Infectious Disease - PowerPoint PPT Presentation

1 / 77
About This Presentation
Title:

Infectious Disease

Description:

Infectious Disease Infectious Disease Emerging Pathogens Anthrax Vancomycin-resistant enterococcus (VRE) Penicillin-resistant Strep pneumoniae Methicillin-resistant ... – PowerPoint PPT presentation

Number of Views:61
Avg rating:3.0/5.0
Slides: 78
Provided by: SparrowHe
Category:

less

Transcript and Presenter's Notes

Title: Infectious Disease


1
Infectious Disease
Infectious Disease

2
Emerging Pathogens
  • Anthrax
  • Vancomycin-resistant enterococcus (VRE)
  • Penicillin-resistant Strep pneumoniae
  • Methicillin-resistant Staph aureus (MRSA)
  • West Nile virus

3
Anthrax
  • Inhalation Anthrax is not pneumonia
  • Hemorrhagic mediastinitis, widened mediastinum on
    CXR
  • Inhaled spores deposit in lungs Macrophages take
    to mediastinal lymph nodes. Spores germinate
    resulting in overwhelming sepsis and toxin
    production

4
Inhalation Anthrax Treatment
  • Doxycycline 100mg IV or PO for 60 days
  • Ciprofloxacin 400 mg IV or 500 mg PO q 12 hr for
    60 days
  • Pen G 4 million u IV q 4h for 60 days
  • Amoxicillin 500 PO q 8 h for 60 days
  • Treat based on confirmed exposure
  • There is no quick, reliable lab test to diagnose
    an individual patient

5
Vancomycin-Resistant Enterococci
  • Most common enterococcal infections are cystitis,
    pyelonephritis and prostatitis
  • Most enterococci are susceptible to ampicillin,
    nitrofurantoin or quinolones
  • Obtain cultures on all serious infections in
    which enterococci are possible etiology

6
Vancomycin-Resistant Enterococci (Contd)
  • If enterococci are vancomycin-resistant, Synercid
    (quinupristin/dalfopristin) may be used

7
Prevention of VRE Infection
  • Nosocomial enterococcal infections are spread by
    direct contact
  • Private rooms with isolation
  • Gloves and gown when entering room
  • Disposable instruments and meal trays

8
Penicillin-Resistant Strep
  • 14 of isolates intermediate resistance (mic
    0.1-1.0)
  • 9.5 high level resistance (mic gt2.0)
  • Resistance to other antibiotics is increasing and
    is related to penicillin resistance
  • Choice of definitive therapy must be guided by
    sensitivity testing

9
Empiric Treatment of Penicillin-Resistant Strep
  • For community-acquired pneumonia, begin with
    macrolide
  • Oral cephalosporins do not have adequate
    bactericidal activity to treat pneumonia caused
    by penicillin-resistant pneumococci
  • Very high level resistance treat with
    levofloxacin or gatifloxacin

10
West Nile Virus
  • First U.S. case seen in 1999
  • Belongs to flavivirus group
  • Primary amplifying hosts are crows and jays
  • Human infection from mosquito bites
  • Peak incidence end Aug/early Sept
  • Incubation period 2-14 days

11
West Nile Virus (Contd)
  • Clinical patterns
  • Asymptomatic 80 of cases
  • West Nile fever 3-6 day self-limited febrile
    illness with flu-like symptoms and sometimes a
    rash
  • CNS involvement encephalitis or
    meningoencephalitis- 1.5 of cases
  • Diagnosis
  • Presence of IgM antibody to WN virus in serum
    and/or CSF
  • WN IgM in CSF indicative of CNS involvement since
    IgM doesnt cross blood brain barrier
  • Beware of cross-reactivity with other
    flaviviruses

12
West Nile Virus (Contd)
  • Prognosis
  • Advanced age is the most important predictor of
    death gt 70 y.o. at highest risk
  • Severe muscle weakness and change in level of
    consciousness risk factors for death from
  • encephalitis
  • Long-term cognitive and neurologic impairment
    common among encephalitis survivors
  • Treatment and Prevention
  • Supportive therapy, mosquito repellants and
    community mosquito control programs

13
General Management of Infectious Disease
  • Get culture and sensitivity whenever possible
  • Use narrow spectrum antibiotics at high enough
    doses and for proper duration
  • Dont treat a viral infection with antibiotics

14
Avoiding Resistance in Hospitalized Patients
  • Diagnose the infection with a culture whenever
    possible
  • Target the pathogen with the most specific
    antibiotic
  • Optimize dose, route, duration
  • Dont treat contamination or colonization
  • Stop antibiotic when infection is not diagnosed,
    cultures are negative

15
Minimize Outpatient Antibiotics
  • Treatment may not be needed or can be delayed
    for
  • Sinusitis
  • Bronchitis
  • Otitis
  • Use first line drugs in appropriate doses

16
Meningitis
  • Meningitis typically presents with fever,
    headache, stiff neck, nausea and vomiting
  • Stiff neck is NOT required
  • Progression from URI to headache and vomiting is
    suspicious
  • Meningeal irritation signs are quite sensitive
    and fairly specific
  • Consider as medical emergency - time is of the
    essence in diagnosis and treatment

17
Physical Signs Which Help to Predict Pathogen in
Meningitis
18
Epidemiology of Meningitis
19
Influenza
  • Typical scenario
  • Acute onset fever, chills, myalgias, headache,
    sore throat, cough, severe malaise
  • Epidemic activity
  • Late fall through early spring
  • Serious complications
  • Highest among the elderly, the very young and
    those with underlying chronic conditions
  • Secondary bacterial pneumonia
  • Pneumococcus, S. aureus or H. influenzae

20
Treatment of Influenza
  • Usually treated symptomatically
  • Amantidine and rimantadine are only active
    against influenza A (not B)
  • Both are equally effective for Type A
  • Zanamivir and oseltamivir are active against both
    Type A and B, but more expensive

21
Influenza Prevention
  • Annual vaccination is the most effective
    prevention
  • Groups to vaccinate over 50 years, children 6-23
    months, chronic pulmonary or cardiac disease,
    diabetes, late pregnancy, health care workers,
    household contacts of high risk persons,
    essential service workers, anyone who wants one

22
Fever of Unknown Origin
  • Defined as fever of 3 weeks duration that is
    gt38.3 C on several occasions failure to diagnose
    after 3 outpatient visits or 3 days of
    hospitalization
  • This functional definition helps exclude acute
    viral illness and most other acute causes as they
    resolve or a source is found

23
Work-up for Fever of Unknown Origin
  • Document the presence of fever and its
    characteristics
  • Thorough history looking at all possible risk
    factors family history, ethnicity, travel
    history, animal exposures
  • Repeat history and exam periodically
  • Discontinue as many medications as possible, both
    prescription and OTC

24
Work-up for Fever of Unknown Origin (Contd)
  • History and exam should guide testing
  • Serial blood cultures (three over 48 hrs)
  • Differential includes infection, neoplasm,
    hypersensitivities, autoimmune diseases
  • In elderly, most common are malignancy, collagen
    vascular disease, and lastly occult infection

25
Treatment of Fever of Unknown Origin
  • Empiric drug trials should be used with caution
    if at all
  • If malignancy is suspected, consider a trial of
    naproxen
  • Neutropenic patients are the only group in which
    empiric broad spectrum antibiotics should be
    used, such as ceftazidime plus an aminoglycoside

26
Sexually Transmitted Diseases
27
Urethritis
  • Gonococcal urethritis is abrupt in onset with
    copious purulent discharge
  • Non-gonoccocal pathogens Chlamydia trachomatis,
    Ureaplasma, Mycoplasma genitalium or Trichomonas
    vaginalis
  • Treatment must assume penicillin-resistant
    gonococcus

28
Cervicitis
  • Purulent or mucopurulent endocervical discharge
  • Gram stain gt10 wbc/hpf
  • Gram negative intracellular diplococci
  • Commonly asymptomatic
  • Suprapubic pain and tenderness may mean pelvic
    inflammatory disease

29
Treatment of Urethritis and Cervicitis
30
Vulvovaginitis
  • Candida pruritis, flocculent white discharge, pH
    4.0-4.5, hyphae on KOH prep
  • Trichomonas soreness, profuse green-yellow
    discharge, pH 5-6, trichomonads on wet prep
  • Bacterial vaginosis often asymptomatic white
    gray discharge, pH gt4.5, amine odor with KOH,
    clue cells on wet prep

31
Vaginitis Treatment
  • Candidiasis topical azole (eg. miconazole) or
    oral fluconazole 150 mg single dose
  • Trichomoniasis metronidazole 500 mg bid x 7 d or
    2 gm single dose
  • Bacterial vaginosis metronidazole 500 mg bid x 7
    d or 2 gm single dose clindamycin or
    metronidazole topically

32
Pelvic Inflammatory Disease
  • Includes endometriosis, salpingitis, tubo-ovarian
    abscess
  • Risk factors multiple partners, frequent
    intercourse, new partners within previous 30 days
  • Symptoms vaginal discharge, pain, fever
  • Exam cervical motion or adnexal tenderness

33
Treatment of PID
34
Urinary Tract Infections
35
Acute Cystitis
  • Women and girls older than 2
  • Acute onset dysuria, frequency
  • Fever is usually not present
  • Pyuria gt 5-10 wbc/hpf or positive leukocyte
    esterase
  • Positive urine culture
  • Most common E. coli, other enterobacteria,
    enterococci, Staph saprophyticus

36
Treatment of Acute Cystitis
  • Single dose better compliance and less side
    effects but lower cure rate
  • Three day better effectiveness than single dose
    as effective as 7-10 day
  • TMP/SMX DS bid x 3d or
  • Amoxicillin 500 mg tid x 3d or
  • Cephalosporin or fluoroquinolone x 3d

37
Acute Pyelonephritis
  • Fever, chills , flank pain
  • Flank or CVA tenderness to percussion
  • Positive urine culture, often positive blood
    culture
  • Same microbiology as cystitis

38
Treatment of Pyelonephritis
  • Hospitalized with IV antibiotics vs. outpatient
    with oral antibiotics
  • No clear evidence either way
  • Low risk patients may be considered for
    outpatient care
  • IV therapy ampicillin plus gentamicin or
    tobramycin
  • Fluoroquinolone may be used IV or PO

39
Prostatitis
  • Acute fever, chills, perineal or low back pain,
    dysuria or frequency
  • Prostate is extremely tender avoid vigorous exam
    in acute prostatitis because of severe pain and
    risk of causing bacteremia
  • Chronic Intermittent episodes of dysuria or
    frequency prostate is enlarged and may be mildly
    tender

40
Treatment of Prostatitis
  • TMP/SMX DS bid
  • Fluoroquinolone
  • Doxycycline 100 mg bid
  • Acute infection
  • Under 35 years old treat for 7 days
  • Over 35 years old treat for 1 month
  • Chronic infections need 1-3 months of treatment

41
Lymphadenopathy
  • Small nodes in back of neck, axillae, or groin
    may be normal
  • Nodes in other regions, or any node gt1 cm is
    potentially abnormal
  • Nodes gt 3 cm suggest malignancy

42
LymphadenopathyHistory and Exam
  • Confirm mass is a lymph node
  • Acute or chronic
  • Associated systemic symptoms
  • Characteristics firm, soft, tender
  • Localized or generalized

43
LymphadenopathyDifferential
  • Localized - look for infections or malignancy in
    the area which the node drains
  • Generalized - systemic infections, AIDS
    toxoplasmosis, leukemia, lymphoma, (Hodgkin's or
    non-Hodgkin's)
  • Hilar - sarcoid, carcinoma, tuberculosis, fungal
    infection

44
When to Biopsy
  • When simpler procedures have failed to give
    diagnosis
  • If undiagnosed after weeks to months especially
    if enlarging
  • In generalized lymphadenopathy, avoid inguinal
    or axillary node biopsy
  • Supraclavicular nodes have best diagnostic yield

45
HIV Disease
46
HIV Disease
  • Caused by a single-stranded RNA retro virus
  • Encodes reverse transcriptase which copies the
    genome into the double- stranded DNA which then
    becomes integrated into the host genome

47
Epidemiology
  • HIV was present in sub-Saharan Africa in the
    1950s
  • In the U.S. by 1970
  • Now reported in 150 countries
  • 920,000 cases and 420,000 deaths through December
    2000
  • Greatest increase in spread is in heterosexual
    population

48
Transmission
  • Transmission by sexual contact , body fluids, and
    perinatally
  • High titers in semen and cervical fluid
  • Infection facilitated by breaks in epithelium
  • Sexual transmission more efficient male to female
  • Perinatal transmission as high as 30 in
    untreated pregnancies

49
Disease Progression
  • Main determinants are CD4 count and viral load
  • Absolute CD4 count and rate of decline determine
    need for treatment
  • Quantitative titer of circulating HIV RNA is the
    single best predictor of long term progression
  • Measured by reverse transcriptase PCR or DNA
    amplification

50
Monitoring
  • Test for viral load and CD4 every 3-4 months
    until treatment is started
  • Begin treatment when CD4 lt350
  • After treatment is begun, re-test 4-8 weeks later
    to determine response
  • Re-check in 3-4 months
  • Once stable, check viral load every 3-4 months

51
Constitutional Symptoms
  • Acute viral syndrome fever, night sweats,
    anorexia, weight loss
  • Early disease (CD4 gt500) similar to non-HIV
  • Mid-stage (CD4 200-500) possible TB or STD as
    unrecognized source of fever
  • Late disease (CD4 75-200) opportunistic
    infections
  • Advanced disease (CD4 lt75) disseminated
    mycobacterium avium and CMV

52
CNS Symptoms
  • Cognitive dysfunction, decreased level of
    consciousness, delirium, psychosis
  • Late disease (CD4 75-200) due to cryptococcal
    meningitis, CMV, HSV, VZV encephalitis, HIV
    dementia
  • Advanced disease (CD4 lt75) due to primary CMV or
    advanced HIV dementia

53
GI Symptoms
  • Dysphagia, odynophagia, food sticking
  • Mid-stage - oral thrush
  • Late disease- candidal esophagitis, herpes
    simplex (I or II)
  • Advanced disease- same as above plus CMV and
    aphthous ulcers
  • Diarrhea- common in HIV caused by HIV itself or
    by opportunistic infections

54
Skin Manifestations
  • Very common affect 90 of HIV patients
  • Early disease may be associated with viral
    exanthem, seborrhea, HSV, HPV, staph cellulitis,
    Kaposis sarcoma
  • Mid-stage candida, oral hairy leukoplakia,
    atopic dermatitis
  • Late-stage above get worse also opportunistic
    fungal infections

55
Treatment of HIV Disease
  • HIV treatment guidelines are changing rapidly but
    there are some general principles
  • Major goals are to suppress viremia and prevent
    immunosupression
  • Start treatment only when patient is ready to
    comply
  • Treat all symptomatic patients

56
Treatment of HIV Disease (Contd)
  • Treat asymptomatic patients when CD4 lt 350 or
    viral load is high (bDNA gt30,000 or PCR gt55,000)
  • Monotherapy is NOT recommended
  • A combination of 3 antiviral drugs is now
    recommended
  • CD4 lt 200 treat with TMP/SMX DS 1 q day to
    prevent Pneumocystis carinii

57
Treatment of HIV Disease (Contd)
  • Nucleoside analogs - inhibit reverse
    transcriptase interfere with the formation of
    DNA
  • Non-nucleoside reverse transciptase inhibitors -
    inhibit reverse transcriptase by a different
    mechanism
  • Protease inhibitors - prevent cleavage of viral
    proteins interfere with viral maturation and
    assembly

58
Treatment of HIV Disease (Contd)
  • Most common recommended program is two nucleoside
    analogs and one protease inhibitor but this is
    rapidly changing and needs to be individualized
  • Treatment Failures
  • Non-compliance, erratic compliance
  • Drug malabsorption, drug-drug interaction
  • True resistance

59
Prevention of HIV Disease
  • A vaccine is not yet available
  • Prevention counseling and post-exposure
    prophylaxis
  • IV drug users should enter rehab if not, use
    clean needles and sterile equipment
  • Promote safer sexual practices
  • Prenatal screening and treatment
  • Prevention of occupational exposures

60
Tuberculosis
  • Dramatic increase in cases since 1985 in
    conjunction with HIV epidemic
  • Multi-drug resistant TB ( resistance to
    isoniazid and rifampin) increasingly common
  • Fever most common symptom of primary TB, hilar
    adenopathy most common X-ray finding
  • Cough, weight loss and fatigue most common
    symptoms of reactivation TB, upper lobe
    infiltrates (apical-posterior segments) most
    common X-ray finding
  • CT scanning more sensitive than plain CXR

61
Tuberculosis (Contd)
  • PPD skin test conversion occurs 4-7 weeks after
    primary infection
  • Positive end-point is induration 48-72 hours
    post-administration
  • 5 mm high risk populations (e.g., known
    contact, HIV)
  • 10 mm moderate risk populations (e.g., health
    care workers, recent arrivals from endemic
    countries)
  • 15 mm populations with no specific risk factors
  • Consider two-step test in populations with
    waning reactivity (booster phenomenon)

62
Tuberculosis (Contd)
  • Rapid nucleic acid assays (NAAs) vs. traditional
    isolation methods
  • NAAs confirm diagnosis in 2-7 hours
  • Isolation methods confirm in 4-8 weeks
  • Treatment protocols
  • Susceptible TB INH, rifampin, pyrazinamide,
    ethambutol X 2 mos then INH and rifampin X 4 more
    mos
  • Multiple drug resistant TB individualized,
    based on sensitivities, consult TB expert
  • Prevention INH X 6-12 mos (monitor liver if
    gt35)
  • Pregnancy Tx warranted, may breast feed

63
Cellulitis
  • Predisposing factors include venous/lymphatic
    compromise, diabetes, alcoholism
  • Systemic toxicity often absent
  • Beta-hemolytic strep and Staph aureus most common
    pathogens
  • Erysipelas distinct form associated with marked
    swelling and sharply demarcated borders
  • Preferred treatment options nafcillin,
    cefazolin, cefalexin, amoxicillin/clavulanate

64
Sepsis
  • Represents systemic response to infection
  • May or may not be associated with shock or
    multiple organ dysfunction syndrome (MODS)
  • Most frequent in middle-aged and elderly patients
  • Primary infection remains unidentified in 10 of
    cases
  • Presence or absence of positive blood cultures
    does not correlate with outcomes
  • Outcome worse for nosocomial vs.
    community-acquired bloodstream infections

65
Sepsis (Contd)
  • Most common manifestations of MODS
  • ARDS
  • Acute renal failure
  • DIC
  • Mortality of sepsis shock with MODS
  • 40-50

66
Septic Shock Treatment
  • Support airway/respiration/perfusion (septic
    shock medical emergency)
  • Supplemental oxygen
  • Intubation/assisted ventilation PEEP
  • Aggressive fluid replacement (crystalloid
    colloid)
  • Vasopressors/inotropes as indicated
  • Low dose steriods
  • 50 mg hydrocortisone q6 hr i.v. fludrocortisone
    50 ug once daily x 7 days
  • Antibiotics
  • Source control is critical targeted intervention
  • Beta-lactam aminoglycoside
  • Stress ulcer/DVT prophylaxis

67
Septic Shock Treatment (Contd)
  • Maximize nutritional support
  • Earlier the better
  • Favor enteral over parenteral if gut working
  • Use supplements rich in branched-chain amino
    acids
  • No clear benefit from corticosteroids
  • Recombinant human activated protein C
  • May be beneficial against coagulation disorders
  • Greatest benefit shown in the sickest patients
  • Approved dose for septic shock is 24 mcg/kg/hr X
    96 hours at a cost of 5,000-10,000 per course
  • Side effects include serious bleeding events

68
Dermatophyte (Tinea) Infections
  • Most common cause of superficial fungal infection
  • Increased susceptibility in immunocompromised
    patients
  • Tinea capitis and onychomycosis most difficult to
    treat

69
Tinea Capitis
  • Black dot most common form in U.S.
  • Enlarging, erythematous, scaling patch(es)
    progressing to alopecia
  • Scalp hairs break off flush with surface
  • Detritus in follicles appears as black dots
  • No fluorescence, in contrast to less common gray
    patch type

70
Tinea Capitis Treatment
  • Micronized griseofulvin preferred 250 mg PO QD
    X 6-12 wks, 10 mg/kg QD X 6-12 wks in children
  • Topical treatment futile
  • Kerion requires addition of Staph antibiotic
  • Identification of asymptomatic carriers important
    treat with selenium sulfide shampoo

71
Onychomycosis
  • Caused by dermatophytes, non-dermatophytes, and
    yeast
  • Distal subungual type most common form
    (Trichophyton rubrum)
  • Nail dystrophies can mimic, so confirm diagnosis
    with KOH or culture

72
Onychomycosis Treatment
  • Terbinafine (preferred) 250 mg QD X 6 wks
    (fingernails), 250 mg QD X 12 weeks (toenails)
  • Itraconazole fixed 200 mg QD X 8 wks
    (fingernails), 200 mg QD X 12 wks pulse 400 mg
    QD 1 wk/4 X 2 mos (fingernails), 400 mg QD 1
    wk/4 X 3 mos (toenails)
  • Nail lacquer (ciclopirox) for mild to moderate
    disease without lunular involvement only, slow
    acting, works in only 1 in 15 patients
  • Check liver enzymes before starting PO
    antifungals
  • For standard dosing protocols, no need to follow
    LFTs unless Hx of liver problems

73
Infectious Diarrhea
  • Salmonella leading cause of foodborne illness in
    U.S. (poultry, eggs, dairy products)
  • Shigella second leading cause
  • Campylobacter associated with undercooked
    infected poultry, enterohemorrhagic E. coli with
    undercooked ground beef
  • Rotavirus and Norwalk agents common viral causes
    (rotavirus predominantly in infants)
  • Cyclospora newly identified small bowel path-
    ogen, intense fatigue and malaise a hallmark

74
Infectious Diarrhea General Work-up
  • Sensitivity/specificity of fecal leukocytes only
    70 and 50, respectively
  • Standard stool cultures not indicated unless Sx
    last gt5-7 days, patient toxic, or for public
    health purposes
  • Clinical context usually obviates need for
    rotavirus and C. difficile tests

75
Infectious Diarrhea Approach to Treatment
  • Antibiotic therapy usually not indicated due to
    self-limited course
  • Rehydration/maintaining hydration top priority
  • Avoid anti-motility agents if fever and/or bloody
    diarrhea
  • No evidence that transition diets make a
    difference (e.g. BRAT)
  • Transient lactose intolerance sometimes occurs

76
Pseudomembranous Colitis
  • Most cases due to Clostridium difficile
  • Can occur 1-3 weeks after stopping an antibiotic
  • Nosocomial diarrhea usually C. difficile
  • Responds to course of metronidazole

77
Travelers Diarrhea
  • Usual agent is enterotoxigenic E. coli
  • Hi risk areas Asia, Africa, South/Central
    America, Mexico
  • Usual onset 5-15 days after arrival
  • Prophylaxis not recommended
  • Prevention avoid ice cubes, fruit salads,
    lettuce, chicken salads, condiments on table,
    steam table buffets
  • Treatment for mild cases, fluids only add
    ciprofloxin 500 mg BID X 3 days and loperamide
    for moderate to severe cases
Write a Comment
User Comments (0)
About PowerShow.com