INFECTION SPREAD, PART 2: COMMUNITY
| HOT TOPICS IN INFECTIOUS DISEASE —Gregory J. Moran, MD, Clinical Professor of Medicine, Department of Emergency Medicine, Division of Infectious Diseases, David Geffen School of Medicine at the University of California, Los Angeles |
| Reasons infectious diseases emerge: global travel; centralized processing and globalized distribution of food; population movements; increased contact with wilderness habitats; changes in habitats (eg, deforestation); human behaviors (eg, sexual; intravenous drug abuse [IVDA]); increased use of antimicrobials |
| Community associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infection: probably new unique strain that has integrated antibiotic resistance genes and virulence genes; initially manifests as spontaneous folliculitis; patients present with skin abscesses that they refer to as spider bites; MRSA most common cause of skin and soft tissue infections; because of increasing prevalence in community, consider possibility of MRSA in any infection that may be caused by S aureus (in cases of serious infection, have very low threshold for giving vancomycin or other agent active against MRSA); also known to cause pneumonia, endocarditis, septic joints, and invasive blood infections |
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Pneumonia: several recent case series reporting severe necrotizing pneumonias due to CA-MRSA; most often occurs after influenza; average age of patients 21 yr, most previously healthy; mortality rate 29%; while pneumonia due to MRSA not common, important to recognize because of severity of disease; if patient presents with pneumonia severe enough to require admission to intensive care unit (ICU), he or she should be given vancomycin or other drug highly active against CA-MRSA (eg, linezolid) |
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Implications for severe sepsis: most common causative organisms seen in severe community acquired sepsis Escherichia coli, Streptococcus pneumoniae, and S aureus; therefore, empiric therapy for life-threatening infection with sepsis should cover MRSA |
| Clostridium difficile-associated disease: in past, C difficile infection seen only in patients in hospital or on antibiotics; however, like MRSA, starting to see new strains of C difficile emerging, and increasing prevalence of severe C difficile- associated disease in community, often in patients who have not taken antibiotics; while C difficile can just cause bothersome diarrhea that resolves if patient taken off antibiotic, it can also cause pseudomembranous colitis, toxic megacolon, perforated colon, and severe sepsis; characteristics of community-associated C difficile-infection—occurs in patients with no traditional risk factors; strains of C difficile much more potent than those usually seen in hospital or after antibiotics (produce 16 times more toxin A, 23 times more toxin B) |
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Case definition for community-associated C difficile-associated disease: diarrhea; no underlying disease; no health care facility stay \>3 mo; laboratory or pathologic confirmation of C difficile |
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Treatment options: traditional first-line treatment metronidazole, 500 mg tid for 10 days; in patients who do not respond, or who present with severe infection, give oral vancomycin; patients who have toxic megacolon may require surgery (eg, colectomy), or intraluminal vancomycin; avoid antiperistaltic agents; other treatment regimens include probiotics, toxin-binding resins, intravenous immunoglobulin (IVIG), and stool transplantation |
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How clinicians should change their practices: consider C difficile infection in all cases of severe diarrhea (even without traditional risk factors); have low threshold for sending stool for C difficile toxin test; consider giving empiric metronidazole in some cases; remember handwashing (alcohol-based sanitizers do not work because of spores) |
| Infant morbidity and mortality from cough and cold medicines: during 2004-2005 cold season, >1500 children <2 yr of age treated in emergency department (ED) for toxicity related to cough and cold medicines (3 deaths in children <6 mo of age in 2005); many children had high levels of pseudoephedrine; in several cases, children given both prescription and over the counter (OTC) medications; no Food and Drug Administration (FDA)-approved dosing of any cough and cold medications for children <2 yr of age; American Academy of Pediatrics (AAP) recommends against giving these medicines to children <2 yr of age |
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OTC cold products: review of 51 studies from 1950-1991; only 27 met minimal methodology criteria; none showed efficacy in children <5 yr of age; antihistamines (4 of 10 studies showed benefit, only from older drugs, eg, diphenhydramine; speaker thinks efficacy due to anticholinergic side effects); decongestants (4 of 5 studies showed benefit); expectorants (1 study met criteria, and it failed to show benefit); antitussives (no studies adequate to evaluate) |
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OTC cough medications: Cochrane review of studies from 1966-2004 (24 trials; >3000 patients); codeine (no better than placebo); dextromethorphan (mixed results); guaifenesin (mixed results); antihistamine-decongestant combination (mixed results); no studies showed efficacy in children |
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Recommendations: avoid cough and cold medications in children <2 yr of age; warn parents about mixing medications that may contain same ingredients; use bulb suction to manage nasal congestion in very young children |
| Influenza A virus subtype H5N1: first known highly pathogenic avian influenza (HPAI) panzootic; only few cases of human- to-human transmission; however, number increasing annually, and mortality rate high among young healthy people |
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Uncertainties related to H5N1: case mortality rate of virus very high (20 times higher than influenza virus responsible for pandemic of 1918); unknown whether increased transmissibility will result in reduced virulence and mortality; unclear whether increased transmissibility will occur suddenly or gradually; historically, influenza transmitted by asymptomatic or minimally symptomatic patients; unclear whether transmission of H5N1 will be similar |
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Problems: vaccine production capacity limited (1950s technology); currently do not have good vaccine for H5N1; limited supply of antiviral drugs; potential for resistance to antivirals; imperfect surveillance |
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Comments: history of influenza pandemics; assume there will be another influenza pandemic in future, and be prepared; have many tools not available at time of last major pandemic (eg, vaccines, antivirals, ventilators, ICUs), but health care facilities do not have enough of them; models looking at impact of influenza pandemic on hospitals in United States estimate moderate scenario would require 19% of non-ICU beds, 46% of ICU beds, and 20% of ventilators; severe scenario (similar to pandemic of 1918) would require 191% of non-ICU beds, 461% of ICU beds, and 198% of ventilators |
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Priorities for hospital preparedness: establish plan to achieve specific surge capacity, eg, 30% of current capacity; infection control (limit spread of disease in hospital; protect staff from contagion); establish protocols for use of limited antivirals and equipment; make specific plans with realistic, obtainable goals and write out in advance how goals will be accomplished; will probably have to participate in regional plan for providing medical care for “supersurge” of influenza patients; have stockpiles of protective equipment, medications, and basic supplies |
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Current recommendations: incorporate plans into hospital disaster preparedness; test for influenza A in severely ill patients (especially if they have traveled to areas associated with bird flu); notify infection control colleagues; in case of suspected H5N1 infection, have low threshold for contacting local health department (can arrange testing through Centers for Disease Control and Prevention [CDC]) |
| HEALTH ISSUES OF IMMIGRANTS —Patricia F. Walker, MD, Assistant Professor, Division of Infectious Diseases and International Health, University of Minnesota Medical School, Minneapolis |
| Demographics: only ≈0.7% of US population Native Americans (≈99.3% immigrants or their children); in 2000, ≈69% of US population non-Latino white; estimated that by 2050, ≈50% will be communities of color and ≈50% non-Latino white; ≈12% of population foreign born (≈50% recent arrivals [since 1990], and of these, ≈50% from Latin America); between 1990 and 2003, United States received ≈1.2 million refugees; in 2005, Minnesota second only to California in number of refugee arrivals |
| Comments: impact of geopolitical and cross cultural issues on health of immigrants (case example [progression of polio]) |
| Medical screening of new arrivals: Minnesota Department of Health Web site excellent resource (including provider’s guide for refugee health); screen for psychiatric disorders, eg, screen for depression by asking, “have you been feeling sad in the last two weeks?”; detailed patient history highly recommended if time available (focus on infectious diseases, eg, history of tuberculosis (TB), malaria, parasites, hepatitis or sexually transmitted diseases [STDs]); directed review of systems; ask about traditional medicines; question reproductive history in women (ask about female circumcision, eg, “when was your circumcision?” before performing pelvic examination; ≈98% of Somali women in Minnesota circumcised) |
| Physical examination: look for leprosy, eg, anesthetic hypopigmented nodules, evidence of neuropathy; chronic otitis media extremely common in refugee children and adults; much higher incidence of endocarditis and rheumatic valvular disease in many refugee populations; pinching, coining, and cigarette burns good clues to chronic left upper quadrant abdominal pain; scarification (check for hepatitis B) |
| Laboratory screening: urinalysis—especially important in women; for TB—purified protein derivative (PPD) skin tests for patients >6 mo of age; chest x-ray if test >10 mm; characteristics of TB in immigrants—much more common than in general population; seen in younger patients; greater incidence of extrapulmonary TB; more drug resistance; in Minnesota, overall TB infection rate in refugees 40%, in those from sub-Saharan Africa, 51%, and in eastern European and Russian immigrants, 33% (reluctant to be treated because they attribute positivity to bacillus Calmette Guerin [BCG] vaccination in childhood); case examples of extrapulmonary TB; parasitic infection —health care providers often do not do differential screening (ie, screen only one stool specimen, and assume that negative result means patient not infected); also, clinicians tend to ignore mild eosinophilia; overall parasitic infection rate in refugees 15%; pathogenic parasites include whipworm (cause of rectal prolapse in refugee children), hookworm (one of most common causes of iron deficiency anemia worldwide), and Ascaris lumbricoides |
| Strongyloides infection: typically presents as asymptomatic eosinophilia; review of 10-yr data from Regents Hospital (St Paul, MN) found 161 cases (most in southeast [SE] Asian immigrants; 5 cases of disseminated Strongyloides infection, with 3 deaths); study—looked at disseminated Strongyloides infection over 10 yr; found 9 cases (all in SE Asian immigrants; all had received steroids before dissemination; 3 deaths); take-home clinical message—if immigrant patient requires steroids, first check eosinophil count; if count high, consider giving empiric albendazole or ivermectin before (or concurrently with) steroid therapy |
| Differential diagnosis of eosinophilia: depends on patient’s country of origin; eg, must have much higher index of suspicion for schistosomiasis in immigrants of African origin; consider filariasis in patients from India or Africa; older study by Nutman et al looked at 128 patients with eosinophilia unexplained after initial stool analysis, and found that when multiple stool specimens or serologies obtained, pathogenic parasite identified in 95% of cases; speaker no longer tests multiple stool specimens, but treats empirically if patient has eosinophilia but stool negative for parasites; patient can harbor Strongyloides ≥60 yr after leaving country where infection acquired; no matter how long patients have been in United States, check stools for ova and parasites when clinically indicated |
| Differential diagnosis of microcytosis in immigrants: consider iron deficiency, but hemoglobin E and thalassemia common as well; glucose-6-phosphate dehydrogenase (G6PD) deficiency common in patients from SE Asia (35% of Cambodians have hemoglobin E trait); certain drugs can cause intravascular hemolysis (avoid use of sulfonamides, eg, trimethoprim-sulfamethoxazole, in Asians unless absolutely necessary, and screen for G6PD before starting drug) |
| Hepatitis B screening: overall hepatitis B infection rate 9%; check patient’s hepatitis A status; be aggressive in screening family members for hepatitis B |
| Peripheral smears for malaria: question whether new refugee arrivals should be screened for malaria; initial screen done only if child has symptoms; study of asymptomatic malaria in children from Liberia—retrospective chart review (3 yr) found >20 cases of malaria; 20 of 29 symptomatic children had parasites; 8 of 14 asymptomatic children had parasitemia, ie, 57% of asymptomatic children had parasites that would not have been detected on routine screening; classic triad of malaria symptoms (fever, splenomegaly, anemia) seen in only 21% of patients with malaria; recommendations—high index of suspicion; consider universal screening or empiric treatment in all children coming from malaria-endemic areas; CDC study of malaria, intestinal parasites, and schistosomiasis in Somali refugees— 7% had malaria, 38% had parasites, 2% had schistosomiasis; decided to treat immigrants for malaria before arrival; children >2 yr of age and nonpregnant women given single dose of albendazole |
| Conclusions: when evaluating immigrants and refugees, keep in mind that many infectious diseases have long latency periods; health care providers in 21st century must be culturally competent; develop good listening skills and learn how to conduct good physical examination and patient history; be knowledgeable about racial and ethnic differences; have set of attitudes, skills, and abilities to care for immigrant populations |
Suggested Reading
Abrahamian FM et al: Update on emerging infections from the Centers for Disease Control and Prevention. Severe Clostridium difficile-associated disease in populations previously at low risk--four states, 2005. Ann Emerg Med 48:55, 2006; Bacaner N et al: Travel medicine considerations for North American immigrants visiting friends and relatives. JAMA 291:2856, 2004; Barnett ED: Infectious disease screening for refugees resettled in the United States. Clin Infect Dis 39:833, 2004; Beigl JH et al: Avian influenza A (H5N1) infection in humans. N Eng J Med 353:1374, 2005; Bubacz MR: Community-acquired methicillin-resistant Staphylococcus aureus: an ever-emerging epidemic. AAOHN J 55:193, 2007; Carballo M, Nerukar A: Migration, refugees, and health risks. Emerg Infect Dis 7(3 Suppl):556, 2001; Cloud J, Kelly CP: Update on Clostridium difficile associated disease. Curr Opin Gastroenterol 23:4, 2007; Goodridge E: Meeting the health needs of refugees and immigrants. JAAPA 15:20, 2002; Gunn VL et al: Toxicity of over- the-counter cough and cold medications. Pediatrics 108:E52, 2001; Irwin RS et al: Diagnosis and management of cough executive summary. ACCP evidence-based clinical practice guidelines. Chest 129(1 Suppl):1S, 2006; Katz JA: Probiotics for the prevention of antibiotic-associated diarrhea and Clostridium difficile diarrhea. J Clin Gastroenterol 40:249, 2006; Koss K et al: The outcome of surgery in fulminant Clostridium difficile colitis. Colorectal Dis 8:149, 2006; McPherson S et al: Intravenous immunoglobulin for the treatment of severe, refractory, and recurrent Clostridium difficile diarrhea. Dis Colon Rectum 49:640, 2006; Moran GJ et al: Methicillin-resistant Staphylococcus aureus in community- acquired skin infections. Emerg Infect Dis 11:928, 2005; Moran GJ, Talan DA: Community-associated methicillin-resistant Staphylococcus aureus: is it in your community and should it change practice? Ann Emerg Med 45:321, 2005; Nutman TB: Asymptomatic peripheral blood eosinophilia redux: common parasitic infections presenting frequently in refugees and immigrants. Clin Infect Dis 42:368, 2006; Oldfield EC III: Clostridium difficile-associated diarrhea: resurgence with a vengeance. Rev Gastroenterol Disord 6:79, 2006; Osterholm MT: Preparing for the next pandemic. N Eng J Med 352:1839, 2005; Palinkas LA et al: The journey to wellness: stages of refugee health promotion and disease prevention. J Immigr Health 5:19, 2003; Pelaez T et al: Reassessment of Clostridium difficile susceptibility to metronidazole and vancomycin. Antimicrob Agents Chemother 46:1647, 2002; Roberts A, Kemp C: Infectious diseases of refugees and immigrants. J Am Acad Nurse Pract 13:7, 2001; Schroeder K, Fahey T: Over-the-counter medications for acute cough in children and adults in ambulatory settings. Cochrane Database Syst Rev (4):COD01831, 2004; Stauffer WM et al: Screening of international immigrants, refugees, and adoptees. Prim Care 29:879, 2002; Walker PF: Preventive health care in a multicultural society: are we culturally competent? Mayo Clin Proc 71:519, 1996; Walker PF, Jaranson J: Refugee and immigrant health care. Med Clin North Am 83:1103, 1999; Wenzel RP et al: Community-acquired methicillin-resistant Staphylococcus aureus (MRSA): new issues for infection control. Int J Antimicrob Agents [Epub ahead of print], Jun 11 2007.
Educational Objectives
| The goal of this program is improve the diagnosis and managementof infectious diseases, including those common among immigrant populations. After hearing and assimilating this program, the clinician will be better able to: |
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1. Consider the possibility of methicillin-resistant Staphylococcus aureus in community acquired skin and soft tissue infections, pneumonia, and sepsis, and administer empiric therapy when clinically indicated. |
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2. Describe how the the emergence and increasing frequency of community associated Clostridium difficile infection and associated disease will change the clinician’s practice. |
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3. Cite recent data on the use of cold and cough medications in very young children. |
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4. Explain potential challenges that would occur with a pandemic of influenza A virus subtype H5N1, and describe recommended steps for hospital prepared-ness. |
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5. Effectively screen for and identify infectious diseases in newly arrived immigrant and refugee populations. |
Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty members to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the following has been disclosed: Dr. Moran has received research sponsorship from Johnson and Johnson, Pfizer Inc., and Wyeth Pharmaceuticals, and is on the Speakers’ Bureaus of Cubist Pharmaceuticals, Pfizer Inc., and the Schering-Plough Corporation.
Acknowledgements
Dr. Moran spoke at the 20th Annual Advances in Emergency Medicine and Primary Care, held April 18-20, 2007, in Las Vegas, NV, and sponsored by the Olive View-UCLA Department of Emergency Medicine and the American College of Emergency Physicians, State Chapter of California, Inc. Dr. Walker was recorded at Emerging Infections in Clinical Practice and Public Health, held November 2-3, 2006, in Minneapolis, MN, and sponsored by the University of Minnesota, Minneapolis Medical School, the Minnesota Department of Health, and the Mayo Clinic College of Medicine. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.
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