Mod IX: Neuro Pathophysiololgy

Question 1

_{Neuro Pathophysiololgy - Ischemia}

The brain is the most sensitive organ to ischemia - What could happen when blood supply to the brain is limited?

Answer 1

Ischemic damage to neurons can occur

Most likely due to decrease energy production (blockage of oxidative phosphorylation)

Leading to decreased activity of ion pumps and accumulation of Na+ and Ca++

Question 2

_{Neuro Pathophysiololgy - Ischemia}

Which two form of ischemia are possible?

Answer 2

Global (cardiac arrest) or

Focal (localized stroke)

Question 3

_{Neuro Pathophysiololgy - Ischemia}

What are the three regions of Focal ischemia?

Answer 3

1st region receives no blood & responds the same as globally ischemic tissue

2nd region is called the penumbra, it receives collateral flow & is partially ischemic

3rd region is normally perfused

Question 4

_{Neuro Pathophysiololgy - Ischemia}

What happens to the cells in the penumbra if the insult lasts?

Answer 4

If the insult lasts, cells in the penumbra will die

More cells will survive if collateral blood flow is increased

The penumbra is considered salvageable if treated fast enough

Question 5

_{Neuro Pathophysiololgy - Brain Edema}

What are the two types of Brain Edema?

Answer 5

Cytotoxic edema

^{Due to neuronal damage which leads to ↑sodium & H2O in brain cells}

^{Frequently due to ischemia or trauma}

Vasogenic edema

^{Due to breakdown of BBB}

^{Movement of protein to the brain’s extracellular space = ↑ osmotic pressure = ↑ interstitial water}

Question 6

_{Neuro Pathophysiololgy - Brain Trauma}

Brain Trauma can produce irreversible neuronal damage Primary damage due to:

Answer 6

Herniation or

Severing of blood vessels

=> Resulting in direct ischemia.

=> Is permanent

Question 7

_{Neuro Pathophysiololgy - Brain Trauma}

Secondary brain injury in trauma patients account for most of the damage and may be due to:

Answer 7

Ca++ influx

Release of vasoconstrictive substances during reperfusion

Hemorrhage

Question 8

_{Neuro Pathophysiololgy}

Sudden, excessive, and synchronous discharge of large numbers of neurons is known as:

Answer 8

Epileptic or seizure activity

CMRO₂ and blood flow are increased greatly

In conditions where blood flow is compromised, must suppress activity to avoid ischemia

Question 9

_{Neuro Pathophysiololgy}

Why must ventilation, oxygenation, and BP be maintained during -epileptic or seizure activity?

Answer 9

Can be accompanied by systemic lactic acidosis, ↓ PaO₂, and ↑ PaCO₂

Lactic acidosis due to local muscle hypoxia during the seizures

Prolonged or recurring activity can lead to profound brain damage

Question 10

_{Neuro Pathophysiololgy}

What’s a cause of the Lactic acidosis noted during epileptic or seizure activity

Answer 10

Local muscle hypoxia

Question 11

_{Neuro Pathophysiololgy}

Expanding, space occupying lesions in the brain are known as:

Answer 11

Brain Tumors

Question 12

_{Neuro Pathophysiololgy}

How do Brain Tumors affect ICP?

Answer 12

↑↑ ICP and leads to↓ CPP or herniation

Question 13

_{Neuro Pathophysiololgy}

Why are Brain Tumors often associated with vasogenic brain edema?

Answer 13

Blood vessels supplying the tumor frequently have a leaky BBB

which contributes to vasogenic brain edema

Question 14

_{Neuro Pathophysiololgy}

What other Processes can trigger neuronal damage?

Answer 14

ATP depletion

Ion imbalance (mainly intracellular Ca++)

Free radical formation

Kinase, protease, and phospholipase activation

Question 15

_{Neuro Pathophysiololgy}

What other Processes can lead to neuronal death?

Answer 15

Necrosis

^{Disintegration of the cell}

Immune response

^{Activates neutrophils & macrophages}

Apoptosis

^{Genetically determined process of cell self-destruction}