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Quiz 4 > Session 9: Respiratory tract infections > Flashcards

Session 9: Respiratory tract infections Flashcards

0
Q

Acute pharyngitis

A

greater than 90% is viral

  • Rhinovirus: common cold
  • Coronavirus: common cold
  • EBV: mono
  • Coxsackle: herpangia
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1
Q

Pharyngitis

A

40% are virus origin: includes common cold, mono, inflammation of pharynx to infectious agent, often co-exists with tonsillitis

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2
Q

common cold

A

more than 100-200 different virus causes, so immunity is not a protective factor, no vaccines available.

  • 30 to 50% are rhinoviruses (113 serotypes)
  • direct contact transmission
  • 15 to 20% are coronaviruses
  • easily spread to sinuses, lower res. tract, middle ear
  • triggers asthma
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3
Q

infectious mono: “Kissing Disease”

A

cause- EBV: HHV 4, enveloped

IM: infectious mononucleosis

  • have it very young and mild infection
  • gets severe when you get older
  • systemic effect on cardiovascular and lymphatic system
  • virus shed intermittently from saliva through life

Symptoms: fever, sore throat, swollen lymph glands in neck, weakness, fatigue, enlarged spleen

  • production of heterophile antibodies, used in lab tests
  • ampicillin rash: systemic syndrome
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4
Q

pharyngitis details

A
  • streptococcus pyogenes (group A), GAS- beta hemolytic streptocci
  • GAS pharyngitis: most common GAS infection, often in school aged children, in 15 to 30% of cases
  • direct contact
  • incubation is 2-4 days
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5
Q

Acute rheumatic fever

A
  • caused by previous GAS pharyngeal infection with latent period of 2-4 weeks
  • disorder most common among children 5-15 years
  • occur in developing countries
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6
Q

Rheumatic fever

A
  • non infectious complication of strep A (s. pyogenes) infection
  • after one month, untreated strep throat infection
  • prevent is to TREAT all throat infections!
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7
Q

scarlet fever

A

symptoms: rash on neck and face around mouth, then spreads to chest and body.

6 days: rash will go away, fever is 101 F and over, sore throat- very red, pass soon after fever

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8
Q

Scarlet fever is caused by….

A

a bacteriophage! (viruses of bacteria that carry DNA that goes into the bacteria) that has a toxin that kills epithelial cells

  • Tonsils: swollen, coated in white substances with yellow dots
  • Strawberry tongue: very red, has white and pink dots
  • other: chills, body aches, throwing up with nausea, decreased appetite.
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9
Q

Whooping cough

A

aka 100 days cough

  • bordetella pertussis: small gram negative, aerobic, coccobacillus
  • important exotoxins: tracheal cytotoxin: damages ciliated cells, pertussis toxin: enters blood stream and cause systemic effects
  • vomiting, droplet and mucous transmission
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10
Q

Diphtheria

A

caused by corynebacterium diphtheriae, gram positive bacillus, non spore forming

  • doesn’t invade tissues: produce exotoxin ( inhibit protein synthesis in host cells)
  • toxin diffuses out into tissues ( tropism) for nerves
  • once leading cause of mortality in children
  • vaccination helped

Symptoms:
-sore throat, fever, malaise, neck swelling, nerve paralysis, white gray membrane across back of throat ( fibrin, dead tissue, bacterial cells, WBC)

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11
Q

Diphtheria pathogenesis

A

pathogenesis: produces toxins that cause death in epithelia cells of the throat
- result is inflammation, accumulation of phagocytes
- thick gray membrane grows at the back of the throat and bleeds if you try to dislodge it
- membrane has dead epithelia cells, fibrin, toxin that can prevent breathing

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12
Q

C. diptheridae bacteria

A

apathogenic unless lysogenized or transduced by a bacteriaphage which transfers a gene that encodes for a toxin

  • all isolates must be tested for toxin production
  • effects are myocarditis, cardiac failure, polyneritis

treatment: antibiotics and antitoxin, vaccine is effective by older people only have 20% protection due to lack of boosters.

COTANEOUS DIPHTHERIA is common in tropics

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13
Q

mycobacterium

A

characteristics: gram positive, non-motile rod, lipid rich cell wall containing myolic acid. 3-8 weeks to grow into colony

morbidity/incidence: active TB: cough, weakness, fever, weight loss, high sweats, cough up blood, chest pain

latent TB: body’s immune system has contained the infection ( 1 in 3 person)

Infectious cycle: TB and AIDS go hand in hand

  • airborne
  • GRANUOLOMA formation is crucial to maintain a control
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14
Q

3 things that happen after M. Tuberculosis exposure

A
  1. Latent infection: no activation of macrophages
  2. Primary tubercle forms, but immune system stops replication
  3. military infection: spread of active infection ( immunocompromised people)

Active infection: aka military infection, can be from primary or reactivation of a latent infection. Symptoms include weight loss, fever, nightsweats, chronic cough , blood, lethargia

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15
Q

TB continued

A

Lab diagnosis: finding of acid fast rods in sputum, culture ( up to 6 weeks for negative result), quantiferon gold test for activated T-lymphocytes

Skin tests: test for cell-mediated acquired immunity, PPD ( purified protein derivative) injected subcutaneously and measured in diameter, Mantoux test

Vaccine: BCG: bacillus calmette-guerin, live culture of M. bovis, only given to children at high risk in North America, effectivity 0% in adults

Treatment: multiple drug regimens to prevent development of drug resistance. takes 6 months to a year. Patient is not infectious after 2-3 weeks on drugs

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16
Q

Pneumonia ( old man’s friend)

A

Cause: typical- S. pneumoniae, responds to penicillin treatment
atypical- caused by other organisms, penicillin resistant, includes virus, bacteira, fungi
- most common cause of infection deaths
- cause in children is viral, cause in adult is bacterial

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17
Q

Pneumococcal pneumonia

A
  • encapsulated gram positive diplococcus (S. pneumoniae- alpha hemolytic)
  • involves alveoli and bronchi

symptoms:
- fever, rust colored blood, breathing problmes, chest pain
- spreads to blood
- vaccines exist ( polysaccharide/conjugate)

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18
Q

RSV

A

Characteristics: RNA, enveloped
cause: tissue damage by synctia formation
spread: direct contact
risks are premature infants, children less than 5 years
- epidemic: late winter and early spring
-causes bronchiolitis and pneumonia in infants, coughing and wheezing

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19
Q

influenza A

A

characteristics: enveloped, orthomyxoviridae. Segmented: negative sense genome, A and B = 8 RNA segments, C=7 segments, only A has subtypes
symptoms: malaise, fever, headache, myalgia, cough, sore throat, severe in smokers

incubation period: small infectious dose, incubation 1-5 days, virus viable on hard surface 24-48 hours, droplet transmission

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20
Q

pandemic vs epidemic influenza

A

pandemic: caused by antigenic SHIFT: preformed antibodies against virus A and have some effect on virus B
3 to 4 in every 100 years, significant mortality rates, global disease spread in 6 to 9 months, usually start in china

epidemic: caused by antigenic DRIFT: reassortment of RNA segment
annual occurrence in late winter, early spring: temperate conditions
-30,000 deaths per year in the US with every epidemic
-nosocimal infections common in nursing homes

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21
Q

Infections of the oral cavity

A
  • bacteria needs iron to grow
  • about 1 to 1.5 L of saliva secreted a day from salivary glands: flush mouth, lysozome, lactofemin, contain secretory IgA, lactoperoxidase, WBC
  • dehydrated patients: mouth overgrown with organisms, bad breath
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22
Q

bad breath

A
  • caused by the waste products of anaerobic oral bacteria
  • most of the compounds cause bad breath (hydrogen sulfide, cadaverine, etc) are waste products of bacterial metabolism.
  • anterior ( front) of tongue often gets flora rubbed off
23
Q

Candida albicans

A
  • opportunistic fungus, yeast like in culture outside of body, pseudohyphae in tissues ( tongue)
  • common cause of mouth and throat infection: inhalation steroids, chemotherapy, broad spectrum antibiotic, immune defects and cancer ( young and old)
24
Q

oral candidasis

A
  • upset in balance of flora
  • thrush: growth of mycelium of pseudohyphae in tongue
  • spread to esophagus
25
Q

Actinomycosis: Lumpy jaw

A
  • painful abscesses caused by an anaerobic bacterium, “Actinomyces israeli” ( normal flora in oral cavity)
  • cause abscesses in pelvis and lung
  • abscess formation, healing and scarring leads to deformation of tissue: lumpy jaw
  • tendency to chronic infection
  • dental procedures ( wounds) trigger infection
26
Q

Vincent’s disease ( trench mouth)

A

also called acute necrotizing ulcerative gingivitis (ANUG) or Vincent’s angina

  • anaerobic gram negative bacilli
  • anaerobic gram negative spirochaetes
  • severe ulcerative disease, pain, breath is foul smelling

treatment is antibiotics and surgery

27
Q

Infection of the parotid gland: Mumps

A

characteristics: RNA, paraymyxovirus, droplet transmission, salivary gland, most infectious 48 hours before symptoms begin
- virus multiple in lymph gland in throat, then penetrate the parotid gland via blood.

symptoms: inflammation and swelling of parotid glands, fever, pain on swallowing
complications: encephalitis, orchitis ( testis), oophoritis, sterility

28
Q

infection of stomach: Helicobacter pylori

A
  • cause of peptic ulcer disease ( gastric and duodenal)
  • spiral shaped gram negative microaerophilic bacterium
  • associated with contaminated water and wells
  • has flagella that allows movement in thick mucus.
  • produces large amounts of urease, urea is broken down to ammonia and pH locally

diagnosis: urea breath test (C14 labelled urea)
- drink solution and breath out, if urease present, then carbon dioxide exhaled will be marked.
- serology, culture of biopsy specimens

29
Q

predominant flora of intestine

A

bactericides ( dominate)
disease of Gi tract are 2 types:
1. infections: pathogens multiples in mucosa ( poisons) or passes to other systemic organs ( fever- vomiting, release of endotoxin-LPS)
2. intoxications: ingestion of a preformed toxin from usually sudden onset and no fever

Result: diarrhea ( MAJOR CAUSE OF INFANT MORTALITY- DEHYDRATION)

30
Q

main pathogenic mechanisms of lower alimentary tract pathogens

A
  • attachment
  • cell invasion
  • loss of microvilli ( function for reabsorption)
  • toxic production ( increase secretion of waste and electrolytes) ( decrease protein synthesis and cause cell death)
31
Q

dysentery vs. gastroenteritis

A

dysentery:

  • severe diarrhea with blood, often pus and or mucous
  • includes E. histolytica, shigella dysenteriae

Gastroenteritis:

  • inflammation of the stomach and intestine mucosa, no pus
  • include vibrio cholerae, crytosporidium

common symptom of both: nausea, vomitting, abdominal cramps, diarrhea

32
Q

causes of intoxications

A

staphylococcus aureus (Vomiting) : meats, custards, salads

bacillus cereus ( Vomitting, diarrhea): rice, meat, veggies

clostridium botulinum ( neuromuscular paralysis): improper preserved veggies, fish, meat

33
Q

S. aureus

A
  • produce exotoxins called enterotoxins
  • heat stable, resistant to enzymatic
  • destruction in GI tract
  • grows quickly and easily in food
  • salt tolerant, osmotically stable
  • 30 minutes to heat
  • temperature in food is warm
  • custard, gravy, cream pie, ham
  • adequate refrigeration prevention
34
Q

S. Enterotoxin

A
  • triggers Vomiting reflex
  • causes abdominal cramps
  • usually occurs in 2 to 4 hours after ingestion
  • complete recovery within 24 hours
  • no lasting side effects
  • GRAVY!
35
Q

Bacillus cereus

A

food associated disease with 2 forms:

  1. diarrhea: production of enterotoxin in gut ( 8 to 16 hour) infection
  2. Vomitting: ingestion of enterotoxin in food (1-6 hour)

gram positive bacilli, aerobic, spore forming
usually harmless otherwise
heating food may not kill spores, common in rice dishes
self-limiting disease

36
Q

salmonellosis ( salmonella enterica ssp enterica gastroenteritis)

A
  • gram negative, non spore forming bacilli, motile
  • sensitive to acid, need large numbers to cause an infection
  • common commensals in GI tracts of animals on reptile skin, turtles and snakes
37
Q

salmonella gastroenteritis

A
  • over 2000 serotypes
  • enteritis and typhimurium most common in developing countries
  • incubation 12-36 hours
  • susceptible to gastric acid, needs lots of bacteria
  • meat products, eggs,poultry
  • s. enteritis infect chicken, but EGGS infected ONLY
  • usually not treated with antibiotics
38
Q

Typhoid Fever (S. enterica typhi)

A

spread only from human to human

  • high fever 40 degrees, headache
  • diarrhea starts in 2 to 3 weeks
  • causes sepsis ( enteric fever)
  • bacteria multiply in phagocytic cells, disseminate quickly to blood
  • carrier state after recovery
  • antibiotics is the treatment
39
Q

Shigellosis

A
  • it is an infection, not intoxication, gram negative bacilli, non-motile
  • 4 species total: S. dysenteriae (A) is most severe!
  • virulent strains has plasma essential for attachment and entry of bacteria into cells
  • transmission is from person to person, no animal reservoir ( fecal oral)
  • produces shigatoxin (cytotoxin)
40
Q

campylobacter gastroenteritis

A
  • gram negative, spiral formed bacilli ( gull wings)
  • leading cause of food-borne illness in Canada and US
  • commensals of poultry and cattle, can be in water
  • 80 to 90% of poultry have campylobacter
  • C. jejuni is the most common cause ( infective dose 500 stomach acid tolerance)
  • self-limiting disease
  • prevention is hygienic measures associated with handling of poultry etc. and monitoring of water
  • can get complications of IBD and Guillan Barre Syndrome
41
Q

E. Coli gastroenteritis

A
  • most strains are apathogenic and normal residents of GI tract
  • pathogenic strains have special fimbriae for attachment (ETEC, EIEC, EPEC, EHEC)
42
Q

Enterohemorrhagic E. Coli (EHEC)- 1982

A
  • Hamburger disease
  • best known serotype is 0157:H7 (O is cell wall, H is flagella)
  • it is in animal intestine, cows
  • produces shiga-like toxins: hemorrhagic colitis (HUS)
43
Q

HUS complication: Hemolytic uremic syndrome

A
  • blood in urine due to kidney failure
  • 5 to 10% of small children get HUS
  • present in poorly handled meat, poultry, raw alfalfa sprouts
  • transmitted by contaminated water
  • usually on adults, but children and elderly can get it as well
  • treatment: rehydration and antimicrobials
44
Q

Clostridium perfringens Gastroenteritis

A
  • gram positive bacilli, spore forming, anaerobic
  • grows in intestinal tract and produce an exotoxin that cause abdominal pain and diarrhea
  • most causes mild pain, 8-12 hours after ingestion
  • spores can withstand heating
  • found in meat dishes
  • bacterium needs amino acid for growth and when meat is cooked, O2 levels go down
45
Q

Vibrio Cholerae

A
  • gram negative “vibrio” comma shaped bacterium
  • can have more than 20 fluid loss a day ( RICE WATER STOOL)
  • survives high pH and high salt
  • killed by acid, need large numbers to cause an infection
  • produce exotoxin (cholera enterotoxin), heat labile
  • fecally contaminated water a major source of infection
  • treatment is rehydration glucose and electrolytes (antibiotics decrease number of bacteria after rehydration)
  • global pandemic
46
Q

Viral gastroenteritis

A
  • seen in all parts of the world
  • in developing countries, it’s a major cause of death especially in children
  • non-distinguishable clinically from other gastroenteritis
  • viruses are specific to humans
  • fecal oral transmission
  • 90% of cases caused by rotaviruses or norwalk viruses
47
Q

rotavirus gastroenteritis

A

RNA, reoviridae, non-enveloped

  • most common cause of viral gastroenteritis in children
  • same incidence in developed and underdeveloped nations
  • disease of children, most happen less than 2 years
  • incubation is 2-3 days
  • often nosocomial
  • symptom is low grade fever, diarrhea, vomiting
  • VAcciNE: Rotorix, Rotatea
48
Q

Norovirus (Norwalk virus)

A
  • RNA, non-enveloped
  • cause major epidemics of viral gastroenteritis (2/3 of cases in food poisioning)
  • 2 day incubation period, similar to Rotavirus
  • symptom is nausea, abdominal cramps, diarrhea, Vomitting for 1-3 days, sudden onset, no prodrome
49
Q

protozoan diseases cause diarrhea include….

A

Giardia lamblia
crytosporidiosis
Entamoeba histolytica

50
Q

helminthic disease ( no diarrhea) includes…

A

tapeworm (cestode)

roundworm (nematode)

51
Q

Hepatitis A (HAV)

A

RNA, non enveloped (picornaviridae)

  • oral fecal route, water, mollusks
  • resistant to chlorine
  • incubation 2-4 weeks
  • patho:virus multiply in intestinal epithelia cells, enter blood stream and infect livers, kidney, spleen cells, cause damage. Virus exits by biliary tract to feces for excretion

Symptoms: nausea, Vomitting, fever, anorexia, jaundice, sudden onset

Clinical: 50% of infections are subclinical, no chronic disease
Diagnosis: HAV IgM antibodies in serum
Immunity: lifelong vaccines exist

52
Q

Hep B

A
  • bloodborne, STI
  • enveloped DNA virus
  • Acute infection: liver inflammation, Vomitting, jaundice
  • Chronic infection: cirrhosis, carcinoma
  • vaccine available
53
Q

Hep. C

A

bloodborne

  • enveloped RNA virus
  • Acute: mild and vague symptoms
  • 80% get affected
  • Chronic: cirrhosis, liver cancer
  • NO VACCINE
54
Q

Hep. D

A
  • coexist with Hep. B to cause disease!
  • bloodborne
  • enveloped RNA virus
  • only happens if Hep B exist!
55
Q

Hep. E

A
  • RNA, calicivirus
  • fecal oral transmission
  • increasing in countries with poor sanitation
  • no chronic disease
  • risk for pregnant women, 20% mortality

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