ENDOCARDITIS (Arch Intern Med 2009;169(5):463)

History

•  RFs: IVDU, congenital or acquired valvular dz, prosthetic valves, structural heart dz, HD, indwelling venous catheters, cardiac surgery, bacteremia, chronic alcoholism, previous endocarditis

•  Difficult to Dx 2/2 nonspecific sx (lethargy, weak, anorexia, low-grade temp), or negative w/u

Findings

•  Fever (96%), new murmur (48%), CHF (32%), splenomegaly (11%), petechiae

•  Classic physical exam findings

•  Roth spots (2%): Exudative, edematous retinal lesions w/ central clearing

•  Osler nodes (3%): Violaceous tender nodules on toes & fingers

•  Janeway lesions (5%): Nontender, blanching, macular plaques on soles & palms

•  Splinter hemorrhages (8%): Nonblanching, linear, reddish-brown under nails

•  Septic emboli (mitral valve vegetations)

Diagnosis

Evaluation

•  EKG, CBC, Chem, coags; CXR, ↑ ESR/CRP (nonspecific), ≥2 blood cx

•  Typically Staph or Strep species; also gram-negative bacilli, Candida (prosthetic)

•  Echo for vegetations or valve ring abscesses; TEE more sens than TTE

Treatment

•  Hemodynamic stabilization if valve rupture, can present w/ acute pulmonary edema cultures

•  Immediate abx in suspected cases, preferably after blood cultures (see table)

Disposition

•  Admit w/ continuous telemetry & IV abx, ICU if hemodynamic compromise

Pearls

•  Infection of endothelium of heart (including but not limited to valves)

•  Consider cardiac surgery consultation for refractory CHF, fungal endocarditis, recurrent septic emboli, conduction disturbance, persistent sepsis, aneurysm rupture of sinus of Valsalva, kissing infection of anterior mitral leaflet w/ aortic valve endocarditis

•  Mortality w/ native valve dz: ∼25%; prosthetic valve higher

•  Worse prognosis if involves aortic valve, DM, S. aureus (30–40%)

•  Left-sided endocarditis (mitral 41%, aortic valve 31%) most common

•  IVDU: Tricuspid valve endocarditis; rheumatic valve dz: Mitral, then aortic valve

ABSCESS

Approach

•  ↓ activity of infiltrated local anesthetic agents b/c of the low pH of abscess area; consider regional nerve or field blocks + IV procedural sedation/analgesia

•  Gram stain & wound cx rarely necessary for skin or perirectal abscesses

•  Cx from intra-abdominal, spinal, or epidural abscesses usually sent from OR to guide therapy

•  Pharyngeal abscess cx can also help tailor antibiotic therapy

•  In diabetic, immunocompromised, w/ systemic sxs, septic, obtain labs & blood cultures, start IVF & abx & admit for IV abx

SOFT TISSUE

Cutaneous Abscess (Clin Infect Dis 2005;41(10):1373)

History

•  ↑ pain, tenderness & induration, usually w/o h/o fever or systemic tox

•  Disruption of skin from trauma or penetrating injury, often pt cannot recall injury

•  H/o IVDA/skin popping, prior MRSA abscesses

Findings

•  Exquisitely tender, soft, fluctuant mass surrounded by erythema

•  Most commonly Staph species, often polymicrobial

Evaluation

•  Blood work rarely needed unless appear systemically ill; US may help w/ localization

•  Culture from abscess only if tx w/ abx, severe infection, systemic illnesses, failed initial tx

Treatment

•  No abx indicated in healthy hosts unless cellulitis, fever, immunosuppression, failed I&D

•  I&D w/ regional nerve or field block ± procedural sedation

•  Create elliptical incision to prevent premature wound closure

•  Break up loculations in abscess cavity w/ hemostat

•  Consider irrigate & pack w/ 1/4-in gauze × 48 h (24 h if cosmetically important)

•  If surrounding cellulitis, nafcillin 2 g IV q4h, cefazolin 1 g IV q8h, or cephalexin PO

•  If for complicated abscess: Clindamycin, Bactrim, tetracycline, linezolid, vancomycin

Disposition

•  D/c w/ wound care instructions, 2-d f/u

•  Warm soaks TID × 2–3 d after removal of packing to allow continued wound drainage

Pearl

•  Can develop essentially anywhere: Furuncle, acne, skin breakdown, insect bites

•  Routine packing of abscesses after I&D is controversial

Paronychia

History

•  Pain & swelling lateral to nail edge; superficial infection of epithelium

•  No inciting injury but can be secondary to contaminated nail care instruments or trauma

Findings

•  Purulent collection lateral to nail bed w/ minimal surrounding erythema

•  Most commonly Staph or Strep species but can have mixed aerobic & anaerobic flora

Evaluation

•  No labs necessary

Treatment

•  No abx indicated in healthy hosts

•  Digital block w/ 1% lidocaine with or without epinephrine in each web space of affected digit

•  #11 blade scalpel to lift cuticle from nail on affected side & express purulent material

Disposition

•  D/c w/ wound care instructions, 2-d f/u

•  Warm soaks to finger TID × 2–3 d to allow complete drainage

Pearls

•  Often h/o manicure/pedicure, nail biting

•  If recurrent or chronic paronychia, consider Candida infection

•  May spread to pulp space of finger (felon) or deep spaces of hand, tendon if neglected

Pilonidal Cyst

History

•  Painful, tender abscess in alar cleft, often in obese or hirsute individuals

•  More prevalent in males; fever & systemic tox very rare

Findings

•  Painful, localized abscess in natal cleavage/midline sacrococcygeal region, 4–5 cm posterior to anal opening; surrounding erythema & fluctuance

•  Mixed flora: Staph or Strep species, anaerobic cocci, mixed aerobic & anaerobic flora

Evaluation

•  No labs necessary unless systemically ill

Treatment

•  Same as for cutaneous abscess, I&D

•  Surgical referral for excision of follicle & sinus tract after acute episode subsides

Disposition

•  D/c w/ wound care instructions, 2-d wound care f/u

Pearls

•  High recurrence rate (40–50%) unless follicle surgically removed

•  Thought to be caused by hair penetrating into subcutaneous tissues creating abscess

Bartholin Gland Cyst/Abscess

History

•  Severe localized pain in labia caused by obstructed Bartholin duct

•  Difficulty walking & sitting secondary to pain

•  Fever & signs of systemic tox are rare

Findings

•  Painful, tender, cystic mass on inferior lateral margin of vaginal introitus, often w/ purulent drainage from sinus tract

•  Typically anaerobes, MRSA, also Staph, Strep, & E. coli species, chlamydia, gonorrhea

Evaluation

•  Culture for chlamydia, gonorrhea

Treatment

•  I&D through mucosal surface, place Word catheter ×48 h

•  Sitz baths TID for the 1st 2–3 d to assist drainage

•  Gyn f/u for consideration of marsupialization to prevent recurrence

Disposition

•  D/c w/ wound care instructions, 2-d wound care f/u

Pearl

•  Recurrence rate still 5–15% after marsupialization; consider gyn malignancy

PERIRECTAL Abscesses (Int J Colorectal Dis 2012;27:831)

History

•  Pain & swelling in rectal area w/ defecation & often w/ sitting down or walking

•  High fever & signs of systemic tox are rare

•  Pts often have h/o Crohn dz, obesity, DM, or PID

Findings

•  Rectal exam essential to ensure abscess localized outside of anal sphincter & to identify upper extent of abscess

•  Typically E. coli species, Enterococcus, Bacteroides species, S. aureus, MRSA

Evaluation

•  Lab studies unnecessary unless systemically ill

•  DM or immunocompromised should have Chem, CBC

•  CT/MRI if concern for intersphincteric or supralevator or postanal abscess or fistula

Treatment

•  ED I&D of superficial abscesses outside the anal verge w/ visible indurated area

•  Pain control; I&D extremely painful, procedural sedation often needed

•  If abscess is only identified on rectal exam & no induration visible, refer to surgery for I&D under general anesthesia

•  DM or immunocompromised pts should undergo I&D in OR to ensure full drainage

•  Pack w/ Vaseline gauze ×48 h, Sitz baths TID for 1st 2–3 d to assist drainage

•  No abx for healthy host w/ superficial abscess

•  Consider abx for immunocompromised, prosthetic device/valve, incomplete I&D

•  Levofloxacin 500 mg QD (ampicillin 1 g + gentamicin 80 mg q8h) + metronidazole 500 mg q8h, consider vancomycin

Disposition

•  D/c w/ wound care instructions, 2-d wound care f/u

•  Admit diabetic & immunocompromised for IV abx

Pearls

•  35–50% treated w/ I&D or spontaneous drainage will develop chronic anal fistula

•  Bilateral tenderness raises possibility of “horseshoe” abscess

INTRACRANIAL ABSCESS

History

•  Caused by contiguous spread (sinus, ear, dental), hematogenous seeding from distant infection, (endocarditis) or post-CNS surgery/penetrating trauma

•  HA (70–90%), fever (50%), meningismus, photophobia, sz (30%), vomiting (25–50%), AMS

•  Subacute time course (vs. meningitis or encephalitis)

Findings

•  Focal neuro deficits, low-grade fever, obtundation (mass effect), sz, AMS, nuchal rigidity (25%), papilledema (10–50%)

•  Wide variety of organisms depending on method of entry, 1/3 polymicrobial

Evaluation

•  Blood cultures, CBC (WBC nonspecific), Chem, coags

•  CT scan w/ & w/o IV contrast; MRI more sens for cerebritis, posterior fossa lesions

•  CSF findings nonspecific, avoid LP

Treatment

•  Emergency neurosurgical consult for drainage in OR; airway management, sz tx

•  Early IV abx w/ good CSF penetration, tailored to likely pathogen

•  Start broad-spectrum IV abx: Ceftriaxone 2 g + vancomycin 1 g + metronidazole 500 mg

•  Corticosteroids ONLY for tx of cerebral edema: Decadron 10 mg IV × 1 then 4 mg q6h

Disposition

•  Neurosurgical intervention for operative washout, 6–8 wk IV abx then 4–8 wk PO abx

Pearls

•  Mortality 24–27%, unless abscess ruptures into ventricular system (mortality 80%)

•  Morbidity from residual neuro deficits, new sz from scar tissue or neuropsych Δ (50%)

SOFT TISSUE INFECTIONS

Approach

•  Careful hx, associated sxs (V/D, cough, abd pain, AMS), progression

•  Check blood sugar if diabetic

•  Assess VS for significant abnormalities that may indicate serious infection (↓ BP, ↑ HR)

•  If immunosuppressed (HIV/AIDS, elderly, malnourished, chronic steroids) or neutropenic, more intensive eval & testing: CBC, Chem, UA & cx, CXR; consider blood cx & admission

•  If recent foreign travel: Consider travel-related infectious etiologies

DERMATOLOGIC

Cutaneous/Subcutaneous Cellulitis (Clin Infect Dis 2005;41(10):1373)

History

•  Often no h/o broken skin; ± local trauma, recent surgery, FB

•  May report fever, chills, malaise

Findings

•  Warm, blanching erythema & tenderness to palpation, mild to moderate swelling

•  ± distal skin disruption (eg, tinea pedis b/w toes w/ cellulitis of anterior shin)

Evaluation

•  If elevated BS, check Chem, UA; Rule out abscess clinically or with bedside ultrasound

•  Consider blood cultures, CBC w/ differential, chemistries, CRP, CPK in systemically ill pts

•  Bacterial cultures of inflamed area not indicated; only 10–50% positive

•  Most often caused by Strep or S. aureus (including MRSA); can be from metastatic seeding

Treatment

•  If LE cellulitis, recommend rest & elevation × 48 h, crutches if needed

•  PO abx: cephalexin 500 mg PO QID, dicloxacillin 500 mg PO QID, or Augmentin 500 mg PO TID

•  IV abx: Cefazolin, ceftriaxone, nafcillin

•  If PCN allergic: clindamycin 500 mg PO QID, or azithromycin 500 mg PO × 1, then 250 mg PO × 4 d, levofloxacin 500 mg QD × 5 d

•  If diabetic or immunocompromised, use broader coverage abx

•  Consider MRSA coverage: Vancomycin, gentamicin, tetracyclines, Bactrim, rifampin, Daptomycin, linezolid

•  Pain control w/ NSAID/APAP; if severe pain consider necrotizing infection

•  Wound débridement if infected, contaminated or devitalized wound

•  Surgery consult if aggressive/necrotizing infection/gas in soft tissue

Disposition

•  D/c w/ PO abx & 24–48 h f/u, strict return instructions

•  Admit if signs of systemic infection, DM, immunocompromise, failure of outpt tx

Pearls

•  Due to inflammation of dermal & subcutaneous tissue due to nonsuppurative bacteria, infection does not involve fascia or muscles

•  Consider Doppler vascular studies in single limb w/ diffuse swelling, posterior calf or medial thigh to rule out DVT

•  Mark border w/ permanent ink, write time & date

Erysipelas

History

•  Extremes of age, obesity, DM, CHF, postop, nephrotic syndrome at higher risk

•  Acute onset pain, erythema, induration

•  Initial fever & chills followed by painful rash 1–2 d later

•  May have systemic sxs: Myalgias, arthralgias, nausea, HA

Findings

•  Skin painful superficial, indurated, raised; erythema w/ sharply demarcated border

•  Irregular erythema w/ lymphangitis, may see desquamation, dimpling, vesicles, LAD

•  70–90% found on lower extremities, 5–20% on face, 5–6% on upper extremity

Evaluation

•  None indicated unless toxic appearing

Treatment

•  PCN G, amoxicillin, cefazolin 1 g IV q8h or azithromycin 500 mg PO

•  PCN allergic: Azithromycin, clindamycin, levofloxacin

Disposition

•  D/c w/ PO abx & analgesics, elevate affected area, 24–48 h f/u, strict return instructions

Pearls

•  Typically caused by group A β-hemolytic streptococcus; involves dermis, hypodermis, & lymphatics

•  More superficial than cellulitis

•  Recurrence rate 10–40%

Staphylococcal Scalded Skin Syndrome (SSSS) (Am J Clin Dermatol 2003;4(3):165)

History

•  Young children <5 yr, rare in adults, fairly rapid progression of prodromal sore throat, conjunctivitis, fever, malaise to painful red skin w/ sloughing

Findings

•  No mucous membrane involvement (vs. TEN)

•  Erythematous cellulitis followed by acute exfoliation: Bullae, vesicles → large sheets of skin loss resulting in scalded-appearing skin

•  General malaise, fever, irritability, tenderness to palpation, does not appear severely ill

Evaluation

•  None indicated unless systemically ill

•  Positive Nikolsky sign (epidermis separates when pressure applied)

Treatment

•  Similar to burns (IVF, topical wound care, burn consult)

•  Most recover w/o abx but still recommended: Nafcillin, vancomycin, clindamycin

Disposition

•  Admit for burn care, IVF; consider ICU

Pearls

•  Caused by exfoliative exotoxins of S. aureus, reports of MRSA

•  Separation of epidermal layers vs. more severe TEN (necrosis at level of basement membrane)

•  Prognosis: Children (4% mortality) often w/o significant scarring; adults (60% mortality)

Toxic Shock Syndrome (TSS)

History

•  Multiple sxs: Prodrome, pain at site of infection (out of proportion to findings), fever, chills, N/V, abd pain, watery diarrhea, myalgias, arthralgias, pharyngitis, HA, AMS

•  Recent surgery, infrequently changed packing (tampons, nasal packing)

Findings

•  Clinical Dx w/ findings from all organ systems:

•  Temp >38.9°C, ↓ BP (shock/hypovolemia), rash

•  “Sandpaper” diffuse, macular rash initially on trunk → spread to arms, legs, palms, soles → flaking full-thickness desquamation, 5–12 d after onset

•  Involvement of 3 organ systems (see table)

Evaluation

•  CBC w/ differential, Chem, UA, LFTs, coags, cultures (blood, urine, throat)

Treatment

•  Remove tampon or packing if still in place, drain abscesses if present; burn care

•  Aggressive resuscitation, pressors if needed, Foley catheter to monitor urine output

•  Abx, may not have impact (toxin-mediated process); tx any identified source

•  Nafcillin, vancomycin, clindamycin to suppress bacterial toxin synthesis; linezolid

•  High-dosed steroids reported to improve TSS in case reports

•  IVIG 400 mg/kg IV (has antibodies to TSS-1 & other exotoxins) for very ill pts w/ pulmonary edema or who require mechanical ventilation may reduce mortality

•  Surgical consult if debridable sources of infection

Disposition

•  ICU admission

Pearls

•  Rate ↓ w/ ↓ in use of superabsorbent tampons

•  Caused by inflammatory response to TSST-1 enterotoxin from Strep & Staph species

•  Strep: Usually after surgery or trauma; scarlet fever-like rash; 30–70% mortality, fulminant

•  Staph: More indolent, 5% mortality

•  Poor prognosis, mortality as high as 70%, 30–50% recurrence, most w/i 2 mo

Necrotizing Fasciitis

History

•  H/o mild trauma, often diabetic, PVD, EtOH abuse or nutritionally compromised

•  Sudden onset of pain & swelling which progresses to anesthesia

Findings

•  Fever, tenderness, erythema, toxic appearing

•  Pain out of proportion to exam &/or numbness, crepitus

•  Rapidly spreading, progressive erythema/infection of deep fascia w/ secondary necrosis of subcutaneous tissues, subcutaneous air (due gas-forming organisms)

•  Can progress to involvement of deeper layers, causing myositis or myonecrosis

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