chp 22 nervous system diseases

Question 1

natural defenses of nervous system ?

Answer 1

• Physical barriers : bone meninges BBB
• Microglial cells ( resident macrophages of CNS)
• Immunologically privileged area
○ Full immune response would be to damaging
○ Fewer MHC less complement
• No normal biota - no indigitous microbes
• Gut-brain axis? Refering a role in our development . A change in microbiom = change in person ..

Question 2

meningitis

Answer 2

• Inflammation of the meninges
• Caused by many dif. Microbes
○ Bacteria : neisseria meningitidis , strptococcus pneumoniae , haemophilus influenzae
○ Fungi: coccidioides immitis (valley fevor)
○ Many virus’ such as HPV
• Signs and symptoms
○ The worst headache I ever had
○ Light sensitivity stiff neck high fever leukocytes
• If suspected perform lumbar tap, gram stain and begin broad spectrum antibotics
• 1st thing broad spectrum antibiotics deliverd thru IV then lumbar tap
○ Lumbar tap lumbar region it should hav 0 bacteria .

Question 3

encephalitis

Answer 3

• Brain inflammation
• Always serious ; brain tissue vulnerable to inflammatory processes
• Can b cause by virus (including rabies and west nile viruses) bacteria . Protozoa and even prions
• Signs and symptoms
○ Symptoms of meningitis
○ Confusion , behavior changes, seizures
• Treatment : depends on causative agent

Refers to the brain… inflammation of brain . Focus on rabies but west nile virus as well  neuro invasive version of westnile sefalitis and meningitis 

R-bo virus transmitted thru tick / mesquito

Question 4

rabies

Answer 4

• Slow, progressive disease characterized by fatal encephalitis
• Zoonotic (transmitted by animals)(usually wild animals)
○ Mammals such as canines, skunk, raccoons, badgers, cats, bats
• Sign and symptoms :
○ 1-2 month incubation: depends on the attack point and also the dosage of rabies
○ “furious” form: disorientation, seizures, twitching ; spasms of neck = painful swallowing and hydrophobia
○ “dumb” form: paralyzed, disoriented , stuporous
○ Both forms progress to coma and death by cardia or respiratory arrest
§ Early symptoms cold or flu symptoms hard to diagnose this
• Dominant host WILD animals
• Causative agent Rabies virus

• Pathogenesis and virulence factors 
	○ Infected animals saliva enters a puncture site 
	○ Enters nerve endings , travel to ganglia -> spinal cord -> brain 
	○ Virus multiplies and spreads , eventually to salivary glands and saliva (because of virulence factors) 
	○ Envelope glycoprotein used to invade spread in cns 
• Diagnosis by PCR(looking for specific genes), detection of Abs in serum / CSF 
• Treatment : antibody injection, infuse wound with antibodies, full course of vaccination started as well

Question 5

tetanus

Answer 5

• Neuromuscular disease resulting in sever muscle spams
• Causative agent : clostridium tetani
○ Anaerobic , gram positive , endospore-forming rod
• Signs and symptoms
○ Inhibition of muscle contraction is blocked , so muscles contract uncontrollably
○ Lockjaw, arching back, flexion of arms, extension of legs
○ Death by spastic paralysis of respiratory muscles

• Pathogenesis and virulence factors 
	○ After infection(parenteral) , bacteria secrete the exotoxin tetanospasmin, a potent neurotoxin 
	○ Tetanospasmin absorbed by neurons and carried to spinal cord, where it attaches to regulatory neurons tht inhibit inappropriate contraction
	○ Muscles contract uncomfortably , strong enuf to break bones 
• Treatment : antitoxins(antibodies for toxins) ; prevention by vaccination(DTaP) 
• Up to 70% mortality rate and as low as 10% 
• Risus sardonicus (sardonicus grin) 
Spores are everywhere but hav to enter a wound almost always parenteral route . Has nothing to do with rust . Usually on sharp object right conditions

Question 6

botulism

Answer 6

• Intoxication associated with eating poorly preserved foods (just by eating this toxin or infection)
• Causative agent : clostridium botulinum
○ Anaerobic , gram positive , endospore-forming rod
• Signs and symptoms :
○ Early symptoms: double vision, difficulty swallowing dizziness
○ Late symptoms include muscular paralysis and respiratory arrest

• Pathogenesis and virulence factors :
	○ Contaminated food contatining endospores , improperly heated under pressure , some spores survive 
	○ Spores germinate in anaerobic consitions 
	○ Botulinum exotoxin is produced , the most potent microbial toxin known(toxic dose = .03 ug/kg body weight)
	○ Prevents exocytosis of Ach at neuomuscular juntion, causing flaccid paralysis of skeletal muscle 
• Treatment antitoxin . Respirators 

Similar to tetanus but vise versa muscle cant contract .

Question 7

describe basic anatomy of N.S.

Answer 7

• Divided into CNS and PNS
○ CNS : brain spinal cord
○ PNS : nerves and ganglia
• What r the major cells of nervous system ?
○ Neurons , send and receive messages
• What are the helper cells called ?
○ Glial cells exchange nutrients and waste
• What is a nerve?
○ One cell axon is not nerve.
○ Thousands of axons from thousands of cells is a nerve
• The brain and spinal cord are protected by bone meninges and CSF
○ Meninges 3 parts of CT
○ In-between deepest 2 layers some fluid CSF and surrounds the brain and creates a cushion and bathing the neurons . Cntrol chm env.

Question 8

neisseria meningitis

Answer 8

• Gram neg. diplococcus
• Cause the acute form of meningitis can be rapidly fatal
○ DIC, cardiac failure coma death shock
• Pathogenesis
○ Portal of entry = URT via respiratoyry dropletes, enters blood stream and penetrates meninges
○ Endotoxin released into blood stimulates inflammation and damages BV . Leading to petechiae
○ IgA proteases and capsule aid in it survival

Question 9

Meningitis : streptococcus pneumoniae

Answer 9

• Part of normal biota in many ppl
• Causes majority of bacterial pneumonias can also cause pneumococcal menigitis
• Similar signs and symptoms as N. meningitis but distinguished by
○ No petechiae
○ Likely presence of pneumococcal pneumonia
○ Gram stain of CSF