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Flashcards in Infectious Disease Deck (148):
1

Pathogenesis of Measles

  • Reservior
  • Route of infection
  • Binds which molecules to enter cells?

  • Reservior: only humans
  • Starts in RT
  • Spreads to reticuloendothelial tissue
  • virus binds CD46 and signaling lymphocytic activation molecule (SLAM) of T cells
  • Dissemination results in shedding into urine and respiratory tract secretions before rash initiates

2

Patient presents with small red spots with a blue/white center on the bucal mucosa, Cough, and conjunctivitis.  A few days later he develops a rash.  Microscopic examination shows cells pictured below.  What is the disease?

Measles (Rubeola)

  • (-) ssRNA
  • Giant cells: Warthin-Finkeldey cells  (characteristic)
  • Koplik spots also characteristic

3

What are possible severe outcomes of measles?

  1. Subacute sclerosing panencephalitis 
    • defective infection of CNS
  2. Postinfectious encephalitis

4

In what secretions is the measles virus found before the rash begins?

  • Urine
  • Respiratory tract secretions

5

Patient presents with swelling of the parotid glands and testicular pain.  

  1. What is the disease?
  2. How is it spread?
  3. What are other complications?
  4. What cell type is found in excess in the parotid glands?

  1. Mumps
  2. by aerosols
  3. Complications:
    • Orchitis (testicular pain)
    • Oophoritis
    • Aseptic meningitis
  4. Mononuclear cell infiltrate, Neutrophils in lumen of parotids

6

Patient presents with history of fever, headache, pharyngitis, and abdominal pain.  Currently presents with paralysis (LMN signs).

  1. What is the disease?
  2. How is it spread?
  3. What are CSF findings?

  1. Poliomyelitis (poliovirus)
  2. Fecal-oral route, so general symptoms are GI
  3. CNS shows
    • elevated WBCs (pleotropy)
    • slight increase in protein (FA)
    • no change in glucose (FA)

7

Patient presents with fever, pharyngitis, and abdominal pain in addition to nuchal rigidity and muscle and back pain.  CSF shows increased WBCs. 

  1. What is the disease?
  2. What is the cause?
  3. How is it spread?

  1. Aseptic meningitis
  2. Poliovirus (major illness)
  3. fecal-oral route

8

Patient presents with rash on trunk, lymphadenopathy, and arthralgia.  In addition they have a fever, headache, stiff neck, and altered CNS function.  Lab tests show elevated IgM in the CSF.

  1. What is the disease?
  2. What is the cause?
  3. How is it transmitted?
  4. What are the reserviors?

  1. Encephalitis
  2. West Nile Virus
  3. blood, transplacentally
  4. Reservior: crows, birds

9

Patient presents with fever, rash, myalgia, joint and bone pain, and vomiting.  Blood has increased leukocytes. History of travel to S. America.

  1. What is the disease?
  2. What is the pathogenesis?

  1. Dengue Fever
  2. Path:
    • circulates in monocytes
    • Lysis of cells causes release of TNF and IFN-gamma
    • TNF: increased vasc permeability
    • complement cascade activated
      • C3a and C5a increase vasc perm

10

Patient presents with 3 day fever, rash, myalgia, joint and bone pain, and vomiting.  Also presents with gingival hemorrhage.

  1. What is the disease?

  1. Dengue hemorrhagic fever.
  2. May progress to hypovolemic shock

11

What are complications of Dengue hemorrhagic fever?

  1. Thrombocytopenia
  2. DIC
  3. Hemorrhage

12

HSV

  1. Nuclear material
  2. Transmission
  3. Location of latent infection
  4. Microscopic presentation

  1. dsDNA
  2. sex, saliva, vesicle fluid
  3. HSV-1: trigeminal ganglia; HSV-2: sacral ganglia
  4. Multinucleated giant cell with eosinophilic intranuclear inclusions (Cowdry inclusions, Picmonic)

13

Patient presents with gingivitis with ulcers and perioral lesions.  Lab tests find dsDNA.

  1. What is the disease?
  2. What is the cause?

  1. Gingivostomatitis (oral-facial herpes)
  2. HSV (1)

14

Patient presents with dysuria and painful, pruritic vesicles with urethral discharge.  Lab analysis shows dsDNA.

  1. What is the disease?
  2. What is the cause?

  1. genital herpes
  2. HSV-2

15

Patient presents with headache, fever, vomiting, stiff neck, cerebral edema, and seizures.  Patient also has anosmia and memory loss.

  1. What is the disease?
  2. What is the cause?
  3. What is the pathology?

  1. Viral encephalitis
  2. HSV-1
  3. Path:
    • All viral:
      • lymphocytic infiltrate
      • glial proliferation in meninges, cortex, white matter
    • HSV:
      • necrosis in temporal lobe

16

Patient presents with headache, fever, vomiting, stiff neck, photophobia and myalgia.  Lab tests show dsDNA.

  1. What is the disease?
  2. What is the cause?

  1. Viral meningitis
  2. HSV-2

17

Patient presents with acute onset of pain in eye, conjunctivitis with a discharge, blurred vision, and "dendritic body" lesion shown below.

  1. What is the disease?
  2. What is the cause?

  1. Keratoconjunctivitis
  2. HSV (1)

18

Patient presents with history of pain, burning, and itching around mouth.  A Papule appeared that turned into a vesicle and is now a crust.

  1. What is the disease?
  2. What is the cause?

  1. Herpes labialis (cold sore)
  2. HSV (1)

19

Which type of HSV causes genital infection?

HSV-2

20

CMV

  1. Reservoir
  2. Transmission
  3. Pathology
  4. Characteristic cytology
  5. Clinical Manifestations

  1. Humans only
  2. body fluids, perinatal, congenital
  3. prevent MHC I expression
  4. Owl's eye cell
  5. Clinical:
    • Cytomegalic inclusion disease
    • Perinatal infection
    • Mono
    • Hepatitis
    • In immunocompromised: Pneumonia, chorioretinitis, esophagitis, CNS infection

21

Patient presents with fatigue, fever, pharyngitis, and mild hepatitis.  Lab tests are negative for heterophile Abs.  Cells found are shown below.

  1. What is the disease?
  2. What is the cause?

  1. Mononucleosis
  2. CMV
    • EBV is positive for heterophile Abs

22

Patient presents at birth with jaundice, rash, and respiratory distress.  Cytology below.

  1. What is the disease?
  2. What is the cause?

  1. Cytomegalic inclusion disease
  2. CMV

23

What can be the long-term effects of Perinatal infection by CMV?

  • loss of hearing
  • developmental effects on intelligence

24

What are the diseases CMV causes in immunocompromised patients?

  1. Chorioretinitis
  2. Esophagitis
    • ulcerations, difficulty swallowing, diarrhea
  3. Hemorrhagic pneumonia
  4. Polyradiculopathy
    • ascending weakness, loss of deep tendon reflexes, loss of bowel and bladder control

25

Patient presents with fever, headache, and sore throat in addition to a rash that started on the head and has spread to the trunk.  Some spots are papules, some are vesicles, some are crusts.

  1. What is the disease?
  2. What is the cause?
  3. How is it transmitted?

  1. Chickenpox
  2. VZV
  3. Respiratory secretions or vesicle fluid

26

Patient has history of pain and neuralgia.  A few days later a rash appears.  The rash is along the lines of a dermatome and does not cross the midline.

  1. What is the disease?
  2. What is the cause?
  3. What is the Pathogenesis?
  4. What is the infiltrate?

  1. Shingles
  2. VZV
  3. Path:
    • latent infection in sensory nerve (dorsal root ganglia)
    • neuronal necrosis
    • Mononuclear infiltrate

27

HBV

  1. Genetic material
  2. Reservior
  3. Transmission

  1. circular, partially-dsDNA (some parts are ssDNA)
    • enveloped
  2. humans only
  3. body fluids, transplacental

28

What is the pathogenesis and end result of chronic hepatitis?

  • Path:
    • mononuclear infiltrate
    • Fibrosis
    • Necrosis
    • In chronic active, no anti-s or c Ab
  • End result:
    • cirrhosis
    • hepatocellular carcinoma

29

To what does EBV bind to enter B-cells?

CD-21

30

What proteins are expressed in EBV infection?

  1. EB Nuclear Ag  (EBNA)
    • EBNA-2 = cyclin D expression to stimulate cell cycle
  2. latent protein
  3. Latent membrane protein (LMP)
    • LMP-1 activates B-cells

31

What events are associated with transformation in EBV?

  1. t8;14 w/ c-myc gene
  2. LMP-1 activates B cells
  3. EBNA-2 stimulates cyclin D and cell cycle progression

32

Patient presents with with fever, fatigue and pharyngitis.  Lab tests are positive for heterophile Abs and the cells shown below.

  1. What is the disease?
  2. What is the cause?
  3. How is it transmitted?
  4. What is the cell called?

  1. Mononucleosis
  2. EBV
  3. intimate contact (eg: saliva)
  4. Downy cell

33

Pathogenesis of EBV

34

HPV

  1. Transmission
  2. Pathogenesis (molecular and cellular)
  3. resulting disease

  1. direct contact or inanimate objects with compromised skin
  2. Path:
    • integrates dsDNA genome into host
    • E6 and E7 are expressed and inhibit cell cycle regulation
    • Hyperplasia of skin and cancer results
    • koilocytic changes to epithelium
  3. Disease:
    • warts (Condyloma acuminatum)
    • cervical squamous cell carcinoma and adenoma

35

What is pictured?

Cervical squamous cell carcinoma

Swirls are called keratin pearls

36

Which of the staphylococcus produce coagulase?

S. aureus

37

In S. aureus infection,

  1. What inhibits opsonization?
  2. What inhibits chemotaxis and phagocytosis
  3. What is a common resistance?
  4. What toxins are produced?

  1. What inhibits opsonization?
    • Protein A
  2. What inhibits chemotaxis and phagocytosis?
    • capsule/biofilm
  3. What is a common resistance?
    • beta-lactamase
  4. What toxins are produced?
    • alpha-toxin (cytolytic/necrosis)
    • Leukocidin (cytolytic for macrophage)

38

What super antigens are produced by S. aureus?  What diseases do they cause?

  1. Enterotoxins
    • food poisoning
  2. Pyrogenic exotoxins (TSST-1)
    • Toxic shock syndrome
  3. Exfoliatins
    • Scalded skin syndrome
    • impetigo

39

What is pictured?

Staphylococcus

Characteristic grape-bunch formation

40

Patient presents with both fluid-filled blisters and crusts.  Lab tests are catalase (+) and coagulase (+).

  • What is the disease?
  • What is the cause?
  • With what toxin is it associated?

  • Bullous impetigo
  • S. Aureus
  • exfoliative toxin/epidermalytic toxin

41

Patient presents with a diffuse rash and flaccid bullae.  Nikolsky's sign is positive (epidermis easily separates with slight pressure).  Lab tests are catalase (+) and coagulase (+).

  • What is the disease?
  • What is the cause?
  • With what toxin is it associated?

  • Scalded skin syndrome
  • S. aureus
  • exfoliative toxin

42

What is the difference between SIRS, sepsis, and septic shock?

  • SIRS (systemic inflammatory response syndrome)
    • fever, increased WBC count, HR, respiration
    • No evidence of infection
  • Sepsis
    • same as above but with infection
  • Septic shock
    • same as above but with organ dysfunction and hypotensive shock (BP <60)

43

Patient presents with fever, chills, petichiae, and heart murmur.  Lab tests are positive for catalase and coagulase.

  • What is the disease?
  • What is the cause?

  • Native valve infective endocarditis
  • S. aureus

44

Patient presents with acute onset of fever, dyspnea, tachypnea, and a mucopurulent sputum.  Lab tests are positive for catalase and coagulase.  

  • What is the disease?
  • What is the cause?

  • Pneumonia
    • often hemorrhagic necrosis with absess/ pneumatocele formation
  • S. aureus

45

What connective tissue disorders are associated with S. aureus? 

  1. Osteomyelitis
    • bone destruction, pain, swelling, fever
  2. Septic arthritis
    • local inflammation, pain, and swelling of one joint

Both may progress to sepsis

46

Patient presents with fever, myalgia, rash, and erythema that blanches on pressure.  Lab tests are positive for catalase and coagulase.

  • What is the disease?
  • What is the cause?
  • With what toxin is it associated?

  • Toxic shock syndrome
  • S. aureus
  • TSST-1

47

What are the virulence factors of S. pyogenes?

  1. M protein
  2. Streptolysin S
    • O2 stable
  3. Streptolysin O
    • O2 labile
  4. SPEA
    • scarlet fever and strep toxic shock

48

Patient presents with pharyngitis and a rash that blanches with pressure with circum-oral pallor.  After almost a week the rash desquamates.  Lab tests are negative for catalase but show SPEA.

  • What is the disease?
  • What is the cause?
  • With what toxin is it associated?

  • Scarlet fever
  • Strep. pyogenes
  • SPEA (exotoxin)

49

Patient presents with pharyngitis and a raised lesion with distinct borders on the face.  Lab tests are catalase negative.

  • What is the disease?
  • What is the cause?

  • Erysipela
  • Strep. pyogenes

50

Patient has history of papule that developed into vesicle, then pustule, and now has a thick, amber-colored crust.  Lab tests are catalase negative.

  • What is the disease?
  • What is the cause?

  • Impetigo
  • Strep. pyogenes

51

What is the most common cause of life-threatening invasive bacterial infection in neonates?

strep. agalactiae

52

Infant presents with respiratory distress, cyanosis, hypotension, and jaundice 10 hours after birth.

  • What is the disease?
  • What is the cause?
  • With what is it associated?
  • What are some complications?

  • Early onset neonatal infection by Strep. agalactiae
  • Associated with obstetric complications
  • Complications:
    • septicemia (60%)
    • pneumonia (30%)
    • meningitis (10%)

53

Patient presents with septicemia and meningitis 2 weeks after birth.

  • What is the disease?
  • What is the cause?

  • Late onset neonate infection by Strep. agalactiae

54

What infections are caused by strep. agalactiae in adults?

  1. bacteremia/septicemia (30-40%)
  2. skin and soft tissue (15-40%)
  3. UTI (5-15%)

55

Streptolysin S or O is indicative of which bacteria?

Strep. pyogenes

56

Pneumolysin O is indicative of which bacteria?  What is its function?

Strep. pneumoniae

Function: cytotoxic; causes alveolar edema and hemorrhage

57

Patient presents with fever, chills, chest pain, and cough productive of rusty-colored sputum.  There is consolidation of the lungs restricted to lobar compartments.

  • What is the disease?
  • What is the cause?
  • What is the composition of the infiltrate?

  • lobar pneumonia
  • Strep. pneumoniae
  • neutrophils followed later by macrophages

58

What diseases are most commonly caused by Strep. pneumoniae?

  1. Meningitis
  2. Otitis media
  3. Pneumonia
  4. Sinusitis

**Think MOPS

59

What are the virulence factors of Strep. pneumoniae?

  1. capsule
  2. pneumolysin O
    • O2-labile hemolysin that causes alveolar edema and hemorrhage

60

Patient presents with pharyngitis with an adherent pseudomembrane.  

  • What is the disease?
  • What is the cause?
  • What is the pathogenesis?

  • diphtheria
  • Corynebacterium diphtheriae
  • Path:
    • A-B exotoxin
      • B binds receptors, A inactivates EF-2 and inhibits protein synthesis

61

What severe manifestations can develop with diphtheria?

  1. Myocarditis (with arrhythmia)
  2. Neurologic symptoms
    • paralysis of soft palate

62

How does Listeria monocytogenes evade the immune system?

  • Intracellular pathogen
  • spreads between cells without leaving a cell
    • forms actin tails (Act A surface protein induces actin polymerization)
    • forms projections that are injested by neighboring cells
  • Reduces MHC expression on host cell

63

How is Listeria monocytogenes transmitted?  What is its path in the body (tissues affected)?

  • Transmitted by
    • food
    • transplacentally
  • blood => CNS

64

What diseases are caused by Listeria monocytogenes?

  • Gastroenteritis
  • Septicemia in pregnancy 
  • Early neonatal infection
    • resp distress and sepsis
  • Late onset
    • meningitis
  • Purulent meningitis in adults
    • followed by seizures and movement disorders**

65

Pregnant patient presents with fever, headache, myalgia and arthralgia.  CSF shows increased monocytes.  What is the disease?  What is the cause?

Disease: septicemia

Cause: Listeria monocytogenes

66

Patient presents shortly after birth with respiratory distress and sepsis.  What is the cause?

Early-onset infection

Listeria monocytogenes

67

Patient presents with fever, nausea, vomiting, and neck stiffness that lasts a few days followed by seizures and movement disorders.  What is the disease?  What is the cause?

  • Disease: (purulent) meningitis
  • Cause: Listeria monocytogenes

68

Patient presents with abdominal pain, fever, chills, bloody diarrhea, and pharyngeal psudomembrane.  Endospores are found in lab tests. What is the disease?  What is the cause?

  • Disease: intestinal anthrax
  • Cause: Bacillus anthracis

Abdominal pain = mesenteric lymphadenitis

Bloody diarrhea = GI necrosis

Fever/Chills with shock = toxemia

69

Patient has a history of flu-like symptoms for the past few days.  He now presents with fever, chills, and dyspnea.  Imaging is shown below.  What is the disease?  What is the cause?  What is its pathology?

  • Disease: Inhalation anthrax
  • Cause: bacillus anthracis
  • Path:
    • Edema factor
    • Lethal factor
    • (Polyglutamic acid capsule = antiphagocytic)
  • Image:
    • left pleural effusion
    • mediastinal widening

70

Patient presents with a pustule with bluish-black fluid.  Lab tests show endospores.  What is the disease?  What is the cause?  What is the next step in the disease process?

  • Disease: Cutaneous anthrax
  • Cause: Bacillus anthracis
  • Lesion will form a crusted, painless eschar

71

What are the exotoxins produced by Bacillus anthracis?  What are their functions?

  1. Edema factor
    • calmodulin-dependent adenylate cyclase
    • Increase cAMP
    • altered ion flux and hypersecretion
  2. Lethal factor
    • metallopeptidase
    • Inhibits MAP kinase
    • apoptosis and necrosis

72

Patient presents with pneumonia. Abcesses and draining sinuses are found in the lungs.  Brain abcesses are also found.  Sulfur granules are found in the lesions and the organism is acid fast. The organism is shown below.  What is the cause? 

Nocardia asteroides

gram stain shows filaments that branch

73

Patient presents with ankle and foot pain and swelling with abcess formation and draining sinuses.  Sulfur granules are found in the lesions, and the organism is acid-fast. What is the disease?  What is the cause?

  • Disease: Madura foot
  • Nocardia brasiliensis

74

Patient presents with fever, headache, vomiting, leukocytosis, and petechiae along the waist where the top of the pants are.  Lab results show thrombocytopenia.  What is the disease?  What is the cause?  What are the associated virulence factors?

  • Disease: meningococcemia
  • Cause: Neisseria meningitidis
  • Virulence factors
    • antiphagocytic capsule
    • LOS
      • proinflammatory
      • induces necrosis and DIC

75

Patient presents with sudden onset of fever, headache, nausea, and myalgia. What is the disease?  What is the cause?  What are the associated virulence factors?

  • Disease: Meningitis
  • Cause: Neisseria meningitidis
  • Virulence factors
    • antiphagocytic capsule
    • LOS
      • proinflammatory
      • induces necrosis and DIC

No seizure (w/ seizure = L. monocytogenes)

76

Neisseria meningitidis

  • Transmission
  • Virulence factors
  • Diseases and characteristic symptoms

  • Transmission
    • inhaled
  • Virulence factors
    • antiphagocytic capsule
    • LOS
      • proinflammatory
      • induces necrosis and DIC
  • Diseases and characteristic symptoms
    • Meningococcemia
      • thrombocytopenia
      • sepsis with petechiae/ecchymoses (found where pressure is applied to skin, belts etc)
    • Meningitis
      • Myalgia
      • absence of seizure (Listeria monocytogenes)

77

Male patient presents with dysuria with a copious purulent exudate in addition to unilateral testicular pain and swelling.  What is the disease?  What is the cause?  What are the associated virulence factors?

  • Disease: Urethritis with epididymitis (genital infection in men)
  • Cause: N. gonorrheae
  • Virulence factors:
    • Pili (bind CD46 for adherance)
    • OPA (penetrate cell membrane)

78

Female patient presents with cervicitis with a purulent vaginal discharge and dysuria. What is the disease?  What is the cause?  What severe complications can result?

  • Disease: Cervicitis and urethritis (female genital infection)
  • Cause: Neisseria gonorrheae
  • Complications:
    • Pelvic inflammatory disease
    • Lower genital tract infection
    • infertility

79

Neisseria gonorrhea

  • What are the virulence factors?
  • What diseases does it cause?

  • Virulence factors:
    • Pili (bind CD46 for adherance)
    • OPA (penetrate cell membrane)
  • Disease:
    • Genital infection

80

Patient presents with paroxysmal cough with inspiratory whoops.  Lab shows lymphocytosis.  What is the disease?  What is the cause?  What are the associated virulence factors?

  • Disease: whooping cough
  • Cause: Bordetella pertussis
  • Virulence factors:
    • Pertussis toxin
    • Invasive adenylate cyclase

81

Bordetella pertussis

  • Virulence factors and function
  • Stages of disease

  • Virulence factors (delivery by type III secretion)
    • Invasive adenylate cyclase: increases cAMP
      • in phagocytes, inhibits phagocytic activity
    • pertussis toxin: ribosylates G-proteins causing increased cAMP
      • increased secretions, histamine sensitization, lymphocytosis, necrosis
  • Disease: Whooping cough
    • Catarrhal stage: flu-like symptoms
      • rhinorrhea, fever
    • Paroxysmal cough stage

82

Patient presents with sepsis with the necrotic lesions shown below.  What is the disease?  What is the cause? 

  • Disease: Sepsis with characteristic ecthyma gangrenosum 
  • Cause: pseudomonas aeruginosa

83

Psuedomonas aeruginosa

  • Virulence factors
  • Diseases

  • Virulence factors:
    • Pyocyanin pigment (proinflammatory, produce ROS) (characteristic)
    • LPS
    • Capsule/glycocalyx/biofilm (resist phagocytosis, opsonization, antibiotics)
    • heat-labile hemolysin
    • Exotoxins A and S (protein synthesis)
    • Antibiotic resistance
  • Disease
    • necrotizing pneumonia
      • especially in cystic fibrosis patients (incurable, associated with biofilm)
    • Sepsis with ecthyma gangrenosum
    • Wound and burn infection
    • Folliculitis (hot tub folliculitis)
    • External otitis
    • Keratitis
    • nosocomial UTI

84

What is the characteristic virulence factor of pseudomonas?

Pyocyanin pigment

85

What bacteria is associated with pneumonia in cystic fibrosis patients?

Pseudomonas aeruginosa

86

Patient presents with abrupt onset of high fever, chills, and headache.  Physical exam shows painful lymphadenopathy.  What is the disease?  What is the cause? How is it transmitted? What are the complications/progression of the disease?

  • Disease: bubonic plague
  • Cause: Yersinia pestis
  • Transmission: flea bite, prarie dogs
  • Progression
    • Pneumonic plague (hemorrhagic and necrotizing)
    • Septicemic plague (endotoxemia, DIC, vascular collapse)

87

Patient presents with genital ulcer and inguinal lymphadenitis with a draining sinus tract.  What is the disease?  What is the cause? 

  • Disease: Chancroid
  • Cause: Haemophilus ducreyi
  • Helps transmit HIV

88

Patient presents with fever, hemoptysis, and chest pain.  The patient is PPD+. What is the disease?  What is the cause? What is the pathogenesis?

  • Disease: Progressive Primary TB
  • Cause: Mycobacteria tuberculosis
  • Path: Th1 hypersensitivity reaction.

89

Patient presents with fever, night sweats, weight loss, and hemoptysis.  New lesions are found on the lungs localized to the apex of the upper lobes.  The patient is PPD+. What is the disease?  What is the cause? 

  • Disease: Secondary TB
  • Mycobacteria tuberculosis

90

Patient presents with mild pneumonitis with flu-like symptoms.  Chest radiography shows hilar adenopathy and subpleural granulomas. Patient is PPD+.  What is the disease?  What is the cause? What is the presentation shown on radiography called? 

Disease: Primary TB

Cause: Mycobacteria tuberculosis

Presentation: Ghon complex

91

Patient is PPD+ and presents with the lesions on the spleen as shown below. What is the disease?  What is the cause?

  • Disease: Miliary TB
  • Mycobacteria tuberculosis

92

Mycobacteria leprae

  • Cellular Pathology
  • Disease

  • Pathology
    • strict intracellular parasite
      • macrophages and schwann cells
    • Capsule: glycolipid and lipoarabinomannan
    • Induces TLR on schwann cells
    • TLR binds lipopeptides of M. leprae and induce apoptosis
    • rapid demyelination of peripheral nerves
    • CMI (Th1) mediates early damage
    • Th2 mediates late damage (lepromatous)
  • Disease: Leprosy

93

Patient presents with few hypopigmented, anesthetic lesions in addition to skin and muscle atrophy.  What is the disease?  What is the cause?  What is the predominant immune response?

  • Disease: Tuberculoid leprosy (hansen disease)
  • Cause: Mycobacteria leprae
  • Response: Th1 (CMI)

94

Patient presents with bilateral, symmetrical distribution of papules and nodules with peripheral neuropathy and hypergammaglobulinemia.  What is the disease?  What is the cause?  What is the primary immune response at this stage?

  • Disease: Lepromatous leprosy
  • Cause: Mycobacteria leprae
  • Response: Th2 (humoral)

95

Patient presents with an inflammatory lesion shown below and inguinal lymphadenopathy.  What is the lesion called?  What is the disease? What is the cause?

  • Lesion = chancre
  • Primary syphilis
  • Treponema pallidum

96

Patient presents with fever, headache, arthralgia, and sore throat.  There are crusted lesions on the skin and a genital lesion shown below.  No bugs were grown on culture.  What is the lesion called? What is the disease? What is the cause?

  • Lesion: condylomata lata
  • Disease: Secondary syphilis
  • Cause: Treponema pallidum

Not able to be grown on culture

97

Which form of syphilis presents with generalized seizures?  What is the cause of the seizures?

Meningovascular syphilis

seizures caused by endarteritis obliterans, causing occlusion of vessels to the CNS

98

Which form of syphilis presents with changes in personality, tremors, ataxia, and other CNS signs?

Parenchymatous syphilis (late/tertiary)

General paresis and Tabes Dorsalis

99

Which form of syphilis causes aneurysm of the ascending aorta?

Cardiovascular syphilis

endarteritis obliterans occludes aorta

100

What is the difference between early and late congenital syphilis?

Early: 

  • Before age 2
  • vesicular rash and systemic signs

Late:

  • After age 2
  • CNS problems
  • bone development issues
    • periostitis
    • osteochondritis
    • Hutchinson teeth (small, notched incisors)

101

Treponema pallidum

  • Transmission
  • characteristics
  • Evasion of immune system
  • Disease

  • Transmission
    • close contact or transplacental
  • characteristics
    • gram negative
    • Doesn't grow on lab medium
  • Evasion of immune system
    • coated with host fibronectin
    • inhibits phagocytosis
  • Disease
    • syphilis

102

Patient has a history of fever, chills, headache, and myalgia, which went away for almost a week before returning.  Presents with hepatosplenomegaly.  A blood smear is shown below.  What is the disease? What is the cause?  What is the vector?

  • Disease: Relapsing fever
  • Cause: Borrelia hermsii
  • Vector: tick

103

What are the vectors that carry Borrelia recurrentis and B. hermsii?

  • Recurrentis: lice
    • most common in S. America
  • Hermsii: ticks
    • most common in western US

104

During first visit, patient presents with skin lesions and facial nerve palsy.  A few weeks later, he returns with arthritis of the large joints.  What is the disease?  What is the cause? What is the vector?

  • Disease: Lyme disease
  • Cause: Borrelia burgdorferi
  • Vector: deer tick

105

What are the stages of lyme disease progression?

106

What is characteristic of infections caused by anaerobes?

abscess formation with foul-smelling exudate

107

What infections are caused by anaerobic, non-spore forming gram positive cocci (streptococcus)?

  1. Brain abcess
  2. Aspiration pneumonia
  3. Intra-abdominal infection
  4. Female pelvic infection

108

P. acnes

  • Characteristics
  • Disease

  • Characteristics
    • gram positive rod
    • non-spore forming
    • anaerobe
  • Disease:
    • acne vulgaris

109

Bacteroides fragilis

  • Characteristics
  • Diseases

  • Characteristics
    • anaerobic
    • gram negative rod
  • Diseases:
    • intra-abdominal infection
    • anaerobic bacteremia
    • Community acquired gastroenteritis

110

Patient presents a green-black lesion with visible gas formation following trauma.  What is the disease?  What is the cause (physiological and organism)? 

  • Disease: myonecrosis (gas gangrene)
  • Physiology:
    • extensive muscle necrosis
  • Organism: 
    • Clostridium perfringens

111

What exotoxins are produced by Clostridium perfringens?

  • alpha-toxin
    • necrosis
    • hepatic tox
    • myocardial dysfunction
  • beta-toxin
    • enteritis necroticans (necrosis and HTN)
  • theta-toxin
    • pore-forming hemolysin

112

Patient presents with lockjaw and spastic paralysis.  What is the disease? What is the cause?  What is the mechanism of disease?

  • Disease: Tetanus
  • Cause: Clostridium tetani
  • Mechanism:
    • tetanospasmin neurotoxin degrades synaptobrevin
    • blocks release of inhibitory neurotransmitters

113

Patient presents with bilateral cranial nerve dysfunction (dry mouth, blurred vision, diplopia, difficulty swallowing) and symmetric descending weakness and paralysis.  What is the disease?  What is the cause?  What is the mechanism of disease?

  • Disease: Botulinum tox?
  • Cause: Clostridium botulinum
  • Mechanism:
    • neurotoxin inhibits ACh release from cholinergic synapses
    • paralysis or autonomic dysfunction

114

Patient presents with fever, abdominal pain, and profuse bloody diarrhea with characteristic inflammatory plaques and ulcerations.  What is the disease?  What is the cause?  What toxins are produced?

  • Disease: pseudomembranous entercolitis
  • Cause: Clostridium difficile
  • Toxins:
    • enterotoxin A: fluid secretion
    • cytotoxin: actin depolymerization and cell death

115

Patient presents with inguinal lymphadenopathy with a painful node that ruptured forming a draining sinus.  Lab tests find elementary and reticulate bodies in cells.  What is the disease?  What is the cause?

  • Disease: Lymphogranuloma venereum
  • Chlamydia trachomatis
    • Serotypes L1-3

116

Patient has history of follicular conjunctivitis with some scarring of the cornea.  Presents with eyelashes that have grown inward, causing more corneal scarring.  What is the disease?  What is the cause?

  • Disease: Trachoma
  • Cause: Chlamydia trachomatis
    • Serotypes A, B, C

117

Patient presents with conjunctivitis and a urogenital infection with dysuria and a moderate purulent discharge.  Lab tests show intracellular elementary and reticulate bodies.  What organism causes this disease?

Oculogenital disease

Chlamydia trachomatis

Serotypes D-K

118

Patient presents with fever, heachache, myalgia, vomiting, and diarrhea.  CSF lymphocytosis and confusion are also present.  Inclusions are found in monocytes.  What is the disease?  What is the cause? What is the vector?

  • Disease: human monocytic ehrlichiosis
  • Cause: Ehrlichia chaffeensis
  • Vector: lone star tick

119

Patient presents with fever, headache, myalgia, vomiting, and CNS manifestations.  Inclusions are found in neutrophils (monocytic cells). What is the disease?  What is the cause?  What is the vector?

  • Disease: Human granulocytic anaplasmosis
  • Cause: Anaplasmosis phagocytophilum
  • Vector: Deer ticks

120

Patient presents with abrupt onset of fever, headache, and myalgia.  A macular rash with petechiae began on the wrists, palms, and ankles and has now become generalized.  What is the disease?  What is the cause?  What is the vector?

  • Disease: Rocky Mountain spotted fever
  • Cause: Rickettsia rickettsii
  • Vector: wood or dog tick

121

Common characteristics of Candida infection of mucous membrane

  • pseudomembrane
    • Oral candidiasis
    • Genital (with burning, itching, purulent discharge)
    • Esophagitis (difficulty swallowing)

122

Patient presents with erythematous, dry, scaly, pruritic lesions of the skin.  Labs show germ tubes. What is the disease?  What is the cause?

  • Disease: Intertriginous candidiasis
  • Cause: Candida albicans
  • may have germ tubes or pseudohyphae

123

Patient presents with a fever and cough productive of mucoid, bloody sputum.  Labs show pseudohyphae and budding yeasts, shown below.  What is the disease?  What is the cause?

  • Disease: Bronchopulmonary candidiasis
  • Cause: Candida albicans
  • May have germ tubes or pseudohyphae

124

What systemic diseases can be caused by Candida infection?

  1. esophagitis
  2. GI candidiasis
  3. Fungemia
  4. Bronchopulmonary candidiasis
  5. UT
  6. Endocarditis
  7. Hepatosplenic candidiasis
  8. CNS candidiasis

125

Which fungus has a capsule?

Cryptococcus neoformans

126

Cryptococcus neoformans

  • Virulence factors
  • Diseases

  • Virulence factors
    • Capsule (only fungus with this)
      • block T cell activation
      • Inhibits phagocytosis
    • Melanin
      • protect from UV damage
  • Diseases:
    • Acute pulmonary
    • Skin lesions
    • CNS infection: meningoencephalitis
      • soap-bubble lesion

127

Patient presents with long history of sinus congestion and pain.  Microscopy shows thin, septate hyphae with acute angle branching.  What is the disease?  What is the cause?

  • Disease: Aspergilloma (fungus ball in sinuses)
  • Cause: Aspergillus

128

Patient presents with persistent productive cough, hemoptysis, wheezing, and dyspnea.  Microscopy shows thin, septate hyphae with acute angle branching.  What is the disease?  What is the cause?

  • Disease: Aspergilloma in lungs
  • Cause: Aspergillus

129

Aspergillus

  • Characteristics
  • Diseases

  • Characteristics:
    • soil fungus
    • septate, acute angle branching hyphae
  • Disease:
    • Allergic bronchopulmonary aspergillosis
    • Aspergilloma (sinus or lung)
    • Invasive pulmonary aspergillosis

130

Patient presents with facial pain, edema, and orbital cellulitis.  Patient also has diabetes.  Microscopy shows fungi with non-septate filaments with right-angle branching.  What is the disease?  What is the cause?

  • Disease: Rhinocerebral mucormycosis
  • Cause: mucormycosis

131

Mucormycosis

  • Characteristics
  • Diseases

  • Characteristics
    • soil fungi
    • nonseptate filaments with right-angle branching
    • Disease limited to immunocompromised and diabetics
  • Disease:
    • Rhinocerebral: skin and possible brain involvement
    • Pulmonary: necrotic pneumonia
    • Cutaneous: Cellulitis

132

In the plasmodium life cycle, what is sporogony?  What is schizogony?  Where does each stage take place?

  • Sporogony = sexual cycle
    • occurs in mosquito
  • Schizogony = asexual cycle
    • occurs in human

133

In the plasmodium cycle, which form infects hepatocytes?  RBCs? 

  • Hepatocytes: infected by sporozoites
    • occurs before RBC can be infected
  • RBCs: infected by merozoites

134

In the Plasmodium life cycle, which stage can remain dormant in the liver?  Which forms of plasmodia produce this life cycle stage?

Hypnozoites

Formed by P. vivax and P. ovale

135

Plasmodium life cycle: Sporogony

136

Plasmodium life cycle: Schizogony

137

What is the malaria paroxysm?  To which step in the life cycle does it correspond?

  • Chills and rigors followed by fever spikes up to 104 F
  • Later profuse sweating and fatigue
  • Corresponds to release of merozoites from rupturing schizonts (RBC lysis)

138

What are the pathology and symptoms of infection by Plasmodium falciparum?

Path:

  • Malaria with microvascular disease
  • trophozoite-infected RBC adheres to endothelium of microvasculature
    • hypoxia with obstruction

Symptoms

  • Malaria paroxysm
  • Hypoglycemia (from parasite feeding)
  • Hemoglobinuria
    • Blackwater fever
  • May progress to Seizures and coma

139

Patient presents with gradual onset of fever and fatigue, followed by hemolytic anemia.  Organisms are found in RBCs in the forms of rings and triads.  What is the infecting organism?  What is the vector?

  • Cause: Babesia microti
  • Vector: tick

140

Patient presents with an ulcerative "pizza" lesion.  What is the infectious agent?  What are the two forms of this agent?  What is the vector? 

  • Cause: Leishmania
  • Vector: Sandfly (only of promastigote)
  • Forms:
    • promastigote: free-living, transmitted
    • amastigote: intracellular form, in reticuloendothelial tissue

141

What are the two life stages of Leishmania?

  • promastigote:
    • free-living
    • transmitted by sand fly
  • amastigote:
    • intracellular form
    • reticuloendothelial tissue

142

Patient presents with fever, chills, facial edema, lymphadenopathy, and myocarditis.  What is the disease?  What is the infectious agent?

  • Disease: Chagas
    • transmitted by reduviid (kissing) bug
  • Cause: 
    • Trypanosoma cruzi

143

Trypanosoma cruzi

  • Transmission vector
  • Life cycle
  • Disease
  • Complications

  • Transmission vector
    • Reduviid (kissing) bug
  • Life cycle
    • trypomastigote: free-living in blood
    • amastigote: intracellular, parasitizes myocardium
  • Disease
    • Chagas
  • Complications
    • CHF

144

Trypanosoma brucei

  • Vector
  • Life Cycle
  • Disease

  • Transmission vector
    • Tsetse fly 
  • Life cycle
    • only one stage
    • trypomastigotes are free form and replicate in blood
  • Disease
    • African sleeping sickness
       

145

Schistosoma: mansoni vs haematobium

  • Type of helminth
  • Path (same for both)
  • Infected tissue

  • Fluke (flat w/ branching alimentary tracts)
  • Path:
    • Formation of granulomas around eggs
    • Fibrosis
  • Infected tissue:
    • Mansoni: GI and liver
    • Haematobium: Bladder

146

What are the differences between Nematodes, Cestodes, and Trematodes?

  • Nematodes (roundworms)
    • cylindrical body
    • tubular GI tract
    • sexes are separate
  • Cestodes (tapeworms)
    • flattened bodies
    • no GI tract
    • both sex organs in same organism
  • Trematodes (flukes)
    • flattened bodies
    • branching GI

147

Patient presents with lymphadenopathy and lymphedema in the legs.  Epithelial hyperkeratosis has left the leg scaly.  What is the disease?  What are the possible infectious agents?

  • Disease:
    • Lymphatic filariasis with elephantiasis
  • Infectious agents:
    • Wuchereria bancrofti (Tropics)
    • Brugia malayi (SE Asia)

148

Patient presents with an itchy dermatitis associated with a granulomatous reaction that develops around adult worms.  There is also keratitis of the cornea.  Samples show worms with cylindrical bodies. What is the disease? What is the infectious agent? Where are larvae found?

  • Disease: Onchoceriasis (river blindness)
  • Cause: Onchocerca volvulus
  • Larvae: in connective tissue of skin