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Internal Med - Jesse > Infectious Disease > Flashcards

Infectious Disease Flashcards

0
Q

3 bugs most commonly responsible for community-acquired acute bacterial meningitis

A

Streptococcus pneumoniae > Neisseria meningitidis, Listeria monocytogenes

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1
Q

4 Sx of acute bacterial meningitis

A

severe headache, fever, altered mental status, and symptoms of meningeal irritation such as neck stiffness (if one of the last 3 are not present, ABM is excluded)

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2
Q

Bugs responsible for nosocomial acute bacterial meningitis

A

Gram-negative bacilli > Staphylococcus aureus, Streptococci and other staphylococci

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3
Q

DDx for fever, headache, and meningeal irritation (5)

A

Meningitis (ABM, Acute aseptic meningitis syndrome eg AVM)
Brain abscess
Cerebral and spinal epidural abscess
Septic intracranial thrombophlebitis
Infective endocarditis with cerebral embolization

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4
Q

HIV-assoc opportunistic diseases (14)

A

Pneumocystis pneumonia (PCP, caused by Pneumocystis jiroveci, formerly known as Pneumocystis carinii) - most serious; 50% occur in prev unDx HIV
Mycobacterium tuberculosis infection
Disseminated Mycobacterium avium complex (MAC) infection
Toxoplasma gondii infection
Recurrent Streptococcus pneumoniae infections
Cytomegalovirus (CMV)
Herpes simplex virus (HSV)
Varicella-zoster virus (VZV)
Cryptococcus neoformans infection
Histoplasma capsulatum infection
Coccidioides immitis infection
Candida albicans infection
Lymphoma
Kaposi sarcoma (associated with infection by HHV-8)

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5
Q

The clinical syndrome of AIDS is defined as:

A

HIV-infected individuals who either:
Have a CD4 count that falls below 200 cells/mm3 OR
Develop one of the so-called AIDS-defining illnesses

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6
Q

A given opportunistic infection tends to occur at specific degrees of immune suppression. ________ is used to quantify immune suppression.

A

The CD4 count

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7
Q

HIV lifestyle modifications (4 groups)

A

1 Sexual exposure: Latex condoms reduce exposure and prevent transmission. Avoid fecal-oral (cryptosporidiosis, amebiasis, hepatitis, and giardiasis).
2 Environmental exposure: Professions with increased risk: healthcare or work in shelters or correctional institutions (TB), child care (giardiasis, hepatitis, CMV), animal care (toxoplasmosis, campylobacteriosis, cryptosporidiosis), gardening (cryptosporidiosis, toxoplasmosis). Monitor pet exposure: cats (bartonellosis, toxoplasmosis), reptiles (salmonellosis), and fish (Mycobacterium marinum).
3 Food- and water-related exposures: Avoid raw or undercooked eggs, meat, seafood, and dairy products. Avoid drinking untreated water, as well as swimming in lakes and rivers. Boiling drinking water in areas with cryptosporidiosis.
4 Travel: Pay attn to risk of diarrheal illnesses (traveler’s diarrhea). Killed vaccines (rabies, diphtheria-tetanus) can be given as recommended for all travelers, but live vaccines (polio, typhoid) should be avoided, except measles vaccine.

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8
Q 
HIV-specific DDx for the following Sx:
Constitutional symptoms (fever, weight loss, fatigue)
Visual changes, eye pain
Headache, mental status changes
Cough, shortness of breath
Oral lesions
Odynophagia, dysphagia
Chronic diarrhea
GU symptoms
Skin lesions
Enlarged lymph nodes
A

Constitutional symptoms (fever, weight loss, fatigue)—mycobacterial infection (tuberculosis [TB] and MAC), HIV wasting syndrome, lymphoma, Bartonella infection

Visual changes, eye pain—CMV retinitis, ophthalmic varicella-zoster

Headache, mental status changes—toxoplasma encephalitis, CNS lymphoma, cryptococcal meningitis, progressive multifocal leukoencephalopathy (JC virus)

Cough, shortness of breath—PCP, TB, recurrent bacterial pneumonia, influenza

Oral lesions—thrush, oral hairy leukoplakia, aphthous ulcers, HSV

Odynophagia, dysphagia—candidal esophagitis, CMV esophagitis, HSV esophagitis

Chronic diarrhea—cryptosporidiosis, isosporiasis

GU symptoms—recurrent HSV infection, syphilis, cervical cancer

Skin lesions—Kaposi sarcoma, molluscum contagiosum, Bartonella infection (bacillary angiomatosis), scabies

Enlarged lymph nodes—lymphoma, mycobacterial infection, HIV lymphadenopathy, Bartonella

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9
Q

Stages in HIV infection

A

Acute retroviral syndrome
Clinical latency (Progressive decrease in CD4 counts and increase in viral load) = 10 years
AIDS

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10
Q

Typical positive findings in newly Dx HIV pt (5)

A 
Generalized lymphadenopathy
Oral candidiasis
Angular cheilitis
Pigmented lesions (Kaposi sarcoma, bacillary angiomatosis)
Fungal nail infections
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11
Q

Initial tests for evaluating a pt with newly Dx HIV

A

CD4 lymphocyte count
HIV RNA quantitation (viral load)
HIV resistance testing (genotyping)
CBC
Routine chemistries (electrolytes, creatinine, LFTs, lipid panel)
Chest radiograph
Titers of antibodies against cytomegalovirus, Toxoplasma gondii, hepatitis B, hepatitis C
Purified protein derivative (PPD) to test for tuberculosis exposure along with anergy panel
RPR or VDRL
Screen for glucose-6-phosphate dehydrogenase (G6PD) deficiency (in patients with appropriate racial or ethnic background because of commonly used HIV drugs that predispose to hemolysis)
Fasting lipid panel (because of metabolic disorders associated with antiviral therapy)
Papanicolaou smear for women
Testosterone level for men

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12
Q

The management of the asymptomatic HIV patient involves: (3)

A

1 characterizing and following the progression of infection (via CD4 counts and viral load)
2 preventing opportunistic diseases (prophylaxis and routine surveillance)
3 attempting to forestall immunologic decline by the administration of drugs that have activity against HIV itself (NRTIs, NNRTIs, PIs –> HAART)

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13
Q

When to initiate antiretroviral Tx in an HIV pt?

A

Treat all patients with a history of an AIDS-defining illness or asymptomatic patients with a CD4 count of <200 cells per mm3.
Recommendation for treatment of other patients is less standardized; many physicians offer treatment to asymptomatic patients with CD4 cell counts between 201 and 350 cells per mm3.

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14
Q

Potentially fatal “do-not-miss” diagnoses that present with fever and rash: (6)

A 
Meningococcemia
Bacterial sepsis (e.g., staphylococcal sepsis)
Endocarditis
Rocky Mountain spotted fever
Gonococcemia
Typhoid fever
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15
Q

Signs of severe systemic illness (e.g., hypotension, meningismus) along with fever and rash suggest a potentially life-threatening condition such as: (5)

A

meningococcemia, toxic shock, endocarditis, Rocky Mountain spotted fever, Kawasaki disease

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16
Q

Fever + urticarial rash DDx (7)

A

Allergy - also pretty much any other type of rash
Hepatitis (acute or chronic)
EBV
HIV (established infection) - also vesiculobullar
Adenovirus - also maculopapular
Enteroviral infection - also pretty much any other type of rash
Mycoplasma - also maculopapular

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17
Q 
Type of rash for the following (1 each; present with fever):
Endocarditis 
Typhoid 
Staph sepsis 
Vibrio vulnificus 
Strep infection 
Ehrlichiosis 
Rocky Mtn spotted fever
Secondary syphilis 
Lyme disease 
Primary HIV infection 
Varicella-zoster 
Herpes simplex 
Erythema multiforme 
Lymphoma
Kawasaki disease
A 
Endocarditis - Petechaial/purpura (P)
Typhoid - maculopapular (MP)
Staph sepsis - vesicular/bullous (VB)
Vibrio vulnificus VB
Strep infection - erythematous (E)
Ehrlichiosis E
Rocky Mtn spotted fever P
Secondary syphilis MP
Lyme disease MP
Primary HIV infection MP
Varicella-zoster VB
Herpes simplex VB
Erythema multiforme MP
Lymphoma E
Kawasaki disease E
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18
Q

Classically, pneumonias present with signs of consolidation: (4)

A

Bronchial breath sounds
Egophony (“e” to “a” changes)
Dullness to percussion
Increased tactile fremitus

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19
Q

Physical findings (6) and lab findings (6) in patients with community-acquired pneumonia that are associated with increased morbidity and mortality include:

A

Tachypnea (respiratory rate ≥30)
Temperature 30 × 109/L, or absolute neutrophil count 50 mm Hg (FiO2 0.21)
Arterial pH <9 g per dL
Serum creatine greater than 1.2 mg per dL or BUN greater than 20 mg per dL
Certain unfavorable chest radiograph findings (e.g., multilobar consolidation, pulmonary effusion, cavity formation)

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20
Q

Noninfectious conditions that can mimic pneumonia include: (4)

A

Pulmonary embolus
CHF
Lung cancer
Inflammatory lung disease (e.g., Wegener granulomatosis, eosinophilic pneumonia)

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21
Q

CURB-65 model for pneumonia

A

Confusion
Blood urea nitrogen >20 mg/dL
Respiratory rate >30 breaths per minute
Blood pressure (systolic less than 90, diastolic 3 may require ICU care.

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22
Q

5 Bugs that cause pneumonia in an outpatient (previously healthy and no use of antimicrobials within the previous 3 months) and Tx

A

S. pneumoniae, M. pneumoniae, C. pneumoniae, H. influenzae, Respiratory viruses

Tx: Advanced-generation macrolide (e.g., azithromycin or clarithromycin), OR doxycycline

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23
Q

In the United States, STDs are most prevalent among young individuals of low socioeconomic class. The notable exception is ___________, which is more evenly distributed across the population.

A

Chlamydia trachomatis infection

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24
Q

Certain STD syndromes can mimic other conditions:
Urethritis: (2)
PID: (4)
Vulvovaginitis/cervicitis: (2)

A

Urethritis: Urinary tract infection, prostatitis
PID: Ectopic pregnancy, appendicitis, pyelonephritis, cystitis
Vulvovaginitis/cervicitis: Normal cyclical changes in vaginal secretions during menstrual cycle, dysfunctional uterine bleeding

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25
Q

What are primary and secondary syphilis?

Physical findings in secondary syphilis commonly include: (6)

Findings in tertiary syphilis (3)

A

Primary stage: painless, indurated ulcer (chancre) at the inoculation site. If untreated, approximately half the patients progress to a disseminated/secondary (hematogenous) stage, and the rest go directly to a stage of latent disease (serologic evidence of infection but no clinical manifestations). In the secondary stage, the organisms are widely dispersed throughout the body.

Physical findings in secondary syphilis commonly include:
Generalized maculopapular rash (characteristically involves palms and soles; Color Plate 10)
Mucous patches (silver gray erosions with an erythematous periphery that are generally painless)
Condylomata (wartlike enlarged papules that are moist and pink to gray white; these lesions are highly infectious)
Generalized nontender lymphadenopathy
The primary chancre (present in approximately 15% of cases)
Nonspecific constitutional symptoms (fever, sore throat, malaise, and headache)

Late/tertiary syphilis is marked by end-organ damage, involving:
Nervous system (general paresis; tabes dorsalis; paresthesias; loss of position, pain, and temperature sensation)
Cardiovascular system (syphilitic aortitis)
Gumma formation (granulomas with central necrosis, most commonly involving the skin, skeletal system, mouth, larynx, liver, and stomach, but all organs have been reported to be involved)
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26
Q

The laboratory diagnosis of syphilis can be performed by: (3)

A

Dark-field microscopy of lesions (to demonstrate the presence of spirochetes)
Direct immunofluorescence microscopy
Serology (both nontreponemal tests such as rapid plasma reagin [RPR] and Venereal Disease Research Laboratory [VDRL], which are used for screening, and direct treponemal tests such as immunofluorescence and hemagglutination to detect antibodies specific for T. pallidum)

The VDRL can be used to monitor response to therapy.

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27
Q

What is PID and what are the sequelae? (3)

A

PID = infection of the upper female reproductive tract (endometrium, fallopian tubes, and pelvic peritoneum); can lead to a variety of sequelae:
Ectopic pregnancy
Tubal infertility
Chronic pelvic pain

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28
Q

Lab finding in urethritis (male) due to gonococcal infection

A

Gram-negative diplococci (N. gonorrhoeae) inside PMNs

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29
Q

The majority (>90%) of UTIs are caused by ________ (aerobic/anaerobic) gram-_______ bacteria.

Approximately 80% of community-acquired and 50% of nosocomial UTIs are caused by __________, with most of the remainder caused by gram-_________ bacteria such as _________ (4).

Another etiologic agent in patients with an indwelling urinary catheter is ___________.

A

aerobic, negative

Escherichia coli; negative; Enterobacter, Klebsiella, Proteus, and Pseudomonas

yeast (most often Candida species)

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30
Q

Some of the organisms that commonly cause UTIs have particular virulence factors that allow them to colonize the urinary tract successfully: (4)

A

Pili/fimbriae (hairlike bacterial appendages that allow adherence to urinary tract epithelial cells)
Hemolysin (often with strains that produce pyelonephritis)
Aerobactin (an iron-scavenging molecule)
Urease

31
Q

As mentioned earlier, most community-acquired UTIs occur among women. Risk factors that increase the incidence of UTIs among women are: (4)

Among men, __________ is the major factor that predisposes to UTIs.

A

History of recent UTI
Sexual activity
Use of diaphragm and/or spermicide
Failure to void after intercourse

the presence of an anatomically abnormal urinary tract (e.g., benign prostatic hypertrophy)

32
Q

Lower tract infection (cystitis) usually presents with the following Sx: (4)

A 
(Sx of bladder irritation:)
Frequency
Urgency
Dysuria
Gross hematuria may sometimes be present but is not a common feature.
33
Q

Upper tract infections (pyelonephritis) may present with symptoms of bladder irritation, but features that tend to distinguish them from lower tract infections are: (3)

A

Fever
Flank pain
Abdominal symptoms of pain, nausea, and vomiting
(Note that there can be much overlap in symptoms between upper and lower tract disease.)

34
Q

A number of other conditions may produce signs and symptoms that can mimic a bacterial UTI, including: (6)

A 
Vulvovaginitis
Gonococcal and nongonococcal urethritis
Bladder calculi
Bladder tumor
Chemical- or drug-induced cystitis
Prostatitis
35
Q

Empirical ____-day courses of antibiotics for lower tract disease and ______-day courses for upper tract infections are usually sufficient.

Treatment failure may suggest __________, and recurrent UTIs may be an indication to check for ____________.

____________ may be needed to prevent recurrent UTIs.

A

3; 7-14

antimicrobial resistance; anatomic abnormalities of the urinary tract

Prophylactic use of antimicrobials

36
Q

Approximately 90% to 95% of immunocompetent individuals control the initial TB infection via a cellular immune response involving M. tuberculosis ingestion by macrophages, both in the lung and the lymph node. Granuloma formation results, with eventual control of the infection. This effective cellular response takes approximately 3 to 9 weeks to develop, at which time the tuberculin skin test becomes positive.
In a minority of patients, the early immune response is so robust that severe necrosis occurs, leading to cavity formation or local extension of disease. In still others, dissemination occurs very early in the course, with systemic spread to ___________ (6).
In most cases, the initial infection is walled off by granuloma formation, but viable organisms may persist within the granuloma. With waning cellular immunity (e.g., with _________ (4)), these organisms may escape from the granuloma, resulting in reactivation tuberculosis.

A

extrapulmonary sites including the pericardium, extrapulmonary lymph nodes (scrofula), kidneys, epiphyses of long bones, vertebral bodies, and meninges

age, advancing HIV, malignancy, or corticosteroid administration

37
Q

Early pulmonary TB is usually asymptomatic; when symptoms do develop later in the disease, they are: (8)

A

(usually nonspecific and constitutional:)
Fevers, chills, night sweats
Anorexia
Weight loss
Fatigue
Cough
Development of hemoptysis denotes advanced disease.

38
Q

A number of different diseases may present with the clinical findings found in TB, including: (4)

A 
Fungal diseases (histoplasmosis, coccidioidomycosis)
Sarcoidosis
Malignancy
39
Q

Evaluation of sputum, when present, may be useful. M. tuberculosis stains ________ in an acid-fast stain. Culture is more sensitive but what is its disadvantage?

A

positive

Culture is time consuming because of the slow growth of M. tuberculosis.

40
Q

The administration of the intermediate (5-TU) skin test is useful in documenting exposure and infection with M. tuberculosis. Population studies have determined levels of skin test reactivity that help identify infected individuals with sufficient sensitivity and specificity: (3 levels)

A

> 15 mm in a normal host from a low-risk group (i.e., no risk factors—it should be noted that it is recommended that persons with no risk factors NOT be routinely tested for TB by skin testing)

> 10 mm in a moderate-risk individual (non-HIV-associated risk factors, e.g., recent immigrant from high prevalence area, injection drug users that are HIV-negative or HIV-known status, residents of high-risk group housing settings, patients with underlying conditions that increase risk for active disease such as chronic kidney disease, silicosis, certain malignancies)

> 5 mm in an HIV-infected individual or individual with high likelihood of infection (e.g., a person with recent close contact with a person with documented TB or a person with known findings on chest radiograph suggestive of old TB) or patients with organ transplants or who are receiving the equivalent of >15 mg prednisone/day for one month or more.

41
Q

What is the newer test for Dx TB? Main advantage?

A

Whole-blood interferon-gamma assay that detects the presence of T cells that have been previously been sensitized to M. tuberculosis antigens and thus will release interferon-gamma upon re-exposure to the antigens. The test appears to have sensitivity and specificity equivalent to the skin test for most indications, and may have greater ability to distinguish between M. tuberculosis and nontuberculous Mycobacteria infections.

42
Q

Important radiographic patterns that can be seen in pulmonary TB include: (5)

A 
Primary parenchymal lesion and mediastinal node (Ghon complex)
Apical pleural scarring 
Cavitary disease
Lobar consolidation 
Diffuse (miliary) disease
43
Q

Immunologically normal patients with only a newly reactive skin test have approximately a ___% chance of going on to symptomatic disease within the first year after conversion. Patients with a positive skin test but no evidence of active disease are defined as having __________ are treated with ___________.

A

3%

latent tuberculosis infection (LTBI); chemoprophylaxis (usually daily Isoniazid (INH) for 9 months)

44
Q

Active TB is treated with various combinations of the so-called first-line TB drugs: (5)

Side FX? (3 drugs)

A 
Isoniazid (INH)
Rifampin
Pyrazinamide
Ethambutol
Streptomycin
(Combinations of the above for several (eg 6) months)

With INH, rifampin, and pyrazinamide, this toxicity is mainly hepatic, requiring monitoring of liver function during therapy.

45
Q

Bacterial pathogens can cause gastroenteritis via several distinct mechanisms: (4)

A

Direct invasion of the mucosa with tissue destruction and inflammation
Growth of the bacteria within the bowel lumen with toxin production and release
Adherence (but not invasion) of the bacteria to the mucosal surface with interference of the normal absorptive process without tissue destruction
Production of a toxin during bacterial growth in food or water, which is then ingested preformed

46
Q

The major bacterial pathogens identified in the United States by the FoodNet surveillance system are _________ (3). Among travelers who develop diarrhea, _________ is the most common bacterial pathogen identified.

A

Salmonella species and Campylobacter jejuni and Shigella species

enterotoxigenic E. coli

47
Q

Ingestion of preformed toxin (e.g., __________(1)) is followed by onset of symptoms within ___ hours.

Infection with a pathogenic bacterium that needs to replicate to cause disease (e.g., _________(2)) does not generally result in symptoms until ______ hours after exposure.

Parasitic infections (e.g., _________ (1)) may not become symptomatic for until ____________ after exposure.

A

Staphylococcus aureus food poisoning; 8 hours

Campylobacter or Salmonella; 24 to 48

Giardia; days to weeks

48
Q

The most commonly encountered viral pathogens in gastroenteritis are _____________ (4). Of these:

_________ is an important pediatric cause of gastroenteritis.

__________ is of particular importance in the adult population, responsible for the vast majority of nonbacterial outbreaks of gastroenteritis (restaurants, hospitals, nursing homes, and schools). These enteric viruses directly infect cells of the small intestine, resulting in alteration of the mucosal architecture (notably shortening or loss of the microvilli), causing diarrhea on the basis of malabsorption. The infection is readily controlled, causing a short-lived (24- to 48-hour) illness.

A

norovirus (a calicivirus), rotavirus, astrovirus and the enteric adenovirus

Rotavirus

Norovirus

49
Q

Protozoan infections are most commonly found in which a patient populations? (2)

__________ are two of the most commonly encountered protozoan pathogens. What type of diarrhea does each give?

A

travelers and people who may be exposed to untreated water (e.g., hikers)

Entamoeba histolytica - invades the colon, causing a bloody diarrhea.
Giardia lamblia - colonizes the small intestine, causing a malabsorptive syndrome and an osmotic diarrhea.

50
Q

The severity of gastroenteritis can be indicated by signs of dehydration such as ________. (3)

A

orthostatic hypotension, dry mucosal membranes, and decreased skin turgor.

51
Q

Antimotility agents such as loperamide- and atropine-containing compounds (Lomotil) can be used symptomatically, particularly in cases where diarrhea can interfere with the functioning of an otherwise healthy individual. Care must be taken, however; these agents can be harmful in which situations?

A

In cases of invasive organisms (e.g., Salmonella) or organisms that produce toxins (e.g., C. difficile or enterohemorrhagic E. coli), antimotility agents can be harmful.

52
Q

The primary therapy in gastroenteritis is what?

A

supportive, with replacement of fluid and electrolytes lost via vomiting and diarrhea. In the majority of cases, the condition resolves on its own with symptomatic therapy. Culture and specific antimicrobial treatment is generally reserved until symptomatic therapy fails or if unusual pathogens are suspected.

Antibiotics are indicated for certain parasitic infections but are generally not routinely administered for bacterial pathogens unless there are signs of severe infection.

53
Q 
For each of the following: mechanism of producing gastroenteritis, and Tx: 
Bacillus cereus
Staphylococcus aureus
Clostridium difficile
Campylobacter jejuni
Salmonella typhi
Salmonella (nontyphi)
Shigella spp.
Vibrio cholerae
Entamoeba histolytica
Giardia lamblia
Viruses (e.g., norovirus, rotavirus)
A

Bacillus cereus: Preformed toxin; no Tx
Staphylococcus aureus: Preformed toxin; no Tx
Clostridium difficile: Toxin production in colon; Tx: Metronidazole, vancomycin
Campylobacter jejuni: Colonization (invasion) of large and small bowel; Tx: Antibiotics
Salmonella typhi: Invasion of small intestine; can then disseminate systemically (via bloodstream); Tx: Antibiotics
Salmonella (nontyphi): Invasion of small and large intestine; Tx: Antibiotics
Shigella spp.: Invasion of colon; Tx: Antibiotics
Vibrio cholerae: Enterotoxin; Tx: Doxycycline
Entamoeba histolytica: Invasion of colonic mucosa; Tx: Metronidazole
Giardia lamblia: Colonization of small intestine; Tx: Metronidazole
Viruses (e.g., norovirus, rotavirus): invasion of mucosa; no Tx

54
Q 
For each of the following types of Escherichia coli: mechanism of producing gastroenteritis, nature of Sx, and Tx:
Enterotoxigenic
Enteropathogenic
Enteroinvasive
Enteroadherent
Enterohemorrhagic (e.g., \_\_\_\_\_\_\_\_(1))
A

Enterotoxigenic: Enterotoxin formation in small intestine; Voluminous watery diarrhea; fever generally absent; fecal/oral transmission; Tx: None.

Enteropathogenic: Localized adherence to intestinal mucosa; Watery diarrhea; can occur in outbreaks among newborns; Tx: Antibiotics

Enteroinvasive: Invasion of the colonic mucosa; Fever, bloody diarrhea; fecal/oral transmission; Tx: Antibiotics

Enteroadherent: Adherence to small intestinal mucosa; Diarrhea, can be prolonged; fecal/oral transmission; Tx: Antibiotics

Enterohemorrhagic (e.g., E. coli O157:H7): Production of a cytotoxin (Shiga toxin) in colon; Causes hemorrhagic colitis; colitis can be followed by TTP/HUS; from contaminated meats (especially ground meat); Tx of Diarrhea: no Tx; Tx of TTP/HUS: generally supportive (but Tx of diarrhea may increase the risk of TTP/HUS)

55
Q

The clinical diagnosis of endocarditis can be made by the presence of ____________(2).

A

persistently positive blood cultures and echocardiographic evidence of infection (vegetations, abscesses, valve perforations)

56
Q

The major risk factor for the development of endocarditis is __________. Examples? (7)

__________(2) are also important risk factors for the development of IE.

A

the presence of a structurally abnormal heart.

Generally, this is valvular disease, but any structural abnormality (including iatrogenic) that leads to turbulent blood flow within the heart increases the risk of IE, including:
Mitral valve prolapse
Rheumatic heart disease (aortic and mitral valve)
Degenerative heart disease (calcifications)
Congenital heart disease (bicuspid aortic valve, patent ductus arteriosus, ventricular septal defect, coarctation of the aorta, tetralogy of Fallot)
Hypertrophic cardiomyopathy
Foreign material (pacemakers, prosthetic valves, pulmonary artery catheters)
Previous history of endocarditis

Diabetes mellitus and IV drug abuse

57
Q

Gram-__________ organisms are the major cause of endocarditis, and empirical therapy is directed against these organisms, with subsequent adjustment based on the results of culture and susceptibility testing.

A

Gram-positive

58
Q

________ (short/long) courses of antimicrobial therapy are employed to treat endocarditis. Cardiac surgery, including valve replacement, may be required for __________.

A

Long - required to ensure sterilization of infected endovascular structures

severe valvular dysfunction

59
Q

Prophylaxis of endocarditis is recommended for which patients?

A

patients with abnormal hearts who undergo procedures that lead to bacteremia

60
Q

Infective endocarditis was originally known as bacterial endocarditis, but it can also be caused by __________(3). Prior to the introduction of antibiotics, it was generally a uniformly fatal disease; IE is still associated with an estimated ____% mortality

A

fungi, rickettsia, and chlamydia

25%

61
Q

IE can be divided into three major groups based on host characteristics:

A

Native valve endocarditis (NVE)
Prosthetic valve endocarditis (PVE); further subdivided into early (i.e., in the first month after valve surgery) and late (occurring thereafter)
Endocarditis in IV drug users

62
Q

The Duke criteria are useful for the clinical diagnosis of IE.
The major Duke criteria are: (3)
The minor Duke criteria are: (5)

How many of each are required for Dx of IE?

A

MAJOR:

  • Persistently positive blood cultures with microorganisms consistent with IE (more than two positive cultures separated by at least 12 hours or more than three cultures at least 1 hour apart or 70% of blood cultures positive if four or more are drawn)
  • A single positive blood culture for Coxiella burnetii or IgG antibody titer >1:800
  • Echocardiographic evidence of endocardial involvement

MINOR:

  • Predisposing heart condition
  • Fever
  • Vascular phenomena (arterial emboli, septic pulmonary emboli, mycotic aneurysm, Janeway lesions)
  • Immunologic phenomena (glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor)
  • Positive blood cultures (not meeting major criteria)

Definitive diagnosis of IE requires two major criteria or one major plus three minor criteria or five minor criteria. Patients with one major criteria and one minor criteria or three minor criteria are classified as possible IE (may require additional testing).

63
Q

IE can be caused by a wide variety of microorganisms, but the majority (80%) of cases are due to __________(2).

Most cases of NVE are caused by __________(2), whereas most cases of IE in IV drug users are caused by _________(1).

Early PVE is thought to be caused by intraoperative contamination with nosocomial pathogens, in particular _________. Late PVE is believed to be community acquired and resembles NVE in microbiology.

A

streptococci and staphylococci

Streptococcus viridans (50%) and Staphylococcus aureus
S. aureus
coagulase-negative Staphylococcus

64
Q

Transient bacteremia can also occur with daily activities such as _________(3). In fact, it is felt that most cases of IE result secondary to bacteremia occurring in the setting of daily activities rather than iatrogenic causes. This realization has recently resulted in a major revision in the recommendations for IE prophylaxis in the setting of dental and medical procedures.

A

tooth brushing, bowel movements, and eating

65
Q

Patients with IE may present with either an acute or subacute course. The majority of patients present with which Sx? (7)

When evaluating a patient with possible IE, it is important to inquire about possible risk factors such as __________ (3).

A 
(systemic, constitutional symptoms:)
Fevers, chills, night sweats
Fatigue, malaise
Anorexia
Weight loss

A history of known valvular disease, rheumatic fever, or dental work should be elicited.

66
Q

What kind of murmurs is assoc with infective endocarditis?

A

Because IE often produces destruction and perforation of valve leaflets, patients generally are found to have regurgitant murmurs. A new or changing murmur is particularly suggestive of IE.

67
Q

Echocardiographic evidence/signs of endocarditis? (5)

A

Vegetations (defined as a mass of abnormal echoes attached to the endocardial surface of a valve, which displays motion independent of the cardiac structures and is seen in multiple views)
Ring abscess (defined as an abnormal echodense or echolucent area within the valvular annulus or perivalvular tissue)
New partial dehiscence of a prosthetic valve
Mycotic aneurysms
Perforation of valve leaflets

68
Q

Besides culture, other laboratory abnormalities seen in IE include: (5)

A

Elevated ESR
Elevated WBC (more in acute IE)
Anemia (in subacute IE)
Hematuria and proteinuria (because of immune-mediated glomerulonephritis)
Positive rheumatoid factor (usually in subacute IE)

69
Q

Empirical antibiotic therapy (following the drawing of initial blood cultures) is the initial step in treatment of suspected endocarditis. One major decision to be made early in the treatment course is the need for cardiac surgery. There are several indications for early cardiac surgery in IE (i.e., prior to completion of a course of antibiotics): (7)

A
  • Severe refractory CHF because of valvular regurgitation
  • Severe aortic or mitral regurgitation with evidence of abnormal hemodynamics (assessed by echocardiography or intravascular hemodynamic monitoring)
  • Refractory infection (lack of clearance of blood culture after 1 week of appropriate antibiotics) or infection with highly resistant organisms (e.g., fungi)
  • Progressive intracardiac spread of infection (ring abscess, heart block, mycotic aneurysm rupture)
  • Prosthetic valve dysfunction (major dehiscence or obstruction from vegetation)
  • Recurrent systemic emboli
  • The presence of large (>10 mm), mobile vegetations
70
Q

LP is essential to the diagnosis of meningitis, but in some cases a CT must be performed first (below). If LP is delayed, what needs to be done immediately (i.e. Before CT)? (2)

Suspected meningitis: conditions/findings that identify patients in whom CT should be performed prior to LP: (6)

A

Empirical antibiotics must be administered immediately if LP is delayed, and blood cultures should be drawn before proceeding to CT, if possible.

Immunocompromised state (HIV or immunosuppressive therapy)
History of central nervous system (CNS) disease (mass, stroke, focal infection)
New onset seizure (within 1 week)
Papilledema
Abnormal level of consciousness
Focal neurologic deficit (dilated nonreactive pupil, abnormal ocular motility, visual field deficits, arm or leg drift)

71
Q

The distinction needs to be made between ABM and so-called aseptic meningitis because _________ has a high mortality and must be diagnosed.

A

Bacterial meningitis

72
Q

The most common etiologic agents of aseptic meningitis are viruses, with __________ accounting for more than 90% of cases for which an etiology can be identified. Other relatively common causes of aseptic meningitis include: (8)

A

non-polio enteroviruses

Other viruses (mumps, lymphocytic choriomeningitis virus, arboviruses, Epstein-Barr virus [EBV], cytomegalovirus, varicella-zoster virus, herpes viruses, human immunodeficiency virus [HIV])
Mycobacterium tuberculosis
Fungi (Candida species, Cryptococcus neoformans)
Rickettsia (Rocky Mountain spotted fever, Coxiella burnetii)
Spirochetes (syphilis, leptospirosis, Lyme disease)
Malignancy (metastatic leukemia, lymphoma, metastatic carcinomas)
Medications (sulfamethoxazole, nonsteroidal anti-inflammatory agents, isoniazid)
Vaccinations (mumps, measles)

73
Q

When an LP is performed, the following routine data should be obtained: (4)

If other patient characteristics are present (e.g., HIV disease, immunocompromise, tuberculosis, STDs, CSF leak, or recent sinus surgery or neurosurgery), some or all of the following additional CSF tests can be sent: (7)

A

Opening pressure (normally between 70 and 180 mm Hg)
Cell counts (often opening and closing) and white blood cell (WBC) differential
Glucose and protein determination
Gram stain and culture for bacterial organisms

Other tests:
Acid-fast stains and mycobacterial culture
Fungal stain and culture
Polymerase chain reaction for herpes viruses
India ink stain with or without cryptococcal antigen testing
Serology for syphilis (Venereal Disease Research Laboratory [VDRL], rapid plasma reagin [RPR], microhemagglutination assay for Treponema pallidum [MHA-TP])
Viral culture
Anaerobic culture

74
Q

For each of Acute Bacterial Meningitis and Acute Viral Meningitis:
CSF WBC count (cells/mm3) and predominance on differential
CSF protein (mg/dL)
CSF glucose (mg/dL)
Opening pressure (mm H2O)
Time of year
Age

A 
Acute Bacterial Meningitis and Acute Viral Meningitis, respectively: 
CSF WBC count (cells/mm3): 200 to 10,000 &amp; PMN predominance; 25 to 100 &amp; lymphocyte predominance
CSF protein (mg/dL): 100 to 500; 50 to 100
CSF glucose (mg/dL): 40
Opening pressure (mm H2O): >200;

Internal Med - Jesse (8 decks)

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