questions from quiz let Flashcards
Name some risk factors for HAI
Hospitalization Surgery Invasive procedures Injectable drug therapies Antibiotic overuse (C diff) Poor hand hygiene Poor environmental cleansing
Name some ways you can prevent HAI’s through your behavior
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
When should periprocedural antibiotics be administered?
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
What should you do if you get a mucosal exposure to patient blood or fluids?
Wash
Report to supervisor
See Occupational Medicine to learn if more needs to be done
If you are exposed to HIV via a needlestick or other means, how can you lower the likelihood of contracting the infection?
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
Where can I learn more about Geisel’s policy on blood borne pathogen exposures?
Page 88 of the student handbook:
https://geiselmed.dartmouth.edu/faculty/pdf/geisel_student_policy_handbook_public.pdf
What is SIRS?
I won’t test you on the details but you should understand the general idea for clinical purposes.
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
What’s the definition of sepsis?
SIRS + infection
Add hypotension and you gotcherself septic shock
What’s the most common site of origin of sepsis?
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.
Describe the pathogenesis of sepsis
(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
What kills people who are septic?
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.
List some key tenants of sepsis resuscitation
IVF
Pressors if mean arterial pressure too low
Support failing organs (ventilator, dialysis, etc)
Good ICU care: avoid infections, clots, pressure ulcers, etc.
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.
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)
Which two pressor agents are most commonly used to treat sepsis?
Norepinephrine and vasopressin
Dopamine use was associated with greater toxicity such as cardiac arrhythmias
Contrast the typical presentation of bacterial meningitis and “aseptic” meningitis
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
What clinical features distinguish meningitis from encephalitis
Features that suggest meningitis: nuchal rigidity, sepsis, purpura fulminans
Features that suggest encephalitis: altered cognition (word salad, hallucinations, weird behavior) and seizures
Name some common causes of bacterial meningitis
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)
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
Bacterial meningitis, because the PMN count is high and (less sensitive) the glucose is low
How does the clinical presentation of a brain abscess differ from that of meningitis?
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
Name some causes of aseptic meningitis
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)
What is the standard empirical antibiotic regimen for a health 25 year-old with bacterial meningitis?
The standard regimen against meningitis while awaiting cultures is vancomycin (to cover resistant Streptococci) and ceftriaxone (to cover Streptococci plus Gram negatives like Neisseria).
What drug should you give to treat viral encephalitis
Acyclovir, while awaiting results of the HSV PCR
Why should you add ampicillin to your empirical antibiotic regimen against bacterial pneumonia in infants, adults >50 years, and immunocompromised patients?
To cover Listeria monocytogenes against which their T cell immunity is likely to be inadequate.
List some interventions proven to reduce the risk of HIV infection
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)
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
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
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
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
A defect of which arm of the immune response is suggested by recurrent thrush, shingles and Pneumocystis jiroveci?
T cells
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
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.)
To which infections are individuals with neutrophil defects predisposed?
Staph aureus (ie frequent boils)
Aspergillus infections
Nocardia infections
List the opportunistic infections to which people with HIV are susceptible at CD4
CD4
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.
What is the risk that an immunocompetent patient will develop TB after exposure?
5% chance in first 2 years, 5% in remainder of life
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)
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
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.)
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
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
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.
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
Latent tuberculosis is typically treated with what drug(s)?
Isoniazid
+/- pyridoxine in patients at risk of developing neuropathy (e.g. diabetes, alcoholism, etc)
Active tuberculosis is typically treated with what drug(s)?
Rifampin
Isoniazid
Pyrazinamide
Ethambutol
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
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
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
Is there scientific evidence for the association of Guillain-Barre syndrome with vaccine receipt in a very small proportion of cases?
Yes
Is there scientific evidence for the association of autism with vaccine receipt in a very small proportion of cases?
No
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
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
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.
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.
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.
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
Name two yeasts, two moulds and two dimorphic fungi
Yeasts: Candida, cryptococcus
Moulds: Aspergillus, Mucor
Dimorphic fungi: Histoplasma, Blastomycosis, Coccidioides, Sporotrichosis
Which two arms of immunity defend against yeast infections
Phagocytes
T cells
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
Name some infections you can treat with fluconazole
Primarily yeast infections:
Candida (except resistant species)
Cryptococcus
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
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
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
List risk factors for HIV infection
Sex Needle sharing Other needle or iatrogenic exposures Transfusion Mother-to-child (pregnancy, birth & breastfeeding)
Which demographic group has the greatest number of HIV cases in the United States and Western Europe?
Men who have sex with men
Which demographic group has the greatest number of HIV cases worldwide?
Heterosexual men and women
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
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
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.
List 10 ways to prevent HIV transmission
- Abstinence
- Be faithful
- 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.]
- Risk reduction e.g. not practicing higher risk activities during sex
- Antiretroviral therapy (“treatment as prevention”)
- Pre-exposure prophylaxis (PrEP) for men who have sex with men and injection drug users (not yet shown to work consistently in women)
- Post-exposure prophylaxis (PEP)
- Maternal therapy to prevent mother-to-child transmission
- Neonatal therapy to prevent mother-to-child transmission
- Avoidance of breastfeeding
- Needle exchange programs
- Serosorting (in which HIV+ patients only have sex with HIV+ patients, the efficacy of which is undermined by uncertainty among patients of HIV serostatus)
- Microbicides
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.
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.
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.
Explain viral escape
The virus mutates any peptide sequence targeted by immune responses in order to become “invisible” to the immune system.
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.
Name which opportunistic infections occur below which approximate CD4 count thresholds
CD4
What is the classic clinical picture of PCP?
Insidious onset hypoxic bilateral pneumonia in an AIDS patient with CD4 count
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
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
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.
Name 10 steps in the HIV life cycle. Which are targeted by an FDA approved drug class?
- CD4
- CCR5*
- fusion*
- reverse transcription**
- integration*
- transcription
- translation
- proteolysis*
- maturation
- budding
- drug class targets this mechanism
- two drug classes target this mechanism (nRTI & nnRTI)
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
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
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
