USMLE secrets step 2 Flashcards
What are the empirical treatments for UTI, what is the causative organism?
meds: TMP-SMX, nitrifurantoin, amoxacillin, quinolones
organism: E. coli
What are the empirical txs for bronchitis? What are the 3 main causative organisms?
no abx help. may see benefit from macrolides or doxycycline
organisms: virus, H. influenzae, moraxella
What is the empiric tx for typical pneumonia? What is the most likely causative organism?
Tx: 3rd generation cephalosporin, azithromycin
Org: strep pneumo and H. influenzae
What is the empirical tx for atypical pneumonia?
What are the most common causes of this disease?
Tx: Macrolide, doxycycline
orgs: mycoplasma, chlamydia
What are the most common causes of osteomyelitis? What is the empiric tx for these orgs?
orgs: strep and staph
tx: cephalexin or dicloxacillin, tmp-smx or clindamycin are used first line because of MRSA
What are the 3 most common causes of neonatal meningitis? What are abx are used to empirically tx neonatal meningitis ?
Orgs: group B strep, E. coli, Listeria
tx: ampicillin + aminoglycoside (gentamicin)
expanded spec 3rd gen cephalosporin should be added if a gram negative org is suspected
What are the 3 most common causes of child/adult meningitis?
What is used to empirically tx this?
cefataxine or ceftriaxone + vanco
What are the 2 most common causes of native valve endocarditis?
staph and strep
tx: antistaph penicillin - (or vanco if allergic to PCN) + aminioglycoside
What are the most common causes of prosthetic valve endocarditis? Tx?
numerous orgs
txs: vanco + gentamicin + cefepime or carbapenem
What are the most common causes of sepsis (3)?
Tx?
gram negative organisms, staph, strep
tx: 3rd gen PCN/cephalosporin + aminoglycocide or imipenem
What are the 3 most common causes of septic arthritis? Tx?
causes: s. aureus, gram neg bacillim gonococci
tx: vanco - s. aureus, cefrazidine or ceftriaxone - gram neg bacilli, spectinomycin - gonococci
What are the empirical abx (2) of choice for strep A/B?
PCN, cefazolin
Erythromycin
What are the empirical abx (2) of choice for S pneumo
3rd gen cephalosporin + vanco
other: fluoroquinolone
What are the empirical abx (3) for enterococcus
pcn or ampacillin + aminoglycoside
other: vanco + aminoglycoside
What are the empirical abx (2) of choice for s. aureus
pcn
other: vanco, tmp-smx, doxy, clindamycin, linezolid
What are the empirical abx (2) of choice for tx of gonococcus?
ceftriacone
other: cefixime or high dose azith followed by test of cure in 1 week
What are the empirical abx (2) of choice for tx of meningiococcus
cefotaxime or ceftriaxone
other: chloramphenicol or pcn G- if proven to be pcn sensitive
What are the empirical abx (2) of choice for tx of haemophilus
2nd gen or third gen cephalosporin
other: amoxicillin
What are the empirical abx (2) of choice for tx of pseudomonas
antipseudomonal pcn - ticarcillin, pipercillin + beta lactamase inhibitor (clavulanate, tazobactam)
other: ceftazidime, cefepime, aztreonam, imipenem, ciprofloxacin
What are the empirical abx (1) of choice for tx of bacteroides?
metronidazole
other: clindamycin
What are the empirical abx (2) of choice for tx of mycoplasma?
erythromycin, azithromycin
other: doxy
What are the empirical abx (1) of choice for tx of treponema pallidum
pcn
other: doxy
What are the empirical abx (2) of choice for tx of chlaydia?
doxy, azithromycin
other: erythromycin, ofloxacin
What are the empirical abx (3) of choice for tx of lyme ds?
cefuroxime, doxy, amoxicillin
other: erythromycin
What does the following gram stain result represent: blue/purple
gram +
What does the following gram stain result represent: red color
gram -
What does the following gram stain result represent:gram + cocci in clusters
staph
What does the following gram stain result represent: gram + in chains
strep
What does the following gram stain result represent: gram + cocci in pairs (diplococci)
s. pneump
What does the following gram stain result represent: gram - coccobacilli
Haemophilus
What does the following gram stain result represent: gram - diplococci
neisseria - STD, septic arthritis, meningitis
moraxella - lungs, sinusitis
What does the following gram stain result represent: plump gram - rod with thick capsule - mucoid appearance
klebsiella
What does the following gram stain result represent:gram - rods that form spores
clostridium, Bacillus
What does the following gram stain result represent: pseudohyphae
candida
What does the following gram stain result represent: acid fast
mycobacterium
What does the following gram stain result represent: gram + with sulfur granules
actinomyces - PID in intrauterine device users. - rare cause of neck mass/cervical adenitis
What does the following gram stain result represent: silver staining
pneumocystis jirovci and cat scratch ds
What does the following gram stain result represent: positive india ink = thick capsule
cryptococcus neoformans
What does the following gram stain result represent: spirochete
treponema, leptospira, - both only seen on dark field
borrelia - seen on regular light microscope
What is the gold standard for dx of pneumonia?
sputum culture. - do this before tx with abx.
obtain blood cultures as well (bacteremia is common with pneumonia)
What is the most common cause of pneumo? What is its presentation?
S. pneumo
rapid onset of shaking chills - 1-2 days after the start of an URI. - fever, pleurisy, and productive cough - yellow-green or rust colored from blood
CXR: lobar consolidation
WBC elevated - high neuts
tx: macrolides (azithromycin, clarithromycin), doxy, 3rd gen ceph with a mac or doxy, or a fluoroquinolone that has atypical coverage - levofloxavin, moxifloxacin
What is the best prevention of S. pneumo?
pneumococcal vaccination - all children and adults over 65, sickle cell pts, splenectomized pts, immunocompromised pts, and all pts with chronic ds
how do you recognize and tx H. influenzae pneumonia?
uncommon - dt vaccination
important org in pts with COPD
presents similar to s. pneumo - but look for gram - coccobacilli on gram stain.
tx: 2nd or 3rd gen cephalosporin or amoxicillin
What are the hallmarks of S aureus - caused pneumonia?
cause of nosocomial pneumonia
pneumonia in cystic fibrosis pts, IV drug users, and pts with chronic granulomatous ds
-empyema and lung abscessed often seen with s aureus
In what clinical situations do you see gram negative pneumonia? - klebsiella, pseudomonas, E coli
klebsiella - homeless, alcoholics - aspiration pneumonia, neutropenia, hospital acquired pneumonia = currant jelly sputum
pseudomonas - cystic fibrosis pts
E coli - aspiration pneumonia, neutropenia, hospital acquired pneumonia
high mortality - these pts are in poor health to begin with -
tx: empirical with antipseudomonals - ticarcillin, piperacillin +/- beta lactamase inhbitor
alt tx: ceftazidime or ciprofloxacin
How do you recognize mycoplasma pneumonia?
- who typically gets this, what is the environment
- what is the presentation - fever, CXR, cough,
- helpful tests
- tx
- college students, military recruits -ppl with sick contacts who live in dorms or barracks
- most common in adolescents and young adults
- long prodrome, gradual and worsening fatigue, HA, dry, non-productive cough, and sore throat
- low grade fever
- CXR - diffuse bronchopneumonia - looks impressive compared to the presentation of the pt.
- helpful test - cold agglutinin ab titers = positive - can cause anemia or hemolysis
tx = empirical - macrolide ab - azithromycin, doxycycline, or broad spec fluoroquinolone - levofloxacin or moxifloxicin
What is the cause and presentation of chlamydial pneumonia?
- tx
- age group ‘
- how common of an atypical pneumonia is this?
- or - cold agglutinin antibody test
tx = erythromycin if 8
- cause = chlamydia
- second most common cause of atypical pneumonia - second to mycoplasma
- neg cold agglutinin ab test
In what setting do you see PCP and CMV pneumonia?
PCP
- HIV pts with CD4 counts
When is the best time to tx PCP?
- use prophylaxis when CD4 counts are below 200
- TMP-SMX
- alt: dapsone or atovaquone
Scenario: pneumonia in the or exposure to bird droppings in the midwest/ Ohio and mississippi valley - cause
histoplasma capsulatum
Scenario: Fungus ball after TB or cavitary lung ds - cause
Aspergillus
scenario: Pneumonia in a pt with silicosis - cause
TB
Scenario: diarrhea after hiking or drinking from a stream - cause and tx
Giardia - tx cysts in stool with metronidazole
Scenario: pregnant woman with cats - cause and tx
toxoplasma gondii
tx with spiramycin
scenario: B12 deficiency and abdominal sxs - cause
diphyllobothrium latum - intestinal tapeworm
scenario - seizures with ring enhancing brain lesion on CT - cause and tx
taenia solium - cysticercosis or toxoplasmosis
tx neurocysticercosis with albendazole or praziquantel –> use with steroids
consider anticonvulsants
scenario: squamous cell bladder cancer in middle east or Africa - cause
Schistosoma haematonium
Scenario: worm infection in children - cause and tx
enterobius - perianal itching
positive tape test
tx: albendazole or mebendazole
scenario: fever, muscle pain, eosinophilia, and periorbital edema after eating raw meat - cause
trichinella spiralis - trichinosis
scenario: gastroenteritis in young children - 2 main causes
rotavirus
norwalk virus
scenario: food poisoning after eating reheated rice - cause and progression of dx
bacillus cereus
infection is self limited
scenario: food poisoning after eating raw seafood - cause
vibrio parahaemolyticus
scenario: diarrhea after travel to mexico - cause and tx
E. coli
tx: coprofloxacin
scenario: diarrhea after abx - cause and tx
clostridium dificile
tx: oral metronidazole, or oral vancomycin
Scenario: baby paralyzed after eating honey - cause and MOA
clostridium botulinum
toxin blocks ach release
Scenario: Genital lesions in children in the absence of sexual abuse or activity - cause
molluscum contagiosum
scenario: cellulitis after cat or dog bite - cause and tx
pasturella miltocida
tx bite and wounds with prophylactic amoxicillin-clavulanate
Scenario: Slaughterhouse worker with fever - cause
Brucellosis
Scenario: Pneumonia after being in hotel or near air conditioner or water tower - cause and tx
legionella pneumophila
tx with azithromycin or levofloxavin
Scenario: Burn wound infection with blue green color
pseudomonas
- s. aureus is also a common burn infection but it does not cause blue green color
How is syphilis dx?
RPR - rapid plasma reagin or VDRL - Venereal disease research laboratory test
confirmation - FTA-ABS = fluorescent treponemal antibody absorption or MHA-TP - microhemagglutinattion test –> many RPR and VDRL tests have false positives –> this is seen most often in pts with lupus
RPR and VDRL become negative then the disease is successfully treated - HOWEVER often times the FTA-ABS and MHA-TP will be positive for life.
alternative - scrape chancre or condyloma lata and look for spirochetes on dark field microscopy
What group of pts should always be screened for syphilis?
pregnant women
early treatment will prevent birth defects
how is syphilis treated?
PCN
- doxycyclin if pt is allergic to PCN
Describe the 3 stages of syphilis
primary stage - painless chancre that resolves on its own within 8 weeks
secondary stage - roughly 6 weeks to 18 months after infection - look for condyloma lata maculopapular rash on palms and soles of feet, and lymphadenopathy
Latent - between secondary and tertiary
tertiary stage - years after initial infection. look for gummas - granulomas in different organs, neurologic symptoms and signs - neurosyphilis, Argyll-Robertson pupil, dementia, paresis, tabes dorsalis, charcot joints, and thoracic aortic aneurysms
How do you recognize measles-rubeola in a child? What is the treatment?
no immunization
pathognomonic Koplic spots - 3 days after high fever, cough, runny nose, and conjunctivitis with or without photophobia.
next day - maculopapular rash begins on the head and neck and spreads down to cover the trunk - cephalocaudal progression
tx = supportive
What are the complications of measles?
Giant cell pneumonia - in very young immunocompromised pts
otitis media
encephalitis
acute or late subacute sclerosing panencephalitis - occurs years later
Why is Rubella (German measles) infection an important disease?
infection in pregnant mothers can cause severe birth defects in the fetus
screen all women of reproductive age and immunize those without evidence of rubella antibodies before pregnancy to avoid this complication
vaccine is contraindicated in pregnant women
How do you recognize Rubella infection in children? What are the complications?
Rubella is milder than measles
low grade fever, malaise, tender swelling of suboccipital and postauricular nodes
arthralgias are common
after a 2-3 day prodrome - faint maculopapular rash appears on face and neck and spread to the trunk - cephalocaudal progression - just like measles
Complications - encephalitis and otitis media
How do you recognize Roseola infantum (exanthem subitum)? What is the cause?
- high temp, no cause for 4 days, possible febrile seizures,
-abrupt return to normal temp., - followed by maculopapular rash on the chest and abdomen
- rare in children over 3 yo
cause - HHV 6
How do you recognize erythema infectiosum - 5th disease - in children? What causes it?
- look for slapped cheek rash + mild constitutional sx (low grad fever and malaise)
- one day later - maculopapular rash appears on the arms, legs, and trunk
- cause = parvovirus B19 - same virus that causes aplastic crisis in sickle cell dx
How do you recognize chickenpox? What causes it?
discrete macules - trunk turn to papules --> vesicles --> rupture --> crust over this all occurs in 1 day - crops are all in different stages - cause = varicella virus
How do you make a definitive diagnosis of chickenpox? At what point in the disease progression is chickenpox not infectious?
- Tzanck smear of tissue from the base of a vesicle - multinucleated giant cells
- presumptive dx can be made if rash is classic
- infectivity ceases only when the last lesion crusts over
What are the complications of chickenpox?
- infection of lesions with strep or staph –> erysipelas, cellulitis, sepsis
- pneumonia
- encephalitis
- do not give aspirin to child with fever - dt risk of Reye syndrome
- herpes zoster = reactivation of herpes-zoster virus late r in life
- unimmunized ppl can catch chickenpox from someone with shingles
What is the treatment and prophylaxis for chickenpox?
Usually - no treatment - supportive care only - acetaminophen, fluids, avoidance of infecting others
- Acyclovir in severe cases
- routine vaccination with varicella vaccine - recommended for all children in US
- Varicella zoster immune globulin is available for prophylaxis in pts with debilitating illness (AIDS, leukemia) - within 4 days of exposure and for newborns of mothers with chickenpox
- IVIG can be given if varicella zoster ig is not available
What is scarlet fever? What causes it? How is it recognized and treated?
- febrile illness with a rash caused by strep species
- look for Hx of untreated strep pharyngitis
- only strep species that produce erythrogenic toxin can cause scarlet fever
- paryngitis is followed by a sandpaper-like rash on the abdomen and trunk with classic circumoral pallor and strawberry tongue
- rash will desquamate when the fever subsides
- oral penicillin V is the treatment of choice for strep pharyngitis to prevent rheumatic fever
- alt therapies: amoxicillin, cephalosporins, macrolides, or clindamycin
What are the diagnostic criteria for Kowasaki disease (7)?
- younger than 5
- fever for more than 5 days –> absolute requirement
- bilateral conjunctival injection
- changes in the lips, tongue or oral mucosa - strawberry tongue, fissuring, injection
- changes in extremities - desquamation, edema, erythema
- polymorphous truncal rash
- rash begins 1 day after the fever starts
- cervical lymphadenopathy
- look for arthralgia or arthritis
What is the most feared complication of Kowasaki disease? How do you prevent this?
- coronary artery aneurysms
- congestive heart failure
- arrhythmia
- myocarditis
- MI
- NOTE: include Kowasaki disease in any child who has an MI
- if suspected: give child aspirin and IVig
- both have been proved to reduce cardiac lesions - follow child with echo to detect heart involvement
Describe the classic findings of EBV infection - infectious mononucleosis.
look for - fatigue, pharyngitis, cervical lymphadenopathy in a young adult
- sx are similar to strep pharyngitis
watch for:
- Splenomegaly - increased risk for splenic rupture and should avoid contact sports and heavy lifting
- Hepatomegaly
- atypical lymphocytes - may look like leukemia - with lymphocytosis, anemia, or thrombocytopenia
- positive serology - heterophile antibodies - monospot test or specific EBV antibodies - viral capsid antigen, Epstein barr nuclear antigens
What is an important differential of EBV diagnosis?
acute HIV infection - this can cause a mono like syndrome
What is the association between EBV and cancer?
EBV associated with
- nasopharyngeal cancer
- African Burkitt lymphoma
- posttransplant lymphoproliferative disorder
Describe the classical vignette for Rocky Mountain spotted fever. What causes it? What is the treatment?
hx of tick bite - east coast - 1 week before development of high temperature/chills, severe HA and srostration of severe malaise
- rash appears 4 days later on palms/wrist and soles/ankles and spreads rapidly to the trunk and face
- pts look very ill - DIC, delerium
cause = Rickettsia rickettsii
tx = doxycycilne or chloramphenicol as second line
How do you recognize and treat the rash of impetigo? What causes it?
cause - staph and strep
hx of break in the skin
rash - thin walled vesicles that rupture and form tellow crusts - appears weeping
- appears on the face and localized
- rash is INFECTIOUS - look for hx of sick contacts
Tx - dicloxacillin, cephalexin, clindamycin to cover both strep and staph
- topical mupirocin can also be used
