Micro Review Flashcards
What are the four most common causes of pneumonia in a neonate (birth-28 days)?
Group B strep
E. coli
Chlamydia trachomatis
HSV
What are the four most common causes of pneumonia in children?
RSV
S. pneumoniae
Mycoplasma pneumoniae
Clamydophila pneumoniae
What are the five most common causes of pneumonia in adults?
S. pneumoniae H. influenzae Mycoplasma pneumoniae Chlamoydophila pneumoniae Influenza virus
What are the five most common causes of pneumonia in elderly adults?
S. pneumoniae H. influenzae Influenza virus S. aureus Gram negative rods (Klebsiella)
What could be the cause of pneumonia in an alcoholic?
Klebsiella
What could be the cause of pneumonia in a patient with decreased level of consciousness?
S. aureus
What could be the cause of pneumonia in a patient with cystic fibrosis?
pseudomonas
What could be the cause of pneumonia in a patient with HIV and CD4 count <200?
pneumocystis jirovecii
What could be the cause of pneumonia in a patient post-influenza?
S. pneumo or S aureus (fatal)
What could be the cause of pneumonia acquired from patio-cooling water mister?
legionella
What could be the cause of pneumonia acquired from travel to the southwestern US?
coccidiodes immitis
What could be the cause of pneumonia after exposure to bird/bat droppings in Ohio/Mississippi River valleys?
Histoplasma capsulatum
What could be the cause of pneumonia in a patient with a pet parrot?
Chlamoydophila psittaci (associated with birds)
What are the 3 most common causes of meningitis in neonates?
Group B strep
E. coli
Listeria monocytogenes
What are the 4 most common causes of meningitis in infants and children?
S. pneumo
N. meningitidis
H. influenzae
Viruses (enterovirus)
What are the 3 most common causes of meningitis in adults?
S. pneumoniae
N. meningitidis
Enteroviruses
What are the 3 most common causes of meningitis in the elderly?
S. pneumoniae
Listeria monocytogenes
gram-negative rods (E. coli)
What organism should be considered as the cause of meningitis in an unvaccinated child?
H. influenza type B
What organism should be considered as the cause of meningitis in an outbreak in a dormitory?
N. meningitidis
What organism should be considered as the cause of meningitis with a petechial rash?
N. menigitidis
What organism should be considered as the cause of meningitis in a patient with HIV?
cryptococcus neoformans
What organism should be considered as the cause of meningitis with RBCs in CSF and temporal lobe involvement on MRI?
HSV encephalitis
What are the CSF findings in bacterial meningitis?
Opening pressure increased WBC very increased Differential: neutrophils Protein very increased Glucose decreased Gram stain positive
What are the CSF findings in fungal/TB meningitis?
Opening pressure increased WBC increased Differential: lymphocytes Protein: increased Glucose: decreased Gram stain negative
What are the CSF findings in viral meningitis?
Opening pressure normal or increased WBC increased Differential: lymphocytes Protein: normal or increased Glucose: normal Gram stain: negative
Management of anthrax exposure
- remove clothing and wash patient with soap and water
- ciprofloxacin or doxycycline
- vaccination
- raxibacumab - monoclonal Ab that neutralizes anthrax toxins (edema factor and lethal factor) - use when other prophylaxis is not available
Smallpox presentation and management of exposure
- remove clothing and wash patient with soap and water
- vaccine available from CDC
Presentation: rash on mouth and face -> spreads to trunk and extremities -> becomes vesicular/pustular
What are the three possible presentations of anthrax?
- cutaneous anthrax - necrotic ulcer with eschar
- pulmonary anthrax - mediastinal LAD -> hemorrhagic mediastinitis (widening on CXR) -> bacteremia -> death
- anthrax meningitis (hemorrhagic)
What infection causes green, frothy vaginal discharge and flagellated cells on wet prep?
trichomonas
What infection causes kilobytes on biopsy of lesion?
condyloma accuminatum caused by HPV (6&11)
What infection causes multiple tender vesicles -> shallow ulcers?
HSV
What infection causes a painless genital ulcer followed by rash that involves plasma and soles?
syphilis (treponema)
What infection causes mucopurulent discharge and cervical motion tenderness?
PID - most commonly caused by chlamydia and gonorrhea
What urinalysis findings would help to confirm the diagnosis of cystitis?
positive nitrites positive leukocyte esterase bacteriuria pyuria hematuria
What organism causes strawberry cervix?
trichomonas
What organism has clue cells?
Gardnerella vaginalis
What organism has bacteria with “school of fish” appearance?
Haemophilus ducreyi
What are the ToRCHeS infections?
Toxoplasma gondii, other (Parvovirus B19), Rubella, CMV, HIV, HSV2, Syphilis
Toxoplasma gondii in neonates
spread through cat feces or ingestion of undercooked meat
neonatal symptoms: classic triad: chorioretinitis, hydrocephalus, and intracranial calcifications
Parvovirus B19 in neonates
can cause hydrops fetalis in fetus -> fluid accumulation throughout fetus’ body
Rubella in neonates
spread through respiratory droplets
neonatal symptoms: classic triad: cataracts, deafness, PDA
could have blueberry muffin rash
CMV in neonates
most common congenital infection
neonatal symptoms: hearing loss, seizures, petechial rash, periventricular calcifications
HIV in neonates
recurrent infections; chronic diarrhea
How should pregnant women with HIV be treated?
Mom should be on HAART during pregnancy
given intrapartum zidovudine
Delivery via C-section
Herpes Simplex virus 2 in neonates
meningoencephalitis, herpetic (vesicular) lesions
How should pregnant women with HSV-2 be treated?
give acyclovir at 36 weeks gestation
C-section if active infection
Syphilis in neonates
often results in stillbirth, hydrops fetalis
If child survives: facial abnormalities, Hutchison teeth, saddle nose, short maxilla, saber shins, CN VIII deafness
What is the treatment for syphilis in pregnant patients? What about with an allergy to that drug?
Tx = penicillin
With penicillin allergy = desensitize to penicillin and then give penicillin again
What is the most likely cause of food poisoning with vomiting 1-6 hours after eating potato salad at a picnic?
S. aureus
What is the most likely cause of food poisoning with vomiting 1-6 hours after eating reheated rice?
Bacillus cereus
What is the most likely cause of food poisoning with vomiting and watery diarrhea on a cruise?
norovirus
What is the most likely cause of food poisoning with watery diarrhea 12 hours after eating meat or poultry from a cafeteria?
salmonella
What is the most likely cause of food poisoning with inflammatory diarrhea after eating undercooked hamburger meat, followed by acute kidney injury?
E. coli 0157:H7
What is the most likely cause of food poisoning with inflammatory diarrhea after eating raw seafood?
vibrio parahemolyticus
What is the most likely cause of food poisoning with inflammatory diarrhea followed by ascending paralysis?
Campylobacter jejuni
What is the most likely cause of food poisoning with descending paralysis after ingestion of homemade canned goods?
Clostridium botulinum (symmetrical flaccid descending paralysis)
What organism is the most likely cause of osteomyelitis in a patient with sickle cell disease?
Salmonella
What organism is the most likely cause of osteomyelitis in a patient with a prosthetic device?
Staph epidermidis
What organism is the most likely cause of osteomyelitis with involvement of the vertebrae?
mycobacterium tuberculosis
What organism is the most likely cause of osteomyelitis following a cat bite?
Pasteurella multocida
What organism is the most likely cause of osteomyelitis in an IV drug user?
S. aureus, Pseudomonas, serrate, candida
What organism is the most likely cause of osteomyelitis in a diabetic with a foot ulcer?
polymicrobial, Pseudomonas, anaerobes
What organism is the most likely cause of osteomyelitis with a puncture wound to foot through the sneaker?
Pseudomonas
What is the gold standard for diagnosis of osteomyelitis?
bone biopsy and culture
What is the most common overall cause of osteomyelitis?
S. aureus
What nosocomial infection should you think of with a patient on a mechanical ventilator?
Pseudomonas
What nosocomial infection should you think of with a patient with decubitus ulcers?
S. aureus
What nosocomial infection should you think of with a patient with intravascular catheters?
S. epidermidis
What nosocomial infection should you think of with a patient with urinary catheterization?
E. coli, Klebsiella, Proteus spp.
What nosocomial infection should you think of with a patient on parenteral nutrition?
candida
What toxin does bacillus anthracis produce? What two factors does it contain? How do they work?
Anthrax exotoxin -> edema factor and lethal factor
Edema factor: increase cAMP by acting as an adenylate cyclase, causing edema and phagocyte dysfunction
Lethal factor: zinc-dep protease that inhibits mitogen-activated protein kinase signaling, causing apoptosis and multi system disruption
What toxins does Bordatella pertussis produce? How do they work?
Pertussis toxin and Adenylate cyclase toxin
Pertussis toxin: disinherits adenylate cyclase through Gi ADP-ribosylation, increasing cAMP levels; causes edema and phagocyte dysfunction
Adenylate cyclase toxin: functions as adenylate cyclase, increasing cAMP levels; causes edema and phagocyte dysfunction
What toxin does Clostridium botulinum produce? How does it work?
Botulinum toxin - blocks presynaptic release of ACh at the NMJ, resulting in flaccid pralysis
What toxins do Clostridium difficile release? How do they work?
Toxin A & B
Toxin A - recruits and activates neutrophils, leading to release of cytokines that cause mucosal inflammation, fluid loss, and diarrhea
Toxin B - Induces actin depolymerization, leading to mucosal cell death, bowel wall necrosis & pseudomembrane formation
What toxin does Shigella dysenteriae produce? How does it work?
Shiga toxin - halts protein synthesis by disabling the 60S ribosomal subunit, leading to interstitial epithelial cell death and diarrhea
What toxins does Streptococcus pyogenes produce? How do they work?
Pyrogenic exotoxin & Streptolysin O & S
Pyrogenic exotoxin - acts a s asuperantigen, inducing fever and shock; associated with scarlet fever and streptococcal toxic shock syndrome
Streptolysin O&S - damages erythrocyte membranes, causing beta hemolysis
