Post on 19-Jan-2016
Eleana M. Zamora
Department of Internal Medicine
Division of Pulmonary/Critical Care/Sleep
THE X, Y, Z’S OF INFECTION
OBJECTIVES• Describe how to approach common inpatient/outpatient
infections
• Meningitis
• Encephalitis
• SSTI
• Diabetic foot
• Septic joint
• Bacteremia
• UTI
CNS INFECTIONS
MENINGITIS
• Definition
• Inflammation of the leptomeninges with an abnormal number of white blood cells in the CSF
• Patients with meningitis have normal cerebral function!
• Caveat: therapy is not based on randomized, controlled trials.
• Usually animal models
MENINGITIS
• Blood cultures are important!
• Timely LP
• Delay in initiation of therapy increases morbidity and mortality significantly
• Don’t delay antibiotics for purposes of obtaining LP!
ROLE OF STEROIDS
• Based on animal models
• SAH inflammatory response is a major factor contributing to morbidity and mortality
• Attenuation of this inflammatory response may be effective in decreasing cerebral edema
STEROIDS IN ADULTS
• Previous data had been inconclusive
• 2007 NEJM, 301 adults
• Dose given before abx
• Lower incidence of unfavorable outcome (15% vs 25%)
• Lower incidence of death (7% vs 15%)
• Benefit was only in pneumococcal meningitis subgroup
• age >60
• h/o CNS disease (e.g., mass lesion, stroke, and focal infection)
• Immunocompromised state (HIV, cancer)
• a history of seizure 1 week before ⩽presentation
• Abnormal neuro findings • Abnormal LOC
• Unable to answer 2 consecutive questions correctly
• Unable to follow 2 consecutive commands
• Gaze/Facial palsy
• Abnormal visual fields, language, neuro exam
ASSOCIATED WITH ABNORMAL CT
OTHER SPECIAL CONSIDERATIONS
• Special condition, special pathogen
• HIV
• ETOH
• Splenectomy
• Age
• Old vs. very young
• Time course
• Acute v. chronic
• Subacute or Chronic: cryptococcus, Syphillis, TB, fungal, abscess
CSF ANALYSIS
RECOMMENDED EMPIRIC THERAPY
• Bacterial Meningitis
• Ceftriaxone 2 gram IV q12h
• Vancomycin 1 gram q8-12h
• +/- ampicillin 2 grams q4 h
• For patients at risk for ______________
ENCEPHALITIS
• Definition vs. meningitis
• Altered mental status, motor or sensory deficits, altered behavior and personality changes, and speech or movement disorders
• Many of the viruses can cause a meningoencephalitis
• EEG is often abnormal
A WORD ON VIRUSES
• Aseptic meningitis
• Cell count <500/µL, >50 percent CSF lymphocytes, TP < 80 to 100 mg/dL, normal glucose concentration, and negative Gram stain.
• Partially treated or early bacterial meningitis is similar
• Most can cause either a meningitis, an encephalitis, or a combination of both
• More common• Enterovirus (seasonal)
• HIV
• HSV
• WNV (seasonal)
• Less common• Mumps
• Tick-borne disease (seasonal)
• Spirochetes
• Cryptococcus
• Cocci
• TB
• Drugs (bactrim, NSAIDS)
• Rabies
CAUSES OF ASEPTIC INFECTION
CHARACTERISTIC OF VIRAL INFECTION
• Increased white blood cell (WBC) count but < 250/mm3
• Usually lymphocyte predominant
• Early infection may be PMN
• Elevated protein concentration but < 150
CHARACTERISTIC : VIRAL INFECTION
• Usually normal glucose concentration (>50 percent of blood value)
• Moderately reduced values are occasionally seen with HSV, mumps, or some enteroviruses.
• Red cells are usually absent
• RBCs suggests HSV-1 infection or other necrotizing encephalitis
EMPIRIC ANTIVIRAL THERAPY
• Available therapy for herpesviruses
• Acyclovir 10mg/kg IV q8h
• Otherwise, supportive care
SKIN AND SOFT TISSUE (SSTI)
SKIN/SOFT TISSUE
• Cellulitis
• Erysipelas (GAS), Impetigo (staph>strep)
• Myositis
• Necrotizing fasciitis
• Abscess
• Risk factors for severe infection:
• Animal contact—MRSA, Plague, Tularemia?
• Jail, high school locker room, etc
MARKERS OF SEVERE INFECTION
• Pain disproportionate to PE
• Violaceous bullae
• Cutaneous hemorrhage
• Skin sloughing
• Skin anesthesia
• Rapid progression
• Gas in the tissue
• Septic shock from the infection
• Lactic acidosis, hypotension, elevated CPK, renal failure
Call Surgery Consult!
DIABETIC FOOT INFECTION
• Common pathogens: gram positives, gram negative, anaerobes (in ischemia)
• Send appropriate cultures before abx
• Biopsy, ulcer curettage, aspiration are far superior to wound swab
• Consider imaging
• Consider possibility of osteomyelitis
NOT SO SOFT TISSUE…
OSTEOMYELITIS
• In general:
• Empiric therapy is not recommended
• Culture data is key!
• Choice of empiric therapy should be guided by ID consult
• Early antibiotics can decrease the yield of cultures
SEPTIC JOINT
• Compared to osteomyelitis, empiric abx are often warranted
• Early consult to orthopaedics for washout
• Treatment = debridement AND abx
• ALL empiric choices are guided by gram stain!
• Monoarticular Acute
• Gram negatives
• Gram positive (staph, strep)
• Chronic
• Brucella
• Mycobacteria
• Fungi
TYPES OF SEPTIC ARTHRITIS
• Polyarticular, Acute
• Gonococcus
• Lyme dz
• ARF
• Viruses (parvo, hepatitis)
• Prosthetic joint
• MUST HAVE CULTURE DATA
TYPES OF SEPTIC ARTHRITIS
BACTEREMIA
BACTEREMIA• Rules of thumb
• Have a good idea of the source and you’ll know what to use
• Broad initial therapy is appropriate IF you narrow down later
• ALWAYS order repeat set of blood cultures to document clearance
• Examine the teeth!
• Contaminants aren’t always contaminants
• Consult ID service early!
FOREIGN BODIES AND BACTEREMIA
• Cure rates of 17-19% if line is not removed (Fowler VG Jr, CID 1998)
• Includes dialysis caths
• Foreign bodies (hardware)
• Presence of hardware increases risk of relapse of infection
• Series of 294 patients: The 23 patients with relapse were more likely to have foreign body than the 271 that didn’t relapse
• Pacemakers: up to 45% relapse
BACTEREMIA: DURATION OF THERAPY
• Staph (MSSA) Short treatment course
• Only if they meet the following criteria
• Valvular abnormalities predisposing to endocarditis are absent.
• Afebrile with no localizing complaints attributable to metastatic staphylococcal infection within 72 hours after initiating intravenous antistaphylococcal therapy and removal of the presumed focus of infection.
• Follow-up blood cultures drawn two to four days after initiating intravenous antistaphylococcal therapy and removing the presumed focus of infection are negative.
• No indwelling devices, such as prosthetic joints, heart valves, or vascular grafts are present.
• Everyone else: 4-8 weeks
BACTEREMIA
• Not every organism causes endocarditis
• Resistant organisms or Pseudomonas/Acinetobacter have to be treated longer than other types
• Repeat blood cultures help determine duration of therapy
• Lots of places to look for help
• IDSA endocarditis guidelines, bacteremia guidelines, CLABSI guidelines…..
URINARY TRACT
URINARY TRACT INFECTION
• Classifications:
• Uncomplicated vs. complicated
• Community vs. Nosocomial
• Symptomatic vs. Asymptomatic
• Catheter-related (CAUTI)
• Remember: # squams count!
ASYMPTOMATIC BACTERIURIA
• Definition:
• Women: ≥ 2 clean-catch samples with the same bacterial strains with ≥ 105 cfu
• Men: single clean-catch with ≥ 105 cfu
• ♀/♂: Single catheterized specimen with ≥ 102 cfu
• Consider what you are going to do with the result before you send the test
• Presence of WBC in UA is not an indication to treat!
IDSA guidelines Asymptomatic Bacteriuria 2005
ASYMPTOMATIC BACTERIURIA
• When it is significant and should be treated:
• Pregnant women
• Before TURP or urologic procedures in men
• Do not screen for bacteriuria in the following asymptomatic patients:
• Premenopausal non-pregnant, diabetics, elderly, spinal cord injury, catherized
CATHETER-ASSOCIATE UTI (CA-UTI)
• The best way to decrease the incidence of CA-UTI is to reduce the use of catheters
• Remove them when they are no longer needed
• Don’t use them if you don’t have to!
• Don’t culture an old foley….
IDSA Guidelines 2009
CA-UTI
• Patient must have symptoms to have a CA-UTI
• Presence of a positive culture alone does not require therapy
• S/Sx UTI along with ≥ 103 cfu
• S/Sx = fever, AMS, pyelo, etc
• Presence of WBC in UA cannot differentiate between UTI and bacteriuria
CA-UTI
• Before beginning abx consider:
• Changing foley if has been present >10-14d
• Repeat UA with culture after foley change
• If foley can be discontinued, then repeat UA from mid-stream clean catch
• Same principles guide your selection of drug
• Community-acquired vs. Nosocomial
A WORD ON CANDIDA
• Candiduria is rarely present in healthy individuals or in the community
• It is a common finding in hospitalized patients, especially in the ICU
• DM, indwelling catheters, and exposure to antimicrobials.
• Most often candiduria represents colonization, and antifungal therapy is not required.
CANDIDA
• The first step in evaluation is to verify funguria by repeating the urinalysis and urine culture AFTER foley change
• If confirmed, next step is imaging to look for fungal ball, pyelo, abscess, etc
• Careful evaluation of the patient for other signs of disseminated candidiasis
• Usually not indicated…
• Fluconazole is preferred
• Echinocandins do not achieve great concentrations in urine
TREATMENT OF CANDIDURIA
SUMMARY: CONSEQUENCES
• No matter the infection, it helps to think of the top three organisms
• Noscomial vs. community-acquired will make your antibiotic selection more appropriate
• Empiric coverage is very important—educated guesses count!
• BMJ 2010
• Individuals prescribed an antibiotic in primary care for a respiratory or urinary infection develop bacterial resistance to that antibiotic
• Resistance is greatest in the month immediately after treatment but may persist for up to 12 months
QUESTIONS?