Chapter 15: Neurological Disorders

Question 1

Neurological Disorders

Answer 1

Brain damage or dysfunction that interrupts normal brain function.

–Migraines
–Strokes
–Head Injuries
–Brain Tumors
–Multiple Sclerosis
–Seizures
–Brain Infections

Question 2

Migraines

Answer 2

Migraines (28% of population) is a neurovascular disorder
Characterized by recurrent headaches, usually accompanied by nausea, vomiting, photophobia and/or phonophobia.

Vascular theory of headache: increased blood flow in brain distends blood vessels, which exert pressure on surrounding tissue.

Migraine Generator: hypothetical structure that when activated leads to migraines—one possibility is the Raphe Nucleus.

Serotonin acts to constrict blood vessels—reduced levels would lead to increased blood flow.
Reduced serotonin levels also activate the trigeminal (V) nerve which releases glutamate and calcitonin gene-related peptide (CGRP), which further dilates CNS blood vessels.

More women experience migraines and depression, both of which might result from reduced serotonin levels.

Question 3

photophobia

Answer 3

extreme sensitivity to light.

Question 4

phonophobia

Answer 4

Phonophobia (from Greek φωνή - phōnē, “sound” and φόβος - phobos, “fear”, also called ligyrophobia or sonophobia) is a fear of loud sounds. It can also mean a fear of voices, or a fear of one’s own voice. It is a very rare phobia.

Question 5

Vascular theory of headache

Answer 5

increased blood flow in brain distends blood vessels, which exert pressure on surrounding tissue.

Question 6

Migraine Generator

Answer 6

hypothetical structure that when activated leads to migraines—one possibility is the Raphe Nucleus

Question 7

Migraines and Serotonin

Answer 7

Serotonin acts to constrict blood vessels—reduced levels would lead to increased blood flow.

Reduced serotonin levels also activate the trigeminal (V) nerve which releases glutamate and calcitonin gene-related peptide (CGRP), which further dilates CNS blood vessels.

More women experience migraines and depression, both of which might result from reduced serotonin levels

Question 8

Migraine Treatment

Answer 8

SSRIs and Triptans, serotonin agonists, reduce migraine severity.
Behavioral changes (better sleep, less anxiety) can decrease frequency and severity of migraines.

Question 9

Strokes

Answer 9

Occurs when the brain’s blood supply is interrupted by bleeding or blockage of blood vessels.

Risk factors:
Hypertension
Diabetes
High cholesterol
Obesity
Smoking
Arteriosclerosis

Question 10

Cerebral Hemorrhage

Answer 10

Bleeding in the brain: results from high blood pressure (hypertension) or structural defects.

Salty blood dehydrates and kills neurons.

Possible culprits:
Aneurysms may rupture.
Blood diseases like leukemia.
Exposure to toxic chemical.

Question 11

Ischemia

Answer 11

an inadequate blood supply to an organ or part of the body.
Blockage of CNS vasculature leads to ischemia, or low oxygen levels (80% of all strokes).
May lead to death of neural tissue, or infarct.

Thrombosis: material that blocks blood vessel without moving from its point of origin

Embolism: material that passes into smaller and smaller vessels until it forms a blockage

Cell death due to ischemia does not occur everywhere in brain— the cortex and hippocampus are particularly susceptible.
Low oxygen levels lead to excess glutamate release, resulting in NMDA receptor excitotoxicity.
Administration of magnesium prevents cell death in the rat hippocampal cells.

Question 12

infarct

Answer 12

a small localized area of dead tissue resulting from failure of blood supply.

Question 13

Traumatic Brain Injury (TBI)

Answer 13

physical damage to the brain; causes include traffic accidents, gunshot wounds, falls, etc.

Open head injuries
Concussions

Question 14

Concussion

Answer 14

Occur in response to blow to the head resulting in “impulsive” force transmitted to the brain.

May result in hematoma and white matter damage.

Chronic traumatic brain injury (CTBI) =
Permanent damage from repeated mild head injuries, resulting in slurred speech, memory impairment, personality changes, lack of coordination, and Parkinson-like syndromes.

Question 15

hematoma

Answer 15

a solid swelling of clotted blood within the tissues.

Question 16

Post-concussion Syndrome (PCS)

Answer 16

Cognitive symptoms: lack of concentration, reduction in processing speed, attention, and memory.
Physical symptoms: headache, depression, irritability.

Question 17

Tumor

Answer 17

independent growth of new tissue that lacks purpose

Question 18

Malignant tumor

Answer 18

lacks distinct boundaries. Cancerous.

Question 19

Metastasis

Answer 19

shed cells can travel and grow, though very rare with brain tumors

Question 20

Gliomas

Answer 20

tumors that develop in glial cells

Question 21

Meningiomas

Answer 21

tumors that develop in meninges cells (usually benign)

Question 22

coup & countercoup

Answer 22

When the head strikes a fixed object, the coup injury occurs at the site of impact and the contrecoup injury occurs at the opposite side. In head injury, a coup injury occurs under the site of impact with an object, and a contrecoup injury occurs on the side opposite the area that was impacted.

Question 23

Grading of the tumors of the central nervous system

Answer 23

Grade I tumors are slow-growing, nonmalignant, and associated with long-term survival.
Grade II tumors are relatively slow-growing but sometimes recur as higher grade tumors. They can be nonmalignant or malignant.
Grade III tumors are malignant and often recur as higher grade tumors.
Grade IV tumors reproduce rapidly and are very aggressive malignant tumors.

Question 24

Angiogenesis

Answer 24

Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels.

Question 25

Multiple Sclerosis

Answer 25

Autoimmune condition disorder.
The body’s own immune system attacks the CNS.

–Demyelination of axons
–Exact cause unknown. A virus or gene defect, or both, are to blame. Environmental factors may play a role.
–You are slightly more likely to get this condition if you have a family history of MS or live in an part of the world (higher latitudes) where MS is more common.

Affects white matter in different locations
Progressive MS
Relapsing-remitting MS

Question 26

Seizures & Epilepsy

Answer 26

Uncontrolled electrical disturbances in the brain correlated with changes in consciousness.
May occur in response to brain injury, infection, drug withdrawal, etc.
Repetitive unprovoked seizures are labeled as Epilepsy.

Photosensitive Epilepsy:
Flashing lights of specific intensity and frequency (3-30 Hz) often found on TV or in videogames

Question 27

Types of Seizures vary widely in causes, durations, and symptoms

Answer 27

• Partial seizures: Originate in identifiable part of brain.
• Simple Partial: movement or sensations experienced are appropriate to the location of seizure.
• Complex Partial: begins in temporal lobes and associated with alterations of consciousness.
• Generalized seizures: No clear point of origin

Question 28

paroxysmal depolarizing shift (PDS).

Answer 28

At the level of single neurons, epileptiform activity consists of sustained neuronal depolarization resulting in a burst of action potentials, a plateau-like depolarization associated with completion of the action potential burst, and then a rapid repolarization followed by hyperpolarization. This sequence can be observed in the EEG.

Question 29

Generalized seizures

Answer 29

No clear point of origin.
Activation of circuits between thalamus and cortex, affects both sides of brain.

• Petit mal seizure: person looses consciousness and movements limited to blinking, head turns, and eye movement; last ~10 sec.
• AKA: absence seizures
• Characteristic EEG pattern
• Grand mal or tonic-clonic seizure.
• 10 sec tonic phase: loss of consciousness, cessation of breathing, muscular contractions.
• 1 min clonic phase: violent rhythmic convulsions, sweat and salivation.
• 5 min of coma: transition out of seizure, patient remains unconscious.

Question 30

Petit mal seizure

Answer 30

person looses consciousness and movements limited to blinking, head turns, and eye movement; last ~10 sec

• AKA: “absence seizures”
• Characteristic EEG pattern

Question 31

Grand mal or tonic-clonic seizure

Answer 31

• 10 sec tonic phase: loss of consciousness, cessation of breathing, muscular contractions
• 1 min clonic phase: violent rhythmic convulsions, sweat and salivation
• 5 min of coma: transition out of seizure, patient remains unconscious

Question 32

tonic phase

Answer 32

10 sec loss of consciousness, cessation of breathing, muscular contractions

Question 33

clonic phase

Answer 33

1 min of violent rhythmic convulsions, sweat. and salivation

Question 34

Brain Infections

Answer 34

Parasites
–Neurocysticercosis – pork tape worm

Bacterial, Viral, and Fungal Infections
–Encephalitis – inflammation of brain after viral infection
–Meningitis – inflammation of membranes that cover and protect the brain and nervous system caused by bacteria, viruses, or fungi.

Transmissible Spongiform Encephalopathies

Question 35

Encephalitis:

Answer 35

inflammation of the brain caused by viral infection

Primary encephalitis occurs when virus directly invades the CNS.

Secondary encephalitis occurs following viral infection of other parts of body—e.g., herpes simplex virus.

As of November 14, 2012, 48 states have reported West Nile virus infections in people, birds, or mosquitoes. A total of 5,128 cases of West Nile virus disease in people, including 229 deaths, have been reported to CDC.

Question 36

Meningitis

Answer 36

inflammation of the meninges caused by bacteria, viruses, or fungi.

Bacterial, viral, or fungal infection of CNS.
Produces flu-like symptoms, defined by neck stiffness, aversion to bright lights, and drowsiness.
The CDCs most recent updates reveal that the fungal meningitis case count is now 461 with 32 resultant deaths due to tainted steroid medications.

Question 37

West Nile Virus Transmission

Answer 37

WNV is most often spread by the bite of an infected mosquito. Mosquitoes become infected when they feed on infected birds.

About one in 150 people infected with WNV will develop severe illness.
Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, or vomiting.
Approximately 80 percent of people who are infected with WNV will not show any symptoms at all.

Question 38

The TSE Mystery

Answer 38

• Scrappie in sheep and goats
• Creutzfeldt-Jakob disease (CJD) human form of TSE
• Kuru in New Guinea provided evidence of transmission
Prions and TSEs

• Abnormal form of prion protein.

Question 39

BSE and Creutzfeldt-Jakob Disease

Answer 39

New TSE variant emerged in humans .

Question 40

BSE and Creutzfeldt-Jakob Disease

Answer 40

New TSE variant emerged in humans.

A human version of mad cow disease called variant Creutzfeldt-Jakob disease (vCJD) is caused by eating beef products contaminated with central nervous system tissue, such as brain and spinal cord, from cattle infected with mad cow disease.