questions from quiz let Flashcards
(208 cards)
1
Q
Name some risk factors for HAI
A
Hospitalization Surgery Invasive procedures Injectable drug therapies Antibiotic overuse (C diff) Poor hand hygiene Poor environmental cleansing
2
Q
Name some ways you can prevent HAI’s through your behavior
A
Wash hands
Use gloves when appropriate
Abide by isolation precautions (masks with TB pt, etc)
Avoid overuse of antibiotics (C diff)
Speak up if you see a problem
Participate in quality improvement efforts
Get immunized
Treat latent TB
Participate in evidence based bundles such as with line insertion
3
Q
When should periprocedural antibiotics be administered?
A
Within 60 minutes of skin incision
Usually one dose
Reducing makes sense for surgeries > 8 hrs
Post-operative courses of therapy, while you will see them, are inappropriate unless infection is present
4
Q
What should you do if you get a mucosal exposure to patient blood or fluids?
A
Wash
Report to supervisor
See Occupational Medicine to learn if more needs to be done
5
Q
If you are exposed to HIV via a needlestick or other means, how can you lower the likelihood of contracting the infection?
A
Wash/flush the site of exposure
Be evaluated to learn if post-exposure prophylaxis is indicated
(It’s extremely effective, but does confer some toxicities, so the million dollar question if it occurs - I hope it doesn’t! - is whether it is indicated
6
Q
Where can I learn more about Geisel’s policy on blood borne pathogen exposures?
A
Page 88 of the student handbook:
https://geiselmed.dartmouth.edu/faculty/pdf/geisel_student_policy_handbook_public.pdf
7
Q
What is SIRS?
I won’t test you on the details but you should understand the general idea for clinical purposes.
A
The criteria for SIRS are two or more of
(1) T >38.5ºC or 90,
(3) RR >20 or PaCO2 12,000 or 10% bands
8
Q
What’s the definition of sepsis?
A
SIRS + infection
Add hypotension and you gotcherself septic shock
9
Q
What’s the most common site of origin of sepsis?
A
Pneumonia and other lung infections
Followed by bloodstream infections, intraabdominal infections, urinary infections and skin/soft tissue infections (in that order).
So: guess the lung.
10
Q
Describe the pathogenesis of sepsis
A
(1) Infection
(2) Failure to contain the infection and/or overly robust immune reaction and/or toxin release
(3) Systemic instability (e.g. SIRS)
(4) Epiphenomena like hyper coagulability, poor organ perfusion due to decreased systemic vascular resistance and (if present) hypotension
(5) Downstream inflammation from effects of the above, for example additional inflammation created by poor tissue perfusion
(6) Vicious cycle that can thwart therapy for the original focus
11
Q
What kills people who are septic?
A
Sometimes hypotension itself kills people, particularly if they don’t reach medical care in time, via poor brain or heart perfusion.
More commonly, hospitalized people with sepsis die from end organ dysfunction such as renal failure, or they succumb to complications of hospitalization like PE or MI, or they experience slow deterioration after failure to bounce back from the original homeostatic insult.
12
Q
List some key tenants of sepsis resuscitation
A
IVF
Pressors if mean arterial pressure too low
Support failing organs (ventilator, dialysis, etc)
Good ICU care: avoid infections, clots, pressure ulcers, etc.
13
Q
Usually it’s obvious where sepsis is coming from - a big honking pneumonia is staring you in the face. But occasionally it’s not clear, so you have to administer empirical antibiotics while you seek a clearer diagnosis. Name a couple of appropriate regimens for use in that context.
A
vancomycin + piperacillin/tazobactam
vancomycin + ceftazidime
(note that the second option above lacks anti-anaerobic coverage so would work for pneumonia - unless aspiration - but not for an intra-abdominal catastrophe such as if you suspect diverticulitis)
14
Q
Which two pressor agents are most commonly used to treat sepsis?
A
Norepinephrine and vasopressin
Dopamine use was associated with greater toxicity such as cardiac arrhythmias
15
Q
Contrast the typical presentation of bacterial meningitis and “aseptic” meningitis
A
Bacterial: more frequent in frail people at the extremes of age or immunocompromised, rapid onset, severe illness, high fever, severe headache, nuchal rigidity, clear mentation unless progressing toward coma, PMN predominance in CSF, low glucose is possible
“Aseptic”: more frequent in healthy young people in the summer, less severe illness, less meningismus, clear mentation, lymphocyte predominance
16
Q
What clinical features distinguish meningitis from encephalitis
A
Features that suggest meningitis: nuchal rigidity, sepsis, purpura fulminans
Features that suggest encephalitis: altered cognition (word salad, hallucinations, weird behavior) and seizures
17
Q
Name some common causes of bacterial meningitis
A
Streptococcus pneumoniae
Neisseria meningitidis
Haemophilus influenzae (in unvaccinated people or from non-vaccine types)
Group B strep or E coli (infants)
Listeria (babies, >50 years, or immunocompromised [including pregnancy])
Cryptococcus (80% of the time in immunocompromised)
18
Q
This CSF analysis pattern is suggestive of what kind of infection?
WBC 400 Percent polymorphonuclear cells 90% Glucose 30 (concurrent blood glucose 100) Protein 45 Gram stain pending
A
Bacterial meningitis, because the PMN count is high and (less sensitive) the glucose is low
19
Q
How does the clinical presentation of a brain abscess differ from that of meningitis?
A
Brain abscess and meningitis can have some similarities. Headache is common in both as is fever.
But brain abscess is a focal infection, so more likely to show focal symptoms such as asymmetric weakness or numbness. Also, since brain abscess is often secondary to hematogenous spread to the brain there can be an associated syndrome of bacteremia, perhaps with some common source like a dental abscess or injection drug use or a skin/soft tissue infection history
20
Q
Name some causes of aseptic meningitis
A
INFECTIOUS:
Enterovirus
HSV
West Nile virus
VZV
TB meningitis (can show up like this, and as chronic meningitis)
Lyme disease
NON-INFECTIOUS:
Drugs (NSAIDS for example)
Cancer (carcinomatous meningitis)
21
Q
What is the standard empirical antibiotic regimen for a health 25 year-old with bacterial meningitis?
A
The standard regimen against meningitis while awaiting cultures is vancomycin (to cover resistant Streptococci) and ceftriaxone (to cover Streptococci plus Gram negatives like Neisseria).
22
Q
What drug should you give to treat viral encephalitis
A
Acyclovir, while awaiting results of the HSV PCR
23
Q
Why should you add ampicillin to your empirical antibiotic regimen against bacterial pneumonia in infants, adults >50 years, and immunocompromised patients?
A
To cover Listeria monocytogenes against which their T cell immunity is likely to be inadequate.
24
Q
List some interventions proven to reduce the risk of HIV infection
A
HIV testing and linkage to care
Antiretroviral therapy
Condoms and sterile syringes
Prevention programs for high risk people like partners of people living with HIV
Substance abuse treatment
Screening and treatment for other STI’s
(These are listed in the CDC page to which the chapter links)
25
List some interventions that our HIV clinic uses to maximize effective therapy for people with HIV
Respectful and non-judgmental communication style
Efforts to redress barriers to accessing care e.g. transportation difficulties, mistrust, work conflicts, poverty, etc.
Substance abuse resources
Provision of therapy that aligns with the patient's social context, for instance not prescribing drugs that need to be refrigerated to a homeless patient without consistent access to refrigeration
26
What is the "HIV treatment cascade?"
Only a quarter of people with HIV in the United States know it, access care consistently, get drugs and take the drugs consistently enough for them to work. At each of these steps there is a drop off in participation influenced in large part by social determinants of health such as poverty, drug use, mistrust, ignorance, and other forms of social chaos.
For a depiction and explanation, please visit this website:
http://www.cdc.gov/hiv/pdf/research_mmp_stagesofcare.pdf
27
Name some obstacles to redressing the social determinants of poor outcomes in HIV prevention or treatment services
Ignorance of the factors that influence patient outcomes
Failure to connect with patients across cultural, racial or other differences
Focus on the assignment of blame to patients for behaviors that may have complex origins
Inadequate funding
Inflexible clinic schedules and other barriers to easy access to care for people with either chaotic schedules or schedules not under their control
Inadequate psychiatric services
Implementation of biomedical interventions without understanding the social context in which they occur
28
Define structural violence and give a few examples of it
Structural violence occurs when a social structure avoidably prevents people from meeting their basic needs.
Examples include racism, poverty, war and stigma.
http: //en.wikipedia.org/wiki/Structural_violence
http: //journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0030449
29
A defect of which arm of the immune response is suggested by recurrent thrush, shingles and Pneumocystis jiroveci?
T cells
30
What infections predominate among people with abnormal antibody defects that are characteristic of common variable immunodeficiency?
Sinopulmonary infections from Streptococcus pneumoniae and persistent gastrointestinal infection with Giardia lamblia
31
A defect of which arm of the immune response is suggested by recurrent Neisseria infections?
Complement
(Pregnancy, menstruation and systemic lupus erythematosus are also mild risk factors for Neisseria infections but pale in comparison to complement defects.)
32
To which infections are individuals with neutrophil defects predisposed?
Staph aureus (ie frequent boils)
Aspergillus infections
Nocardia infections
33
List the opportunistic infections to which people with HIV are susceptible at CD4
CD4
34
Describe the architecture of a TB granuloma
Partially digested TB resides within phagolysosomes within activated macrophages. Sheets of these macrophages are ringed by T cells which facilitate macrophage containment of TB via IFN-g and other signaling.
35
What is the risk that an immunocompetent patient will develop TB after exposure?
5% chance in first 2 years, 5% in remainder of life
36
What is the yearly risk of developing active TB among exposed people with HIV?
5-10% per year (depends on whether pt is on antiretroviral therapy and what their CD4 count is)
37
Contrast latent TB with active TB
Latent TB:
- asymptomatic
- normal exam
- positive tuberculin skin test (PPD) or interferon gamma release assay (IGRA)
- chest x-ray normal or shows granuloma
- requires single drug therapy typically for 9 months
Active TB:
- typically symptomatic
- exam may reveal pneumonia or other signs of local disease
- chest x-ray will show infiltrate or abscess etc if lungs involved
- testing with tuberculin skin test or interferon gamma release assay not recommended for the diagnosis of active TB (too insensitive)
- requires multiple drug therapy for at least 6 months
38
When interpreting a tuberculin skin test result, which skin finding should you measure?
Induration (not erythema)
(Officially this should be done across the forearm not along the length of the forearm although your course director is challenged to understand why this is a good idea.)
39
The threshold for positivity of a tuberculin skin test depends on individual patient risk factors.
In which patients is >=5 mm induration considered a positive?
HIV+ or otherwise immunocompromised
Recent TB case exposure
Fibrotic changes on chest xray
40
The threshold for positivity of a tuberculin skin test depends on individual patient risk factors.
In which patients is >=10 mm induration considered a positive?
Those with medical conditions that increase the risk of TB (to a lesser degree than HIV) for instance renal disease or COPD
Children
Mycobacteriology lab personnel
41
PPD and IGRA have similar sensitivities. In which patients is the specificity of IGRA higher?
Those already exposed to non-TB mycobacterial infections e.g. BCG vaccination or infection with Mycobacterium lepra etc.
42
Contrast the clinical presentation of primary vs reactivation TB
Primary:
- looks like a typical pneumonia: infiltrate in any lobe
Reactivation:
- stereotypically a cavitary lesion in the upper lobe(s) in the setting of deteriorating immunity
Note that these are not mutually exclusive and in particular HIV infection can blur such distinctions
43
Latent tuberculosis is typically treated with what drug(s)?
Isoniazid
+/- pyridoxine in patients at risk of developing neuropathy (e.g. diabetes, alcoholism, etc)
44
Active tuberculosis is typically treated with what drug(s)?
Rifampin
Isoniazid
Pyrazinamide
Ethambutol
45
Amid the 2014-2015 Ebola outbreak, some patients have been treated via infusions of serum from other patients who have successfully recovered from Ebola virus disease. This is an example of _____ immunization.
Passive
46
Some immunocompromised patients should not receive live vaccines for fear they could develop vaccine-associated illness from attenuated vaccine organisms that would not otherwise cause disease in a normal host. Name three live vaccines
```
bacille Calmette Guerin
oral typhoid
oral polio
MMR
yellow fever
```
47
Vaccination is generally beneficial but associated with adverse reactions, mostly mild. Name some mild adverse reactions to vaccination.
Discomfort at immunization site
Low grade temperature
Muscle aches
Fatigue
48
Is there scientific evidence for the association of Guillain-Barre syndrome with vaccine receipt in a very small proportion of cases?
Yes
49
Is there scientific evidence for the association of autism with vaccine receipt in a very small proportion of cases?
No
50
Name vaccinations that are routinely recommended for all US citizens
```
Yearly flu shot at most ages
birth: hepatitis B
childhood: tetanus, polio, pertussis, pneumococcal, etc
adolescents: HPV
pneumococcal vaccination among elderly
```
51
Name three vaccinations that are recommended for various individually specific risk factors
Pneumococcal immunization is recommended for adults with immunological deficiencies or certain chronic medical illnesses
Typhoid, hepatitis A and yellow fever vaccines are recommended for travelers to endemic countries
Men who have sex with men should receive hepatitis A immunization
Veterinarians often receive rabies vaccination as do people bitten by animals thought to be rabid
BCG vaccination is administered at birth to all children in countries where TB is endemic
52
A 45 year-old dude named Harley who lives in the Ohio River Valley snorfles some moist soil and soon thereafter develops fever, cough and hilar lymphadenopathy that start improving in a week. A urine antigen is positive.
(1) What infection do you suspect?
(2) Will you treat him?
(1) Histoplasmosis
(2) Probably not. We only treat people with severe or progressive sx or when illness occurs in vulnerable patients like people with AIDS.
53
That same 45 year-old guy named Harley who spends a lot of time taking deep breaths at the shores of a large pond in south central United States develops mild cough and fevers associated with a pulmonary nodule with associated infiltrate.
(1) What infection do you suspect?
(2) Will you treat him?
(1) Blastomycosis. (Geographic distribution overlaps with hits, more South Central and Midwest.)
(2) Yes, you will probably give him itraconazole because this illness is less likely to resolve on its own.
54
Harley, the hapless 45 year-old with a bad habit of inhaling fungal spores, now emigrates to the San Joaquin Valley in California where he shortly after working a job in construction he develops fever, cough, fatigue and arthralgias with mild eosinophilia on blood smear.
(1) What infection do you suspect?
(2) Will you treat him?
(1) Coccidioidomycosis
| (2) Probably not. But perhaps educate him about the dangers of snorfling.
55
Trying to stay out of trouble, Harley tries out a new habit: rose gardening. A week after cutting himself on some rose thorns, he develops streaking erythema up his right forearm accompanied by small skin nodules.
(1) What infection do you suspect?
(2) What therapy will you prescribe?
(1) Sporotrichosis
| (2) Intraconazole or perhaps topical potassium iodide
56
Name two yeasts, two moulds and two dimorphic fungi
Yeasts: Candida, cryptococcus
Moulds: Aspergillus, Mucor
Dimorphic fungi: Histoplasma, Blastomycosis, Coccidioides, Sporotrichosis
57
Which two arms of immunity defend against yeast infections
Phagocytes
| T cells
58
A 31 year-old with AIDS develops difficulty swallowing and mild enduring chest pain plus a bad taste in his mouth. He is not on any medications and on exam you see a friable white patches and plaques on his lateral tongue and buccal membranes.
What is causing his difficulty swallowing?
Esophageal candidiasis
59
Name some infections you can treat with fluconazole
Primarily yeast infections:
Candida (except resistant species)
Cryptococcus
60
A bone marrow transplant patient develops fever and a lung nodule with associated inflammation by CT scanning. A serum galactomannan is positive.
Name three drugs that could treat this infection
Micafungin
Voriconazole or posaconazole (not fluconazole)
Amphotericin B
61
A diabetic man with a hemoglobin A1c over 10 develops right sided sinus pain and a dark bruise of the overlying facial skin. Examination of the oropharynx reveals some pallor of the upper palate. CT of the sinuses shows sinus inflammation and adjacent bony destruction. Otolaryngology conducts sinus endoscopy and notices some necrosis of the sinus mucosa which they biopsy. Pathological evaluation shows right angle hyphae.
Name two treatments for this condition and characterize its prognosis
prognosis This is mucormycosis. It's possible this patient could have Aspergillus sinusitis but the invasion and right angle hyphae suggest mucor more strongly.
Interventions:
(1) Surgery - debridement is often required
(2) Antibiotics - choices include posaconazole and amphotericin B
Prognosis:
Bad
62
What is the typical presentation of cryptococcal meningitis?
Who: often (but not always) in immunocompromised patients e.g. AIDS
Timing: Gradual onset
Sx: Fevers, headache, fatigue
Physical exam: mild meningismus, usually not as severe as bacterial meningitis, might have photophobia and other signs of elevated intracranial pressure
CSF findings: elevated opening pressure, lymphocytic pleiocytosis (often fewer than bacterial meningitis e.g. 100, usually
63
List risk factors for HIV infection
```
Sex
Needle sharing
Other needle or iatrogenic exposures
Transfusion
Mother-to-child (pregnancy, birth & breastfeeding)
```
64
Which demographic group has the greatest number of HIV cases in the United States and Western Europe?
Men who have sex with men
65
Which demographic group has the greatest number of HIV cases worldwide?
Heterosexual men and women
66
Rank the following activities from highest to lowest likelihood of transmitting HIV infection: vaginal sex, oral sex, anal sex
Anal sex
Vaginal sex
Oral sex
67
In the natural history of untreated HIV infection, on average how many years elapse from initial infection to death?
10 years
| 7-8 from infection to AIDS, 1-2 from AIDS to death
68
DO people with the CCR5delta32 variant exhibit resistance to initial infection with HIV or resistance to the development of AIDS?
Rare individuals - most of them caucasian - exhibit fairly impressive resistance to infection. They can only be infected by much rarer virus that use a different non-CCR5 co-receptor for HIV. They do also exhibit a somewhat slower speed of progression to AIDS, but this effect is fairly mild.
69
List 10 ways to prevent HIV transmission
1. Abstinence
2. Be faithful
3. Condoms
[The above are often called the "ABC's" of HIV prevention. Note that abstinence works if practiced, of course, but abstinence only programs are less effective than programs that include messaging directed at the likelihood of sexual and other behaviors.]
4. Risk reduction e.g. not practicing higher risk activities during sex
5. Antiretroviral therapy ("treatment as prevention")
6. Pre-exposure prophylaxis (PrEP) for men who have sex with men and injection drug users (not yet shown to work consistently in women)
7. Post-exposure prophylaxis (PEP)
8. Maternal therapy to prevent mother-to-child transmission
9. Neonatal therapy to prevent mother-to-child transmission
10. Avoidance of breastfeeding
11. Needle exchange programs
12. Serosorting (in which HIV+ patients only have sex with HIV+ patients, the efficacy of which is undermined by uncertainty among patients of HIV serostatus)
13. Microbicides
70
Why does the CDC now recommend that all US adults get tested for HIV at least once regardless of risk factors?
About 20% of people with HIV in the US don't know they have it.
Clinicians don't always ask about risk factors either due to time constraints or shyness.
Patients aren't always forthcoming about their risk factors, either because they don't know they have them or because they may not want to disclose them.
Access to HIV diagnosis begets access to life saving therapies.
71
A 19 year-old sexually active woman develops fevers, fatigue, diffuse lymphadenopathy, a slightly sore throat, and a faint erythematous macular rash on her chest. A primary care doc suspects "mono." What other condition should they always consider in the same breath? (Hint: it has to do with HIV.)
Acute HIV.
Yes, that was just me making sure you pair "mono" and "acute HIV" in your brains.
72
Explain the seroconversion window
Early after initial HIV infection, the body has not had time to mount an antibody response to HIV of big enough magnitude to be detectable by standard tests. Our testing technology is getting better. While the seroconversation window used to last as long as six months, with the latest 4th generation immunoassays we now detect nearly all cases of HIV infection within one month of initial infection.
73
Explain viral escape
The virus mutates any peptide sequence targeted by immune responses in order to become "invisible" to the immune system.
74
Name some ways other than opportunistic infections that people die as a result of HIV infection
Cancer - most cancers especially lymphomas are more common among people with HIV
Liver disease from co-infection with hepatitis C and alcohol use, often both
Heart disease
Suicide and other manifestations of mental illness
As antiretroviral therapy improves, patients with HIV fall into two general groups: those who develop the same illnesses as people without HIV over roughly the same time period and those whose behavior-related risks factors like injection drug use-related hepatitis C cause earlier mortality.
75
Name which opportunistic infections occur below which approximate CD4 count thresholds
CD4
76
What is the classic clinical picture of PCP?
Insidious onset hypoxic bilateral pneumonia in an AIDS patient with CD4 count
77
What is the classic clinical picture of Toxoplasma encephalitis?
Focal neurological defect (such as left arm weakening) in an afebrile AIDS patient with CD4 count
78
What is the classic clinical picture of CMV retinitis
Monocular floaters progressing to complete blindness in an AIDS patient with CD4 count below 50 followed by, in the absence of treatment, the same biblical syndrome in the contralateral eye
79
What is the classic clinical picture of Kaposi sarcoma?
(Which, BTW, you should pronounce "ka-POH-shee." Note the h - it's a Hungarian name and apparently that's how the Hungarians roll.)
Single or multiple purplish brown raised skin lesion in AIDs patient with CD4 count below 50 or so. Sometimes can be associated with disseminated disease such as via diffuse lymphadenopathy, organomegaly, gut involvement and what looks like a perihilar pneumonia from "bronchovascular" extension.
80
Name 10 steps in the HIV life cycle. Which are targeted by an FDA approved drug class?
1. CD4
2. CCR5*
3. fusion*
4. reverse transcription**
5. integration*
6. transcription
7. translation
8. proteolysis*
9. maturation
10. budding
* drug class targets this mechanism
* * two drug classes target this mechanism (nRTI & nnRTI)
81
Highly active antiretroviral therapy (HAART) - which is now often just called ART because no fool would go back to the bad old days of single drug therapies - is made up of how many drugs from how many drug classes
At least 3 drugs from at least 2 drug classes
82
Why do HIV drug cocktails work better than single drugs
Combined selection pressure at multiple sites constrains viral evolution which helps slow the development of drug resistance
83
Why should you check HLA-B5701 prior to starting the nucleoside reverse transcriptase inhibitor abacavir?
People with this MHC class are vulnerable to life-threatening abacavir hypersensitivity reaction
84
For patients with HIV infection who can access and take antiretroviral therapy, how does longevity compare to demographically equivalent patients without HIV infection?
It is the same.
Nowadays longevity for HIV patients who can access and take ART is indistinguishable from that of their HIV-negative peers.
Note the huge caveat though: to reap these historically remarkable benefits people with HIV have to be able to access and take HIV therapy.
Many fall through the cracks.
85
Name reasons why the HIV treatment cascade happens, i.e. why fewer than 20% of people with HIV get the life-saving benefits of ART?
1. Unknown diagnosis
2. Diagnosed but not in care
3. Not prescribed antiretroviral therapy
4. Not taking prescribed antiretroviral therapy
5. Taking antiretroviral therapy either consistently or in the presence of resistance
Each of the above are affected by restricted access to healthcare, poverty, education, stigma, discrimination, the challenge of cross-cultural communications, substance abuse, and other forms of structural violence.
86
How does HIV cause AIDS?
MAJOR CAUSE
Abortive infection of CD4+ T cells triggers intracellular sensing of the virus, which in turn causes pyroptosis of the vast majority of T cells, in turn leading to immunodeficiency
MINOR CAUSES
Chronic immune activation --> apoptosis
Gut translocation of bacterial products --> activation
CD8 killing of infected CD4's
87
List some common blood culture contaminants
Coagulase negative staphylococci (Staph epidermidis)
viridans streptococci
Propionibacterium
Corynebacterium (aka "diptheroids")
All can be true blood stream infection pathogens, especially the first two, so it's important to make sure you don't disregard or believe these results inappropriately.
88
A positive blood culture should always be followed by...
... another blood culture. In the case of potential contaminants this helps you see if the infection is real. When you believe the patient has a blood stream infection, then repeat blood cultures help you determine how sustained the bacteremia is and whether it has responded adequately to interventions.
89
Describe the type of antibiotics typically used to treat bloodstream infections
The big guns: hardcore, highly bioavailable often intravenous antibiotics.
Note that by this I do not mean antibiotics that have a wide antimicrobial spectrum of activity. That's a different issue. Broad spectrum carbapenems are no better at treating Staphylococcus aureus than penicillin and may exert a needless antibiotic resistance selection pressure during the process, for instance.
90
A 45 year-old who was recently seen by her dentist for a tooth abscess develops protracted fever, exhaustion, and dyspnea. Physical examination reveals fever and a new heart murmur as well as painless purple spots on the tips of three fingers and two toes.
Question 1: What should you do before starting antibiotics?
Draw blood cultures. At least two bottles. If the patient is stable - i.e. without sepsis or heart failure - you should consider observing off of antibiotics and repeating two more sets of blood cultures in 12 hours.
91
A 45 year-old who was recently seen by her dentist for a tooth abscess develops protracted fever, exhaustion, and dyspnea. Physical examination reveals fever and a new heart murmur as well as painless purple spots on the tips of three fingers and two toes.
Question 2: Why will this patient need a transesophageal echocardiogram?
Your suspicion for endocarditis is so high that you would not believe a negative (lower sensitivity) transthoracic echocardiogram. The transesophageal echocardiogram will help you confirm (or, surprisingly, rule out) endocarditis and it will also allow you to evaluate for important complications thereof such as an abscess at the valve annulus.
92
Contrast bugs that cause acute vs subacute endocarditis
Acute endocarditis is typically caused by Staphylococcus aureus, Strep pneumoniae and Gram negative rods.
Subacute endocarditis typically results from infection from less virulent organisms like viridians streptococci and coagulase negative staphylococci.
93
Name some clinical complications of severe endocarditis
```
Sepsis
Heart block
Valvular abscess
Heart failure
Emboli --> splenic, kidney, mesenteric, ischemia + stroke
Glomerulonephritis
```
94
Is it a good idea to review the Duke criteria (around page 169 of the iBook) to remind yourself of the clinical manifestations of endocarditis and also to help yourself do well when quizzed about this on the medicine wards?
Yes. Yes it is.
95
Are the Duke criteria for endocarditis the whole story?
No. It is not uncommon for us to diagnose endocarditis and treat for it in people who do not have confirmed or even probable endocarditis. Clinically, if the suspicion is high enough, we'll treat to avoid the devastating consequences of missed infection. The threshold for diagnosis comes through clinical experience.
96
Describe the typical treatment course for infective endocarditis
Several weeks of intravenous antibiotics
97
Which hurts, Janeway lesions or Osler's nodes?
Osler's nodes. Patients with them say "OOOOO" that hurts. It wouldn't make sense if they said, "JJJJ" that hurts.
98
Name some clinical features of infective endocarditis that might make surgical intervention more necessary
Blood cultures don't clear
Valve abscess or dehiscence
Highly resistant bug (fungus, highly drug resistant bacteria)
Big vegetation (>1 cm)
99
A college student develops acute onset afebrile vomiting within four hours after eating some reheated rice. Name the culprit and explain why reheating the rice didn't protect him.
Bacillus cereus.
Illness is from a heat-stable toxin
100
Twenty people develop profuse emesis in less than 6 hours after attending a church picnic. If you were partially psychic and knew this outbreak was due to Staphylococcus aureus-related toxin-mediated illness, but not psychic enough to know whom to blame, which types of foods would you investigate so you can out the culprit and make them feel really bad?
First, don't do this. The transmission of infectious diseases has a long history of stigmatization - don't contribute. What were you thinking? For shame!
Second, Staph aureus likes to hop a ride on creamy sauces and dressings. Were you bound and determined to be vindictive, check into that Caesar salad, potato salad, tuna salad and other picnic atrocities.
101
Name two bugs with intermediate incubation time (8-12) hours
```
Clostridium perfringens
Bacillus cereus (which can also happen acutely)
```
102
A medical school classmate develops emesis and diarrhea within 8 hours of eating undercooked chicken at your house. You hear about this when his lawyer calls requesting you cover his hospital bills. Which of the following is the right response?
A. Apologize and pay the bill.
B. Admit fault but don't pay the bill because, what was he thinking, eating undercooked chicken?
C. Tell him you couldn't possibly be at fault, but you're looking forward to seeing him next weekend for the big game.
D. Tell him you couldn't possibly be at fault and also suggest that he try a different career because he should know that plus, PS, he's being obnoxious.
D. The incubation time of Salmonella is longer than 8 hours so you can't be at fault. But don't serve undercooked chicken.
PS, freebie: don't hang out with people who sue you.
103
Name four STI's that can cause proctitis
Shigella
Gonorrhea
Chlamydia
LGV
104
What kind of pets transmit salmonellosis?
Reptiles: lizards, snakes, turtles
105
Name five causes of non-inflammatory and thus watery diarrhea
```
Vibrio cholera
Clostridium perfringens
Bacillus cereus
ETEC
Rotavirus
Giardia
Cryptosporidium
```
106
Name five causes of inflammatory diarrhea i.e. diarrhea associated with bleeding and/or mucous
```
Shigella
Salmonella (non typhi)
Campylobacter
EHEC
EIEC
Y enterocolitica
Vibrio parahemolyticus
Clostridium difficile
Entamoeba histolytica
```
107
You return from two months in Malawi - where you ate without restrictions as a demonstration of solidarity with your local hosts - with fever, abdominal cramping and fatigue. You have no vomiting or diarrhea or rash although near the end of your stay in Malawi you had a diarrheal illness. This presentation is consistent with which vaccine-preventable illness?
Typhoid, which causes enteric fever.
108
Which infections cause protracted diarrhea > 2weeks?
Cryptosporidium parvum
Giardia lamblia
(Yersinia enterocolitica
Campylobacter usually lasts a week but can last a long time in rare cases especially if poor Ig responses)
Don't forget to consider non-infectious causes in this differential e.g. inflammatory bowel disease, medication side effects, post-infectious irritable bowel syndrome, etc
109
What is the typical story of norovirus illness?
Acute onset
110
A 43 year-old woman develops crampy diarrhea and fever after you give her an unnecessary and frankly kind of pathetic course of azithromycin for bronchitis. Nice job. For a change you decide to prescribe some indicated antibiotics. Which one of the below would work?
```
A. Penicillin by mouth
B. Amoxicillin by mouth
C. Metronidazole by mouth
D. Ampicillin/sulbactam intravenously
E. Vancomycin intravenously
```
C
Both metronidazole and vancomycin work, but the former is given ideally by mouth and only oral vancomycin helps against C diff because it stays within the colonic lumen
111
A pregnant woman develops meningitis after eating cole slaw. What empirical antibiotic regimen would you prescribe while awaiting the results of cerebrospinal fluid cultures?
Vancomycin - covers resistant Streptococci
Ceftriaxone - covers Streptococci better, H. flu and misc GNR's (use cefuroxime in babies)
PLUS
ampicillin for Listeria, to which she is susceptible by virtue of immune compromise (pregnancy) and coleslaw consumption
112
Name some adverse consequences of STI's
```
Discomfort
Infertility
Increased risk of HIV transmission
Poorer pregnancy outcomes
Congenital infection (for example syphilis)
Perinatal infection (for example of HSV)
Stigma
```
113
Which populations are most at risk of STI
(1) Young people
(2) Marginalized populations (minorities, runaways, homeless people, people who are incarcerated, etc)
(3) People with multiple sexual partners
(4) People who are immunologically naive to endemic infections
114
In contrast to most other infections, STI's are treated even when asymptomatic. Why?
Treating STI's prevents their spread which benefits not only the person you are treating but also their sexual partners and potentially even their kids. Plus, adverse consequences of STI's like infertility or poor pregnancy outcomes occur among people who are asymptomatic.
115
Name three STI's that are commonly reportable to the state and thus can trigger free support for partner notification
HIV
Syphilis
Gonorrhea
116
Which STI's cause genital ulcers?
Herpes, syphilis, chancroid
117
Contrast how women acquire the three major causes of vaginitis: Candida, bacterial vaginosis and trichomoniasis.
Candida is overgrowth of a normal colonizer that can occur in normal women after perturbations in the vaginal ecosystem such as via antibiotic receipt or stress. Diabetes can predispose to Candida (which like sugar) as can immunodeficiency like HIV.
Bacterial vaginosis is overgrowth of bugs like Gardenerella and others and undergrowth of healthy bugs like Lactobacillus. Its cause isn't totally clear but sexual habits do contribute.
Trichomoniasis results from acquisition of Trichomonas vaginalis via sex.
118
What are characteristic symptoms of proctitis?
Rectal pain (at rest or with defectation or intercourse), anal discharge, tenesmus, and sometimes constipation
119
Name the two STI's from Chlamydia species
Chlamydia trachomatis
| Lymphogranuloma verneum
120
What antibiotic therapy should you give to someone diagnosed with Chlamydia?
Azithromycin + ceftriaxone
121
What antibiotic therapy should you give to someone diagnosed with gonorrhea?
Azithromycin + ceftriaxone
122
Which test is best for the diagnosis of cervical Chlamydia?
Cervical swab for Chlamydia nucleic acid amplification test (NAAT)
123
Which test is best for the diagnosis of pharyngeal gonorrhea?
Throat swab for gonorrhea nucleic acid amplification test (NAAT)
124
Why should women
Chlamydia is often asymptomatic so awaiting symptoms allows the bug to cause more adverse consequences in more people
125
What are the features of reactive arthritis associated with Chlamydia infection?
Conjunctivitis, back or knee arthritis, sometimes aortitis. Testing for Chlamydia trachomatis is often negative at the time of presentation.
126
Describe the four stages of syphilis
Primary: chancre
Secondary: rash (including of palms and soles)
Latent: asymptomatic
Tertiary: CNS involvement (meningitis, pachymeningitis [tabes dorsalis] and meningovascular [stroke]), Luetic aneurysm, gummas
127
Name at least two blood tests used to diagnose syphilis
Treponemal:
Syphilis IgG
Fluorescent treponema antibody absorption (FTA-ABS)
Non-treponemal:
Rapid plasma reagen (RPR)
Venereal disease research laboratories (VDRL)
RPR is the standard test but syphilis IgG is easier to do logistically and so is being used in more and more labs. It's likely as good as RPR.
Although you can get ID experts to talk at length about the complementary uses of treponemal or non-treponemal tests. This is part of the lore of syphilis - but I'm not convinced it's that important.
128
What is the best antibiotic against syphilis
Penicillin
- usually a single shot IM
- tertiary is treated IV
129
Why do women develop more UTI's than men?
Shorter urethras primarily.
130
Why do elderly men develop more UTI's than younger men?
Prostatic hyperplasia causes partial urinary outflow obstruction which impedes the cleansing outflow of urine
131
From where do most UTI pathogens arise?
Bugs like Escherichia coli, Staphylococcus sapprophyticus and enterococci usually gain entry to the urinary tract via the perineum and thence into the urethra. Hematogenous spread to the kidney and downward to the urethra is much less common.
132
Greater than how many WBC's in a urinalysis suggests UTI?
5-10
133
What should you do when someone has no symptoms, and no pyuria, but greater than 10^5 bacteria grown in urine culture?
Do not treat. Typically asymptomatic bacteruria is not treated.
134
List some causes of "sterile pyuria," i.e. elevated WBC seen in a urinalysis but negative off-antibiotic cultures
```
Chlamydia urethritis
Gonococcal cervicitis
Tuberculous cystitis
Non-infectious causes e.g. nephritis
Imperfect urine collection (check for extra epithelial cells)
```
135
List three antibiotics given as empirical therapy for uncomplicated UTI
Trimethoprim-sulfamethoxazole (TMP/SMX)
Nitrofurantoin
Ciprofloxacin
Ciprofloxacin is reserved for empirical treatment of UTI in areas where TMP/SMX and nitrofurantoin resistance is very common. Otherwise we try to save this drug for use in more resistant infections.
136
How many days should empirical therapy for uncomplicated UTI last?
3 days
137
In whom should you suspect prostatitis?
Elderly men with recurrent UTI in the setting of prostatic enlargement. Prostatic tenderness can be a clue.
138
Name three factors that signal that UTI is a "complicated UTI" and might need more aggressive workup and/or longer therapy
Immunocompromised patient
Abnormal urinary tract anatomy
History of drug resistance
Recurrent UTI's
139
Joyce has been having lots of urinary tract infections since becoming sexually active with Harvey. She really loves Harvey and doesn't want to stop having sex - but, she says, "this is getting ridiculous doc!" What steps can you and she take to protect her from UTI's while having an active sex life?
(1) Make sure she's been correctly treated for the original UTI's: (a) confirm the diagnosis via urinalysis and urine culture; (b) make sure she doesn't have a resistant bug i.e. target bugs grown in culture with antibiotics; and (c) make sure this isn't relapsing infection such as would merit anatomical work up such as for a stone that's harboring infection resistant to therapy.
(2) Teach her about post-coital voiding.
(3) If that doesn't work sometimes women take prophylactic antibiotics around the time of coitus.
140
Which physical examination findings suggest a coughing febrile patient has pneumonia and not just bronchitis?
Tachypnea, crackles, egophony, dullness to percussion, whispered pectoriloquy, increased vocal fremitus
141
If you detect physical exam findings suggestive of pneumonia, should you start antibiotics?
NO. NO. NO. NO. And NO.
You must get a chest x-ray first.
142
A man drinks himself into a stupor, and awakes to find he has vomited. Two days later he develops cough, pleurisy and fever as well as dyspnea. A chest x-ray shows left lower lobe consolidation. What sort of pneumonia should you suspect AND what kind of bacterium is thus newly in need of antibiotic coverage?
Aspiration pneumonia, oral anaerobes.
143
Which Gram positive organism is a more common cause of community acquired pneumonia among patients admitted to the ICU compared to those in the clinic or hospital ward?
Staphylococcus aureus - it's a rare cause of CAP except among ICU patients
144
Besides Staphylococcus aureus, which pathogens are more common in healthcare associated pneumonia compared to community acquired pneumonia and more common still among patients with ventilator acquired pneumonia?
Drug resistant Gram negative rods
145
The three most common bacterial causes of community acquired pneumonia
The three most common bacterial causes of community acquired pneumonia Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydiophila pneumoniae.
They compete with viruses for the top slots.
146
Why are Gram negative rods more common when pneumonia occurs in hospitalized or mechanically ventilated patients?
Because those bugs are more common in the hospital and ICU environments than in the outside world, AND sick patients are more vulnerable either via weakening of immunological defenses or mechanical defenses (e.g. airway protection) or both
147
What antibiotics should you give as empirical therapy to Mary, a patient who develops pneumonia while hospitalized on the floor for acute kidney injury due to contrast nephropathy?
Vancomycin to cover Staphylococcus aureus, and either ceftriaxone or a quinolone to cover Gram negatives or if she was highly antibiotic exposed you might use a bigger gun like piperacillin-tazobactam. A carbapenem would be overkill.
148
Why is azithromycin not necessary to include in your empirical antibiotic regimen for Mary, a patient who develops pneumonia while hospitalized on the floor for acute kidney injury due to contrast nephropathy?
Azithromycin, typically included in community acquired pneumonia regimens, covers atypical pathogens circulating in the community but far less commonly transmitted in healthcare environments
149
Azithromycin plus ceftriaxone is the first line antibiotic regimen for hospitalized patients with community acquired pneumonia. Quinolones like moxifloxacin or levofloxacin (not ciprofloxacin) are second line. Why?
Quinolone have activity against drug resistant Gram negative rods, and so we try to preserve them for that heavy lifting rather than waste them on patients for whom there are better options like azithromycin +/- ceftriaxone
150
Azithromycin alone will suffice for patients with mild community acquired pneumonia (CAP) whereas azithromycin + ceftriaxone is given to hospitalized patients with CAP. Why is ceftriaxone added for hospitalized patients?
Ceftriaxone covers Streptococcus pneumoniae that are resistant to azithromycin. Stable outpatients can withstand the risk of uncovered bugs better than fragile hospitalized patients.
151
Name some clinical situations in which you should stop and say, "hey, wait a minute, maybe my typical approach to working up and treating this patient with community acquired pneumonia won't work. Maybe I should look for a broader range of pathogens or conduct additional diagnostic/therapeutic maneuvers."
```
Empyema
Immunocompromised patients
Patients amid an unusual outbreak (c.f. SARS)
Lung abscess
Unusual travel history
```
152
What two vaccines can prevent pneumonia?
Vaccines against Streptococcus pneumonia
Vaccines against influenza
(BCG would be a reasonable choice here too although caveats apply)
153
Sometimes sputum Gram stain and culture reveal the obvious: the mouth is not sterile. But occasionally they reveal monomorphic signs of a plausible pneumonia pathogen. In the latter case, what should you do?
Narrow antibiotic therapy to cover that plausible pathogen
154
Which two viruses are the most frequent cause of the common cold?
Rhinovirus & coronavirus
155
How does transmission route differ between rhinoviruses and influenza, adenovirus and parainfluenza.
Rhinovirus is transmitted by fomites whereas the others hop from person to person via aerosols
156
Give four reasons why it is a bad idea to treat the common cold with antibiotics "just in case?"
(1) It exposes people to the risks of antibiotics without any counterbalancing upside.
(2) It contributes to the spread antibiotic resistance.
(3) It is intellectually lazy.
(4) It is morally bankrupt.
157
The presence of which three symptoms is most potently associated with increased likelihood of group A strep throat?
(1) Tonsillar exudates
(2) Fever
(3) Lymphadenopathy
If all three, the chances are over 40%.
158
Preferred diagnostic test for group A streptococcal pharyngitis
Rapid enzyme immunoassay
>95% sensitive, >80% specific which is good enough
159
Streptococcal pharyngitis is rarely life threatening by itself. Why treat it?
To prevent rheumatic fever
160
Both group A strep and mononucleosis cause pharyngitis. What symptoms make mono more likely?
(1) Longer-lasting syndrome: the cold usually ends
161
Beyond its characteristic clinical syndrome, name three blood tests can support the diagnosis of infectious mononucleosis?
(1) CBC showing atypical lymphocytosis
(2) Monospot (aka heterophile antibodies)
(3) EBV serology
(4) EBV PCR - not typically used for this indication
162
There is substantial overlap between the common cold and the clinical syndrome of influenza (aka "the flu"). Which symptoms up suspicion of the flu?
Abrupt onset of symptoms
Prominent fever, headache, myalgias
Less prominent pharyngitis
General severity
163
Differentiate between antigenic shift and antigenic drift
Drift: more minor changes to hemagglutinin (HA) and neuramidase (NA) that occur year-to-year. This shift is why each year we revise the flu shot.
Shift: more dramatic shift to a whole new virus type, such as from H1N1 to N5N9. This is thought to trigger more severe epidemics because fewer people have any effective immunity to the circulating strain.
164
Name some types of people who particularly should be vaccinated against influenza
(1) Elderly (>=65)
(2) People with chronic medical conditions, esp pulmonary
(3) Immunocompromised people
(4) Healthcare workers and other caregivers
(5) People on chronic aspirin therapy (who might develop Reye syndrome)
165
What is the cardinal symptoms of bronchitis?
Cough
166
Name symptoms, signs and findings on diagnostic testing that suggest the patient has pneumonia instead of bronchitis
(1) Severe illness: sepsis, high fever, etc
(2) Pleurisy
(3) Crackles or consolidation on lung exam
(4) Infiltrate on chest x-ray
All suggest pneumonia. Only the last is specific.
167
Is it appropriate to diagnose pneumonia without chest imaging?
NO. NO. NO. NO. NO.
| No.
168
Much acute sinusitis is viral. Among bacterial causes, which two organisms are the most frequent culprits?
treptococcus pneumoniae
Haemophilus influenzae
Moraxella catarrhalis (this is more common in kids)
169
If you elect to give antibiotics to a sinusitis patient due to severe or persistent symptoms*, then name one good antibiotic choice for people with and without penicillin allergy
* A phrase not meant to be synonymous with you like them or you're in a hurry or "just in case" or because they have a busy life
If you elect to give antibiotics to a sinusitis patient due to severe or persistent symptoms*, then name one good antibiotic choice for people with and without penicillin allergy
* A phrase not meant to be synonymous with you like them or you're in a hurry or "just in case" or because they have a busy life No penicillin allergy: amoxicillin/clavulanate
Penicillin allergy: cefuroxime
(Try to avoid using the quinolones levofloxacin and moxifloxacin - they'll work but also have activity we're trying to preserve against resistant Gram negatives such as infect sicker people.)
170
Name some techniques used to defer antibiotic use in patients with viral sinusitis or bronchitis
(1) Education
(2) Cough suppressants
(3) NSAIDs or Tylenol
(4) Nasal saline
(5) Re-evaluation if they don't get better in the expected time.
(6) Some advocate for deferred prescription, i.e. give them one and suggest they fill it if not better in a certain period of time. This is better than just giving a prescription but still risks treating a virus with antibiotics.
171
After ingestion of this bug's egg, the mature worm matures in the small bowel, sometimes causing bowel or biliary obstruction. Occasionally pneumonitis can occur during migration.
Ascaris
172
Name of bug causing hyperinfection syndrome can cause Gram negative rod sepsis in immunocompromised patients
Strongyloides
173
Name of syndrome typified by serpiginous erythematous lines on the skin
Cutaneous larva migrans
174
Larva of this bug are ingested from pork or game, ultimately invade striated muscle, causing aches, eosinophilia and in heavy infestations periorbital swelling, headache and even CNS or heart infection
Trichinella
175
Some parasites that respond to albendazole
Roundworms: pinworm (Enterobius), Ascaris, hookworms, Strongyloides, visceral and cutaneous larva migrans, trichinosis
176
Clinical manifestations of infection with Wuchereria bancrofti
heavy infection can lead to lymphatic obstruction aka elephantiasis
177
Organism that causes river blindness
Onchocerca volvulus
178
Which form of Schistosoma causes hematuria and bladder cancer?
S. hematobium
179
Which bug's cercariae penetrate the skin, migrate to lung and portal circulation, then cause inflammation at sites of egg deposition?
Schistosoma
180
Which form of Schistosoma causes liver disease?
S mansoni and S japonicum
181
Which bug creates cysts in the brain and other tissues after humans ingest its eggs? Hint: it's a major cause of seizures in South America?
Taenia solium
182
Which two bugs creates red blood cell inclusions which ultimately lead to hemolysis?
Malaria and Babesia
183
What adverse event can occur if a hydatid cyst ruptures during removal?
Anaphylaxis
184
Someone with vitamin B12 deficiency might have ingested this fresh water worm
Diphyllobothrium latum
185
Some bugs that respond to praziquantel
Schistosoma, Taenia spp., Diphyllobothrium latum
186
Following an enteritis characterized by "flask shaped" intestinal ulcers seen on endoscopy, a traveler develops a huge liver abscess full of what looks like "anchovy paste" upon drainage. Cultures are negative. What blood test should you draw to shape antibiotic therapy?
Amoeba serology
187
Foul smelling floating stools result from this cause of protracted diarrhea after camping which can affect anyone but which is worse among immunocompromised patients like people with AIDS
Giardia lamblia
188
Name two diagnostic tests through which a woman with dyspareunia and frothy vaginal discharge could be diagnosed with trichomoniasis
Wet mount (which shows swimming parasites with tails) or nucleic acid amplification test (NAAT)
189
What is the prognosis of a 25 year-old med student who develops meningoencephalitis after swimming in warm fresh water contaminated with Naegleria spp.
Really, really bad. http://www.cdc.gov/parasites/naegleria/illness.html
190
An AIDS patient with a CD4 count under 100 develops right arm weakness and MRI shows multiple ring-enhancing cerebral lesions. Blood cultures are negative. You should start empirical therapy with pyramethamine and sulfidiazine if this blood test is positive whereas if it is negative then arrange a brain biopsy looking for lymphoma.
Toxoplasma serology
191
Typical story of immunocompetent person infected with Cryptosporidium
Self-limited watery diarrhea
192
Typical story of immunocompromised person infected with Cryptosporidium
Protracted watery diarrhea; they can also get cholangitis
193
Which form of malaria is most likely to kill you?
Plasmodium falciparum
194
Which two forms of malaria form hypnozoites and can thus appear clinically many months after initial exposure
Plasmodium ovale and vivax.
| These two app have five letters, as does "sleep."
195
Name some manifestations of severe malaria
Severe hemolysis, acute kidney injury, brain edema, coma, hypoxia
196
What's the stereotypical story of someone with severe babesiosis?
Alcoholic with functional splenomegaly develops fever and severe hemolysis plus acute kidney injury after a visit to Nantucket
197
Contrast the clinical syndromes associated with American vs African trypanosomiasis
American (aka Chagas dz): triatomine bug bite, often asymptomatic acute phase, chronic phase typified by dilated cardiomyopathy, megaesophagus or megacolon
African: tsetse fly, acute phase typified by red sore, swollen lymph node(s) (Winterbottom's sign), then sleeping sickness during chronic phase
198
Primary cause of cellulitis
Group A streptococcus (aka Strep pyogenes)
199
Primary cause of skin and soft tissue abscesses
Staphylococcus aureus
200
Organism frequently implicated in skin/soft tissue infections after cat bites
Pasteurella multocida
201
Which fungus causes nodular skin lesions streaking up the hand and forearm in a rose gardener?
Sporothrix schenckii
202
Which mycobacterium causes nodular skin infection on the hand of a man who cut him self while cleaning his fish tank?
Mycobacterium marinum
203
Which of the following is the most important treatment of staphylococcal boils:
A. Nafcillin
B. Trimethoprim-sulfamethoxazole
C. Incision & drainage
D. Mupirocin
C, incision & drainage.
This intervention alone is likely to cure most boils. Antibiotics are only indicated if the boil is really big or if there is significant associated cellulitis. Mupirocin is used the reduce staphylococcal carriage in people with recurrent boils, but does not treat the boils themselves.
204
Which life threatening infection should you suspect in a healthy young man who presents with the acute onset of rapidly spreading leg erythema associated with pain out of proportion to the physical exam, development of skin bullae, and associated septic shock?
Necrotizing fasciitis
205
A healthy baby develops a patch of honey-colored flaky crust under her nose. What is that infection called and which bacterium most commonly causes it.
Impetigo is most commonly caused by group A strep
206
A man with hypercholesterolemia develops a well-demarcated erythema of both cheeks - in a "butterfly wing" distribution - plus a fever. What is that infection called and which group of bacteria most commonly causes it.
Erysipelas is most commonly caused by streptococci (group A and others).
207
Which oral drug should you use to treat cellulitis and other mild infections suspected to be caused by group A streptococci?
Penicillin
208
Which oral drugs should you use to treat mild staphylococcal infections?
Trimethoprim/sulfamethoxazole for MRSA (or unknown), dicloxacillin if MSSA
