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Flashcards in Systems Deck (98):
1

Normal flora: nose

Staph epidermidis, colonized by staph aureus

2

Normal flora: oropharynx

Strep viridans spp

3

Normal flora: Dental plaque

Strep mutans

4

Normal flora: Colon

B.fragilis>E.coli

5

Normal flora: vagina

Lactobacillus, colonized by E.coli and group B strep

6

Food poisoning: reheated rice

B.cereus
Starts and ends quickly

7

Food poisoning: canned foods or honey

C.botulinum
Improperly canned foods (toxins - adults), raw honey (spores - infants)

8

Food poisoning: reheated meats

C.perfringens

9

Food poisoning: undercooked meat

E.coli O157:H7

10

Food poisoning: Poultry, meat, eggs

Salmonella

11

Food poisoning: Meats, mayonnaise, custard

S.aureus
Preformed toxin (start quickly and ends quickly)

12

Food poisoning: Contaminated seafood

V.parahaemolyticus & V.vulnificus

13

Bloody diarrhea

Campylobacter - comma or S-shaped organisms; growth at 42C
E.histolytica - protozoan, amebic dysentery, liver absces
enterohemorrhagic E.coli - O157:H7; can cause HUC, shiga-like toxin
Enteroinvasive E.coli - invades colonic mucosa
Salmonella - lactose -, flagella the motility; has animal reservoir; esp. Poultry & eggs
Shigella - lactose -, very low ID, produces shiga-toxin (human reservoir); bacillary dysentery
Y.enterocolitica - day care outbreaks, pseudoappendicitis

14

Watery diarrhea

C.difficile - pseudomembranous colitis; caused by antibiotics, occasionally bloody diarrhea
C.perfringens - also causes gas gangrene
Enterotoxigenic E.coli - travelers diarrhea; produces heat-labile (LT and heat-stable (ST) toxins
Protozoa - giardia, cryptosporidium
V.cholerae - comma-shaped organisms; rice water diarrhea; often from infected seafood
Viruses - rotavirus, Norovirus, adenovirus

15

Common causes of pneumonia: Neonates (

Group B strep
E.coli

16

Common causes of pneumonia: Children (4wk-18yr)

Viruses (RSV)
Mycoplasma
C.trachomatis (infants-3yr)
C.pneumoniae (school age children)
S.pneumoniae
*Runts May Cough Chunky Sputum*

17

Common causes of pneumonia: Adults (18-40yr)

Mycoplasma
C.pneumoniae
S.pneumoniae
Viruses (influenza)

18

Common causes of pneumonia: Adults (40-65yr)

S.pneumoniae
H.influenzae
Anaerobes
Viruses
Mycoplasma

19

Common causes of pneumonia: Elderly (>65yr)

S.pneumoniae
Influenza virus
Anaerobes
H.influenzae
Gram - rods

20

Special causes of pneumonia: Alcoholics

Klebsiella
Anaerobes (peptostreptococcus, fusobacterium, prevotella, bacteroides)

21

Special causes of pneumonia: IV drug users

S.pneumoniae
S.aureus

22

Special causes of pneumonia: Aspiration

Anaerobes

23

Special causes of pneumonia: atypical

Mycoplasma
Legionella
Chlamydia

24

Special causes of pneumonia: Cystic Fibrosis

Pseudomonas
S.aureus
S.pneumoniae
Burkholderia cepacia

25

Special causes of pneumonia: Immunocompromised

S.aureus
enteric gram - rods
Fungi
Viruses
P.jirovecii (with HIV)

26

Special causes of pneumonia: Nosocomial (hospital acquired)

S.aureus
Pseudomonas
Other enteric gram - rods

27

Special causes of pneumonia: Postviral

S.pneumoniae
S.aureus
H.influenzae

28

Common causes of meningitis: Newborn (0-6mo)

Group B strep
E.coli
Listeria

29

Common causes of meningitis: Children (6mo-6yr)

S.pneumoniae
N.meningitidis
H.influenza type B
Enteroviruses

30

Common causes of meningitis: 6-60yr

S.pneumoniae
N.miningitidis (#1 cause in teens)
Enteroviruses
HSV

31

Common causes of meningitis: 60+yr

S.pneumoniae
Gram - rods
Listeria

32

Viral causes of meningitis

Enteroviruses (Coxsackievirus)
HSV-2 (HSV-1 = encephalitis)
HIV
West Nile virus (also causes encephalitis)
VZV

33

Treatment of meningitis

Give ceftriaxone and vancomycin empirically
Add ampicillin if Listeria is suspected
Note: incidence of HiB meningitis has decreased dramatically due to the conjugate HiB vaccine (usually seen in non-immunized pts)

34

CSF findings in meningitis: Bacterial

Increased opening pressure
Increased PMNs
Increased proteins
Decreased sugar

35

CSF findings in meningitis: fungal/TB

Increased opening pressure
Increased lymphocytes
Increased protein
Decreased sugar

36

CSF findings in meningitis: viral

Normal to increased opening pressure
Increased lymphocytes
Normal to increased proteins
Normal sugar levels

37

Infections causing brain abscess

Most commonly viridans streptococci and S.aureus. If dental infection or extraction precedes abscess, oral anaerobes commonly involved
Multiple abscesses are usually from bacteremia; single lesions from contiguous sites:
-otitis media and mastoiditis --> temporal lobe and cerebellum
-sinusitis or dental infection --> frontal lobe
Toxoplasma reactivation in AIDS

38

Osteomyelitis with no risk factors

S.aureus (most common overall)

39

Osteomyelitis: risk factor of sexual activity

Neisseria gonorrhoeae (rare)
Septic arthritis is more common

40

Osteomyelitis: risk factor - sickle cell disease

Salmonella
S.aureus

41

Osteomyelitis: risk factor - prosthetic joint replacement

S.aureus
S.epidermidis

42

Osteomyelitis: risk factor - Vertebral involvement

S.aureus
Mycobacterium tuberculosis (Pott disease)

43

Osteomyelitis: risk factor - cat and dog bites

Pasteurella multocida

44

Osteomyelitis: IV drug abuse

Pseudomonas
Candida
S.aureus

45

Osteomyelitis

Elevated CRP and ESR common but nonspecific finding
MRI is best for detecting acute infection and detailing an atomic involvement
Radiographs are insensitive early but can be useful in chronic osteomyelitis

46

Urinary Tract Infections

Cystitis: dysuria, frequency, urgency, suprapubic pain, & WBCs in urine
Primarily caused by ascension of microbes from urethra to bladder
-Males: infants with congenital defects, vesicoureteral reflux
-elderly: enlarged prostate
Ascending to kidney results in pyelonephritis, which presents with fever, chills, flank pain, CVA tenderness, hematuria, WBC casts in urine
Ten times more common in women (shorter urethra colonized by fecal flora)
-other factors: obstruction, kidney surgery, catheterization, GU malformation, diabetes, pregnancy

47

UTI bugs: E.coli

Leadin cause of UTI
Colonies show green metallic sheen on EMB agar
Diagnostic markers - +leukocyte ester are (evidence of WBC activity) & + nitrite test = reduction of urinary nitrates by E.coli

48

UTI bugs: Staph saprophyticus

second leading cause of UTI in sexually active women
Diagnostic markers: + leukocyte esterase (evidence of WBC activity)

49

UTI bugs: Klebsiella pneumoniae

3rd leading cause of UTI
Large mucoid capsule and viscous colonies
+leukocyte esterase & +urease test

50

UTI bugs: Serratia marcescens

Some strains produce a red pigment; often nosocomial and drug resistant
+leukocyte esterase

51

UTI bugs: Enterococcus

Often nosocomial and drug resistance
+Leuocyte esterase

52

UTI bugs: Proteus mirabilis

Motility causes "swarming" on agar; produces urease
Associated with struvite stones
+leukocyte esterase and +urease test

53

UTI bugs: Pseudomonas aeruginosa

Blue-green pigment and fruity odor
Usually nosocomial and drug resistant
+leukocyte esterase

54

Bacterial vaginosis

S&S: No inflammation, thin white discharge with fish odor
Labs: clue cells; pH>4.5
Treatment: metronidazole
Gardnerella vaginalis

55

Trichomonas vaginitis

S&S: inflammation ("strawberry cervix"), frothy yellow-green, foul smelling discharge
Labs: motile trichomonads (pear shaped); pH>4.5
Treatment: metronidazole (treat sexual partner as well)

56

Candida vulvovaginalis

S&S: Inflammation, thick white "cottage cheese" discharge
Labs: pseudohyphae, normal pH (4.0-4.5)
Treatment: -azoles

57

ToRCHeS infections

Microbes that may pass from mother to fetus
Transmission is transplacental in most cases or via delivery (esp HSV-2)
Nonspecific findings: hepatosplenomegaly, jaundice, thrombocytopenia, growth retardation
other infectious agents: Strep agalactiae (group B), E.coli, Listeria monocytogenes - all causes of meningitis in neonates
Parvovirus B19 - hydrops fetalis

58

ToRCHeS: Toxoplasmosis gondii

Transmission: cat feces or ingestion of undercooked meat
Maternal symptoms: asymptomatic with rare lymphadenopathy
Neonatal symptoms: chorioretinitis, hydrocephalus and intracranial calcifications +/- "blueberry muffin" rash

59

ToRCHeS: Rubella

Transmission: respiratory droplets
Maternal symptoms: rash, lymphadenopathy, polyarthritis, polyarthralgia
Neonatal symptoms: abnormalities of eye (cataract) and ear (deafness) and congenital heart disease (PDA) +/- blueberry muffin rash
(*I heart Ruby Earrings*)

60

ToRCHeS: Cytomegalovirus

Transmission: sexual contact, organ transplants
Maternal symptoms: usually asymptomatic; mononucleosis-like illness
neonatal symptoms: hearing loss, seizures, petechial rash, "blueberry muffin" rash, periventricular calcifications

61

ToRCHeS: HIV

Transmission: sexual contact, needle stick
Maternal symptoms: variable presentation depending on CD4+ count
Neonatal symptoms: recurrent infections, chronic diarrhea

62

ToRCHeS: HSV-2

Transmission: skin or mucous membrane contact
Maternal symptoms: usually asymptomatic; hermetic (vesicular) lesions
Neonatal symptoms: encephalitis, herpetic (vesicular) lesions

63

ToRCHeS: Syphilis

Transmission: sexual contact
Maternal symptoms: chancre (primary), disseminated rash (secondary)
Neonatal symptoms: often results in still birth, hydrops fetalis; if child survives presents with facial abnormalities (notched teeth, saddle nose, short maxilla), saber shins, CN VIII deafness

64

Red Rashes of Childhood: Coxsackievirus type A

hand-foot-mouth disease
Oval-shaped vesicles on palms and soles
Vesicles and ulcers in oral mucosa

65

Red Rashes of Childhood: HHV-6

Roseola (exanthem subitum)
Asymptomatic rose-colored macules appear on body after several days of high fever
Can present with febrile seizures, usually affects infants

66

Red Rashes of Childhood: Measles virus

Measles (rubeola)
Beginning at head and moving down; rash preceded by cough, coryza, conjunctivitis and blue-white (Koplik) spots on by cal mucosa

67

Red Rashes of Childhood: Parvovirus B19

Erythema infectiously (fifth disease)
Slapped cheek rash of face
Can cause hydrops fetalis in pregnant women

68

Red Rashes of Childhood: strep pyogenes

Scarlet fever
Erythematous, sandpaper like rash with fever and sore throat

69

Red Rashes of Childhood: VZV

Chickenpox
Vesicular rash begins on trunk; spreads to face and extremities with lesions of different stages

70

STIs: AIDS

Opportunistic infections. Kaposi sarcoma, lymphoma
Organism: HIV

71

STIs: Chancroid

Painful genital ulcer with exudate, inguinal adenopathy
Organism: Haemophilus ducreyi
(*it's so painful, you "do cry"*)

72

STIs: Chlamydia

Urethritis, cervical is, epididymitis, conjunctivitis, reactive arthritis, PID
Organism: Chlamydia trachomatis (D-K)

73

STIs: Condylomata acuminata

Genital warts, koilocytes
Organism: HPV 6&11

74

STIs: Genital herpes

Painful penile, vulvar or cervical vesicles and ulcers; can cause systemic symptoms such as fever, HA, myalgia
Organism: HSV-2 (less commonly HSV-1)

75

STIs: Gonorrhea

Urethritis, cervicitis, PID, prostatitis, epididymitis, arthritis, creamy prudent discharge
Organism: Neisseria gonorrhoeae

76

STIs: Hepatitis B

Jaundice
Organism: HBV

77

STIs: Lymphogranuloma venereum

Infection of lymphatic system, painless genital ulcers but painful lymphadenopathy (burboes)
Organism: C.trachomatis (L1-L3)

78

STIs: Primary syphilis

Painless chancre
Organism: treponema pallidum

79

STIs: secondary syphilis

Fever, lymphadenopathy, skin rashes, condylomata lata
Organism: treponema pallidum

80

STIs: Tertiary syphilis

Gummas, tabes dorsal is, general paresis, aortitis, Argyll Robertson pupil
Organism: treponema pallidum

81

STIs: Trichomoniasis

Vaginitis, strawberry cervix, motile in wet prep
organism: trichomonas vaginalis

82

Pelvic Inflammatory Disease (PID)

Top bugs: Chlamydia trachomatis (subacute - often undiagnosed), Neisseria gonorrhoeae (acute), C.trachomatis (most common bacterial STI in US)
Cervical motion tenderness (chandelier sing), purulent cervical discharge
PID may include salpingitis (risk factor for ectopic pregnancy, infertility, chronic pelvic pain, adhesions) endometriosis, hydrosalpinx & tubo-ovarian abscess

83

Fitz-Hugh-Curtis syndrome

PID with salpingitis --> infection of the liver capsule and "violin string" adhesions of peritoneum to liver

84

Nosocomial infections: Antibiotic use

Clostridium difficile
Watery diarrhea, leukocytosis

85

Nosocomial infections: aspiration (secondary to altered mental status, old age)

Polymicrobial gram - bacteria, often anaerobes
Right lower lobe infiltrate or right upper middle lobe (patient recumbent); purulent malodorous sputum

86

Nosocomial infections: decubitus ulcers, surgical wounds, drains

S.aureus (including MRSA); S.epidermidis (long term), enterobacter
Erythema, tenderness, induration, drain gins from surgical wound sites

87

Nosocomial infections: intravascular catheters

S.aureus (including MRSA), gram - anaerobes (bacteroides, prevotella, Fusobacterium)
Erythema, induration, tenderness, dating from access sites

88

Nosocomial infections: Mechanical ventilation, endotracheal intubation

Late onset: P.aeruginosa, Klebsiella, Acinetobacter, S.aureus
New infiltrate on CXR, increase sputum production, sweet odor (pseudomonas)

89

Nosocomial infections: Renal dialysis unit, needlestick

HBV

90

Nosocomial infections: urinary catheterization

E.coli, Klebsiella, Proteus spp.
Dysuria, leukocytosis, flank pain or CVA tenderness

91

Nosocomial infections: Water aerosols

Legionella
Signs of pneumonia, GI symptoms (N/V), neurological abnormalities

92

Unvaccinated Kids: Rubella virus

Dermatologic
Rash - beginning at head and moving down with postauricular lymphadenopathy

93

Unvaccinated Kids: Measles virus

Dermatologic
Rash - beginning at head and moving down; rash preceded by cough, coryza, conjunctivitis and blue-white Koplik spots on buccal mucosa

94

Unvaccinated Kids: HiB

Neurologic
Meningitis - microbe colonized nasopharynx

95

Unvaccinated Kids: Poliovirus

Neurologic
Meningitis - can also lead to myalgia and paralysis

96

Unvaccinated Kids: HiB (respiratory)

Respiratory
Epiglottitis - fever with dysphagia, drooling and difficulty breathing due to edematous "cherry red" epiglottis; "thumbprint" sign on XR
Can also cause epiglottitis in fully immunized kids as well

97

Unvaccinated Kids: C.diptheriae

Respiratory
Pharyngitis - grayish oropharyngeal exudate (pseudomembranes that may obstruct airway), painful throat
-elaborates toxin that causes necrosis in pharynx, cardiac and CNS tissue

98

Normal flora: skin

Staph epidermidis