible Herniation is reversible Treat before scanning Treat before scanning