Patho 2 Exam 3 up to Alzheimers

Acetylcholinesterase inhibitors are used for patients with?

Mild to moderate Alzheimer disease

An increased amount of CSF & an increased sized of ventricles leads to what?

Hydrocephalus

Aura/prodrome:

• Subjective sense of impending seizure

• Clue to the location of epileptogenic focus

Bacteria invade leptomeninges causing the accumulation of inflammatory exudate which leads to?

Obstructive hydrocephalus

Bipolar neurons are commonly found in?

Retina, cochlea, olfactory

Broca aphasia

(verbal motor/expressive) consists of poor articulation & sparse vocab

Cerebral aneurysm

Lesion of an artery that results in dilation & ballooning of a segment of the vessel

Classic manifestation of meningitis?

• Headache

• Fever

• Stiff neck (meningismus)

• Signs of cerebral dysfunction (confusion, delirium)

Clinical manifestation of ischemic stroke?

• Contralateral hemiplegia (paralysis of one body side)

• Contralateral visual field blindness- Hemisensory loss (alter sensation down one side of the body)

Clinical manifestations of cerebral aneurysm?

• Very severe headache w/ meningismus (meningeal irritation)

• Photophobia (visual sensitivity to light)

• Nausea/ vomiting

• Stiff neck

Clinical manifestations of concussion?

Headache, nausea, vomiting dizziness, blurred vision, cognitive & emotional disturbances

Common clinical manifestation of increased Intracranial Pressure?

• Headache

• Vomiting

• Altered level of consciousness (drowsiness)

• Blurry vision

• Edema of the optic disk (Papilledema)

Conduction of action potential is faster in what type of axons?

Large & myelinated

Diffuse injury

Due to movement of the brain w/in the skull causing widespread axonal injury
- Ex. Shaken baby syndrome

Early clinical manifestation of Alzheimer:

• Memory loss, especially short-term memory, long term memory may be preserved

• Thinking ability declines

• Decrease ability to fxn at work & in social settings

• Anxiety, agitation

Encephalitis

Inflammation of the brain

Excitatory interneurons helps to maintain what?

Balance

Excitatory neurotransmitters creates?

EPSPs, caused by opening of channels that allows Na+ influx

Focal (coup) injury

Localized to site of impact

Frontal lobe function:

Motor cortex, prefrontal involved in complex thought, ethical behavior, & morality

General seizure: Absence (petit mal)

• Occurs in children (not < 4 y/o & after puberty)

• Staring spells that lasts only seconds

Homunculus Map:

A somatotopic representation of the body along a strip of the cortex created a distorted human body

How are action potentials initiated?

In axon hillock, by binding neurotransmitters to receptors on dendrite & cell body allowing cations (mainly Na+) to leak in ligand gated ion channels:
- High density of fast Na+ channels, lower threshold

How are the 3 nervous systems interrelated?

They are not anatomically or functionally distinct, & they work together as an integrated whole

How do organisms gain access to the CNS?

• Bloodstream

• Direct extension from primary site or along peripheral & cranial nerves

• Through maternal fetal exchange

How do primary & secondary brain injury differ?

• Primary: Happens rapidly which limits prevention, occurs as a direct result of initial insult

• Secondary: Occurs over time & can be prevented (high mortality & morbidity), progressive damage from physiologic response to initial insult

How do you treat a patient that has traumatic brain injury who is showing an acutely elevated ICP?

• Administer mannitol (osmotic diuretic)

• Sedation, hypothermia, & mild hyperventilation

How does calcium overload happen?

Excess glutamate stimulates nearby neurons that takes up large amounts of injurious calcium ions causing calcium overload injury which will lead to mitochondrial dysfunction

How does increased Intracranial Pressure manifest as the ICP rises to higher levels?

• Level of consciousness decreases

• Pupil responsiveness to light becomes impaired

• Altered respiratory patterns & unresponsive to stimulation

• Unable to move, verbalize, or open eyes

How does Ischemia sets the stage for secondary injury?

By oxygen free radicals, excitatory amino acids, & inflammatory cells causing abnormal autoregulation, vasospasm, & vascular compression

How is a cerebral aneurysm diagnosed?

• CT/ MRI

• Lumbar puncture

How is Alzheimer characterized?

• Degeneration of neurons in temporal & frontal lobes

• Brain atrophy (wt. <20% NI)

• Amyloid plaques (Specific/ unique to Alzheimer)

• Neurofibrillary tangles

How is meningitis prevented?

Vaccination for Hib & N. meningitidis

How is the CNS protected?

• CSF

• BBB

• Meninges

• Bony structures of the skull & vertebral column

How many minutes w/out oxygen can cause irreversible damage?

5-10 mins

Hypothalamus functions:

• Regulator center for ANS

• Along w/ pituitary, produces & secrete hormones

• Sleep

• Body temp

• Appetite

• Sex drive

Hypoxia vs. Hypoxemia

• Hypoxia is the lack of oxygen released to tissues from blood

• Hypoxemia is insufficient oxygen in the blood, therefore lack of oxygen reaching tissues

Inhibitory neurotransmitter creates?

IPSPs, caused by opening of channels that allows Cl- influx or K+ efflux

Ischemia: Primary Insult causes?

Inability of neurons to generate ATP (Kreb cycle cannot happen)

Ischemic stroke

Sudden occlusion of cerebral artery secondary to thrombus or emboli

Later clinical manifestation of Alzheimer

• Increasing difficulty w/ judgement, abstract thinking, problem solving, & communication

• Assistance for completing activities of daily living (personal hygiene, bathing, grooming, oral, hair)

• Difficulty w/ eating & swallowing

• Weight loss

• Loss of bladder & bowel control

• Complete loss of the ability to ambulate

• Personality & behavior changes

Lateral hemisphere functions:

Involved in planning & programming voluntary movements, especially learned, skilled movements

M-methyl-aspartate (NMDA) receptor antagonist is used for patients with?

Moderate to severe Alzheimer disease

Management of ICP:

• Based on diagnostic brain imaging (CT or MRI) to determine treatment surgically or medically

• ICP & cerebral perfusion pressure (CPP) measured

• Removal of lesion or CSF

• Treatment focuses on managing cerebral oxygenation

Meningitis & cerebral abscess are commonly associated w/ what?

- Bacterial infections, most commonly streptococcus Pneumoniae

Name the 3 layers of meninges (outer to inner):

Dura mater, Arachnoid mater, and Pia mater

Neural plasticity/ Brain plasticity

Ability & adaptability to change structure function

Occipital lobe function:

Visual cortex

Parietal lobe function:

Somatosensory cortex

Polar (coup contrecoup) injury

Due to acceleration-deceleration movement of the brain w/in the skull causing double injury

Receptors send action potentials to the spinal cord through the dorsal root and travel up to the brain via which tracts?

• Dorsal column (medial lemniscal) tract, the ipsilateral side of the cord: touch, pressure, vibration, & proprioception

• Anterolateral tract, contralateral side: pain, itch, & temperature

Seizure:

Transient neurologic event of paroxysmal abnormal or excessive cortical electrical discharges

Synaptic transmission Steps:

• Depolarization

• Opens voltage-gate Ca2+ channels

• Calcium influx mediates

• Exocytosis of neurotransmitter into synaptic cleft

T or F: Body's response to initial injury may cause more harm than the initial injury

True

T or F: The rate of CSF is independent of the blood pressure or intraventricular pressure

True, therefore CSF will continue to be produced even when its path of circulation or absorption is blocked leading to increased ventricle size & increased CSF which results in hydrocephalus

Temporal lobe functions:

• Hearing

• Equilibrium

• Emotion

• Memory

Thalamus Functions:

• Processes & relay most signals (relay center)

• Motor functions

• Emotion

• Language

• Creativity

• Complex thought

Thrombus vs Emboli

• Thrombus is a clot that stays in place

• Emboli is a clot that moves to another place

Tracts of the spinal cord are organized in what manner?

Somatotopically, innervation of a particular body region is connected to a specific region in the cerebral cortex (homunculus map)

Treatment for traumatic brain injury:

• Cardiopulmonary stabilization

• Radiologic screening to evaluate need for emergent surgical management

• Maintenance of normal body temp or mild hypothermia

• Normal PaCO2, normal serum glucose level, and normal intravascular volume

Typical manifestation of Herpes Simplex that causes encephalitis are?

• Fever

• Headache

• Seizure

• Stupor

• Coma

• Confusion

Typical manifestations of West Nile virus that causes encephalitis are?

• Muscle pain

• Rash

• Malaise

• Fever

• Headache

Wernicke aphasia

(sensory, acoustic, receptive) characterized by impaired auditory comprehension & speech that is fluent but does not make sense

What 2 mechanism can cause brain cell death?

• Anaerobic metabolism

• deterioration of ion gradients

What 3 elements compose the volume of the cranium?

• Brain tissue

• CSF

• Blood

What are the 2 cell types of the nervous system? What do they do?

• Neurons: Generate & transmit nerve impulses

• Glial cells: provide supportive functions to neurons, they do not transmit action potential

What are the 2 main classification of seizure disorder?

• Partial (focal): Only part of the brain surface is affected during the seizure

• Generalized: Whole brain surface is affect during the seizure

What are the 3 type of neurons?

• Multipolar

• Bipolar

• Unipolar

What are the 6 major classes of neurotransmitters?

• Amines

• Amino acid: Inhibitory- Acetylcholine

• Polypeptide

• Purines

• Gases

What are the factors that affect the permeability of BBB?

• Inflammation (Infection)

• Neovascularity (tumors have neo-vessels)

• Toxins

• Infants < 6 months, the BBB of their immature nervous system in more permeable to substances

What are the functions of the CNS?

• Receives/ process sensory info

• Create responses that are relayed to muscles & glands

• Coordinates emotion, cognition, memory, and learning

What are the functions of the spinal cord?

• Conveys nervous impulses b/t the brain & 31 pairs of spinal nerves

• Mediates spinal reflexes involved in maintenance of posture

• Protective responses to pain, urination, & muscle tone

What are the stimulants for the sensory receptors?

• Mechanical stretch

• Temperature

• Chemicals

What assists w/ repolarization?

Voltage-gated K+ channels, when K+ flows out of cell

What cells make the myelin sheath in PNS?

Schwann cells

What connection is needed in order to maintain consciousness & allow higher brain functions?

Connection b/t the thalamus, brainstem, & cortex

What determines whether an action potential will be initiated?

The summation of IPSPs & EPSPs at the axon hillock

What does gamma neurons do?

• Contract muscle fibers w/in the muscle spindle

• Regulate spindle sensitivity

What global brain injury causes impairment of autoregulation?

Generalized Cerebral Edema

What happens after a neurotransmitter crosses the synaptic cleft?

It acts on receptor of second neuron to:

• Excite

• Inhibit

• Modify

What happens to neurotransmitter after they are released?

They are either transported:

• Back into axon terminal for reuse OR

• Destroyed by enzyme activity

What is a Concussion?

Mild traumatic brain injury

What is autoregulation normally influenced by?

PaCO2 & PaO2

What is critical for transmission of impulses b/t the brain & spinal cord?

Brainstem

What is CSF produced by?

Choroid plexus

What is dependent on activity in the RAS neurons?

State of alertness & attentiveness to one's environment & situation

What is encephalitis commonly caused by?

• West Nile virus

• Western equine encephalitis

• Herpes simplex

What is the blood supply to the brain?

• Anterior circulation: Internal carotid arteries

• Posterior circulation: Vertebral arteries

What is the critical factor in determining the neuronal cell fate after injury?

Degree of ATP depletion

What is the last ditch to survival after a brain injury?

Cushing reflex (ischemic response)

What is the Monro-Kellie hypothesis?

Describes compensatory responses to changes in volume in any of the 3 components that make up the volume of the cranium:
- A slight increase in one component can be offset by a reduction in the volume of the other two

What is the most common form of stroke?

Ischemic stroke

What is the rate that CSF is produced/ reabsorbed?

500ml/day

What is the ring of vessels that united the anterior & posterior circulation at the base of the brain?

Circle of Willis

What local brain injury causes impairment of autoregulation?

Thrombosis

What maintains the Blood Brain Barrier (BBB)?

Astrocytes

What protects & supports the PNS?

A sheath of connective tissue covering the nerves (myelin sheath)

What type of motor neurons release acetylcholine to contract all fibers in the muscle unit?

Alpha motor neurons

Where are the potential spaces that only become evident in the presence of pathologic processes (epidural, subdural)?

The spaces b/t:

• The dura mater & skull

• The dura mater & arachnoid space

Where is the safest place to do a lumbar puncture?

L4-L5