CNRN generalized study

anatomy/terms/definitions

What is the pathway of cerebrospinal fluid from ventricle one to ventricle four?

CSF is in the first two ventricles, it goes into the third ventricle where it gains more CSF, then goes through the cerebral aquaduct, then finally down through the fourth ventricle.

It then enters the subarachnoid space where it zooms around the brain and spinal cord.

What do neurons do?

send signals through electrical impulses

What do neuroglial cells do?

support brain homeostaiss and neuronal functions.

what do supraentorial cells do?

Supraentorial cells are involved in various functions such as supporting neuronal health and maintaining homeostasis; they are located in the cerebral hemispheres, above the tentorium cerebelli.

what do astrocytes do?

Astrocytes provide structural support for neurons, regulate blood flow, and maintain extracellular ion balance. They also play a role in neurotransmitter uptake and the blood-brain barrier.

what do oligodendocytes do?

Oligodendrocytes produce myelin sheaths that insulate axons in the central nervous system, enhancing the speed of electrical impulses and supporting neuronal communication.

what do embryo cells do?

Embryo cells, or embryonic stem cells, are capable of differentiating into various cell types, contributing to the formation of tissues and organs during development. They have the potential for self-renewal and play a crucial role in growth and tissue repair.

the term supraentorial refers to what area of the brain?

cerebral cortex, above the tentorium

the term infratentorial refers to what area of the brain?

the area below the tentorium, including the brainstem and cerebellum.

What is the difference between benign and malignant tumors?

Benign tumors are made of mutated cells that stay in the tumor mass and do not cross the basement membrane.

Malignant tumors are made of mutated cells that do NOT stay in the tumor mass, breaking free of the basement membrane and spreading to other tissue.

what is an expected mechanism of injury for diffuse axonal injury?

high-velocity rotational accelerated and deceleration forces, such as traumatic falls, MVC, etc.

How does a high-velocity rotational acceleration/deceleration force cause a diffuse axonal injury?

the forces cause a shearing effect, where the brain tissues of different densities (gray matter vs. white matter) slide past each other at different speeds. This stretches, twists, and tears the microscopic axons, disrupting cellular transport.

Common anatomical sites of diffuse axonal injury?

Common anatomical sites include the:
corpus callosum (severe)

brainstem (most severe) and the

gray-white matter junction areas (mild/moderate)

Symptoms of diffuse axonal injury?

immediate, profound coma post-trauma (GCS<8) with NO LUCID INTERVAL.

What would the CTH show of diffuse axonal injury?

it would either be completely normal or show subtle, tiny punctuate (dot like) hemorrhage at the gray/white region

what would the MRI show for diffuse axonal injury?

It typically shows multiple small lesions or areas of high signal intensity in the white matter, particularly affecting the axonal tracts.

what type of MRI is best for diagnosing diffuse axonal injury?

The best type of MRI for diagnosing diffuse axonal injury is the diffusion-weighted imaging (DWI), which can identify areas of restricted diffusion corresponding to axonal damage.

what neurological injuries can cause a patient to display decorticate positioning?

rising intracranial pressure and early brain herniation

what neurological injuries can cause a patient to display decerebrate positioning?

-diffuse axonal injury
-brainstem contusion
-transentorial brain herniation
-infarction or ischemia affecting the midbrain, pons, or basilar artery distribution
-meningitis
-encephalitis

transentorial

brain herniation caused by pressure from the cerebrum, leading to central herniation of brain tissue through the tentorial notch.

sympathetic storming

a phenomenon seen in patients with severe brain injury, characterized by episodes of increased sympathetic nervous system activity such as hypertension, tachycardia, and diaphoresis.

what causes sympathetic storming

Sympathetic storming is caused by disruptions in the central nervous system, often due to severe traumatic brain injury. This leads to a hyperactive sympathetic response, resulting in episodes of tachycardia, hypertension, and increased sweating.

what can cause a sympathetic storm, nursing wise?

Nursing interventions such as inappropriate stimuli or lack of adequate pain management can exacerbate sympathetic storming in patients. This may lead to heightened sympathetic responses like tachycardia and hypertension.

**also such as turning, suctioning, or bathing

what feeding tube do you place for basilar skull fractures?

an orogastric tube, NG tube is contraindicated.

whats the difference between a concussion and a contusion?

a concussion will have a normal CT scan, a contusion will have actual bruising or bleeding on the brain thats visible on neuroimaging.

what is ADEM?

Acute Disseminated Encephalomyelitis (ADEM) is a rare inflammatory condition that affects the brain and spinal cord, often following a viral infection or vaccination. It is characterized by rapid onset of neurological symptoms and can lead to significant disability.

***it is a post immunization or post infectious autoimmune response causing perivenous demyelination in the white matter.

what is the hallmark clinical presentation for ADEM?

a rapid onset of multifocal neurological deficits paired with acute encephalopathy (behavioral changes, confusion, coma), typically following a viral infection or vaccination.

what is the gold standard of diagnostic testing for ADEM?

MRI

what will an MRI show for ADEM?

shows widespread fluffy, hyperintense multifocal lesions predominantly in the cerebral white matter.

treatment for ADEM

typically includes high-dose corticosteroids (first line) and supportive care to manage symptoms.

Second line is ivIG and therapeutic plasma exchange if steroids fail.

GB syndrome

is an acute inflammatory demyelinating polyneuropathy that affects the peripheral nervous system, often leading to rapid onset muscle weakness and potential polyneuropathy.

*Guillain-Barre Syndrome

when to suspect GB syndrome

it is often triggered by a past bacterial or viral infection (like a stomach bug or the flu)

symptoms of GB syndrome

tingling of pins and needles in the hands and feet

rapidly worsening muscle weakness

trouble walking or climbing stairs

Severe cases can lead to full paralysis or respiratory arrest

treatment for GB syndrome

includes supportive care, physical therapy, and treatments like intravenous immunoglobulin (IVIG) or plasmapheresis to reduce symptoms and improve recovery.

encephalitis

an accute inflammation of the brain parenchyma

what causes encephalitis

Typically viral infections, such as herpes simplex virus, varicella-zoster virus, or enteroviruses. It can also result from autoimmune reactions or post-infection complications.

symptoms of encephalitis

include fever, headache, confusion, seizures, and altered mental status.

when encephalitis spreads from the parenchyma to the meninges what symptoms present

Symptoms may include nuchal rigidity, photophobia, and increased sensitivity to light, along with the typical symptoms of encephalitis.

diagnostics for encephalitis

include lumbar puncture, MRI, CT scans, and PCR testing to identify causative agents.

what does the lumbar puncture show for encephalitis

lymphocytic pleocytosis, normal to slightly elevated protein, and normal glucose levels.

what does the mri show for encephalitis

localized edema or inflammation, particularly in the temporal lobes, and possible brain atrophy.

treatment for encephalitis

acyclovir IV
monitor for cerebral edema and increased intracranial pressure
seizure precautions and anti-seizure meds
HOB elevated, quiet environment, manage hyperthermia aggressively

glioblastoma

a highly aggressive brain tumor that originates from glial cells, characterized by rapid growth and resistance to treatment, often leading to significant neurological deficits.

astrocytoma

a type of brain tumor that arises from astrocytes, often infiltrative, and can vary in grade from low to high malignancy, affecting brain function depending on its location and size.

oligodendroglioma

a type of brain tumor that originates from oligodendrocytes, typically slower growing than glioblastomas, and associated with better prognosis when treated effectively.

list all major glial and primary brain tumors

Major glial tumors include astrocytomas, oligodendrogliomas, and glioblastomas, while primary brain tumors also encompass meningiomas and ependymomas.

meningioma

a type of brain tumor that arises from the meninges, the protective membranes surrounding the brain and spinal cord, usually benign but can cause pressure effects on adjacent structures.

pituitary adenoma

a benign tumor that develops from the pituitary gland tissue and can affect hormone production, leading to various endocrine disorders.

schwannoma

a tumor that arises from Schwann cells, which form the myelin sheath around nerves, typically benign and can occur on peripheral nerves.

what type of tumor typically affects the CN VIII?

Schwannoma, commonly known as vestibular schwannoma or acoustic neuroma, typically affects the eighth cranial nerve (CN VIII) and can cause hearing loss and balance issues.

cranial nerve one

(olfactory nerve) responsible for the sense of smell.

cranial nerve two

(optic nerve) responsible for vision.

cranial nerve three

(oculomotor nerve) responsible for eye movement, pupil constriction, and maintaining an open eyelid.

cranial nerve four

(trochlear nerve) responsible for controlling the superior oblique muscle of the eye, enabling downward and lateral movement. c

cranial nerve five

(trigeminal nerve) responsible for sensation in the face and motor functions such as biting and chewing.

cranial nerve six

(abducens nerve) responsible for controlling lateral movement of the eye.

cranial nerve seven

(facial nerve) responsible for controlling the muscles of facial expression and providing sensation to parts of the face, as well as taste sensations from the anterior two-thirds of the tongue.

cranial nerve eight

(vestibulocochlear nerve) responsible for hearing and balance. cr

cranial nerve nine

(glossopharyngeal nerve) responsible for providing taste sensations from the posterior one-third of the tongue, as well as sensations from the throat, and helping with swallowing.

cranial nerve ten

(vagus nerve) responsible for autonomic control of the heart, lungs, and digestive tract, as well as sensation from the throat and voice box. c

cranial nerve eleven

(accessory nerve) responsible for controlling certain neck and shoulder muscles, aiding in head and shoulder movement.

cranial nerve twelve

(hypoglossal nerve) responsible for controlling tongue movements and facilitating speech and swallowing.

cranial nerve one originates in what part of the brain

the forebrain, specifically the olfactory bulb, and is responsible for the sense of smell.

cranial nerve two originates in what part of the brain

the midbrain, specifically the optic chiasm, and is responsible for vision.

cranial nerve three originates in what part of the brain

the midbrain, specifically the oculomotor nucleus, and is responsible for eye movement, pupil constriction, and maintaining an open eyelid.

cranial nerve four originates in what part of the brain

the midbrain, specifically the trochlear nucleus, and is responsible for eye movement, specifically the downward and lateral movement of the eye.

cranial nerve five originates in what part of the brain

the brainstem, specifically the pons, and is responsible for sensation in the face and motor functions such as chewing.

cranial nerve six originates in what part of the brain

the brainstem, specifically the pons, and is responsible for lateral eye movement.

cranial nerve seven originates in what part of the brain

the brainstem, specifically the pons, and is responsible for facial expressions and taste sensations from the anterior two-thirds of the tongue.

cranial nerve eight originates in what part of the brain

the brainstem, specifically the pons and medulla, and is responsible for hearing and balance.

cranial nerve nine originates in what part of the brain

the brainstem, specifically the medulla oblongata, and is responsible for taste sensations from the posterior one-third of the tongue and autonomic functions such as heart rate and digestion.

cranial nerve ten originates in what part of the brain

the brainstem, specifically the medulla oblongata, and is responsible for autonomic functions such as heart rate, gastrointestinal peristalsis, sweating, and a variety of functions involving the throat and voice.

cranial nerve eleven originates in what part of the brain

the brainstem, specifically the medulla oblongata, and is primarily responsible for the movement of the shoulder and neck muscles.

cranial nerve twelve originates in what part of the brain

the brainstem, specifically the medulla oblongata, and is responsible for the movement of the tongue.

medulloblastoma

a type of brain tumor that originates in the cerebellum and primarily affects children. It is classified as a primitive neuroectodermal tumor (PNET) and can spread to other parts of the central nervous system.

ependymoma

a type of brain tumor that arises from the ependymal cells lining the ventricles of the brain and the central canal of the spinal cord. It can occur in both children and adults.

intramedullary spinal cord tumor

a type of tumor that develops within the spinal cord itself, often arising from the nervous tissue or glial cells. These tumors can cause various neurological symptoms depending on their location and size.

extramedullary-intradural spinal cord tumor

a type of tumor located outside the spinal cord but within the protective layer covering the spinal cord. These tumors can be benign or malignant and may compress spinal structures, leading to neurological deficits.

extradural lesion spinal cord tumor

a type of tumor located outside the protective dural covering of the spinal cord. These lesions can arise from structures such as bones or soft tissues surrounding the spinal column and may lead to compression of the spinal cord.

supraentorial craniotomy

accesses cerebrum above tentorium

place HOB at 30-45 degrees and facilitate a venous trial

venous trial

a procedure to assess the venous drainage of the brain, typically involving the evaluation of venous sinus patency and function.

infratentorial/posterior fossa craniotomy

assesses cerebellum and brainstaim

maintain flat or slightly elevated HOB (0-15 degrees) avoiding neck flexion

transsphenoidal resection

assesses pituitary gland via nasal cavity

removes tumors or lesions affecting pituitary function.

monitor for CSF leaks, avoid straining/coughing/blowing nose

how long after cranial surgery does intracranial pressure or cerebral edema peak?

Intracranial pressure and cerebral edema typically peak between 48 to 72 hours after cranial surgery.

normal ICP

Refers to the intracranial pressure range typically considered to be between 7 and 15 mmHg in adults. Normal ICP is essential for proper brain function and blood flow.

diabetes inspidus

A condition characterized by excessive thirst and urination due to insufficient production of antidiuretic hormone (ADH) or response to it, often following pituitary surgery.

complications to monitor for post-op aside from cerebral edema, ICP changes, and CSF leaks

diabetes insipidus (high urine output and hypernatremia)

SIADH (excess ADH causing fluid retention; results in low urine output and dilutional hyponatremia)

cerebral salt wasting (renal sodium wasting causing severe volume depletion; leads to true hyponatremia and dehydration).

Frontal Lobe

Brain region responsible for executive function, judgment, personality, motor planning, and contains Broca speech area in the dominant hemisphere.

Parietal Lobe

Brain region responsible for somatosensory processing, spatial awareness, and integration of sensory input.

Temporal Lobe

Brain region responsible for memory, auditory processing, Wernicke speech area, and frequently serves as a seizure focus.

Occipital Lobe

Brain region responsible for vision and visual interpretation.

Cerebellum

Brain structure responsible for coordination, balance, motor learning, and smooth movement.

Brainstem

Brain region containing cranial nerves, the reticular activating system, and respiratory/cardiovascular centers.

Basal Ganglia

Deep brain structures involved in movement regulation and muscle tone.

Thalamus

Brain structure serving as a sensory relay network and facilitating consciousness.

Cerebral Perfusion Pressure (CPP)

Neurologic measurement defined by $CPP = MAP - ICP$; cerebral perfusion falls when $ICP$ rises or $MAP$ drops.

Mean Arterial Pressure (MAP)

Estimate of average driving pressure for organ perfusion, calculated as $MAP \approx \frac{SBP + 2 \times DBP}{3}$.

Monro-Kellie Doctrine

Physiological principle stating that skull volume equals brain plus blood plus CSF ($\text{Skull Volume} = \text{Brain} + \text{Blood} + \text{CSF}$), meaning an increase in one component must be offset or $ICP$ rises.

Cushing Response

Late sign of increased $ICP$ and impending brain herniation characterized by hypertension with a widened pulse pressure, bradycardia, and irregular respirations.