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Urgencies and Emergencies of

Ambulatory InfectionsHEATHER CHAMBERS, DNP, FNP-C, APRN-NP INFECTIOUS DISEASESIMMANUEL MEDICAL CENTERHEATHER.CHAMBERS@ALEGENT.ORG

I have no relevant financial relationships to disclose

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Objectives

Describe skin and soft tissue infections Discuss respiratory infections Identify bone and joint infections

Skin and Soft Tissue Infections (SSTI)

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Cellulitis: A misunderstood diagnosis

Clinical diagnosis No labs or imaging will confirm the diagnosis

Consider alternative diagnoses Very itchy rash

Bilateral rash

Not improving with antibiotics

In a risky location (inner thigh, over a joint, genitals)

Extreme pain or totally painless

Lasts for months

Beware of diagnostic momentum

Hart A & Mehta S. Skin and soft tissue infections – Cellulitis, skin abscesses, and necrotizing fasciitis (April 2018). https://emergencymedicinecases.com/skin-soft-tissue-infections/

Cellulitis mimics Peripheral artery disease (PAD) Stasis dermatitis Erythema migrans of Lyme disease Deep vein thrombosis (DVT) Bee and wasp stings Monoarthritis Flexor tenosynovitis

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Cellulitis vs Mimics Cellulitis: Erythema, pain, warmth, swelling, chills, well demarcated,

unilateral Stasis dermatitis/PAD: red inflamed skin on lower legs, warm, non-

tender Lift the leg 45º for 1-2 minutes

DVT and cellulitis rarely co-exist Monoarthritis (septic arthritis/gout): significant pain on passive ROM Flexor tenosynovitis: Exquisite pain on passive ROM of finger Bee and wasp stings: cellulitis takes time to develop

Ask timing of incident Cellulitis is really uncommon

Erythema migrans: painless and nontender, seasonal

Hart A & Mehta S. Skin and soft tissue infections – Cellulitis, skin abscesses, and necrotizing fasciitis (April 2018). https://emergencymedicinecases.com/skin-soft-tissue-infections/

Cellulitis: Diagnosis and Management Predominant causes: Streptococcus spp and Staphylococcus aureus Blood cultures are positive in <10% of cases Wound or tissue cultures are negative in ~ 70% of cases Skin infections with purulent fluid associated with Staph aureus Animal bites or scratches

Pasteurella: Amp/Sulb or Augmentin (Levaquin covers but not DOC)

Capnocytophaga: PCNs, Augmentin, Cephalosporin, Carbopenems Variable susceptibility to Bactrim and Fluroquinolones

Salt water: Vibrio vulnificus (from shellfish): Doxycycline + Ceftriaxone Fresh water: Aeromonas spp: Ciprofloxain/Levofloxacin or Ceftriaxone

or Cefepime for severe wounds

Sullivan T & deBarra E. Diagnosis and management of cellulitis. 2018; 18 (2): 160-163.

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Erysipelas Caused by Strep pyogenes, Group A Strep

Less common: Staph aureus including MRSA

Most common in elderly Fiery red or salmon colored, well-demarcated edges Desquamation after 5-7 days Located on face or lower extremities Treatment

Penicillin 125-250mg po q6-8 hrs Amoxicillin 875mg po bid or 500mg po tid PCN Allergy: Clindamycin 300mg po tid

Duration: 5-10 days

Staph aureus (MSSA and MRSA) Furuncles = “Boils” Folliculitis Flea-”bitis” Treatment MSSA

Augmentin 875mg po bid Keflex 1gm po tid or 500mg po qid

Covers Strep as well

Treatment MRSA Clindamycin 300mg po tid Bactrim DS 1tab po bid Doxycycline/Minocycline 100mg po bid Linezolid 600mg po bid

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Coverage for Strep and MRSA SSTI

Clindamycin 300mg po tid Watch for C. diff!!

Bactrim with Amoxicillin Doxycycline/Minocycline with Amoxicillin Linezolid Delafloxacin (MRSA quinolone)

IV vs PO treatment Cephalexin has good bioavailability if covering MSSA and/or Strep

No difference in clinical resolution compared to Cephazolin Recommend IV antibiotics

Immunocompromised patients Signs of systemic infection (SIRS) Hemodynamic instability Altered mental status

Treatment failure or alternative diagnosis after 48-72hrs No improvement in pain No improvement in warmth Progression of erythema

Dalbavancin 1,500mg IV x1 Oritavancin (Orbactiv) 1,200mg IV x1

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Stanford Obesity Dosing

http://med.stanford.edu/bugsanddrugs/guidebook/_jcr_content/main/panel_builder_584648957/panel_0/download_1186887683/file.res/SHC%20Obesity%20Dosing%20Guide.pdf

Necrotizing fasciitis: Diagnosis Two types

Type 1: polymicrobial infection and is often gas-forming Type 2: monomicrobial, usually Group A Strep (GAS) causing a

robust immune stimulation

Manifestations Often pre-existing trauma Extremities, perineum, abdominal wall Rapid spread Crepitus Systemically ill

NF vs cellulitis: pain is out of proportion, crescendo pain, hypotension, necrosis, bullae

Best diagnosis is surgical evaluation

Puvanendran R, Huey JCM, & Pasupathy S. Necrotizing fasciitis. Canadian Family Physician October 2009; 55: 981-987.

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Necrotizing Fasciitis: Bugs & Drugs

Microbiology Monomicrobial

Strep pyogenes

MSSA and MRSA

Clostridia spp → gas gangrene

Others: Vibrio vulnificus, A. hydrophilia

Polymicrobial More common

Mixed aerobic/anaerobic organisms

Associated with GU/GI areas, penetrating trauma, IV drug use

Treatment Mortality 30-40% with treatment

Empiric antibiotics Pip/Tazo or Carbapenem + Vanco

+ Clindamycin

De-escalate based on cultures Strep spp: PCN + Clindamycin

MRSA: Vanco + Clindamycin

Clostridium: PCN + Clindamycin

Discharge antibiotics Augmentin

Guevel, LH & Shifrin MM. Necrotizing fasciitis in the adult patient: Implications for Nurse Practitioners. The Journal for Nurse Practitioners 2020; 16: 335-337.

Fournier’s Gangrene

Necrotizing fasciitis in genital region May be confined to scrotum, or also involve the perineum

and abdominal wall

Risk factors: DM, long-term alcohol misuse, trauma/surgery Polymicrobial Early aggressive surgical debridement

Thwaini A et al. Fourier’s gangrene and its emergency management. Postgrad Med J 2006; 82: 516-519

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Clinical Infectious Diseases, Volume 59, Issue 2, 15 July 2014, Pages e10–e52, https://doi.org/10.1093/cid/ciu296

Herpes Zoster Epidemiology Belongs to the α-herpesvirus family Primary infection leads to chickenpox Lifelong latency in cranial nerve and dorsal root ganglia Reactivation is shingles

Dermatomal distribution

Secondary complications Bacterial superinfection

Postherpetic neuralgia

Chronic neuropathic pain

Meningitis

Ocular complications

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Clinical Presentation

Infectious for about 48hours prior to onset of rash until all lesions are crusted

Cessation of new lesions occurs in about 3-5 days Complete lesion healing is 2-3 weeks Fever Malaise Nausea/vomiting Vesicular rash!

Herpes Zoster (Ophthalmicus)

Medical Emergency Needs IV Acyclovir Needs Lumbar puncture Needs ophthalmology consult Treatment

Acyclovir 10mg/kg IV q8hrs

Valgancyclovir (Valtrex) 1-2gms po tid

Acyclovir 800mg po 5x/day

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Herpes Zoster Prevention

Adult > 18 years: Shingrix Insurance coverage >50 years

2 injections 0, 2-6 months

Efficacy with Shingrix is 91% compared to 51% for Zostavax Revaccinate those who have received Zostavax Attenuated so can be given to immunosuppressed patients Can be given once lesions have crusted Shingrix more expensive for the vaccine but more cost effective

because more effective

Respiratory Infections

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Influenza Epidemiology

Person-to-person spread Close contact with infected person. Large droplets land on upper respiratory mucosal surfaces Virus replication in respiratory epithelium

Incubation – 1- 4 days

Viral shedding Can begin 1 day BEFORE the onset of symptoms Peak shedding first 3 days of illness: correlates with fever Subsides usually by 5-7 days Infected persons are reservoirs of influenza virus

Disease Transmission

Coughing Sneezing Talking (within 6 feet) Contaminated hands Contaminated objects Contagious 1 day before symptoms Viral shedding for 3-7 days

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Diagnosis & Treatment

Diagnosis Culture (3-7 days)

Swab for virus culture from nasopharynx or throat;

Nasal wash or bronchoscopy specimen

Rapid Influenza Tests (15 min) Throat swab Use within first 3 days of illness 50-70% sensitive for detecting

influenza but only 10-51% sensitive for H1N1

RVP (2-4 hours)

Treatment Rimantadine (Flumadine)

Can not use for H1N1

Resistance >95% **Don’t use**

Oseltamivir (Tamiflu) 75mg po bid x5days minimum Approved for >1yr old

Zanamivir (Relenza) 5mg each(2 inhalations) bid x5days Approved for >7 yrs old

Baloxavir 40mg po x1 (80mg if wt >80kg) Approved fro >12 yrs old

Peramivir 600mg IV x1 (CrCl >60) or qday if severe illness

Start within 48hrs of exposure If exposure occurs but no symptoms, start

prophylaxis(qday dosing x10days)

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Complications Pneumonia with/without bacterial

superinfection Other respiratory tract infections

Bronchiolitis Bronchitis

Otitis media Parotitis

Extrapulmonary Myositis/Rhabdomyolysis Mycocarditis Encephalitis

Toxic shock syndrome Post-Influenza Guillian-Barre

Immunosuppressed patients Longer viral replication Start therapy regardless of duration

of symptoms

Consider longer therapy in critically ill and immunosuppressed

Avoid use of corticosteroids Don’t give antibiotics if

uncomplicated Influenza Suspect bacterial pneumonia

Strep pneumoniae Group A Strep Staph aureus

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COVID

Kovalchick,J. How to prepare patients for the new influenza season during COVID-19 pandemic. Clinical Advisor, 2020 August 13. https://www.clinicaladvisor.com/home/topics/infectious-diseases-information-center/how-to-prepare-for-the-new-flu-season-during-covid-19/3/

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Solomon DA, Sherman AC, & Kanjilal S. Influenza in the COVID-19 Era. JAMA. Published online August 14, 2020. doi:10.1001/jama.2020.14661

Spread a virus

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Pneumocystis Pneumonia

Pneumocystis jirovecii pneumonia (PJP) Pneumocystic carini pneumonia (PCP) Develops in lungs with decreased immune system

Most common opportunistic infection with HIV infection (CD4 <200)

High doses of steroids or immunosuppressive drugs

Can cause severe respiratory failure with fevers and dry cough Symptoms: hypoxemia, SOB, +/- fevers CXR: diffuse bilateral infiltrates CT: Ground-glass opacities

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PJP vs Mimics

Bacterial Pneumonia

Fungal Pneumonia

Heart failure

Pulmonary edema

COVID-19

Diagnosis & TreatmentDiagnosis Need bronchoscopy

Sensitivity is 85-90%

Send cytology

PJP PCR

Serum Beta-D-glucan (Fungitell) Normally very high >500

Treatment Moderate-to-severe disease

TMP-SMX (Bactrim) 20mg/kg/day divided q6 or q8hrs x21 days (OR) Bactrim DS 2tabs po tid x21 days

Corticosteroids Pred 1mg/kg bid x 5 days, then 0.5mg/kg bid x 5

days, then 0.5mg/kg qday x 11 days

Mild-to-moderate disease TMP-SMX

Prevention High dose Bactrim 8mg/kg/day

TMP-SMX allergy Atovaquone 750mg po bid Clindamycin 600mg po q6hrs + Primaquine 15-

30mg po qday

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Prophylaxis

Who Qualifies? HIV with CD4 <200

Prednisone >20mg for > 1 month

Hematopoietic and solid organ transplants

Prevention Bactrim DS 1 tab po qday (OR) MWF

Bactrim SS 1 tab po qday

Pentamadine 300mg IH q4 weeks

Dapsone 100mg po bid Need to check G6PD

Atovaquone 1,500mg po qday

Community Acquired Pneumonia

“Typical” organisms Streptococcus pneumoniae (20-60%)

Haemophilus influenza (3-10%)

Moraxella catarrhalis

Staphylococcus aureus (3-5%)

“Atypical” organisms Mycoplasma pneumoniae

Chlamydophila pneumoniae

Legionella pneumophila

Strep pneumo

Mycoplasma

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Diagnosis Clinical evaluation

Fever, tachypnea, tachycardia, rales Sudden onset of fever +/- chills and rigors Pleuritic chest pain Cough, productive purulent sputum

CXR (not required in outpatient setting) Microbiological testing

CBC Sputum gram stain with culture Inflammatory markers (CRP, Procalcitonin) Pulse oximetry Urine for Legionella and Strep pneumo Ag RVP

Moberg AB, et al. Community-acquired pneumonia in primary care: clinical assessment and the usability of a chest radiography. Scandinavian Journal of Primary Health Care 2016; 34 (1): 21-27.

Day #4

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When to hospitalize

Minor Criteria Respiratory Rate >30

Multilobar infiltrates

Confusion/Disorientation

Uremia (BUN >20)

Leukopenia (WBC <4)

Thrombocytopenia (plts <100)

Hypothermia (temp <36ºC)

Hypotension

Major Criteria Septic shock with need for pressors

Respiratory failure requiring ventilation

Treatment

Outpatient No comorbidities or risk factors for

MRSA or Pseudomonas Amoxicillin Doxycycline No Macrolide

With comorbidities Combination therapy

Augmentin or cephalosporin + Doxycycline

Respiratory Quinolone Levofloxacin or Moxifloxacin

Inpatient Ceftriaxone

Cefepime if risk factors for Pseudomonas

+/- Doxycycline or Macrolide for atypical coverage

Respiratory Quinolone

Vancomycin if risk factors for MRSA or recent viral infection

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Bone and Joint Infections

Osteomyelitis

Definition: An acute or chronic inflammatory process of the bone and its structures secondary to infection with pyogenic organisms Hematogenous: bone infection seeded through remote source

Contiguous inoculation: infection spread from adjacent soft tissues/joints

Direct inoculation: infection with vascular insufficiency with multiple organisms

Bone exposed = bone infection (89% PPV) Treatment dependent on acute vs chronic

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Commonly isolated Organisms

Diagnosis

Laboratory data WBC usually <15

Elevated inflammatory markers (ESR/CRP)

Microbiologic data Essential for best antibiotic therapy

Culture: blood, bone biopsy, abscess drainage

Imaging Plain x-ray (changes delayed by >14 days)

CT

MRI

Hatzenbuehler J & Pulling TJ. Diagnosis and management of osteomyelitis. American Family Physician 2011; 84 (9): 1027-1033.

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General Principles of Therapy

Improve health status of patient and optimize underlying medical conditions Good nutrition-increase protein

Smoking cessation

Diabetes control

IV antibiotics Surgical management Treatment with IV x6 weeks +/- additional po antibiotics

“Give me the bug, and I’ll give you a drug”Microorganism First-line Antibiotic AlternativeMSSA Nafcillin or Oxacillin 2gms IV q4hrs Cefazolin 2gms IV q8hrsMRSA Vancomycin (trough 15-20) Linezolid 600mg IV/po bid (or)

Daptomycin 6mg/kg IV qday(or) Levofloxacin 750mg Iv/po+ Rifampin 600-900mg po qday

Streptococci (Penicillin sensitive)

Penicillin 4mU IV q6hrs (or) Ceftriaxone 2gm IV q24hrs (or) Cefazolin 2gm IV q8hrs

Vancomycin (trough 15-20)

Coagulase-negative Staph Vancomycin (trough 15-20) Linezolid 600mg IV/po bidPseudomonas Cefepime 2gm IV q12hrs Ciprofloxacin 750mg po bid

(or) Ceftazidime 2gm IV q8hrsEnterobacteriaceae Ceftriaxone 2gms IV q24hrs Ciprofloxacin 750mg po bidEnterococcus PCN 20mU IV con’t over 24hrs (or)

Ampicillin 12gms IV con’t over 24hrs

Vancomycin (trough 15-20) +/-Gentamicin

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Chronic Osteomyelitis

Typically no systemic symptoms May see sinus tract

Treatment Surgical debridement

Antimicrobials based on cultures

May not need any antibiotics

Prosthetic Joint Infections (PJI)

Significance: >1 million TKA and THA surgeries in U.S. each year Cost: $30,000 - $60,000 for each surgery Route: Local (60-80%) and Hematogenous (20-40%) Risk for infection:

Knee (1-2%)

Hip (0.3-1.3%)

Shoulder (<1%)

Higher risk Revision procedures (hip 3% and knees 6%)

Rheumatoid arthritis (2.2%) and osteoarthritis (1.2%)

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Risk Factors

Postoperative site infection or hematoma Complications with wound healing Prior joint arthroplasty with a large prosthesis Prior surgery or infection of the joint or adjacent bone Remote infections Rheumatoid arthritis Less common factors: Diabetes, chronic steroids, obesity, poor

nutrition, malignancy, sickle cell, prolonged preoperative hospitalization

Matthews PC, Berendt AR, & McNally MA. Diagnosis and management of prosthetic joint infection. BMJ 2009: 338: b1773.

Clinical Presentation

Early (<3 months after surgery) Acute onset of joint pain and effusion

Erythema, warm, and tender

Purulent drainage

Organisms: Staph aureus, Streptococci, Gram negatives

Delayed/Chronic (3-24 months after surgery Chronic pain and implant loosening

Worsens with time with decreased function

Organisms: Coagulase-negative Staphlococci, Propionibacterium acnes

Late (>24 months) Hematogenous seeding of

prosthesis

Organisms: variable

Staph aureus bloodstream infection with stable prosthesis with 34% rate of implant infection

Bloodstream infection can seed joint at any time after implantation

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Diagnosis

History &Physical important Type of prosthesis, date of

placement, problems with joint, symptoms, antibiotic history, infection history

Laboratory data ESR and CRP (CRP >13.5 is highly

sensitive/specific for PJI)

Blood cultures if has fevers

Radiology: not recommended by IDSA

Arthrocentesis Cell count, gram stain with culture,

crystals

Knee: WBC >1,700 or neutrophil >65%

Early post-op TKA: WBC >27,800 or neutrophil >89%

Hip: WBC >4,200 or neutrophil >80%

With osteoarthritis, WBC ,2,000 and neutrophil <50% have high PPV for absence of infection

Culture positive ~90% with PJI Keep off antibiotics for >14 days

prior to surgery

Osman DR et al. Diagnosis and management of prosthetic joint infection: Clinical practice guidelines by the Infectious Diseases Society of America. CID 2013; 56: e1-e25.Trampuz A et al. Sonication of removed hip and knee prosthesis for diagnosis of infection. N Engl J Med 2007; 357: 654-663.

Treatment

Obtain specimens for culture first (no preoperative antibiotics) Empiric therapy

Vancomycin + Cefepime or Pipercillin/Tazobactam, or Meropenem

Change antibiotics when pathogens are isolated with known susceptibilities

Course of 4-6 weeks of IV antibiotics or highly bioavailable oral antibiotic

May need chronic oral antibiotic suppression

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Septic Arthritis

Causes Hematogenously acquired (70%)

Inoculation from trauma, osteomyelitis, cellulitis, abscess, septic bursitis

Symptoms Typically monoarticular joint pain

Erythema and edema

Warmth

Pain on palpation

Sometimes fevers but can be afebrile

Organisms

Gram positive organisms (~75%) Staphlococci (56%)

Cause: Skin breakdown, cellulitis over site, recent surgery, damaged joint Joint function loss (27-46%)

Streptococci (16%) Cause: bacteremia (66%), polyarticular disease (32%) Risk: splenic dysfunction or splenectomy, DM, cirrhosis

Gram negative organisms (15%) Pseudomonas, E. coli, Proteus, Klebsiella

Risk: Immunosuppressed, GI disorders, IVDU, UTI (50%)

Other (12%)

Long B, Koyfmn A, & Gottlieb M. Evaluation and management of septic arthritis and its mimics in the Emergency Department. Western Journal of Emergency Medicine 2019; 20 (2): 331-341.

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Diagnosis & Treatment

Diagnosis Gold standard: Joint aspiration

WBC >50,000

Culture positive in ~80% of patients

Blood cultures (50-70% positive)

Treatment Surgery to wash out joint

Antibiotics 2-4 weeks S. aureus or GNRs: 4 weeks

Refer if joint aspiration is positive or unable to aspirate joint

Mimics

Gout Can predispose to septic arthritis Check for crystals in synovial fluid

Avascular necrosis Most common in hip Diagnosis by xray or MRI

Cellulitis Lyme disease

Early stages: red macule or papule that expands to form annular erythematous lesion

Late stages: monoarticular arthritis

Malignancy Most common in 10-14 year olds

Osteomyelitis Reactive arthritis

Inflammatory arthritis cause by a culture-proven infection at another site

UTI, GI, respiratory

Rheumatoid arthritis Pain in multiple joints Morning stiffness

Transient synovitis Self-limited, unknown etiology Most common in 3-8 year olds Hip pain, limping, refuse to bear weight

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