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Pathophysiology II > Infectious Diseases > Flashcards

Flashcards in Infectious Diseases Deck (26):

Measles (Rubeola)

-acute viral infection
-caused by paramyxovirus
-transmitted via respiratory droplets
-replicates in respiratory tract and lymph
-t cell mediated immunity (causes rash)
-S/S= immunosuppressive, 2 week incubation period then cough runny nose and fever. Second phase = high grade fever. White spots on tongue



-acute viral infection
-caused by paramyxovirus
-transmitted via respiration
-starts in upper respiratory tract, then goes to lymph, blood, and salivary glands
1. Pain and swelling in salivary glands (sialadenitis)
2. Orchitis and pancreatitis
3. Aseptic meningitis



-acute viral infection
-caused by polio virus (enterovirus)
-transmitted via fecal-oral route; contaminated food and water
-replicates in the gut and pharynx (Peyers patches and tonsils)
-1% of cases it travels along motor neuron axons to the CNS and causes poliomyelitis
S/S = usually asymptomatic
In 1%- limb paralysis.
*similar presentation to GBS


Hemorraghic fever

-acute viral infection
-caused by: filovirus (Ebola), bunyavirus, flavivirus, arenavirus
-transmitted via infected rodents/insects, direct skin contact
-infects endothelial cells and antigen presenting cells (macrophages and dendritic cells) —> massive cytokine release —> overwhelming inflammatory response
-then you have increased permeability from inflammation, leading to hemorrhage and shock (major)
- minor = fever, headache, rash, myalgia, neutropenia, thrombocytopenia



-chronic productive infection
-has a high mutation rate so immune system is unable to eliminate the virus
-prolonged release of the infected agent



-chronic productive infection
-has a high mutation rate so unable to eliminate it
-chronic release of infected agent


Alpha HSV 1

-chronic viral infection
-caused by herpes simplex 1
-transmitted sexually, through bodily fluids, skin, mucous membrane
-infects epithelial cells
-replicate in skin and mucosa
-becomes latent in the trigeminal nerve ganglia, so can spread anywhere that nerve goes
-reactivates under favorable conditions like stress, cold, fever, surgery
-affects are above the hip so S/S =
1. Cold sores
2. Encephalitis
3. Corneal blindness
4. Gingivostomatitis
-in general can cause herpetic meningitis, hepatitis and bronchopneumonitis


Alpha HSV 2

-chronic viral infection
-caused by herpes simplex 1
-transmitted via sexual contact, bodily fluids, childbirth, skin, mucous membranes
-infects epithelial and mucosal cells, stays latent in the trigeminal nerve and is reactivated under favorable conditions
-infects below the hip so S/S=
1. Genital sores
-in general can cause herpetic meningitis, hepatitis, bronchopneumonitis


Alpha HV - Varicella Zoster Virus

-chronic viral infection
-caused by VZS or Herpes zoster (shingles)
-second exposure to the virus (first is chickenpox)
-transmitted via respiratory aerosols that originate from open blisters
-infects mucous, skin and neurons
-evades immune response by manipulating MHC complex
-infects sensory nerves and stays latent in the dorsal root ganglia, usually trigeminal, then the nerve carries the virus to skin
-S/S = dermatome rash w/ open skin lesions (unilaterally usually, and dried isn’t contagious), also causes encephalitis, pneumonia transverse myelitis


Beta-HV - Cytomegalovirus

-chronic viral infection
-caused by cytomelagovirus
-transmitted via saliva, bodily fluids, sexual contact, organ transplant
-infects monocytes and dendritic cells causing immunosuppression
-stays latent in the bone marrow progenitor cells
-in healthy adults, they are asymptomatic or have general mono like symptoms
-in immunosuppressed pts, it causes pneumonitis, hepatitis, meningoencephalitis
-babies: mental retardation and malformation
-most common pathogen acquired with AIDs
-if mother gets pregnant after infection, the baby will be fine. If she gets infected during pregnancy, there is higher risk


Gamma HBV- EBV

-transforming viral infection
-caused by Epstein Barr Virus
-transmitted via saliva mainly
-“kissing disease”
-infects oral mucosa
-enlarged CD8 T
-in normal people it resolves in 4-6 weeks and causes regular symptoms like fever
-in immunosuppressed people it can cause Burkitts Lymphoma
*diagnostic feature = heterophile antibodies



-gram positive bacterial infection
-caused mainly by s. Aureus
-transmitted via contact
-infects skin and mucosa
-has superantigen which causes excessive T cell stimulation and cytokine release for toxic shock syndrome
-protein A attaches onto the tail to avoid detection
-forms a biofilm to avoid phagocytosis
-releases bacterial toxins
-damages demoglein (skin glue) causing blisters
-S/S= skin lesions, boils, impetigo, abscesses, sepsis, endocarditis, food poisoning, and osteomyelitis
-frequently seen in catheterization


4 strains of streptococcal infection

- s. Pneumonia
- s. Viridians
- s. Pyogenes
- s. Agalactiae


Streptococcus (s.pneumonia)

-alpha strep
-gram positive bacterial infection
-most common cause of community acquired pneumonia
-uses hyaluronic acid capsule to evade immune response
-M protein - disables complement system and phagocytosis
-protein F- adheres to fibronectin
-streptokinase- cleaves plasminogen and causes bleeding
-pneumolysin- drills a hole to lyse the host cell
-S/S = scarlet fever (d/t tiny hemorrhages), otitis media, rheumatic fever, glomerulonephritis


Streptococcus (S. Viridians)

-alpha strep
- only one that does not use the hyaluronic acid capsule
- found in normal flora of the oral cavity that causes endocarditis


Streptococcus (s. Pyogenes)

-beta strep
-gram positive bacterial infection
-evades immune response by hyaluronic acid capsule
-M protein inhibits complement system and phagocytosis
-protein F adheres to fibronectin
-streptokinase cleaves plasminogen and causes bleeding (tiny hemorrhages)
-pneumolysin lyses the host cell
-S/S = rheumatic fever, scarlet fever, glomerulonephritis, otitis media
**virulent pyogenes causes necrotizing fasciitis


Streptococcus (s. Agalactiae)

-beta strep
gram positive bacterial infection
-evades immune response by hyaluronic acid capsule
-M protein inhibits complement system and phagocytosis
-protein F adheres to fibronectin
-streptokinase cleaves plasminogen and causes bleeding (tiny hemorrhages)
-pneumolysin lyses the host cell
-S/S = rheumatic fever, scarlet fever, glomerulonephritis, otitis media, pharyngitis and tonsilitis
**also causes chorioamnionitis (stillbirth)



-gram positive bacterial infection
-caused by corynebacterium diptheriae
-transmitted via respiratory droplets
-produced AB toxin to stop protein synthesis of host cell
-secretes an exotoxin that causes necrosis of epithelial cells
-S/S = Overall vague
1. Damage to kidney, liver, nerves, heart
2. Causes. Pseudomembrane


Two types of neisserial diseases

Neisserial meningitidis
Neisserial ghonorrhea


Neisserial Meningitidis

-gram negative bacterial infection
-transmitted through respiratory tract
-Causes bacterial meningitis
-only get sick if you are infected with a new strain that underwent antigenic shift
-has a thick capsule to avoid getting opsonized
-new strain causes vascular damage = meningitis rash


Neisserial Gonorrhoeae

-gram negative bacterial infection
-transmitted sexually, through childbirth, bodily fluids
-attacks epithelial cells of the genitourinary tract
-second most common STD
-S/S= in females, usually asymptomatic
“Can’t see, pee, or climb the tree”
-vaginitis/ urethritis/ cervicitis; conjunctivitis, arthritis



-gram negative bacterial infection
-caused by Bordatella pertussis bacteria
-transmitted via respiratory tract
-attacks cilia and cells of respiratory tract
-secretes AB toxin to prevent protein synthesis
-“whooping cough” during inhalation there is a whoop noise
-damage to cilia causes mucous buildup
-laryngotracheobronchitis = croup



-gram negative bacteria
-caused by P. Aeruginosa
-opportunistic pathogen in cystic fibrosis, severe burns, or neutropenia
-secretes AB toxin to prevent protein synthesis
-leads to death of host cells by secreting elastace, leukocidin, and hemolysis
-in CF: pulmonary failure
-skin burns: sepsis
-in contact lenses: corneal keratitis
-swimmers ear
-in IV drug users: endocarditis and osteomyelitis



-caused by m. Tuberculosis
-bacteria hides in the macrophage to replicate. Macrophage cannot kill it so it secretes IL-1 cytokines
-stimulates T cells, they secrete cytokines
-forms a caseating granuloma
-primary: asymptomatic
-secondary: sputum production, weight loss, hemoptysis, low grade fever
-causes Ghons Focus = the macrophage that is the initial site of infection. Ghons complex = includes the surrounding lung parenchyma
-gold standard for testing for TB = check sputum
-can do PPD/Mantoux test but it may show positive if you have been sensitized to TB, even if you got vaccine. Next is chest XRAY



-spirochete bacteria
-caused by tryptonema pallidium
-transmitted via sexual contact/transplacental
-grows inside the macrophage similarly to tb
1. Primary = 3 weeks Painless blisters “chancre”
2. Secondary = 10 weeks. Palmar rash, condylomata Latum, lymphadenopathy
3. Tertiary = 5 years. It becomes latent, then you have aortitis, brain disease (tabes dorsalis d/t CN VIII and deafness) and gumas
-children get Hutchinson teeth w/ congenital syphilis


Lyme Disease

-spirochete bacteria
-caused by Borrelia burgdorferi
-transmitted via rodents/ticks
-antigenic variation to avoid immune response
-triggers T cells and cytokines
-the bacteria does not secrete any toxins itself, pt just gets sick because of inflammatory response
-spreads via blood so it can infect anywhere
-S/S = acute tick bite and bullseye rash
-chronic= arthritis, encephalitis, neuropathy
-resembles SLE
-have to treat it before it becomes chronic