Remember this!

ABCs of Treatment

A--Airway, B--Breathing, C--Circulation (check with EKG, heart rate) If airway is compromised or Pt can't protect own airway, must *intubate* Stabilize Pt with IVs for easy drug admin before beginning diagnostic tests

Modified Fischer score

Amount of settled blood (mainly in lateral ventricles) Ranges 1-4 Settled blood irritates brain tissue and leads to vasospasm, so need to minimize

SAH complications

Blood irritating cortex can lead to *vasospasm* (seizures, comatose and otherwise) and *edema* (swelling)

Brain Stem Anatomy

Bottom to top: spinal cord (hyperdense circle surrounded by ring of hypodense CSF) passing thru C1 (ring of bone), medulla (baser instinct regulation), pons (source of facial nerves), midbrain (motor fibers run here)

Hydrocephalus

Buildup of excess CSF (cerebrospinal fluid) in brain Caused by blocked ventricles (appear swollen on CT) Treatments: extraventricular drain placed thru right hemisphere (to avoid language center) into foramen of monroe where lateral ventricles drain to 3rd

Symptom: Difficulty breathing

Cause: Blood or CSF buildup causing downward shift (herniation), placing pressure on *medulla*

Symptom: Projectile vomiting

Cause: intracranial pressure on *area postrema*

Symptom: Gaze deviation

Causes: seizures (due to hydrocephalus or otherwise), damage to frontal eye fields

Hematoma

Collection of clotted blood outside circulation system (thus abnormal) If you see rings/arcs of hypodensity on CT, there's *active bleeding* Rim of hypodensity around blood could indicate edema or dead brain tissue Can cause midline shift and/or hydrocephalus (shift is worse issue)

Types of Hydrocephalus

Communicating: CSF flow is blocked in subarachnoid space after leaving ventricles, entire system swells Obstructive: CSF flow blocked in a ventricle, only parts of system before that blockage are swollen

CTA

Diagnostic test CT Angiogram Large-bore IV enters femoral artery as access point Risks: allergy to contrast, impaired renal function (kidneys) won't allow contrast to be excreted, radiation effects

Ipsilateral control

Ex. Cerebellum: Left hemisphere controls left side of body's balance/coordination/etc., and right hemisphere controls right side of body

Contralateral control

Ex. Cortex: Left hemisphere controls right side of body, and right hemisphere controls left side of body

Ventricles

Lateral ventricles lead to 3rd ventricle on midline, which leads to 4thventricle (deeper on midline) 4th ventricle is final CSF exit from skull

Hunt-Hess score

Level of comatose appearance Higher score = worse condition Can lead to dangerous labeling that dooms a patient from refusal to treat (since easily-treated conditions can produce comatose appearance)

Houndsfield units

Measures density in Ct scan Air = 0 (most hypodense) Bone = 1000 (most hyperdense)

Blood Pressure

Normal is 120/80 Top # is systolic BP (at maximum heart contraction) Bottom # is diastolic BP (at relaxed heart)

Intubation

Placing breathing tube through throat to lungs Set breathing machine to hyperventilate Hyperventilation lowers CO2 levels, which increases body alkilinity (more basic), so blood vessels vasoconstrict and reduce bleeding in brain Poor breathing leads to CO2 buildup, then acidosis, then vasodilation, and more bleeding

Brain Circulation

Revealed via CTA Vasillar supplies brain stem Posterior cerebral supplies occipital lobe External carotid supplies face Internal carotid leads to anterior and middle cerebral Anterior cerebral supplies frontal lobe

Seizure

Synchronized hyperexcitability of neurons in cortex

Traumatic brain injury

This type of brain injury is more common in frontal and temporal lobes because skull here has bony ridges

Problem: Hematoma causing midline shift wit hydrocephalus

Treatment: craniotomy, remove settled blood Corrects problem and hopefully relives blockage on ventricles

Treating Cerebral Aneurysms: Clipping vs. Coiling

Use high contrast, subtract bone interference, locate largest aneurysm Clipping pinches together the neck of the aneurysm Pack aneurysm with platinum coils ($$$)

A and Ox3

When PT enters ER Alertness, Orientation (person, place, time)

Hyperdensity (on CT)

substances of higher density, appear lighter Ex. blood, bone

Hypodensity (on CT)

substances of lower density, appear darker Ex. dead tissue (takes ~6 hours to show up on scan), CSF