Chapter 26

Question 1

What is the central nervous system?

Answer 1

Brain and Spinal cord

Question 2

What is the peripheral nervous system?

Answer 2

Nerves

Question 3

What protects the brain?

Answer 3

The skull and three meninges (the dura mater, arachnoid mater, and pia mater).

Question 4

What are tissues of the PNS and CNS formed out of?

Answer 4

Glial cells and neurons.

Question 5

Does the CNS have a normal microbiota?

Answer 5

No, bc of blood-brain barrier.

Question 6

What is encephalitis or meningitis?

Answer 6

Inflammation of the brain or meninges caused by infection (breach blood-brain barrier). Can lead to blindness, deafness, coma, and death.

Question 7

What types of bacteria can cause bacterial meningitis?

Answer 7

Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae, and Streptococcus agalactiae (group B streptococci) (vaginal microbiota)

Question 8

How are Haemophilus influenzae, Neisseria meningitidis, Streptococcus pneumoniae spread?

Answer 8

Person to person by respiratory secretions.

Question 9

Who does H. influenzae primarily affect?

Answer 9

Young children and neonates

Question 10

What are the effects of and who does N. Meningitidis or Meningococcal Meningitis infect?

Answer 10

Nonfatal cases can result in irreversible nerve damage (hearing loss and brain damage, or amputation of extremities because of tissue necrosis).
Its prevalence is highest among infants, adolescents, and young adults.
N. meningitidis has a high affinity for mucosal membranes (IgA protease) in the oropharynx and nasopharynx.

Question 11

What is a unique sign of meningococcal meningitis?

Answer 11

The formation of petechial rash on the skin or mucous membranes, characterized by tiny, red, flat, hemorrhagic lesions.

Question 12

Why does the rash caused by M. meningitis occur?

Answer 12

This rash is a response to LOS endotoxin and adherence virulence factors that disrupt the endothelial cells of capillaries and small veins in the skin → triggers the formation of tiny blood clots, causing blood to leak into the surrounding tissue → infection progresses (the levels of virulence factors increase) → the hemorrhagic lesions can increase in size as blood continues to leak into tissues. Lesions larger than 1.0 cm usually occur in patients developing shock.

Question 13

Who does S. pneumoniae or Pneumococcal meningitis mostly affect?

Answer 13

Young children

Question 14

What are the major virulence factors produced by S. pneumoniae?

Answer 14

PI-1 pilin for adherence to host cells (pneumococcal adherence) and virulence factor B (PavB) for attachment to cells of the respiratory tract; choline-binding proteins (cbpA) that bind to epithelial cells and interfere with immune factors IgA and C3; and the cytoplasmic bacterial toxin pneumolysin that triggers an inflammatory response.

Question 15

Who does S. agalactiae affect?

Answer 15

Newborns during or shortly after birth,

Question 16

What is S. agalactiae?

Answer 16

The infant initially becomes infected by S. agalactiae during childbirth, when the bacteria may be transferred from the mother’s vagina. Signs and symptoms of early onset disease include temperature instability, apnea (cessation of breathing), bradycardia (slow heart rate), hypotension, difficulty feeding, irritability, and limpness.

Question 17

What are the symptoms of bacterial meningitis?

Answer 17

Symptoms of bacterial meningitis include fever, neck stiffness, photophobia, headache, confusion, convulsions, coma, and death → shock, convulsions, coma, and death.

Question 18

How is bacterial meningitis diagnosed?

Answer 18

Through observations and culture of organisms in CSF. Bacterial meningitis is treated with antibiotics. H. influenzae and N. Meningitidis have vaccines available.
- CSF is obtained by a lumbar puncture. Abnormal levels of polymorphonuclear neutrophils (PMNs) (> 10 PMNs/mm3), glucose (< 45 mg/dL), and protein (> 45 mg/dL) in the CSF are suggestive of bacterial meningitis.

Question 19

What does Clostridium species cause?

Answer 19

Neurological diseases, including botulism and tetanus, by producing potent neurotoxins that interfere with neurotransmitter release (botulinum neurotoxin (BoNT) and tetanus neurotoxin (TeNT)). The PNS is typically affected.

Question 20

How are Clostridium infections treated?

Answer 20

Treatment of Clostridium infection is effective only through early diagnosis with administration of antibiotics to control the infection and antitoxins to neutralize the endotoxin before they enter cells.
* Tetanus
* Botulism

Question 21

What is tetanus?

Answer 21

A noncommunicable disease characterized by uncontrollable muscle spasms (contractions) caused by the action of TeNT.
* It generally occurs when C. tetani infects a wound and produces TeNT, which rapidly binds to neural tissue, resulting in an intoxication (poisoning) of neurons.
* Localized (group of muscles), cephalic (eye muscles group) → Generalized.
* Symptoms: lockjaw (inability to open the mouth), progressing uncontrollable, sudden muscle spasms that are powerful enough to cause tendons to rupture and bones to fracture. Spasms in the muscles in the neck, back, and legs may cause the body to form a rigid, stiff arch, a posture called opisthotonos → diaphragm, and muscles of the chest? = Death

Question 22

What is botulism?

Answer 22

Wound botulism (traumatic injury, deep puncture wound, or injection site). Infant botulism (younger than 1 year of age) and adult intestinal toxemia, which occurs in immunocompromised adults, results from ingesting C. botulinum endospores in
When BoNT enters the bloodstream in the gastrointestinal tract, wound, or lungs, it is transferred to the neuromuscular junctions of motor neurons where it binds irreversibly to presynaptic membranes and prevents the release of acetylcholine from the presynaptic terminal of motor neurons into the neuromuscular junction. food.

Question 23

How is Botulism treated?

Answer 23

With an antitoxin specific for BoNT. If administered in time, the antitoxin stops the progression of paralysis but does not reverse it.

Question 24

What is Listeria monocytogenes (causes listeriosis)?

Answer 24

It is a foodborne (soil or animal manure used as fertilizer contamination) pathogen that can infect the CNS, causing meningitis.
The infection can be spread through the placenta to a fetus. Surface proteins called internalins (InlA and InlB) help it invade.
Diagnosis is through culture of blood or CSF. Treatment is with antibiotics and there is no vaccine.

Question 25

What is Hansen’s disease (leprosy)?

Answer 25

Caused by the intracellular parasite Mycobacterium leprae (acid-fast bacterium). Person-to-person transmission occurs by inhalation into nasal mucosa or prolonged and repeated contact with infected skin.
Infections cause demyelination of neurons (PNS), resulting in decreased sensation in peripheral appendages and body sites (cooler temperatures).

Question 26

How is Hansen’s disease diagnosed and treated?

Answer 26

Hansen’s disease is diagnosed on the basis of clinical signs and symptoms of the disease and confirmed by the presence of acid-fast bacilli on skin smears or in skin biopsy specimens. M. leprae does not grow in vitro on any known laboratory media, but it can be identified by culturing in vivo in the footpads of laboratory mice or armadillos.
Treatment is with multi-drug antibiotic therapy, and there is no universally recognized vaccine.

Question 27

What is the typical behavior of arboviral encephalitis?

Answer 27

Various types of arboviral encephalitis are concentrated in particular geographic locations throughout the world. These mosquito-borne viral infections of the nervous system are typically mild, but they can be life-threatening in some cases.

Question 28

What is the typical behavior of viral meningitis?

Answer 28

Viral meningitis is more common and generally less severe than bacterial meningitis. It can result from secondary sequelae of many viruses or be caused by infections of arboviruses (arthropod borne).

Question 29

What are the types of arboviral diseases?

Answer 29

• Eastern equine encephalitis (EEE) is caused by eastern equine encephalitis virus (EEEV), which can cause severe disease in horses and humans.
• Western equine encephalitis (WEE) is caused by western equine encephalitis virus (WEEV).
• St. Louis encephalitis (SLE), caused by St. Louis encephalitis virus (SLEV), is a rare form of encephalitis with symptoms occurring in fewer than 1% of infected patients.
• Japanese encephalitis, caused by Japanese encephalitis virus (JEV), is the leading cause of vaccine preventable encephalitis in human. Among those who recover, 30–50% have psychiatric, neurologic, or cognitive impairment.

Question 30

How are arboviral diseases treated?

Answer 30

There are no drugs to treat them, so treatment is supportive care and management of symptoms.

Question 31

What is Zika virus?

Answer 31

An emerging arboviral infection with generally mild symptoms in most individuals, but infections of pregnant women can cause the birth defect microcephaly.

Question 32

What is polio?

Answer 32

A mild intestinal infection but can be damaging or fatal if it progresses to a neurological disease (small percentage of cases). Replication of poliovirus in motor neurons of the anterior horn cells in the spinal cord, brain stem, or motor cortex results in cell destruction and leads to flaccid paralysis.

Question 33

What is rabies?

Answer 33

Is nearly always fatal when untreated and remains a significant problem worldwide.
It is primarily transmitted through the bite of an infected mammal (rabies virus (RV) - zoonotic).
The incubation period for rabies can be lengthy, ranging from several weeks or months to over a year.

Question 34

What path does rabies follow in the body?

Answer 34

As the virus replicates, it moves from the site of the bite into motor and sensory axons of peripheral nerves and spreads from nerve to nerve using a process called retrograde transport, eventually making its way to the CNS through the spinal ganglia. When it reaches the brain, the infection leads to encephalitis caused by the disruption of normal neurotransmitter function, resulting in the symptoms associated with rabies (the action of rabies virus is neurotoxic rather than cytotoxic). Then, traveling out of the CNS to tissues such as the salivary glands, where the virus can be released.
Symptoms: Pain and itching in the bite site, flu-like symptoms → CNS → Terminal rabies: either furious or paralytic rabies → Cardiac or respiratory arrest

Question 35

Transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease
and kuru are caused by?

Answer 35

Prions
(These diseases are untreatable and ultimately fatal. Similar prion diseases are found in animals)

Question 36

How is TSE diagnosed?

Answer 36

The gold standard for diagnosing TSE is the histological examination of brain biopsies for the presence of characteristic amyloid plaques, vacuoles, and prion proteins.

Question 37

What are neuromycoses?

Answer 37

Neuromycoses are uncommon in immunocompetent people, but immunocompromised individuals with fungal infections have high mortality rates. Treatment of neuromycoses require prolonged therapy with antifungal drugs at low doses to avoid side effects and overcome the effect of the bloodbrain barrier.

Question 38

What is cryptococcus neoformans?

Answer 38

A fungal pathogen that can cause meningitis. This yeast is commonly found in soils and is particularly associated with pigeon droppings.

Question 39

What is amoebic meningitis?

Answer 39

Primary amoebic meningoencephalitis (PAM) is caused by Naegleria fowleri. This amoeba flagellate is commonly found free-living in soils and water. Individuals are typically infected by the amoeba while swimming in warm bodies of freshwater such as rivers, lakes, and hot springs. The pathogenic trophozoite infects the brain by initially entering through nasal passages to the sinuses and making way to the brain.

Question 40

What is neurotoxoplasmosis?

Answer 40

Toxoplasma gondii is an ubiquitous intracellular parasite that can cause neonatal infections. Cats are the definitive host, and humans can become infected after eating infected meat or, more commonly, by ingesting oocysts shed in the feces of cats.

Question 41

What is neurocysticercosis?

Answer 41

Caused by the larval form of the pork tapeworm, Taenia solium. It is treated using antihelminthic drugs or surgery to remove the large cysts from the CNS. Leading cause of adult-onset epilepsy in the developing world.