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?