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Patho > bacteria and viruses > Flashcards

bacteria and viruses Flashcards

1
Q

Non-obligate intracellular parasites

A

Mycobacteria, Mycoplasma, and Spirochetes

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2
Q

Mycobacterium tuberculosis

world incidence 1/4 of pop-> highest cause of mortality worldwide

A

Transmission:
obligate aerobic rods
ACID FAST STAINING
Lung is main infection

History:
exposure-> 70-90% not infected, 10-30% infected-> latent 90% and active 10% = reactivation disease-> then die

Patho: SURVIVES WITHIN PHAGOSOMES OF MACROPHAGES-> protein prevents fusing with lysosome so escapes degradation
2 types of lesions:
1. Exudative/active lesions= draining nodes= Ghon complex
2. Latent area of caseating necrosis walled off by tubercle (firbous tissue)= Granulomas

PRIMARY LESIONS IN LOWER LOBES & REACTIVATION LESIONS IN APICES

Spread:
1. tubercle erodes into bronchus-> empties caseous contents
2. Disseminates via bloodstream

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3
Q

Clinical presentation of tb

A

Primary tuberculosis:
* CNS- appetite loss and fatigue
* Lungs- coughin up blood, productive prolonged cough
* Skin- NIGHT SWEATS

Extrapulmonary tuberculosis:
* scrofula
* tuberculosis pleurisy
* pott’s disease in spine
* Urogenital tuberculosis

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4
Q

Immune response to Primary Tuberculosis

A
  1. Granuloma formation- fibrous calcification of tubercules
  2. Cellular immunity fight-> CD4 cells, IFN-Y, and Macrophages (AB present but not useful bc intracellular)

Positive PPD skin test- delayed hypersensitivity reaction

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5
Q

Interpretation of PPD

A

IFNY release assays = highest sensitivity/specificity
Bc induces macrophages to release

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6
Q

BCG V

A

Live attenuated M. bovis
DOES NOT PREVENT INFECTION BUT REDUCE SYMPTOMS

uses: countries iwth high incidence
RECOMMENDED FOR CHILDREN IN US THAT LIVE WITH SOMEONE WITH ACTIVE TB

Testing implications:
PPD positive for 2-3 mon but decrease w/ time
<10 mm at 10 yrs

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7
Q

Atypical Mycobacteria

MAK

A
  1. M. kansasii- tb like in immunocomp
  2. M. marinum- swimming pool granuloma
  3. M. avium-intracellulare complex- tb like in immunocomp
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8
Q

M. avium intracellulare complex

MAC

A

Pulmonary disease: Clinical syndromes
1. disease with known underlying lung disease WHITE, MIDDLE AGED MALE OFTEN SMOKERS AND ALCOHOL UNDERLYING copd OR CF PT
2. Disease without underlying lung disease- non smoking women >60 yrs who have nodules on cxr and no known lung

Less common: hot tub lung- hypersensitivity pneumonitis and MAC infxn with solitary pulmonary nodules resembling lung cancer

Disseminated disease: IMMUNOCOMPROMISED PTS
HIV, TNF ALPHA INHIBITORS

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9
Q

Mycoplasma pneumoniae

atypical pneumonia

A

walking pneumonia- human pathogen with respiratory droplet transmission

Clinical course: teens, young adults, college students
* Non specific prodrome- nonproductive cough, sore throat, earache
* Fever, headache, malaise, myalgia
* xray shows inflitrates but pulmonary exam unremarkable
assosciated w/ stevens johnson, raynauds, guillain barre, arrhythmia

can see hemolysis- and clinical signs of anemia

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10
Q

Spirochetes

A
  1. Treponema pallidum-> Syphilis
  2. Borrelia burgdorferi- lyme disease
  3. Borrelia recurrentis- relapsing fever
  4. L. interrogans- Leptospirosis
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11
Q

Syphilis

TORCH INFECTION

A
  • Hx: sexual contact
  • Primary: spirochetes multiply at site of inoculation-> chancre forms 2-10 wks later (nontender ulcer)-> spread via bloodstream-> enlarged regional lymphnodes
  • Darkfield microscopy = godl standard
  • Secondary: 1-3 months after
  • **generalized maculopapular rash- palms and soles
  • Condylomata lata-> moist papules on genitals and mimic warts/molluscum**
  • fever, malaise, anorexia, weight loss
  • Tertiary:
  • Aortitis, aneurysms, aortic regurgitation-> cns disorders

IM PENICILLIN G q week x3 weeks

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12
Q

Neurosyphilis

can b any tie in disease

A

Tabes dorsalis:
disease of posterior columns of spinal cord and dorsal roots-> sensory ataxia and stabbing pains
Argyll- Robertson pupils- not reactive to light and pain

syphilitic meningitis, meningovascular syphilis, ocular syphilis, otosyphilis

Labs: Positive CSF-VDRL
TX: IV Penicillin G

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13
Q

Lyme disease

Most common vector borne illness in US

A

Borrelia burgdorferi-> Ixodes tick
1. Early localized stage
* erythema migrans (macular erythematous target)
* flu like
* lymphadenopathy
* 40% resolve after this phase
2. Early disseminated stage
* neuro involvement-> aseptic meningitis, cranial neuropathy, motor/sensory radiculopathy
* Bells palsy
* Cardiace involvement-> variable AV blocks
* Multiple erythema migrans lesions
3. Late disseminated stage
* arthritis of large joints with visible swelling
* encephalopathy, encephalomyelitis

Testing:
1. Enzyme immunoassay or Immuno fluoro
2. IgM, IgG, western blot

TX:
prophylactic tx available but tx clinically

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14
Q

Obligate intracellular parasites

A
  1. chlamydia
  2. rickettsiae
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15
Q

Chlamydiae

clamydophila and clamydia

A
  1. Chlamydia trachomatis
    * Urethritis, pneumonia, conjunctiviis, lymphogranulom a vereum, trachoma
    * diag: NAAT
    * tx: doxycycline
  2. Chlamydophila pneumoniae
    * atypical pneumonia
    * diag: serologic testing
  3. Chlamydophila psittaci
    * psittacosis/pneumonia
    * birds carry
    * inhalation of dried bird feces
    * Diag: serologic test NAAT
    * tx: doxycycline
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16
Q

Chlamydia trachomatis

TAG

A
  1. Trachoma- chronic keratoconjunctivitis leads to eyelid scarring and blindness
  2. Genital tract infections STI- Neonatal conjunctivitis and lymphogranuloma venereum (genital papule, lymphadenopathy, from MSM)
  3. Autoimmune- Reactive arthritis and reiter’s syndrome
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17
Q

Reactive arthritis

Reiter’s syndrome

A
  1. Conjunctivitis
  2. Urethritis
  3. Arthritis

Cause:
Urogenital: chlamydia trachomatis
Enteric: Campylobacter, salmonella, shifella, yersinia

HLAB27 +

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18
Q

C. pneumoniae

chlamydia

A
  • bronchitis and pneumona in adolescents and young adults
  • cough, dyspnea, fever
  • Pharyngitis, laryngitis, sinusitis
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19
Q

Rickettsiae

A
  1. Rocky mountain spotted fever- rickettsia rickettsii-> ticks-> southeastern states
  2. Q fever-> cattle, sheep, goats
  3. Ehrlichiosis-> from ticks
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20
Q

Rocky Mountain spotted fever

A

SXS: fever, headache, myalgia, prostration-> later Rash (macules to petechiae from hands and feet towards trunk-> children in warm months in the southeastern US

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21
Q

Q fever

know this one

A

Agent: Coxiella
Reservoir: cattle, sheep, goats
Transmitted: inhalation of aerosolized animal waste
Progress: PNEUMONIA AND OR HEPATITIS
ranchers and shepherds

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22
Q

Ehrlichiosis

AAgent: Ag

A

Agent: Ehrlichia
Lymphopenia
thrombocytopenia
elevated LFTs
LONE STAR TICK

TESTING:
INDIRECT FLUORESCENT AB TEST

23
Q

Gram variable Odd balls

A
  1. Gardnerella vaginalis
  2. Actinomycetes
    * actinomyces israelii- dental infxn-> normal oral flora
    * nocardia asteroides- pneumonia, skin infxn, brian abscesses
24
Q

Gardnerella vaginalis

all bolded

A

Bacterial vaginosis-> due to shift in microfloral populations, replaced by gardner
SXS: white/gray colored discharge, fishy odor, subjective irritation but no inflamm changes

Labs: = whiff test
clue cells- fried egg with pepper

25
Q

Actinomyces

a. israelii causes most infxn

A

Normal oral flora-> minor trauma
hard nontender swelling that eventually drains

26
Q

Nocardia asteroides

A

2 forms:
Pulmonary-> acute bronchopneumonia
Cutaneous-> skin trauma leads to cellulitis

Disseminated to organs and to brain abscess
Immunocompromised at risk-> opportunistic infxn

27
Q

Summary

A
28
Q

Viral general info

A

DNA or RNA
obligate intracellular parasites with capsi surounding nucleic acid
Envelope is a lipoprotein membrane that is virus specific
outer proteins can be antigenic

29
Q

Viral replication

A

Absorption= specific for host cell proteins
Genome replicates using host machinery
* dna virus-> replicate in nucleus
* RNA -> replicate in cytoplasm

Lysis vs exocytosis to escape

30
Q

Fetal and Neonatal

A

TORCH- Toxoplasmosis, Other (syphilis), Rubella, cytomegalovirus, Herpes simplex

  1. Transplacental- cytomegalovirus, rubella virus
  2. Perinatal- Herpes simplex virus type 2
  3. Breast feeding
31
Q

viruses with animal reservoir

dont mem just understand

A
  1. Rabies- skunks, raccoons, bats-> from bite
  2. Hantavirus- deer mice
  3. Encephalitis viruses- birds- bite from mosquitoes
  4. Avian influenza- fowl- aerosol droplets
32
Q

Viral pathogenesis

A
  1. Death of infected cells-inhibition of macromolecule synth
  2. Immunopathogenesis-killing of virus infected cell by cd8 tcells
  3. Evasion of host defenses-altering ag
33
Q

Persistent viral infections

A
  1. Chronic carrier infection- infected and produce virus for a long time
  2. latent infections-recovers and stops production
  3. slow virus infections-prolonged period btwn initial infection and onset of disease
34
Q

Nonspecific Host Defenses

A

1.Interferons
2.NK cells
3.Phargocytosis
4.Defensins
5.Apolipoprotein B RNA-editing enzyme
6.Fever
7.Mucociliary clearance

Factors that modify defenses- extremes of age, increased corticosteroid levels, malnutrition

all highlighted

35
Q

Specific host defenses

A

Active immunity- CD8 and 4
Passive immunity- IgG and IgA
Herd immunity- interrupts transmission

36
Q

Lab tests

A

Culture
Microscopic: Inclusions, MGCs (Tzanck smear), Fluorescent tests
Serology: IgM, complement fixation
Direct ag detection: ELIS
Nucleic acid detection: PCR

37
Q

Poxviruses

A
  1. Smallpox (variola)
  2. Cowpox (vaccinia)
  3. Molluscum Contagiosum (only one we have to worry about)
38
Q

Smallpox virus

A

eradicated in 1977
Transmission: respiratory aerosol- incubate in 1-2 wks
SXS: sudden fever and malaise-> Centrifugal rash (more at edges

Bioterrism-> ring vaccine within 4 days of exposure

39
Q

Molluscum Contagiosum

A

Transmitted by close contact
SXS: round, flesh colored, waxy, umbilicated papule on skin or mucous membrane, painless, nonpruritic
immunosuppressed can get extensive infection

can be mistaken for basal cell carcinoma

40
Q

Human papillomavirus

DNA virus

A

SXS: warts and carcinoma of cervix, penis, and anus
Transmission: skin to skin contact
Incubation: 1-20 months

Immunosuppressed pts have more warts and higher rates of cervical cancer

HPV type 16 most highly indicated for cervical cancer

41
Q

HPV Vaccines

A

Gardisil-quadrivalent- 1st gen
Gardisil 9: nonavalent- 9 strains
types: 16, 18, 31, 33, 45, 52, 58- 97% of cervical cancer
Females 9-26 or males 9-15

42
Q

Juvenile laryngeal papillomatosis

A

Transmission: infected mother to neonate during birth-> warts in mouth and resp tract of infant
SXS: cough, pneumonia, HOARSENESS
infancy or any age

43
Q

Herpes viruses

A
  1. HSV-1- Gingivostomatitis-> in ganglia-> recurrent infxn: herpes labialis, encephalitis, keratitis
  2. HSV-2- Herpes genitalis, perinatal disseminated dx-> ganglia-> herpes genitalis
  3. VZV- varicella (chickenpox)-> ganglia-> Zoster
  4. EBV- infectious mononucleosis-> B LYMPHOCYTES
  5. CMV- congenital infection, mononucleosis-> monocytes
  6. HHV-6,7- Roseola-> lymphocytes
  7. HHV-8- lymphadenopathy, fever, exanthema-> B cells-> Kaposi sarcoma
44
Q

HSV1 VS HSV2

A

HSV1:
* lesions above waste
* gingivostomatitis in mouth
* Keratoconjunctivitis eye
* Encephalitis of temporal lobe
* rare in neonates
* can disseminate to viscera in immunocompromised pts

HSV2:
* below the waist
* rare mouth
* rare eye
* Meningitis
* Neonate skin lesions and disseminated infection
* rare dissemination

incubation 2-10 days

diag with PCR or Tzanck smear

45
Q

HSV1

A
46
Q

HSV2

A

Genitals and TORCH prego

47
Q

Varicella-Zoster virus VZV

A

Varicella (chickenpox)- primary disease
Zoster (shingles)- recurrent form

infects mucosa of Upper resp tract then spreads to blood then sensory neurons to dorsal root ganglia -> latent

48
Q

Varicella

A
  • chickenpox
  • incub 14-21 days
  • brief prodrome of fever and malaise
  • teens/adults: varicella pneumonia

dew drop on rose petal

49
Q

Varicella

A
  • chickenpox
  • incub 14-21 days
  • brief prodrome of fever and malaise
  • teens/adults: varicella pneumonia

dew drop on rose petal

50
Q

Zoster

shingles

A

latent infection reactivated -> dermatome vesicular rash
immunocomp-> disseminated disease

opthalmic herpes zoster

51
Q

Ramsey-Hunt syndrome

A
  • Herpes zoster oticus
  • facial nerve affected-> ipsilateral facial paralysis, ear pain, vesicles in auditory canal

tx: antivirals and steroids-> same as BELLS PALSY

52
Q

Epstein-Barr virus

A

Causes: Infectious mononucleosis
SXS: Fever, pharyngitis, lymphadenopathy over a wk, splenomegaly
Assoc w/: Burkitt lymphoma

No physical activity bc of burst spleen

53
Q

Cytomeglovirus

MC infectious cause of congenital abnormalities

LEADING CAUSE OF MENTAL RETARDATION

A
  • MOST ARE ASYMPTOMATIC
  • heterophile negative monosyndrome- Fever, lethargy, abnormal lymphocytes in blood smear

Immunocompromised:
* systemic infxn- pneumonitis, esophagitis, hepatitis
* AIDS PTS COMMONLY HAVE COLITIS WITH DIARRHEA-> RETINITIS THAT LEADS TO BLINDNESS

Testing: PCR is a gold standard
TX: Ganciclovir

Patho (4 decks)

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