IDS Flashcards
Staphylococcal and streptococcal organisms are effectively treated by medications such as the
_____ including oxacillin, nafcillin, dicloxacillin, and cloxacillin
semisynthetic penicillins,
Methicillin is not used clinically, however, because it may cause____
interstitial nephritis
MRSA is treated primarily with ____
vancomycin.
____ are alternatives for MRSA.
Linezolid, telavancin, daptomycin, ceftaroline, and tigecycline
These agents are effective against streptococci, such as S. pyogenes, viridans group streptococci,
and S. pneumonia, but not against staphylococci
Penicillin G, penicillin VK, ampicillin, and amoxicillin
Ampicillin and amoxicillin are only effective
against staph when ______
ampicillin is combined with the beta-lactamase inhibitor sulbactam
or when amoxicillin is combined with clavulanate
In addition to staphylococci and streptococci, firstand
second-generation cephalosporins will also cover some _____
Gram-negative organism
Firstgeneration agents will only reliably cover _____
Moraxella and E. coli.
Second-generation agents will
cover everything a first-generation cephalosporin covers, as well as a few more Gram-negative bacilli such as ____
Providencia, Haemophilus, Klebsiella, Citrobacter, Morganella, and Proteus
Third-generation agents, particularly _______ are not reliable in their staphylococcal coverage
ceftazidime,
For persons with a genuine allergy to penicillin, there is only a ____ risk of cross-reaction with cephalosporins
<1%
Cross reaction to PCN. Alternatives include?
For minor infections, use a ____
macrolide (clarithromycin or azithromycin)
or one of the new fluoroquinolones (levofloxacin, gemifloxacin, or moxifloxacin).
Cross reaction to PCN. Alternatives include?
For serious infections in those with a life-threatening penicillin allergy, you should use______
vancomycin, linezolid, or daptomycin.
These agents are alternatives to penicillins and cephalosporins for Gram-positive infection. This is not be used for serious staph infections
Macrolides (erythromycin, clarithromycin, azithromycin), fluoroquinolones
(levofloxacin, gemifloxacin, moxifloxacin), and clindamycin
The new quinolones are very good
for streptococcal infections, particularly _____ in the absence of outright penicillin resistance
Strep pneumoniae
These agents are alternatives for Gram-positive infections. They are your answer when there is either a life threatening penicillin allergy or there is MRSA
Vancomycin, linezolid, tigecycline, ceftaroline, telavancin
Linezolid is the only oral medication
available against ___
MRSA.
____ is the only cephalosporin to cover MRSA.
Ceftaroline
These agents are fully active against the full range of Gram-negative bacilli, such as the Enterobacteriaceae as well as Pseudomonas
Penicillins (piperacillin, ticarcillin, mezlocillin)
Ampicillin/Sulbactam and amoxicillin/clavulanate will also cover staph
and Gram-negative bacilli, but not ___
Pseudomonas
Third- and fourth-generation agents are fully active against the full range of Gram-negative bacilli such as the ____
Enterobacteriaceae
Although predominantly for use against Gram-negative organisms,_____ and ___are the best answers for penicillin-insensitive pneumococci-causing
meningitis or pneumonia.
ceftriaxone
and cefotaxime
These agents all cover most of the Enterobacteriaceae, such as E. coli, Proteus, Enterobacter, Haemophilius, Moraxella, Citrobacter, Morganella, Serratia, and Klebsiella.
Quinolones (ciprofloxacin, levofloxacin,gemifloxacin, moxifloxacin, ofloxacin
The new fluoroquinolones (moxifloxacin, levofloxacin, and gemifloxacin) are also active against Gram-positive cocci, in particular _____
Strep pneumoniae
QUinolones
They are amongst the first-line therapies for empiric treatment of pneumonia because they will also cover ______
Mycoplasma, Chlamydia, and Legionella
Although aminoglycosides can be synergistic with a penicillin in the treatment of staph, they are essentially exclusively _____
Gram-negative agents
_____ is exclusively a Gramnegative
agent, with no strep or staph coverage at all
Aztreonam
Fully active against Enterobacteriaceae and Pseudomonas, they are similar in Gram-negative coverage to the aminoglycosides and third-generation cephalosporins. In addition, they have excellent staph and anaerobic coverage
Carbapenems (imipenem, meropenem, ertapenem, doripenem)
Ertapenem will not cover _____
Pseudomonas
The agent most active against anaerobes is _____
metronidazole
Clindamycin is less active against
______
intraabdominal anaerobes
Metronidazole has some advantages against the anaerobic Gramnegative
bacteria in the bowel, such as____
Bacteroides fragilis
____may have some advantages against the anaerobic streptococci found in the mouth.
Clindamycin
TMP/SMZ, clindamycin, doxycycline, and linezolid are oral agents useful for _____
MRSA.
_______ is the most common cause of bacterial meningitis
for all patients beyond the neonatal period
Streptococcus pneumoniae
_____ is spread by respiratory droplets and is the most common cause of meningitis in adolescents
Neisseria meningitidis
_______ is more common in
those with immune system defects, particularly of the cellular (T-cell) immune system and sometimes neutrophil defects.
Listeria monocytogenes
_____ is more common in those who have had any form of neurosurgery because instrumentation and damage to the skin introduce the organism into the
CNS
Staphylococcus aureus
_____ is more common in those who are HIV positive and who have profound
decreases in T-cell counts to levels <100 cells.
Cryptococcus
_____ is common in those who have been exposed to ticks in the appropriate geographic area.
Rocky mountain spotted fever (RMSF)
_____ is the most common cause of meningitis in the neonatal period
Group B Streptococcus
Streptococcus agalactiae
A rash on the wrists and ankles with centripetal spread toward the body
is suggestive of_____
RMSF
Empiric therapy of bacterial meningitis in adults is best achieved with _____
vancomycin (because of the increasing prevalence worldwide of pneumococci with decreasing sensitivity to penicillins) plus a third-generation cephalosporin, such as ceftriaxone
_____ is added to those with immune defects to cover Listeria and for patients age >50 years or ≤ 1 month old.
Ampicillin
_____is used if you know you have definite or suspected pneumococcal resistance to penicillin or if there is a chance of staphylococcal infection after neurosurgery
Vancomycin
Lyme disease is best treated with ___
ceftriaxon
Although virtually any virus can cause encephalitis, the most common cause is ____
herpes simplex, usually type I (HSV-1).
_____ for HSV has a 98% sensitivity and >95% specificity, making it at least equal to the biopsy.
PCR
HSV encephalitis is best treated with IV ____
acyclovir
Although _____ AND ____
have activity against HSV, they are not available intravenously
famciclovir and valacyclovir
_____ are active against CMV
Ganciclovir or foscarnet
Etiology of brain abscess
Brain abscesses most commonly have Streptococcus in 60−70%, Bacteroides in 20−40%, Enterobacteriaceae in
25–35% and Staphylococcus in 10%, and are often polymicrobial.
In HIV-positive patients,
90% of brain lesions will be either ______
toxoplasmosis or lymphoma
MC organisms for OM
The most common organisms are Strep pneumoniae (35−40%), H. influenzae (nontypeable; 25−30%), and Moraxella catarrhalis (15−20%).
OM
The most sensitive clinical finding is ____
immobility of the membrane on insufflation of the ear with air
OM Tx
Oral therapy with____is still the best initial therapy
amoxicillin
OM Tx
_____ is used if there has been recent amoxicillin use or if the patient does not respond to amoxicillin.
Amoxicillinclavulanate
Patients with severe penicillin allergies should receive macrolides such as _____
azithromycin or clarithromycin
Sinusitis
The most common site is the_____
maxillary sinus, followed by ethmoid, frontal, and sphenoid sinuses.
Mild or acute uncomplicated sinusitis can be managed with______
decongestants, such as oral pseudoephedrine or oxymetazoline sprays
Although the majority of pharyngeal infections are from viruses, the most important cause is from____
group A beta-hemolytic streptococci (S. pyogenes
Sore throat with cervical adenopathy and inflammation of the pharynx
with an exudative covering is highly suggestive of _______
S. pyogenes
Most viruses do not give an exudate, although the _____ can
Epstein-Barr virus can
The rapid streptococcal antigen test is ___ sensitive but____ specific.
80%
> 95%
Influenza
Confirmation is best achieved initially with rapid antigen detection methods of
______
swabs or washings of nasopharyngeal secretions.
Specific antiviral medications for both influenza A and B are the neuraminidase inhibitors_____ and _____
oseltamivir and
zanamivir.
_____ is an infection of the lung, which is limited to the bronchial tree with limited involvement of the lung parenchyma
Bronchitis
Acute bronchitis is an acute inflammation of the tracheobronchial tube. The vast majority of cases are caused by____
viruses
The most common organisms responsible for chronic bronchitis are
Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella
____ is the most common causative factor for bronchitis
Cigarette smoking
MC etiology of lung abscess
The most commonly implicated anaerobes are Peptostreptococcus, Prevotella, and
Fusobacterium species, which are oral anaerobes found in the gingival crevices
Lung abscess
85−90% have a clear association with _____ or ____
periodontal disease or some predisposition to aspiration (e.g., altered sensorium, seizures, dysphagia).
the features associated with lung abscesses are ____ in 60−70%, and a more chronic course
putrid, foul-smelling sputum
The_____ are the most common sites of aspiration in the upright position, and the _____ is the most common site in the supine position.
lower lobes
posterior segment of the right upper lobe
what is the best initial therapy for a lung abscess,
is antibiotics such as clindamycin
The most common cause of community-acquired pneumonia in all groups is_____when an actual cause is identified
S. pneumoniae
Specific predispositions are as follows:
• ______smokers, COPD
•______young, otherwise healthy patients
• ______epidemic infection in older smokers, particularly when located near
infected water sources, such as air-conditioning systems
Haemophilus influenzae
Mycoplasma
Legionella
Specific predispositions are as follows
- _____pneumoniaHIV-positive persons with <200 CD4 cells not on prophylaxis
- ______exposure to animals, particularly at the time they are giving birth
Pneumocystis jiroveci (formerly carinii)
Coxiella burnetti (Q-fever)
Specific predispositions are as follows
- _______alcoholics
- _______following viral syndromes or viral bronchitis, especially influenza
• _______exposure to the deserts of the American Southwest, particularly
Arizona
• _______—birds
Klebsiella
Staphylococcus aureus
Coccidioidomycosis
Chlamydia psittaci
Specific predispositions are as follows
- _____—exposure to bat or bird droppings, spelunking (recreational cave exploration)
- ______—cough with whoop and post-tussive vomiting
- _______—hunters, or exposure to rabbits
- _______—travel to Southeast Asia
- Bacillus anthracis, Yersinia pestis, and Francisella tularensis—_____
Histoplasma capsulatum
Bordetella pertussis
Francisella tularensis
SARS, Avian influenza
bioterrorism
_____ has been associated with sputum
described as being like currant jelly
Klebsiella pneumoniae
Interstitial infections such as those caused by Pneumocystis pneumonia (PCP),
viruses, Mycoplasma, and sometimes Legionella often give a____
nonproductive or “dry” cough
Commonly, pleuritic pain is associated with lobar pneumonia, such as that caused
by _____
Pneumococcus.
Interstitial infiltrates are associated with
_____
PCP, viral, Mycoplasma, Chlamydia, Coxiella, and sometimes Legionella pneumoniae
Organism-specific diagnostic methods are as follows:
• _______Specific serologic antibody titers. Cold agglutinins have both limited
specificity and sensitivity.
• Legionella______
Mycoplasma
Specialized culture media with charcoal yeast extract, urine antigen tests,
direct fluorescent antibodies, and antibody titers
Organism-specific diagnostic methods are as follows:
• PCP______
• Chlamydia pneumoniae, Coxiella, Coccidioidomycoses, and Chlamydia psittaciAll of
these are diagnosed with specific antibody titers
Bronchoalveolar lavage, increased LDH
Empiric therapy for pneumonia managed as an outpatient is with a _____
macrolide, such as azithromycin or clarithromycin
Alternatives Tx for Pnx at OPD:
new fluoroquinolones:
Levofloxacin, moxifloxacin, gemifloxacin
Orals meds for Inpatient Mx of Pnx
New fluoroquinolones (levofloxacin, moxifloxacin, or gemifloxacin)
IV meds for Inpatient Mx of Pnx
Second- or third-generation
cephalosporins (cefuroxime or ceftriaxone)
combined with a macrolide or doxycycline
Empiric therapy of hospital-acquired pneumonia is with _____
third-generation cephalosporins with antipseudomonal activity (such as ceftazidime) or carbapenems (such as imipenem) or with beta-lactam/beta-lactamase inhibitor combinations
(such as piperacillin/tazobactam) and coverage for MRSA with vancomycin or linezolid
Treatment of specific organisms is as follows:
- Haemophilus influenzae____
- Mycoplasma______
- Legionella______
Second- or third-generation cephalosporins
Macrolides, doxycycline, or a quinolone
Macrolides, doxycycline, or a quinolone
Treatment of specific organisms is as follows:
Pneumocystis pneumonia
Trimethoprim/Sulfamethoxazole (TMP/SMZ). Steroids should be used if the infection is severe
Treatment of specific organisms
- Coxiella brunetti (Q-fever)____
- Klebsiella_____
- Staphylococcus aureus____
Doxycycline (or erythromycin as an alternative)
Third-generation cephalosporins and the other drugs for Gram-negative bacilli
Semisynthetic penicillins (oxacillin, nafcillin, etc.) if methicillin sensitive. In the nosocomial setting, isolates are invariably methicillin-resistant, and vancomycin or linezolid is administered
Effectivity of Pnx vax
The vaccine is 60−70% effective
Re-dosing of Pnx Vaccine
Re-dosing in 5 years is only necessary for those with severe immunocompromise or
in those who were originally vaccinated before the age of 65
There are several types of food poisoning, such as_____ and ______that present predominantly with vomiting
Bacillus cereus and Staphylococcus aureus,
The most common agent causing food poisoning is______
Campylobacter.
The most commonly associated agent with contaminated poultry and eggs is _____
Salmonella
_____ is still the most common cause of travelers’ diarrhea; it produces a wide spectrum of disease depending on whether it makes toxin or is invasive
E. coli
_____ is associated with undercooked hamburger meat
E. coli 0157:H7
____ is associated with fried rice;
Bacillus cereus
____ and_____ are acquired from contaminated water sources that have not been appropriately filtered, such as fresh water found on a
camping trip.
Giardia lamblia and cryptosporidiosis
______is also associated with HIV, particularly when there is profound
immunosuppression and CD4 count drops <50 cells
Cryptosporidiosis
–– V. cholera is very rare in the United States.
–– _______ is associated with ingestion of contaminated shellfish such as
clams, oysters, and mussels.
–– ________ is associated with ingestion of raw shellfish; it causes severe disease in
those with underlying liver disease; it is also associated with iron overload and the
development of bullous skin lesions
V. parahaemolyticus
V. vulnificus
Clostridia associations are as follows:
–– ______ with previous antibiotic use
––________ with ingestion of infected canned foods
–– ______ with ingestion of meat contaminated with spores due to unrefrigeration
C. difficile
C. botulinum
C. perfringens
Blood in the stool is most commonly
associated with invasive enteric pathogens, such as _______
Salmonella, Shigella, Yersinia, invasive E. coli, and Campylobacter
Ingestion of ____causes symptoms within 2–6 hours, which includes paresthesias,
numbness, nausea, vomiting, and abdominal cramps
ciguatera toxin
__ and ____ are associated with hemolytic uremic syndrome (HUS
E. coli 0157:H7 and Shigella
Bacillus cereus and Staphlococcus predominantly present with vomiting within 1–6 hours of their ingestion because they contain a______
preformed toxin.
When ingested, scombroid can
give symptoms within a few minutes:
rash, diarrhea, vomiting, and wheezing, along with a burning sensation in the mouth, dizziness, and paresthesia
When there is no blood present in the stool, the best initial method of determining
the etiology of the diarrhea is to test the stool for the presence of WBCs with ___
methylene blue testing
A special modified _____ is necessary to detect Cryptosporidia.
Stool ELISA is also used for _____
AFB stain
Giardia
Organism-specific therapy is as follows:
• Campylobacter_____
• Giardia______
• CryptosporidiumControl of underlying HIV disease with antiretrovirals, _____
Erythromycin
Metronidazole
nitazoxanide
What hepa?
They cause symptomatic disease for several days to weeks, have no
chronic form, and do not lead to either cirrhosis or hepatocellular carcinoma
Hepatitis A and E
What hepa?
are transmitted by the parenteral route. They can be acquired perinatally
or through sexual contact, blood transfusion, needlestick, and needle sharin
Hepatitis B, C, and D
_____ has been identified in a small number of patients through screening of the blood supply but has not yet been associated with clinical disease.
Hepatitis G
_____can lead to a chronic form, which can cause cirrhosis and hepatocellular carcinoma
Hepatitis B and C
______is the most common disease leading to the need for liver transplantation in the United States
Hepatitis C
Hepatitis B and C can also give symptoms similar to ____ such as joint pain, rash, vasculitis, and glomerulonephritis
serum sickness,
What hepa?
They also lead to cryoglobulinemia
Hepatitis B and C
What hepa?
____has been associated
with the development of polyarteritis nodosa (PAN).
Hepatitis B
What hepa?
_____has been associated with a
more severe presentation in pregnant women.
Hepatitis E
Viral hepatitis will produce both elevated ALT and AST, but _____
ALT is usually greater than the AST
With drug- and alcohol-induced hepatitis, ______
AST is usually more elevated than the ALT
____ and ___ are less often elevated because these enzymes usually indicate damage to the bile canalicular system or obstruction of the biliary system
Alkaline phosphatase and GGTP
Hepatitis A, C, D, and E are diagnosed as acute by the presence of the ____
IgM antibody to each of these specific viruses.
IgG antibody to hepatitis A, C, D, and E indicates ______
old, resolved disease
Hepatitis C activity can be followed with PCR-RNA viral load level. However, do not
use PCR to ____
establish the initial diagnosis
Hepa B
The _____indicates high levels of viral replication and is a marker for greatly
increased infectivity
e antigen
Hepa B
Resolution of the infection is definitively indicated by the ____ and ____
loss of surface antigen activity and the development of hepatitis B surface antibody
There is no effective therapy for acute hepatitis B. Chronic hepatitis B can be treated with either _______
interferon, entecavir, adefovir, or lamivudine
_____, the current preferred HCV treatment, is 2 drugs formulated in to one daily pill
Sofosbuvir/ledipasvir
MOA of Sofosbuvir/ledipasvir
directly interfere with hepatitis C virus replication
_____is a polymerase inhibitor while
ledipasvir, an_____
Sofosbuvir
NS5A inhibitor
After a needlestick from a hepatitis B surface-antigen−positive patient, the person stuck should receive _______
hepatitis B immunoglobulin (HBIg) and hepatitis B vaccine
Nongonococcal urethritis caused by either \_\_\_\_\_ (50%), \_\_\_\_\_\_ (20%), \_\_\_\_\_ (5%), \_\_\_\_\_ (1%) \_\_\_\_\_\_
Chlamydia trachomatis Ureaplasma urealyticum Mycoplasma hominis Trichomonas herpes simplex
Serology (fluorescent antibodies) for chlamydia by swabbing the urethra, or by ____ test of voided urine
ligase chain reaction
Gonococcal urethritis Tx
______is now the treatment of choice.
Single-dose ceftriaxone intramusculary and single-dose azithromycin orally
Gonococcal urethritis alternative
An alternative regimen with doxycycline for 7 days can also be used.
_____should not be used as first-line therapy for gonorrhea.
Ciprofloxacin
_____ is the only definitive test for PID
Laparoscopy
Pelvic Inflammatory Disease etiology
N. gonorrhoeae, Chlamydia, Mycoplasma, anaerobic bacteria, or Gram-negative bacteria.
Inpt TX for PID
Doxycycline and cefoxitin (or cefotetan) for inpatient therapy
Outpatient therapy is with _____
single-dose ceftriaxone intramuscularly and doxycycline orally for two weeks
Congenital
• Early: ______
• Late: _____
symptomatic; seen in infants up to age 2
symptomatic, Hutchinson teeth, scars of interstitial keratitis, bony abnormalities
(saber shins
Describe primary stage of Syph
Chancre that appears within the third week and disappears within 10–90 days; also, regional lymphadenopathy is painless, rubbery, discrete, and nontender
to palpation
Describe Secondary stage of Syph:
Cutaneous rashes appear 6–12 weeks after infection, usually found symmetrically and more marked on the flexor and volar surfaces of the
Describe Latent stage of Syph: : ____
Asymptomatic; may persist for life, and one-third of patients develop late or tertiary syphilis.
Benign tertiary develops 3–20 years after
the initial infection, and the typical lesion is
the gumma (a chronic granulomatous reaction), found in any tissue or organ.
Syphilis
- Screening tests are the _____
- False–positives ______
VDRL and RPR; specific tests are the FTA-ABS, MHA-TP, and Darkfield exam of chancre.
VDRL with EBV, collagen vascular disease, TB, subacute bacterial endocarditis
Primary, secondary, and latent syphilis are treated with ____
2.4 million units of intramuscular benzathine penicillin given once a week.
An acute, localized, contagious disease characterized by painful genital ulcers and
suppuration of the inguinal lymph nodes
Chancroid
Etiology of Chancroid
Haemophilus ducreyi (Gram-negative bacillus).
SSx of channcroid
Small, soft, painful papules that become shallow ulcers with ragged edges.
Tx of channcroid
Azithromycin single dose or ceftriaxone intramuscularly (single dose).
Erythromycin for 7 days or cipro for 3 days are alternatives
Definition. A contagious, sexually transmitted disease having a transitory primary lesion followed by suppurative lymphangitis.
Etiology. Chlamydia trachomatis
Lymphogranuloma Venereum
Lymphogranuloma Venereum SSx
A small, transient, nonindurated lesion that ulcerates and heals quickly; unilateral enlargement of inguinal lymph nodes (tender); multiple draining sinuses (buboes)
develop (purulent or bloodstained);
Tx of LGV
Treatment. Doxycycline (or erythromycin as an alternative).
A painless, red nodule that develops into an elevated granulomatous mass. In males, usually found on the penis, scrotum, groin, and thighs; in females on the vulva,
vagina, and perineum.
Granuloma Inguinale
Granuloma Inguinale Dx
• Clinically and by performing a Giemsa or Wright stain (Donovan bodies) or smear of
lesion
• Punch biopsy
Treatment of Granuloma Inguinale Dx.
Doxycycline ceftriaxone or TMP/SMZ. Erythromycin as an alternative
SSx of Genital Herpes
Vesicles develop on the skin or mucous membranes; they become eroded and
painful and present with circular ulcers with a red areola.
Dx of Genital Herpes
Diagnosis. Tzanck test and culture.
Treatment of Genital Herpes.
Oral acyclovir, famciclovir, or valacyclovir. Must explain to the patient the relapsing
nature of the disease
Genital Warts
Definition. Also known as condylomata acuminata or venereal warts.
Etiology. _____
Papilloma virus.
Genital Warts
Differentiation must be made between flat warts and ______
condylomata lata of secondary syphilis
Genital Warts Tx
- Destruction (curettage, sclerotherapy, trichloroacetic acid)
- Cryotherapy
- Podophyllin
- Imiquimod (an immune stimulant)
- Laser removal
Etiology for genital warts
E. coli in >80%; second are other coliforms (Gram-negative bacilli) such as Proteus, Klebsiella, Enterobacter, etc.; enterococci occasionally, and Staph. saprophyticus
in young women.
UTI
Best initial test is the_____
urinalysis looking for WBCs, RBCs, protein, and bacteria; WBCs
is the most important
UTI
Nitrites in UA are indicative of _____
Gram-negative infection
UTI
confirmatory
Urine culture with >100,000 colonies of bacteria per mL of urine confirmatory but
not always necessary with characteristic symptoms and a positive urinalysis
For uncomplicated cystitis TX,
3 days of trimethoprim/sulfamethoxazole, nitrofurantoin, or any quinolone is adequate
Seven days of therapy for cystitis in ____
diabetes
____ is a single-dose oral therapy for cystitis only
Fosfomycin
How to dx of acute pyelo
Diagnosis. Dysuria, flank pain and confirmation with:
• Clean-catch urine for urinalysis, culture, and sensitivity
• >100,000 bacteria/mL of urine in the majority of cases.
Abx of pyelo
Antibiotics for 10–14 days (fluoroquinolone), or ampicillin and gentamicin, or a
third-generation cephalosporin are all acceptable
A collection of infected material surrounding the kidney and generally contained within the surrounding Gerota fascia. Very uncommon.
Perinephric Abscess
MC RF for Perinephric Abscess
Although any factor predisposing to pyelonephritis is contributory, stones are the most important and are present in 20–60%.
Organisms for perinephric abscess
1) The same coliforms as in cystitis and pyelonephritis; 2) E. coli most common, then Klebsiella, Proteus; 3) Staph. aureus sometimes accounts for hematogenous
cases
MC sx perinephric abscess
Fever is the most common symptom
Imaging for perinephric abscess
Imaging is essential; U/S is the best initial scan but CT or MRI scan offers better imaging
Tx of perinephric abscess
Third-generation cephalosporins, antipseudomonal penicillin, or ticarcillin/clavulanate, often in combination with an aminoglycoside, for example
MC Org of Osteomyelitis
The most common organism
is Staphylococcus aureus
Osteomyelitis
The most commonly involved bones are the ______, and the location is usually metaphyseal due to the anatomy of the blood vessels and endothelial
lining at the metaphysis
tibia and femur
Etiology of Osteomyelitis
Acute hematogenous
Secondary to contiguous infection:
Vascular insufficiency
The earliest tests to detect osteomyelitis are the ______ and _____
technetium bone scan and the
MRI.
MC initial finding of Xray in OM
Periosteal elevation is the first abnormality visible
This is the best diagnostic test but also the most invasive for OM
Bone biopsy and culture:
Mx of OM in children
Acute hematogenous osteomyelitis in children can usually be treated with antibiotics alone
Mx of OM in adults
osteomyelitis in adults requires a combination of surgical (wound drainage and debridement, removal of infected hardware) and antibiotic therap
ABx for OM
A semisynthetic penicillin (oxacillin, nafcillin) or vancomycin (if MRSA is suspected) plus an aminoglycoside or a third-generation cephalosporin would be adequate until a specific diagnosis is obtained
Chronic osteomyelitis must be treated for as long as______of antibiotic therapy, and in some cases, even longer periods of antibiotics may be required.
12 weeks
Septic arthritis
The most common etiology is bacterial;
specifically, _____
Neisseria gonorrhoeae, staphylococci or streptococci, but Rickettsia, viruses,
spirochetes, etc., may also cause it.
____ is the only significant risk factor for gonococcal septic arthritis.
Sexual activity
Nongonococcal bacterial arthritis is usually
spread by the_______
hematogenous route.
Microbiology. Nongonococcal of septic arthritis
- Gram-positive (>85); (S. aureus [60%], Streptococcus [15%], Pneumococcus [5%])
- Gram-negative (10−15%)
- Polymicrobial (5%)
MC SSx of non-gonococcal arthritis
Monoarticular in >85%, with a swollen, tender, erythematous joint with a
decreased range of motion. Knee is the most common. Skin manifestations are rare
SSx of Gonococcal.
Polyarticular in 50%; a tenosynovitis is much more common. Effusions are less
common. Migratory polyarthralgia are common. Skin manifestations with petechiae or purpura are common
TX of septic arthritis
Bacterial arthritis is usually treated by a combination of joint aspiration and antimicrobial therapy
Nongonococcal. In the absence of a specific organism seen on a stain or obtained from culture, good empiric coverage is_____
nafcillin or oxacillin (or vancomycin) combined with an aminoglycoside
or a third-generation cephalosporin.
_____ is largely due (80%) to the spread of infection from wounds contaminated by Clostridium perfringens (the toxins produced by clostridia play a significant role in tissue damage).
Gas gangrene
SSX of Gas Gangrene
Symptoms usually begin_______ of incubation after the wound and
include pain, swelling, and edema at the site of the wound. Later hypotension, tachycardia, and fever can occur
<1–4 days
Gas gangrene
Gas bubbles on x-ray are
suggestive but may be caused by _____as well
streptococci
Mx of gas gangrene
High-dose penicillin (24 million/day) or clindamycin (if penicillin allergic)
is necessary, but surgical debridement or amputation is the absolute center of treatment
Gas gangrene
____ is of possible benefit, but this is still controversial
Hyperbaric oxygen
COnsidered HR for IE
Prosthetic valves* Aortic valve disease Mitral regurgitation Patent ductus arteriosus Arteriovenous fistula Coarctation of the aorta Indwelling right heart catheters (hyperalimentation) Previous infective endocarditis Marfan syndrome
Microorganisms Responsible for Infective Endocarditis
Native valves
Streptococcus viridans: 50−60%
Enterococci: 5−15%
Staphylococcus aureus 20−30%
Staphylococcus epidermidis 1−3
Microorganisms Responsible for Infective Endocarditis
In narcotic addicts
Staphylococcus aureus 60−95
Staphylococcus epidermidis 5−10
Microorganisms Responsible for Infective Endocarditis
Prosthetic valves
Staphylococcus epidermidis
Streptococcus viridans
Staphylococcus aureus
IE
- _____ is the most common cause of acute endocarditis
- Seed previously normal valves, producing necrotizing, ulcerative, invasive infection
- Produces large, bulky vegetations (2 mm to 2 cm) on the____ side
S. aureus
atrial
With subacute infective endocarditis, ______is the most common organism and is associated with low virulence.
viridans group streptococci
Clinical course of subacute infective endocarditis
Clinical course: 1) Slow onset with vague symptoms; 2) malaise, low-grade fever,
weight loss, flulike symptoms; 3) destruction of valves is also present; and 4) less fatal than acute, with 5-year survival 80–90% with treatment
Petechiae (20−30%): red, nonblanching lesions in crops on conjunctivae,
buccal mucosa, palate, extremities
Pathogenesis and etiology?
Vasculitis or emboli
Streptococcus, Staphylococcus
linear, red-brown streaks most
suggestive of IE when proximal in nailbeds
Splinter hemorrhages (15%):
____ 2−5 mm painful nodules on pads of
fingers or toes
Osler’s nodes (5−10%):
_____macular, red, or hemorrhagic, painless patches on palms or soles
Janeway lesions (10–15%):
Pathogenesis and etiology?
Janeway lesions (10–15%):
Emboli
Staphylococcus
Pathogenesis and etiology?
Osler’s nodes (5−10%):
Vasculitis
Streptococcus
_____: oval, pale, retinal lesions surrounded
by hemorrhage
Roth’s spots (<5%)
Therapy of Specific Microorganisms Causing Endocarditis
Strep. viridans
Penicillin
Penicillin-allergic: ceftriaxone or
vancomycin
Penicillin or ceftriaxone + 2 weeks of
gentamicin
Strep. viridans duration of tx
4 wks
Therapy of Specific Microorganisms Causing Endocarditis
Staph. aureus, native valve
Methicillin-sensitive
Nafcillin (+ 5 days of gentamicin)
Penicillin-allergic: cefazolin or
vancomycin + gentamicin for first 5 days
Therapy of Specific Microorganisms Causing Endocarditis
Staph. aureus, native valve
Methicillin-sensitive
Nafcillin (+ 5 days of gentamicin)
Penicillin-allergic: cefazolin or
vancomycin + gentamicin for first 5 days
Therapy of Specific Microorganisms Causing Endocarditis
Staph. aureus, native valve
(Methicillin-sensitive)
Duration
4-6 weeks
Therapy of Specific Microorganisms Causing Endocarditis
Enterococcal
Penicillin (or ampicillin) and
gentamicin (vancomycin if penicillinallergic)
Penicillin-allergic or resistant:
vancomycin and gentamicin
Therapy of Specific Microorganisms Causing Endocarditis
Enterococcal
Duration of tx
4-6 wks
T or F
AS, MS, AR, and MR no longer need prophylaxis, even for dental procedures
T
Meds for dental prophylaxis
amoxicillin; for penicillin-allergic patients, use clindamycin, azithromycin, clarithromycin, or cephalexin
Cardiac Conditions Which Do Require Prophylactic Therapy
1
2
3
• Prosthetic cardiac valves, including bioprosthetic and homograft valves
• Previous bacterial endocarditis, even in the absence of heart disease
• Most congenital cardiac malformations, especially cyanotic lesions (negligible risk
with isolated ASD) if not repaired
Conditions Which Do Not Require Prophylactic Therapy
- Surgically corrected systemic pulmonary shunts and conduits
- Rheumatic and other acquired valvular dysfunction, even after valvular surgery
- Hypertrophic cardiomyopathy
- Mitral valve prolapse with valvular regurgitation
- Surgically repaired intracardiac defects
Dental or Surgical Procedures Which Predispose to Endocarditis
1
2
- Dental procedures known to induce gingival or mucosal bleeding, including professional cleaning
- Tonsillectomy and/or adenoidectomy
Procedures in Which Indication for Prophylaxis Is Unclear
_____
• Surgical operations that involve intestinal or respiratory mucosa
Anatomic Defects or Conditions Which Require Prophylaxis
- Prosthetic valves
- Unrepaired cyanotic heart disease
- Previous endocarditis
- Transplant status
Lyme dse
Symptoms begin____ after the bite of the tick. Eighty percent of patients develop the ____ rash at the site of the bite
3−30 days
erythema migrans
An erythematous patch, which may enlarge in the first few days, may have partial central clearing, giving it a “bull’seye” appearance, although this is not commonly seen.)
erythema migrans rash
MC neuro SSx of Lyme
This is most commonlyparalysis of the seventh cranial nerve (facial paralysis) and may be bilateral
Lyme
Cardiac symptoms develop in <10% of patients and is most commonly ___
AV heart block
Lyme
An ______is the standard method of establishing the diagnosis
ELISA test combined with a western blot
Lyme
Minor symptoms are treated with ____
doxycycline or amoxicillin
Lyme
More serious manifestations such as heart
block, meningitis, myocarditis, or encephalitis are treated with _____
IV ceftriaxone
abrupt onset of fever, headache, and rash (erythematous maculopapules).
This disease starts at wrist and ankles and spreads centripetally (can involve palms and soles).
ROCKY MOUNTAIN SPOTTED FEVER
Dx of RMSF
Specific serology: Biopsy of skin lesion
Tx of RMSF
Doxycycline
Transmission of AIDS in developing countries
In most developing countries,
including Africa, Asia, and Latin America, heterosexual transmission is the primary mode
There is often a 10-year lag between contracting HIV infection and developing the first symptoms because?
This is because CD4 cells drop at a rate of 50−100/mL/year without therapy
Opportunistic Infections in AIDS
pneumonia; dyspnea on exertion; dry cough; fever; chest pain; usually
subacute onset and progression
Pneumocystis jirovecii (formerly carinii) (CD4 count <200/μL)
Dx of Pneumocystis jirovecii
Bronchoscopy with bronchoalveolar lavage for direct identification of the organism.
Chest x-ray reveals bilateral, interstitial infiltrates
Tx of Pneumocystis jirovecii
Trimethoprim-sulfamethoxazole (TMP-SMZ) is the first-line therapy for mild-severe
disease and may cause a rash
ALternative Tx of Pneumocystis jirovecii
Alternative therapy for mild-moderate disease is a combination of dapsone and trimethoprim or primaquine and clindamycin or atovaquone or trimetrexate (with leucovorin).
Prophylaxis (in Order of Preference for Pneumocystis jirovecii
- TMP/SMZ orally—this is most effective.
- Dapsone
- Atovaquone
- Aerosolized pentamidine—fails the most
Prophylaxis of PCP may be discontinued if _____
antiretrovirals raise CD4 count >200/mL
for >6 months.
Cytomegalovirus (CD4 <50/μL)
Principal Manifestations
Retinitis:
Colitis:
Esophagitis
Encephalitis:
Endoscopy of Esophagitis in CMV
(endoscopy reveals multiple shallow ulcers in the distal esophagus)
Principal Diagnostic Tests for CMV
1
2
- Funduscopy for retinitis
* Colonoscopy with biopsy for diarrhea or upper GI endoscopy with biopsy of ulcers
An oral prodrug of ganciclovir, achieves levels in the serum comparable
to IV ganciclovir. This drug can be used to treat CMV retinitis (along with intravitreal
ganciclovir) and GI manifestations of CMV disease
Valganciclovir
Primary prophylaxis is not
indicated for CMV retinitis
T
A ubiquitous atypical mycobacteria found in the environment; mode
of infection is inhalation or ingestion. Fevers, night sweats, bacteremia, wasting, anemia, diarrhea
Mycobacterium avium complex (CD4 <50/mL)
Principal Diagnostic Tests of MAC
- Blood culture
* Culture of bone marrow, liver, or other body tissue or flu
MAC prophylaxis
Prophylaxis
• Azithromycin orally once a week or clarithromycin twice a day
When to dc prophylaxis in MAC
Prophylaxis may be discontinued if antiretrovirals raise the CD4 count >100/mL for several months.
Toxoplasmosis (CD4 <100/μL) Tx
Pyrimethamine and sulfadiazine. Clindamycin can be substituted for sulfadiazine in the sulfa-allergic patient. Leucovorin is given to prevent bone marrow suppression
The following is an approximate breakdown of when the risk of certain diseases begins to increase.
______ Oral thrush, Kaposi sarcoma, tuberculosis, Zoster
______ Pneumocystis carinii pneumonia, disseminated histoplasmosis and
coccidiomycosis
_______Toxoplasmosis, Cryptococcus, cryptosporidiosis, disseminated herpes
simplex
\_\_\_\_\_\_: Cytomegalovirus, Mycobacterium avium complex. Progressive, multifocal leukoencephalopathy (PML), CNS lymphoma
200–500/mL:
100–200/mL:
<100/mL:
<50/mL
Nucleoside Reverse Transcriptase Inhibitors
- Zidovudine (ZDV or AZT)_____
- Didanosine (DDI)______
- Stavudine (D4T)________
- Lamivudine (3TC)Nothing additional to placebo
Leukopenia, anemia, GI
Pancreatitis, peripheral neuropathy
Peripheral neuropathy
Nucleoside Reverse Transcriptase Inhibitors
- ________—Structurally related to lamivudine; few side effects as for lamivudine
- ________is a nucleotide analog as compared to the others that are nucleoside analogs
Emtricitabine
Tenofovir
