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Infectious Diseases Pearls

Infectious Diseases Pearls. Randall S. Edson, MD, MACP Professor of Medicine Mayo Clinic College of Medicine Internal Medicine Program Director, CPMC San Francisco, CA. Disclosures, etc. No financial disclosures or discussion of off-label drugs, etc. Coming clean…………………….

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Infectious Diseases Pearls

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  1. Infectious Diseases Pearls Randall S. Edson, MD, MACPProfessor of Medicine Mayo Clinic College of Medicine Internal Medicine Program Director, CPMC San Francisco, CA

  2. Disclosures, etc • No financial disclosures or discussion of off-label drugs, etc.

  3. Coming clean…………………….. • Went through express lane with > 12 items • Forgot to return shopping cart to corral on one occasion • Deliberately avoids using the stairs at all costs, despite ubiquitous signage and propaganda

  4. Public Service Announcement

  5. Learning objectives • Recognize important travel-acquired infections • Understand the approach to the diagnosis of LTB • Diagnose CNS infection based on pattern recognition • Review updated guidelines for UTI management • Diagnose a mystery rash

  6. 25 yr old ♂ with three week history: fever, sore throat, fatigue, sweats. Grad student; just returned from 3 week trip to Southern Africa. Ate local food, swam in fresh water, took brief course of ciprofloxacin for traveler’s diarrhea Exam: Appears ill; T 38.80; oral ulcers, exudative pharyngitis, post-cervical nodes, rash rash Lab: HCT 38%; WBC 12,000(↑lymphs, “atypical”); mild ↑AST; Mono spot neg; HIV Ab negative

  7. Which of the following would most likely establish diagnosis? • EBV serology • CMV serology • Dengue serology • PCR for HIV RNA • Rickettsia africae serology

  8. Acute HIV: Don’t miss!!! • Occurs in 30-50% of HIV-infected patients • “Hyper-transmitters” with formidable viral load • Should be suspected in sexually active patients with prolonged “mono” syndrome • Negative HIV antibody common (too early) • Order PCR/quantitative HIV test Ann Int Med 1996;125:257 NEJM 1998;339:33

  9. Symptom onset within 2 weeks of acquisition • Peak viremia • 10 fold + ↑ risk of transmission JID 2010:202(Suppl 2):S270

  10. What’s in your travel kit?? >50,000 new cases of HIV/year in US

  11. STD in Returning Travelers Casual sex: 5-51% of short term travelers, ↑ among long term travelers Meta analysis: 20% have casual sex abroad;50% unprotected* Not usually addressed in pre-travel consults * Intern J of Inf. Dis 2010;14(10):e842-51 CID 2001;32:1063 J Travel Med 2009;16:79

  12. Distribution of STD’s in ill travelers:1996-2010 Geo Sentinel Surveillance database; Lancet ID 2013;13:205

  13. Pre-employment evaluation • 28 yr. old ♀respiratory tech about to begin work at your hospital • Mild asthma, controlled with occasional albuterol; otherwise healthy • Immigrated to US from Philippines 3 years ago • Cervical cytology, all adult immunizations current; received BCG as a child

  14. Your hospital requires screening for LTB Which of the following would be the most appropriate screening test for latent TB? • Chest x-ray • Interferon-γ release assay • PPD(5 TU) • PPD(10 TU)

  15. TB and Latent TB • 1/3 of world population infected with TB • Latent TB develops in ≈ 30% exposed • Estimated cases of LTB in US ≈11 million • Lifetime risk of reactivation 5-10% • Most clinical TB in US occurs in immigrants from high prevalence countries Herrera et al.Clin Inf Dis 2011;52(8):1031

  16. Screening options for Latent TB* TST(PPD) Interferon γ release (IGRA) assays • QuantiFERON®-TB Gold (QFT-GIT) • T-SPOT®. TB test (T-Spot) • Mechanism of action • Patient’s WBC + MTB antigens: ↑ γ-IFN * Targeted screening only for those at highest risk

  17. Pros Cons IGRA • Single visit • Results in 24 hours • Not affected by BCG • Minimal cross-reactivity with other mycobacteria • Circumvents technical “challenges” of PPD administration, interpretation • Must process in 8-30 hrs. • Limited data: children < 5, immunosuppression, recent exposure • ↑False + in low prevalence* *Chest 2012 Jul 1;142:55 and 10

  18. When to use IGRA? • Most situations where PPD is used • Patients not likely to return at 48-72 hours • Foreign born patients who received BCG Both TST and IGRA may be used: • Foreign-born HCW who attribute + PPD to BCG • Initial test negative in high risk patients • “Tie breaker” in low risk patients with + test MMWR 2010;59(RR-5):1-25

  19. Game changer in the treatment of latent TB 900mg INH plus 900mg of Rifapentine once weekly for three months Equally effective as 9 months of daily INH ≈ $40 total Perfect situation for Directly Observed Therapy (DOT) Rifapentine is expensive: ≈ $325 for 3 month course

  20. 55 yr. old ♂ farmer with fever and confusion • 8/2012: difficulty with concentration, spatial perception; co-workers noted distraction and trouble with word finding. Day 2: severe HA • DM2, s/p bariatric surgery, hypertension • Sexually active, farms and road maintenance Exam: T 38.50; drowsy; mild neck stiffness CSF: WBC 165 cells/µL(mostly lymphs) Protein 150 mg/dL; glucose 61mg/dL Gram stain: no organisms seen

  21. Develops significant weakness and cog-wheeling several hours later Which one of the following tests would most likely establish the correct diagnosis? • MRI of head with gadolinium • CSF PCR for Herpes simplex virus • CSF IgM for West Nile virus • CSF serology for enterovirus

  22. 4891 cases, 2293(51%) Neuro-invasive, 223 deaths; 70% from 10 states; highest number to date since 2003

  23. Unintended consequence of foreclosure

  24. WNV transmission, life cycle Hi, I’m Culex sp.

  25. West Nile Virus 101 Flavivirus St Louis Encephalitis; Yellow fever; JE Acquisition: mosquito, transfusion, transplant Peak incidence: Late August, early September Incubation: 2 to 14 days 80% asymptomatic • 20% WN fever; < 1% Neuro-invasive

  26. When to suspect West Nile infection • Mosquito season(especially August) • West Nile fever is nonspecific: fever and HA • Characteristic features of neuro-invasive disease • Acute flaccid paralysis • Parkinson-like symptoms • 10% mortality with neuro-invasive disease • Profound, prolonged fatigue may persist for a year JAMA 2003;290:511 and Lancet Inf. Dis 2002;2:519 Am J Trop Med Hyg 2012:87:179 Annals of Int Med 2008;149:232

  27. Diagnostic time course of West Nile Virus Serum or CSF IgM best diagnostic test IgM antibodies may persist for a year www.mayomedicallaboratories.com/articles/communique/2008

  28. A 20 yr old female college student with a 2 day history of dysuria, urgency and frequency in the absence of fever, chills, vaginal irritation or discharge; she has had two previous UTI’s this year, most recently 3 months ago and received three days of TMP/SMX with resolution. • What would you do next? • Obtain urine for gram stain and culture • Prescribe trimethoprim-sulfa for 3 days • Prescribe amoxicillin for 3 days • Prescribe nitrofurantoin 5 days • Prescribe ciprofloxacin for 3 days

  29. When words fail……………

  30. NEJM 2012;366:1028-37 and Clin Inf Dis 2011;52(5):e103-e120

  31. Key facts in UTI management • E.coli increasingly resistant to TMP/SMX, FQ • Avoid TMP/SMX if local resistance is ≥ 20% or used w/n last 3 months • Avoid FQ if local resistance is ≥ 10% Mayo Antibiogram 2011

  32. More key facts in UTI management Do not treat asymptomatic bacteriuria(AB) even with pyuria except: Pregnancy; post renal transplant Prior to urologic instrumentation Unintended consequences of AB Rx ↑ frequency of subsequent symptomatic UTI1 Asymptomatic bacteriuria may be “protective” Alarming increase in community-acquired multidrug resistant E. coli 2 1ClinInfect Dis 2012;55:771 2Mayo Clin Proc 2012;87(8):753

  33. Antimicrobial Cost Considerations $4 for TMP/SMX and Cipro1

  34. Bottom line in UTI management • Alarming increase in antimicrobial resistance among community-acquired E. coli • Treatment guidelines reflect this resistance • Nitrofurantoin, TMP/SMX, Fosfomycin are top 3 choices • DO NOT screen for and/or treat AB

  35. 67 yr old man with a rash • Developed painless nodular, pustular rash 2 weeks ago • Did not respond to several oral antibiotics and five infusions of vancomycin • Swab culture: rare Pseudomonas fluorescence • Treated with ciprofloxacin without improvement Examination • Vital signs normal, afebrile • Rash on dorsum of left forearm

  36. What would you do next? • Begin anti-mycobacterial Rx • Start trimethoprim-sulfa for suspected Nocardia • Start antifungal Rx • Send to Derm for biopsy

  37. Most likely diagnosis? • Squamous cell carcinoma • Blastomycosis • Nocardiosis • Non-tuberculous mycobacterial infection • Dermatophyte

  38. Additional history • 5 days before rash onset cleared brush, had exposure to mud, thorns; recalls many scratches, wearing short-sleeve shirt • Has cattle, dogs, cats

  39. Results of biopsy/culture Lab reports growth of Trichophyton verrucosum Majocchi’s granuloma Deep folliculitis due to dermatophyte infection Can be transmitted from cows, horses to humans

  40. Trichophyton verrucosum

  41. Clinical bottom line • The occupational and exposure history can be critical in broadening the differential diagnosis

  42. 56 year old ♂ with chronic cough, sweats • 3 month history of productive cough, sweats, weight loss. No response to several AB courses • PMH: MS, COPD • SH: divorced, disabled miner; 50 pack year smoking history; former daily marijuana smoker, now using marijuana “chocolates.” Lives in wooded area of Michigan’s UP • Recently moved into old house with obvious mold; spent several weeks using leaf blower; several local dogs ill with respiratory symptoms

  43. MBF

  44. Malignancy suspected; second opinion sought Physical examination • Appears cachectic(“hunter-gatherer diet”) • Afebrile • Many missing teeth and periodontal disease • Few rales at right lung base CBC, electrolytes, etc. all normal

  45. CT chest, 2/20/2013

  46. Bronchoscopy done on 2/20/13 • Mucopurulent secretions noted in right lower lung. • A diagnostic result was received……..

  47. Direct smear from BAL fluid

  48. What is the most likely diagnosis? • Bronchogenic CA with post-obstructive pneumonia • Mixed aerobic/anaerobic pneumonitis • Pulmonary blastomycosis • Pulmonary nocardiosis

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