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Board Review

Board Review. Infectious Diseases. Exposure History. Southwest US: Coccidioidomycosis Midwest US: Histoplasmosis Parrots/exotic birds: Psittacosis Cat : Pasteurella, Toxo-, Bartonella Rats: Plague, Lepto, Hanta- Pigeons: Cryptococcus.

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Board Review

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  1. Board Review Infectious Diseases

  2. Exposure History • Southwest US: Coccidioidomycosis • Midwest US: Histoplasmosis • Parrots/exotic birds: Psittacosis • Cat : Pasteurella, Toxo-, Bartonella • Rats: Plague, Lepto, Hanta- • Pigeons: Cryptococcus

  3. Exposure History • Turtles/Iguanas Salmonella • Ticks RMSF, Lyme, Ehrlichia, Babesia • Rabbits Tularemia • Shellfish Vibrio, Hepatitis A • Sheep/Cattle Q fever • Goat Cheese Brucella • Hamburgers E Coli 0157

  4. Exposure History • Antibiotic use C. difficile • Hot tub Pseudomonas folliculitis MAC pneumonitis • Showers Legionnaires • Gardening/Roses Sporothrix • Mosquitoes Malaria, Arboviruses, West Nile Virus • Chicken coop Histoplasma

  5. Viral Infections

  6. West Nile Virus • Culex Mosquito Bite • Cases: transfusion, organ transplant • Peak time in August • Usually a non-specific febrile illness • 1/150: Meningitis, encephalitis, flaccid paralysis • CSF: lymphocytic predominance • Dx: IgM+ serum&CSF; PCR CSF • May have elevated lipase • Tx: Supportive • ?interferon alfa 3N, ?IVIG • Deaths in elderly, diabetics • Long-term neuropsych complaints • Prevention: DEET; no vaccine

  7. Rabies • History of a bite • Incubation 20-90 days (as long as 20 yrs) • Symptoms: • Local parasthesias • Encephalitis • Hydrophobia, Aerophobia • Death: Clinical disease is always fatal • Tx: Supportive; avoid transmission via saliva

  8. Clinical Rabies

  9. Clinical Rabies

  10. Rabies: Diagnosis • Suspect clinically • Confirmation: • Brain examination • Skin biopsy at nape of the neck • Techniques: • Histopath: Negri bodies • DFA • Reverse transcription polymerase chain reaction (RT-PCR) - saliva, CSF, or tissue

  11. Negri Body

  12. DFA

  13. Rabies: Treatment • Clinical Disease: • None confirmed • Case in St. Louis treated with induced coma, ribavirin • Coenzyme Q10, l-arginine, and vitamin C also were administered in an attempt to replenish neurotransmitter substrates MMWR, December 24, 2004 / 53(50);1171-1173

  14. Rabies: Treatment • Before clinical disease: • Post-exposure: • Vaccine and HRIG (HRIG only if no hx of vaccination) • HRIG: 1/2 at wound & 1/2 IM • Vaccine at a different site • Cleanse wound • Pre-exposure: • Rabies vaccine in 3 shots for those at risk- vets, spelunkers, 3rd world travelers for >3mos • Following animal bite give 2 boosters

  15. RabiesPost-exposure Prophylaxis • Animal bites • Bats, raccoon, fox, skunk, coyote: treat with rabies vaccine & HRIG (different sites) • Domestic cat/dog: observe for 10 days or brain examination; hold therapy unless evidence that animal is rabid • Other animals: livestock, squirrels, rodents, rabbits, chipmunks, hamsters- almost never rabid; therapy generally not recommended; check with P.H.

  16. Bats • Most common animal exposure associated with rabies in the US • Most patients DO NOT recall a bite • Simply exposure to a bat without actual evidence of a bite should be treated • Finding a bat in the room of a child should be treated

  17. Bite Management • Consider the need for tetanus immunization • Leave the wound open; avoid sutures or wound closure • Consider antibiotics for prevention of wound infection (Augmentin, Unasyn)

  18. Herpesviruses • VZV • HSV 1 and 2 • CMV • HHV6 • HHV8

  19. Antivirals for Herpes • Acyclovir, valacyclovir, famciclovir, penciclovir • Valtrex most bioavailable • Risks: nephrotoxicity, seizures (with incr Cr), TTP/HUS with high doses of valtrex in HIV patients • Resistance: decreased thymidine kinase activity • Idoxuridine, trifluridine; flomivirsen • Topical; HSV keratitis; flomivirsen for CMV retinitis • Ganciclovir • Side effects: kidney dysfunction, neutropenia • Foscarnet • Does not require thymidine kinase • Kidney function, electrolytes • Cidofovir • Nephrotoxic

  20. Varicella zoster virus • Chickenpox & shingles • Transmission: • Respiratory secretions/direct contact • Incubation: • 9-21 days • Hence med student who is VZV neg and is exposed to case, should avoid work from days 9-21 especially if working in heme/onc ward

  21. VZV • Adults with chickenpox • Higher risk for PNA, hepatitis, and encephalitis • Tx: adults (>12 yrs): acyclovir 800 mg 5x/d x 7 days • Administer within 24 hrs of rash • Decreases symptoms x 1 day • Complicated disease, immunocompromised, 3rd trimester: use IV acyclovir 10 mg/kg q8 for 5-7 d • DX: clinical; IFA or culture of lesion • VZV negative adults should receive varicella vaccine • Pregnant women and immunocompromised s/p exposure: give VRIG within 96 hours; some would also begin acyclovir

  22. Chickenpox

  23. VZV • Shingles • Vesicles in dermatomal pattern • DX: clinical; can perform IFA / cx of lesion • TX: antiviral (Valtrex) within 72 hrs (esp. in age>50, severe pain, or facial/eye involvement) • Speeds initial recovery; no data on PHN effect • Steroids: controversial; decreases acute pain • PHN: big issue; esp age>50 yrs • Try local tx, pain meds, elavil, anti-seizure meds • Immunocompromised with >1 dermatome: IV acyclovir • Vaccination of elderly: • ZOSTAVAX is indicated for prevention of shingles in individuals >60 years

  24. Shingles Herpes viruses resistant to acyclovir are treated with foscarnet

  25. HSV1/2 • Orolabial • 1 day of valtrex • ACV for 5-7 days • Healing 1 day faster • Genital • Valtrex for 3 days • ACV for 7 days • Other: Herpes gladiatorum (wrestlers), whitlow (HCW) • Treat with any of the 3 agents • Keratitis: oral agent plus topical • CNS or immunocompromised with widespread disease • IV Acyclovir • Resistant herpes: foscarnet • Prophylaxis: > 6 episodes/year: ACV 800 po daily

  26. Cytomegalovirus • Retinitis • AIDS patients CD4<50 • Valganciclovir, fomivirsen • Disseminated disease • Transplant patients, HIV patients • Colitis, pneumonia, etc. • Pp65 antigenemia, PCR positive • Tx: valganciclovir or iv ganciclovir

  27. Smallpox • Variola virus; last case in 1978 in Somalia • Recent threat is due to bioterrorism • Group of patients seeking care for unexplained skin lesions, sepsis, respiratory illness, etc. • Clinical: • Oral enanthem occurs 1st • Vesicles beginning on face and spread distally to legs/arms including palms/soles (trunk is relatively spared) • Lesions are firm, nodular • All lesions in the same stage of disease • Incubation - 14 days • Diagnosis: fluid from vesicle

  28. Smallpox • Tx: Supportive • Consider cidofovir • Vaccination if within 4 days of exposure • Mortality - 30% • Prevention: • Glove/gowns/mask in isolated negative pressure room • Vaccinate contacts within 4 days of exposure • Consider specific immune globulin for contacts who cannot receive the vaccine • Pre-exposure vaccination: avoid in immunocompromised, pregnancy, ezcema

  29. Smallpox

  30. Smallpox

  31. Eczema vaccinatum “Smallpox shot infects soldier's toddler son Boy critically ill; mom also stricken” Treatment: vaccinia immune globulin, or VIG. He also received cidofovir and the experimental drug ST-246

  32. Hantavirus Pulmonary Syndrome • Sin Nombre virus • Four Corners/Southwest US • Exposure to rodents (Peromyscus-deer mouse) via inhalation of saliva/excreta • Acute fever, HA, cough, low platelets and non-cardiogenic pulmonary edema, leading to respiratory failure

  33. Hantavirus Pulmonary Syndrome • Dx: IFA of sputum or serology • Clues to Dx: • Hemoconcentration • Low Platelets • Immunoblasts on smear • Tx: Supportive; 40% mortality • No evidence for the use ribavirin

  34. Influenza • Winter months • Incubation: 48 hrs • Sxs: Fevers, headache, pharyngitis and severe body aches • Signs: conjunctivitis, nasal d/c, pharynx inflammation • Secondary infections: Strep pneumoniae or Staph aureus (MRSA)

  35. Influenza • Children: Reye’s Syndrome (Avoid ASA) • Dx: • Clinically with local influenza activity • Confirm dx with rapid testing (culture takes too long) • Tx: -Symptomatically

  36. Influenza • Antiviral therapy: • Give <48 hours of onset, fever/cough, known community cases • Reduces symptom duration by 50 % (1-2 days) • Medication Choices: • Amantadine and rimantadine: only for type A • Side effects: insomnia, anxiety, change MS, not in pregnancy • Rimantidine – less side effects and better efficacy • Amantidine – adjust dose if CrCl<50 • Rimantidine – adjust dose with liver dysfunction

  37. Influenza • Treatment cont. • Neurominidase inhibitors: • Effect against types A, B and avian H5N1 • Oseltamivir (oral) – may cause GI side effects • Zanamivir (inhaler)- may induce bronchospasm • Useful for both influenza A & B • Treat for 5 days

  38. Influenza Prophylaxis • Influenza in community and unvaccinated person- • Give short course of antiviral medication • Influenza in a nursing facility • Chemoprophylaxis to all resident for duration of outbreak and for 1 week thereafter • Use of amantidine/rimantidine to treat outbreak cases, use neuroaminidase inhibitor for prophylaxis • Resistance to amantadine/rimantidine can occur within 2-3 days of therapy

  39. Influenza: Prevention • Vaccination indicated for: • >50 years • Chronic medical conditions • Health care workers • Family members of those with med condition • Institutionalized • Pregnancy - 2nd-3rd trimesters during the flu season • Children on chronic ASA

  40. Most cases with direct contact with poultry Symptoms: Typical influenza-like symptoms (e.g., fever, cough, sore throat, and muscle aches) to eye infections (conjunctivitis), pneumonia, acute respiratory distress Treatment: oseltamivir H5N1 Avian Influenza

  41. Severe Acute Respiratory Syndrome (SARS) • Coronavirus • China • Civet cats • Bilateral PNA/hypoxia • Diagnosis: culture • Treatment: ?ribavirin in trials • Positive pressure ventilation

  42. Parvovirus B19 • Child: Fifth’s disease with ‘slapped cheeks’ • Adult • Sickle cell, etc.: aplastic crisis • HIV: chronic anemia • Pregnant: hydrops fetalis • Immunocompetent: arthritis (esp women), rash • Transmission: • Respiratory, blood, congenital

  43. Parvovirus B19 • Dx: • Immunocompetent: serology IgM • Immunocompromised: PCR • BMB: pronormoblasts • Tx: • Supportive • Severe anemia: IVIG • Arthritis: NSAIDS

  44. Acute HIV Infection • Consider in sexually active with ‘mono’ like illness • May have false positive monospot or CMV IgM • Dx: HIV viral load (>10,000) • ELISA may initially be negative • Tx: Consider beginning HAART; no absolute guideline

  45. Viral Transmission • Needlestick Injury • Hepatitis B 30% • Hepatitis C 3% • HIV 0.3% • “Rule of Three’s”

  46. Tick Bites

  47. Ticks • S/p tick bite: • Empiric therapy only in endemic area with observed nymphal partially engorgeddeer tick – doxycycline 200 mg x 1 given within 72 hours of exposure • Otherwise, do not give prophylaxis • Hard Ticks: • Ixodes: Lyme, Babesia, HGE (risk of coinfection) • Dermacentor: RMSF, Tularemia, Tick paralysis • Amblyomma: HME, RMSF, Tularemia • Soft Ticks: • Ornithodoros: Relapsing Fever

  48. Babesia • B. microti • Transmission: • Tick bite by Ixodes dammini • Blood transfusion • Nantucket Island, Martha’s vineyard, Shelter Island, Wisconsin, Washington State • Sxs: HA, fevers, myalgias • Can cause overwhelming infection in asplenic patients

  49. Babesia • Labs: hemolytic anemia, low plts, increased creatinine • Dx: parasites on smear “Maltese cross” • Tx: • Atovaquone and azithromycin (fewer side effects): now the preferred agents • Quinine and clindamycin is the alternate regimen • Severe disease: exchange transfusion

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