Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Exam 3 (final) modules 6, 7, 8 > chapter 17 > Flashcards

chapter 17 Flashcards

1
Q

17.1 The Nervous System and Its Defenses

A

two components:
CNS - brain and spinal cord
PNS - nerves that come from brain and spinal cord ang disperse into (think nerves going into peripherals)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

three important functions of the NS

A

sensory, integrative, and motor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

sensory function of NS

A

sensory function is fulfilled by sensory receptors at the end of peripheral nerves; they generate nerve impulses that are transmitted to the CNS where they are translated or integrated into sensation or thought which = motor function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

cells that make up tissues of the brain and spinal cord that receive and transmit signals to and from the PNS and CNS; make up the ______ and _________

A

nerves;

brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

soft tissue of the brain and spinal cord is encases within a tough casing of three membranes called the _________; tri layer membrane covering the brain and spinal cord

A

meninges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

consists of the dura mater, arachnoid mater, and pia mater (going outermost to innermost)

A

meninges

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is in the subarachnoid space?

: subarachnoid space is the space between the arachnoid mater and pia mater

A

filled with a clear serumlike fluid called cerebrospinal fluid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

function of CSF

A

provides nutrition to CNS and provides a liquid cushion for the sensitive brain and spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

the meninges are a common:

A

site of infection; ie. meningitis

—> microorganisms can be found in CSF during meningitis, which is supposed to be sterile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

bacteria that often cause meningitis

A 
Neisseria meningitidis (the meningococcus)
Haemophilus  influenzae
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

swelling in the nerve where the cell bodies of the neuron aggregate; part of PNS

A

ganglion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

PNS consists of _________ and _________

A

nerves and ganglion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

bundles of neuronal axons that receive and transmit nerve signals

A

nerves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what communicate in the synapse?

A

the axons and dendrites of adjacent neurons communicate in the synapse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

chemicals called ______ are released from one cell and act on the other cell in the synapse

A

neurotransmitters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

the defenses of the NS are mainly ________

A

structural

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

list some defenses in the NS

A
  • bony casings of the brain and spinal cord protect from traumatic injury
  • cushion of CSF
  • vascular system: vessels that serve NS in brain have special permeability creating the BLOOD-BRAIN BARRIER, which allows few molecules to pass through and prohibits more microbes from passing into the CNS
  • –> drawback is that drugs and antibiotics are difficult to introduce into CNS
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

along with the uterus and eyes, the CNS is considered an _____________ ___________ site.

A

immunologically privileged site, meaning these sites are only able to mount partial or at least a different immune response when exposed to immunologic challenge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

the functions of the CNS are so vital for life of organisms that even temporary damage that could potentially result from “normal” immune responses could be __________

A

detrimental

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

microglia and brain macrophages

A

microglia: specialized cells in the CNS; cell with phagocytic capabilities
brain macrophages: phagocytic

—> activity of both of these cells is thought to be less than that of phagocytic ells elsewhere in the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

17.2 Normal Biota of the NS

A

it is still believed there is no normal biota in either the CNS or PNS
–> finding microbes of any type in these tissues represents a deviation from the healthy state

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

viruses such as _______-_______ live in a dormant state in the NS between episodes of acute disease, but are not considered _________ _______

A

herpes simplex

normal biota

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

there is a lot of research suggesting that the ___ microbiome influences the NS in many ways, in fact: the development of the brain, blood brain barrier, and proper construction of peripheral nerves are influenced by the microbiome in the developing ______

A

gut

gut

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

17.3 NS Diseases Caused by Microorganisms

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Meningitis (inflammation of the meninges) treatment and diagnosis

A

when meningitis is suspected: lumbar puncture (spinal tap) is performed to obtain CSF, which is then examined by gram stain and/or culture
—> tx often begins with broad-spectrum antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

most serious forms of acute meningitis are caused by _________, but it is though that their entrance to the CNS is often facilitated by coinfection or previous infection with ___________ _________

A
  1. bacteria

2. respiratory viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

meningitis s and s

A

no matter the cause the typical sx are:

  • severe headache
  • painful or stiff neck
  • fever
  • nausea and vomiting
  • photophobia (sensitivity to light) may also be noted
  • skin rashes in specific types of meningitis
  • usually increased WBCs in CSF

-can be acute or chronic, depends on infectious agent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Meningitis: Neisseria meningitidis (G-)
“meningococcus”
Hint: often associated with epidemic forms b/c of endotoxins which cause rapid decline marked by petechiae and HIGH FEVER, but can be helped with ceftriaxone and cefotaxime; IgA PROTEASE

A

Trans: droplet contact (reservoir: humans who harbor patho in nasopharynx)

V Factors: capsule, endotoxin, IgA protease

Culture/dx: Gram stain/culture of CSF, rapid antigenic tests, oxidase tests (test CSF, blood, or nasopharyngeal samples); cultivation is preferred method of dx on Modified Thayer-Martin or chocolate agar medium

Prevention: conjugated vaccine; ciprofloxacin, rifampin, or ceftriaxone used to protect contacts

Tx: Penicillin, ceftriaxone, cefotaxime

Distinct Feats: Petechiae(damage to blood vessels by cytokines) on trunk and appendages, meningococcemia (bacteria enter blood), RAPID DECLINE, sudden onset marked by HIGH fever, sore throat, chills, delirium, bleeding in the skin, shock, and coma

Epidemiological Feats:
US 2018: 329 cases
Meningitis “belt” in Africa: 1000 cases per 100,000 annually
Serotypes B, C and Y are responsible for more cases of infection

Highest risk pop: young children, 6-36 months old (3 y/o)
and young adults (10-20 y/o)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Meningitis: Streptococcus pneumoniae (G+) “pneumococcus”
Hint: causes the majority of bacterial pneumonias, and causes meningitis; most frequent cause of community-acquired meningitis

A

Trans: droplet contact

V Factors: capsule that protects from phagocytosis, brain cell apoptosis, hemolysin and hydrogen peroxide production

Culture/dx: Gram Stain/culture of CSF

Prevention: Two vaccines: PCV13 (Prevnar) and PPSV23 (Pneumovax 23)

Tx: Penicillin, vanco + ceftriaxone; in SERIOUS THREAT cat. in antibiotic resist.

Distinct Feats: serious, acute, MOST COMMON meningitis in adults

Epidemiological Feats:
US incidence before vaccine for children: 7.7 hospitalizations per 100,000 —> after vaccine for children: 2.6 per 100,000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Meningitis: Haemophilus influenzae (G-)

A

Trans: droplet contact

V Factors: capsule

Culture/dx: culture on chocolate agar

Prevention: Hib (H. influenzae serotype b) vaccine, ciprofloxacin, rifampin, or ceftriaxone

Tx: Ceftriaxone

Distinct Feats: serious, acute, less common in US since vaccine became available; SEVERE

Epidemiological Feats:
Before ***Hib vaccine, 300,000-400,000 deaths worldwide per year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Meningitis: Listeria monocytogenes (G+)

Hint: think Listeria= Listerine which goes in mouth like food, everyone eats food (adults, neonates, elderly, immunocompromised), and everyone can die from choking: range of shapes of bacteria -> think shaped noodles, and think food has different temps and pH needs just like Listeria (not fastidious)

A

Trans: Vehicle (food) -> most cases but the primary reservoir is water/soil

V Factors: intracellular growth

Culture/dx: cold enrichment, rapid methods ELISA/immunofluorescence/gene probe

Prevention: cooking food, avoiding unpasteurized dairy products

Tx: Ampicillin, trimethoprim-sulfamethoxazole, gentamicin

Distinct Feats: asymptomatic in healthy adults; meningitis in neonates, elderly, pregnant, and immunocompromised -> can result in septicemia

Epidemiological Feats: mortality can be as high as 33%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Meningitis: Cryptococcus neoformans (Fungus)
HINT: think AIDS patients were thought of as FUNGUS right from NEOnate stage, and required lots of TESTING

A

Trans: vehicle (air, dust)

V Factors: capsule, melanin production

Culture/dx: negative staining, biochemical tests, DNA probes, cryptococcal antigen test

Prevention: no prevention

Tx: Amphotericin B and fluconazole

Distinct Feats: acute or chronic, most common in AIDS patients and is frequently fatal

Epidemiological Feats:

  • in US, mainly a concern for HIV+ patients; 90% drop in incidence in the 1990s due to better management of AIDS
  • worldwide 1 million new cases per year

most common sx: headache, nausea, neck stiffness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

Meningitis: Coccidioides immitis (Fungus)
Hint: Coccidioides causes cocci (spherule) shaped granulomas on Sabouraud’s agar in endemic regions

A

Trans: vehicle (air, dust, soil)

V Factors: Granulomas (spherule) formation

Culture/dx: identification of spherules, cultivation on Sabouraud’s agar; arthroconidia (arthrospores) grow at incubation of 37-40degrees and develop into spherules in the lungs

Prevention: avoiding airborne endospores

Tx: Fluconazole or Amphotericin

Distinct Feats: almost exclusively in endemic regions, causes Valley Fever

Epidemiological Feats: incidence increasing in recent years

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Meningitis: Viruses “aseptic meningitis”

Hint: viral meningitis is ruled out by searching for bacteria, fungi, and protozoa, and then performing antigen tests —> lucky because milder than B or F, BUT is lytic to cells :(

A

Trans: droplet

V Factors: lytic infection of host cells

Culture/dx: initially, absence of bacteria, fungi, and protozoa, followed by antigen tests

Prevention: no prevention

Tx: usually none (unless specific virus identified and specific antiviral exists)

Distinct Feats: generally milder than bacterial or fungal forms; 90% caused by enteroviruses

Epidemiological Feats:
In US, 4 of 5 meningitis cases are caused by viruses: 26,000-42,000 hospitalizations per year

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Neonatal Meningitis

A

Trans: almost always a result of infection transmitted by the mother in utero or during passage through birth canal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Neonatal Meningitis: Streptococcus agalactiae (G+) group B

A

Trans: vertical (during birth)

V Factors: capsule

Culture/dx: culture mother’s genital tract on blood agar; CSF culture of neonate

Prevention: culture and treatment of mother between 35 and 37 weeks gest.

Tx: Ampicillin and penicillin G (PENICILLIN IS DRUG OF CHOICE)

Distinct Feats: MOST COMMON; positive culture of mother confirms diagnosis

Epidemiological Feats:
Before intrapartum antibiotics intro’d in 1996: 1.8 cases per 1000 live births
After intrapartum antibiotics: 0l32 cases per 1000 live births

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Neonatal Meningitis: Escherichia coli, strain K1 (G-)

A

Trans: vertical during birth

V Factors: none

Culture/dx: CSF gram stain/culture

Prevention: no prevention

Tx: Ceftazidime or cefepime +/- gentamicin

Distinct Feats: suspected if infant is premature; second most common cause

Epidemiological Feats: estimated as 0.2-5 per 1000 live births; 20% of pregnant women colonized; poor prognosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Neonatal Meningitis: Listeria monocytogenes (G+)

A

Trans: vertical

V Factors: intracellular growth

Culture/dx: cold enrichment, rapid methods (ELISA)

Prevention: cooking food, avoiding unpasteurized dairy products

Tx: ampicillin, trimethoprim-sulfamethoxazole

Distinct Feats: none

Epidemiological Feats: mortality can be as high 33%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Neonatal Meningitis: Cronobacter sakazakii

A

Trans: vertical (baby formula)

V Factors: ability to survive dry conditions

Culture/dx: chromogenic differential agar, or rapid detection kits

Prevention: safe preparation of formula, avoidance of powdered formula

Tx: begin with broad spectrum drugs until susceptibilities determined

Distinct Feats: none

Epidemiological Feats: rare (a handful of documented cases in US annually), but DEADLY (mortality rates as high as 40%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Zika Virus Disease (RNA virus that is closely r/t viruses causing dengue fever, West Nile fever, and yellow fever)

A

-starting in 2015 and into 2016 but known since mid-1990’s, in Brazil babies were being born with microencephaly, determined to be Zika virus

Trans: vertical, vector-borne (Aedes mosquito), sexual contact, likely through blood transfusions

V Factors: none

Culture/dx: PCR testing

Prevention: avoiding mosquitos, unprotected sex with infected; vaccines in trial

Tx: supportive measures

S/S:
Adults: skin rash, conjunctivitis, muscle/joint pain, can trigger Guillain-Barre syndrome (immune system attacking peripheral nerves)
Babies: microencephaly, vision problems, seizures, involuntary movements, irritability, swallowing dysfunction

Epidemiological Feats: originated in Africa but spreading throughout world; latest outbreak, leading to many microencephalies, started in 2015

41
Q 
Poliomyelitis (Poliovirus) 
RNA virus (naked capsid with chemical stability and resistance to acid, bile, and detergents)
A

-acute enteroviral infection of the spinal cord that can cause neuromuscular paralysis (formerly known as infantile paralysis)

Trans: fecal-oral, vehicle

V Factors: attachment mechanisms (adsorption to receptors of mucosal cells in oropharynx and intestine)

Culture/dx: viral culture, serology

Prevention: live attenuated (OPV) (developing world) or inactivated vaccine (IPV) (developed world)

Tx: none, supportive, palliative

S/S: most infections are contained as short-term, mild viremias; some develop nonspecific sx of fever, headache, nausea, sore throat, and myalgia; if viremia persists, viruses can be carried to the CNS through its blood supply

  • –> infiltrates the motor neurons of the anterior horn of the spinal cord, or it can attack spinal ganglia, cranial nerves, and motor nuclei
  • in paralytic disease, invasion of motor neurons causes various degrees of flaccid paralysis

Epidemiological Feats:
Eradicated from Western Hemisphere; still endemic in Pakistan and Afghanistan as of 2020. Vaccine strains caused 196 cases of paralytic polio in Africa. :(

42
Q

Poliovirus is ________, meaning it attacks the nervous system

A

neurotropic

43
Q

Bulbar poliomyelitis

A

rare; the brain stem, medulla, or even cranial nerves are affected

  • –> this situation leads to loss of cardiorespiratory regulatory centers, requiring mechanical respirators
  • –> unused muscles leads toa atrophy, growth is slowed, and severe deformities of the trunk and limbs develop (spine, shoulder, hips, knees, feet)
44
Q

Post-polio Syndrome (PPS)

A

diagnosed in long-term survivor of childhood infection; manifests as a progressive muscle deterioration that develops in 25-50% of patients

45
Q

Meningoencephalitis: Primary Amoebic Meningoencephalitis (PAM)

Naegleria fowleri (P)

A

Trans: vehicle (exposure while swimming in water)

V Factors: Invasiveness

Culture/dx: examination of CSF; brain imaging, biopsy

Prevention: limit warm freshwater or untreated tap water entering nasal passages

Tx: Amphotericin B; mostly ineffective

S/S: rapid, massive destruction of brain and spinal tissue after amoeba migrates into brain from olfactory nerve; hemorrhage, coma. and invariably death

Epidemiological Feats: US: 0.7 cases annually; 97% case-fatality rate
Spreading to northern states as climate warms

46
Q

Meningoencephalitis: Granulomatous Amoebic Meningoencephalitis

Acanthamoeba (P)

A

Trans: direct contact and invades broken skin, the conjunctiva, and occasionally the lungs and urogenital tracts

V Factors: invasiveness

Culture/dx: examination of CSF; brain imaging, biopsy

Prevention: no prevention

Tx: surgical excision of granulomas; ketoconazole may help

Epidemiological Feats: predominantly occurs in immunocompromised patients

47
Q

Encephalitis

A

inflammation of the brain

48
Q

subacute meaning

A

indicates an intermediate status between acute and chronic disease

49
Q

Acute Encephalitis: Arboviruses
(West Nile virus, La Crosse virus, Jamestown virus, St. Louis encephalitis virus, Powassan virus, Eastern Equine encephalitis virus)

A

Trans: vector (arthropod bites)

C Factors: attachment fusion, invasion capabilities

Culture/dx: history, rapid serological tests, nucleic acid amplification tests

Prevention: insect control

Treatment: none; support measures to control seizures, fever, convulsions, etc.

S/S: extremely variable; can include coma, convulsions, paralysis, tremor, loss of coordination, memory deficits, changes in speech and personality, and heart disorders

Distinct Feat: history of exposure to insect important

Epidemiology Feat: 20% increase in incidence 2014-2018; young children and elderly most sensitive to injury by arboviral encephalitis

50
Q

Acute Encephalitis: Herpes simplex 1 or 2

A

Trans: vertical or reactivation of latent infection

V Factors: none (latency?)

Culture/dx: clinical presentation, PCR, Ab tests, growth of virus in cell culture

Prevention: maternal screening for HSV

Tx: acyclovir

Distinct Feat: in infants, disseminated disease present; rare between ages 30 and 50

Epidemiology Feat: HSV-1 more common cause of encephalitis; 2 cases per million per year; can cause in newborns born to HSV-positive mothers

51
Q

Acute Encephalitis: JC virus

A

Trans: ? ubiquitous

V Factors: none

Culture/dx: PCR of cerebrospinal fluid

Prevention: none

Tx: Zidovudine or other antivirals

Distinct Feat: in severely immunocompromised, especially AIDS

Epidemiology Feat: affects 5% of adults with untreated AIDS; often asymptomatic

52
Q

arboviruses

A

arthropod-borne viruses

  • feed on blood of hosts
  • infections show peak incidence when the arthropod is actively feeding and reproducing, usually from LATE SPRING through EARLY FALL
53
Q

S/S of acute encephalitis

A

vary, but may include behavior changes or confusion b/c of inflammation; decreased consciousness and seizures frequently occur

—> sx of meningitis are often also present

54
Q

JC Acute Encephalitis can cause a condition called _____________

A

progressive multifocal leukoencephalopathy (PML)

  • uncommon, fatal complication of infection with JC virus (polyoma virus)
  • -> result of virus attack on accessory brain cells
55
Q

Subacute Encephalitis

A

when encephalitis sx take longer to show up, and when the sx are less striking, the condition is termed subacute encephalitis

  • –> most common cause is a protozoan called Toxoplasma
  • –> can be caused by persistent measles virus as many as 7 to 15 years after the initial infection
  • –> prions can cause spongiform encephalopathy
56
Q

Subacute Encephalopathy: Toxoplasma gondii (P)

A

Trans: vehicle (meat), or fecal-oral

V Factors: intracellular growth

Culture/dx: serological detection of IgM

Prevention: personal hygiene, food hygiene

Tx: Pyrimethamine and/or leucovorin and/or sulfadiazine

S/S: most cases are asymptomatic or marked by mild sx like sore throat, lymph node enlargement and low grade fever

Distinct Feat: subacute, slower development of disease; infection in fetus, immunodeficient people is severe and often fatal

Epidemiology Feat:

  • 15%-29% of US pop. is seropositive
  • internationally seroprevalence is up to 90%
  • disease occurs in 3-15% of AIDS patients
  • designated a “neglected parasitic infection” in the US by CDC

Interesting Fact: people with hx of Toxoplasma infection are often more likely to display thrill-seeking behaviors and seem to have slower reaction times (researchers are looking into possible association between schizophrenia and hx of Toxoplasma infection)

57
Q

Subacute Encephalopathy: Subacute sclerosing panencephalitis

A

Trans: persistence of measles virus

V Factors: cell fusion, evasion of immune system

Culture/dx: EEGs, MRI, serology (Ab versus measles virus)

Prevention: none

Tx: none

Distinct Feat: history of measles; infection sx occur years after an initial measles episode

Epidemiology Feat: occurs in 1 in 609 persons who had measles

58
Q

Subacute Encephalitis: Prions

A

Trans: CJD = direct/parenteral contact with infected tissue, or inherited vCJD = vehicle (meat, parenteral)

V Factors: avoidance of host immune response

Culture/dx: biopsy, image of brain

Prevention: avoiding infected meat or instruments; no prevention for inherited form

Tx: none

Distinct Feats: long incubation period; fast progression once it begins

Epidemiological Feats:

  • CJD: 1 case per year per million worldwide
  • vCJD: 98% cases originated in UK
59
Q

other conditions that may display subacute encephalitis sx:

A 
Rickettsial diseases
Rocky Mountain Spotted fever
Lyme disease
Bartonella or Anaplasma disease
Tapeworm disease
Syphilis
60
Q

Congenital infection with subacute encephalitis occurring in the first or second trimester is associated with what abnormalities?

A

stillbirth, severe abnormalities such as liver and spleen enlargement, liver failure, hydrocephalus, convulsions, damage to the retina that can result in blindness

61
Q

list come neglected parasite infections in the US

A

Chagas disease - Trypanosome cruzi, protozoan
Neurocysticercosis - Taenia sodium, tapeworm
Toxocariasis - Toxocara, roundworm
Toxoplasma - Toxoplasma gondii, protozoan
Trichomoniasis - Trichomonas vaginalis, protozoan

62
Q

Toxoplasma (protozoa) is an ___________ intracellular parasite; and T. gondii has ______ host specificity, allowing it to attack at least 200 species of birds and mammals

A

obligate

low

63
Q

For which disease processes are immunizations available?

a. cryptococcus neoformans
b. Listeria monocytogenes
c. Haemophilis influenzae
d. Streptococcus pneumoniae
e. Neisseria meningitidis

A

c, d, e

64
Q

S/S of CJD (transmissible spongiform encephalopathy - prions)

A 
altered behavior
dementia
memory loss
impaired senses
delirium
premature senility

death usually occurs within 1 year of dx

65
Q

what does spongiform damage confer

A

holes in the brain

66
Q

PrP proteins

A

fx in normal brain development/function; altered in CJD and then begin to alter other Prp proteins = abnormal proteins; until they accumulate and cause holes in the brain

67
Q

_______ can withstand prolonged autoclaving

A

prions

68
Q

Rabies

A

only rhabdovirus that infects humans; zoonotic disease characterized by a fatal meningoencephalitis

69
Q

Rabies S/S

A

Average inc. period is 2 weeks to even years depending on wound site, its severity, and the inoculation dose
–> inc. period is shorted in facial, scalp, or neck wounds because of closer proximity to the brain

Prodromal phase begins with FEVER, NAUSEA, VOMITING, HEADACHE, FATIGUE, and other nonspecific symptoms

*In the past if you got rabies you would die but now with intensive and long-term tx people are recovering

70
Q

How does rabies infection work/V factors

A

infected animal saliva enters puncture site or is inhaled or inoculated through membranes of the eye

virus remains at trauma site for up to a week where it multiplies

virus gradually enters nerve endings toward the ganglia, spinal cord, and brain

viral multiplication throughout the brain is eventually followed by migration to diverse areas such as the eye, heart, skin, and oral cavity

infection cycle is completed when the virus replicates in the salivary gland and is shed into the saliva

V Factor: envelope glycoprotein allows virus to spread in CNS and invade certain neural cells

71
Q

Primary reservoirs of rabies

A

wild mammals such as canines, skunks, racoons, badgers, cats, and bats that can spread the infection to domestic dogs and cats

72
Q

Diagnosis of rabies

A

requires multiple tests

Reverse Transcriptase PCR is used with saliva samples; but must be accompanied by detection of antibodies to the virus in serum or spinal fluid

Direct fluorescent antigen testing

73
Q

treatment of rabies

A

one of few infectious diseases for which a combination of passive and active postexposure immunization is indicated (and successful)

74
Q

Tetanus

A

neuromuscular disease whose alternate name, lockjaw, refers to a early effect of the disease on the jaw muscle

75
Q

Tetanus S/S

A

C. tetani releases a powerful exotoxin that is a neurotoxin, tetanospasmin, that binds to target sites on peripheral motor neurons in the spinal cord, brain, and sympathetic NS
—>toxin acts by blocking inhibition of muscle contraction = muscles uncontrollably contracting

First Symptoms: clenching of jaw, followed by extreme arching of the back, flexion of arms, and extension of legs

death most often occurs due to paralysis of resp muscles and then resp arrest

*Lockjaw confers the bizarre appearance of risus sardonicus (sardonic grin), which looks eerily as though the person is smiling

76
Q

tetanus bacteria (G+) is a strict ___________

A

anaerobe

77
Q

transmission/epidemiology of tetanus

A

endospores enter body through accidental puncture wounds, burns, umbilical stumps, frostbite, and crushed body parts

most cases are among geriatric pts and drug users

78
Q

tetanus tx and prevention

A

patient with clinical appearance suggestive of tetanus should immediately receive antitoxin therapy with human tetanus immune globulin (TIG) and also Penicillin G

  • –> vaccination with DTaP (diphtheria, tetanus, and cellular pertussis) for 1-3 month old babies (three injections two months apart)
  • -> offers 10 years of protection

neonate protection = vaccinate pregnant mother

79
Q

V Factor of tetanus

A

Tenanospasm exotoxin

80
Q

Botulism

A

poisoning that results from the introduction of a toxin (exotoxin) into body tissues through ingestion of injection

—> is associated with eating poorly preserved foods, although it can occur as a true infection

81
Q

Botulism S/S

A

sx are largely the same for all three forms

from the circulatory system, an exotoxin called the botulinum toxin travels to its principal site of action, the neuromuscular junction of skeletal muscles
—> effect of toxin is to prevent release of neurotransmitter acetylcholine which initiates the signal of muscle contraction = flaccid paralysis (opposite of tetanus)

usual time before onset of sx is 12 to 72 hours, depending on size of dose

neuromuscular sx first affect the muscles of the head and include double vision, difficulty in swallowing, and dizziness, but there is no sensory or mental lapse
–>later ex are descending muscular paralysis and respiratory compromise

82
Q

Infant Botulism (66%)

A

infection followed by intoxication

  • most common type of botulism in the US (approx. 140 cases annually)
  • food source of cause, ie. raw honey has been implicated
  • endospores are common in dust and soil
  • endospore can gain foothold in intestine and normal biota in infants

Culture/dx: finding the toxin/organism in the feces confirms dx

83
Q

Wound Botulism (14%)

A

infection followed by intoxication

  • 3-4 cases per year in the US
  • endospores enter puncture or wound and cause sx like in foodborne infection
  • cases of this form have increased several-fold in the last several years due to IV drug use

Culture/dx: toxin should be demonstrated in the serum, or the organism should be grown from the wound

84
Q

Foodborne Botulism (10%)

A

pure intoxication

  • many infections occur in home-processed foods including canned vegetables, smoked meats, and cheese spreads
  • endospores can be present on vegetables or meat at the time of gathering and are difficult to remove completely
  • when contaminated food is put into jars and steamed in a pressure cooker that does not reach reliable pressure and temp, some endospores survive (botulinum endospores are highly resistant to heat)

Culture/dx: some labs attempt to identify the toxin in the offending food

  • alternatively, if multiple pts present with the same sx after ingesting the same food, a presumptive dx may be made
  • cultivation of Clostridium botulinum in feces is considered confirmation of fx because the carrier rate is very low
85
Q

some reasons for botox (exploitation of exotoxin)

A 
vanity 
migraine
excessive sweating
MS
urinary incontinence
tennis elbow
86
Q

both Clostridium tetani and botulinum are endospore-forming _______, that does its damage through the release of exotoxin

A

anaerobe

87
Q

Botulism treatment and prevention

A

CDC maintains a supply of antitoxin, which, when admin’d soon after dx, can prevent the worst outcomes of the disease

  • -> pts also managed with resp and cardiac support
  • > 5% mortality

Antitoxin, Penicillin G for wound botulism, supportive care

category A bioterrorism agent

88
Q

which pathogen has evolved to make its rodent host less avoidant of cats?

A 
Toxoplasma gondii (P)
(Subacute Encephalitis)
89
Q

What cellular structure do several of the organisms that cause meningitis share?

A

capsules

90
Q

which of the following organisms is anerobic?

a. poliovirus
b. Cryptococcus
c. Clostridium
d. Coccidioides

A

c. Clostridium

ie. C. tetani and botulinum

91
Q

Which disease is caused by an infectious agent that carries no nucleic acid?

a. rabies
b. CJD
c. polio
d. meningitis

A

b. CJD (prions)

92
Q

the normal gut microbiota in adults, but not infants, inhibit the growth of which pathogen?

A

Clostridium botulinum

Infant Botulism

93
Q

subacute encephalitis may be caused by

a. Toxoplasma gondii
b. Streptococcus agalactiae
c. Naegleria fowleri
d. Haemophilus influenzae

A

a.

94
Q

Neisseria meningitidis
Streptococcus pneumoniae
Haemophilus influenzae
Listeria monocytogenes
Cryptococcus neoformans(AIDS patients, lots of testing, fungi)
Coccidioides immitis (fungus) (granuloma spherule formation)
Viruses

A

causative organisms of meningitis

95
Q 
Streptococcus agalactiae (G+)
E. coli strain K1 (G-)
Listeria monocytogenes (G+)
Cronobacter sakazakii (G-)
A

causative organisms of neonatal and infant meningitis

96
Q

Primary Amoebic: Naegleria fowleri (vehicle - swimming)

Granulomatous Amoebic: Acanthamoeba (direct contact)

A

causative organisms + transmission of Meningoencephalitis

97
Q

Arboviruses ie. West Nile, La Crosse, Jamestown Canyon, St. Louis, Powassan, Eastern Equine viruses) (vector - arthropod bites)

Herpes Simplex 1 & 2 (vertical or reactivation)

JC virus (ubiquitous)

A

causative organisms of Acute Encephalitis

98
Q

Toxoplasma gondii (P) - vehicle (meat)/oral-fecal route
Subacute sclerosing panencephalitis - persistence of measles virus
Prions - CJD or vCJD

A

causative organisms of Subacute Encephalitis

Exam 3 (final) modules 6, 7, 8 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions