Category: Infectious Disease

Podcast # 326: Valley Fever

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Author: Michael Hunt, MD

Educational Pearls:

  • Valley fever is a fungal infection known as Coccidiomycosis that can present with vague symptoms like cough, fever, myalgias.
  • A thorough history is critical to the diagnosis. Disease is localized to  the Southwestern US (California, New Mexico, Arizona, Nevada, Utah) and parts of Central/South America.
  • Disease is caused by inhaling fungal spores which damage the lung. Rarely, the disease can disseminate and cause infections that require systemic anti fungal therapy.

 

References:

Centers for Disease Control and Prevention (CDC). Increase in reported coccidioidomycosis–United States, 1998-2011. MMWR Morb Mortal Wkly Rep 2013; 62:217.

Saubolle MA, McKellar PP, Sussland D. (2007). Epidemiologic, clinical, and diagnostic aspects of coccidioidomycosis. Journal of Clinical Microbiology. 45:26.

Taylor AB, Briney AK. (1949). Observations on primary coccidioidomycosis. Annals of Internal Medicine. 30:1224.

Podcast #313: Flu Screening

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Author: Peter Bakes, M.D.

Educational Pearls:

  • High risk patients: underlying lung disease, immunocompromised, extremes of age (<2 or >65), underlying cardiac/renal/neurologic disease, and pregnant women.
  • Testing: RT-PCR (RNA based test that is both sensitive and specific)
  • Workup: comorbidities dictate whether or not they are screened; CXR indicated in high risk patients with respiratory symptoms.
  • Morbidity from flu comes from secondary pneumonia, sepsis, and septic shock.
  • Treatment options are Tamiflu and Relenza (Relenza is contraindicated in patients with lung disease).
  • High risk patients see average of 2.5 days shortening of illness and a decrease in illness severity. Low risk patients see average of 1.5 days shortening of illness.

References:

https://www.cdc.gov/flu/about/disease/high_risk.htm

Binnicker MJ, Espy MJ, Irish CL, Vetter EA. Direct Detection of Influenza A and B Viruses in Less Than 20 Minutes Using a Commercially Available Rapid PCR Assay. J Clin Microbiol. 2015 Jul; 53(7): 2353-4.

Longo, Dan L. (2012). “187: Influenza”. Harrison’s principles of internal medicine (18th ed.). New York: McGraw-Hill. ISBN 9780071748896.

Podcast #307: Guillain-Barre Syndrome

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Author: Peter Bakes, M.D.

Educational Pearls:

  • Rare disease with 1-2 patients out of 100,000. About 60% of patients report a preceding diarrheal illness and classically presents with an ascending motor weakness.
  • Pathophysiology is likely due to molecular mimicry where the immune system creates antibodies against a pathogen (C. jejuni ) which appears similar to the myelin of peripheral nerves resulting in autoimmune demyelination.
  • Diagnosis is made by clinical presentation +/- a spinal tap with a characteristic high protein count but without cells.
  • Treatment is IVIG or plasmapharesis. It is important to monitor respiratory function because about 15% of patients progress to respiratory failure.

References:

Sejvar, James J.; Baughman, Andrew L.; Wise, Matthew; Morgan, Oliver W. (2011). “Population incidence of Guillain?Barré syndrome: a systematic review and meta-analysis”

van den Berg, Bianca; Walgaard, Christa; Drenthen, Judith; Fokke, Christiaan; Jacobs, Bart C.; van Doorn, Pieter A. (15 July 2014). “Guillain?Barré syndrome: pathogenesis, diagnosis, treatment and prognosis”. Nature Reviews Neurology. 10 (8): 469?482.

Yuki, Nobuhiro; Hartung, Hans-Peter (14 June 2012). “Guillain?Barré Syndrome”. New England Journal of Medicine. 366 (24): 2294?2304.

Podcast #302: Flu

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Author: Jared Scott, M.D.

Educational Pearls

  • Flu is widespread throughout the US (through Jan 20th 2018).
  • All age groups have seen surge in hospitalizations, but 65 + age group has seen the largest surge in hospitalizations due to flu.
  • New recommendations for treating with Tamiflu! Treat the following high-risk groups at any stage of illness:  Children under age 2, Adults 65 and older, patients with comorbidities such as chronic lung disease, heart disease, blood disorders, kidney disorders, liver disorders, neurological disorders, immunosuppressed, pregnant women, American Indians, extreme obesity, women under 19 on long-term aspirin, and nursing home residents.

References:

https://www.cdc.gov/flu/about/disease/high_risk.htm

https://www.cdc.gov/flu/weekly/summary.htm

Podcast #300: Probiotics

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Author: Peter Bakes, M.D.

Educational Pearls

  • Probiotics are living bacteria that are taken as an oral supplement.
  • Most of the data to support their use is in the prevention of antibiotic-related diarrhea and the reduction of the symptoms of ulcerative colitis (UC).
  • Some studies have some a reduction of the incidence of antibiotic-related diarrhea in children of up to 12% with the use of probiotics.
  • There may be a reduction of up to 60% in the incidence of antibiotic-related C. diff infection in adults with probiotic use
  • Studies have shown a 10% or more reduction in the duration and severity of the symptoms of UC with probiotic use.
  • Proposed mechanisms of probiotics include a decrease in gut permeability and a decrease in pathogenic gut bacteria due to resource competition.

References: http://www.cochrane.org/CD006095/IBD_use-probiotics-prevent-clostridium-difficile-diarrhea-associated-antibiotic-use

Podcast #299: Black Death, Lice, Math, and Pottery

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Author: Chris Holmes, M.D.

Educational Pearls

  • It’s estimated that about 25 million people died during the Black Plaque. Researchers have confirmed this number by assessing how much old, broken pottery was buried in front of homes and churches from that time period.
  • Traditional thinking has been that the Black Plague was spread primarily by flea bites. However, using mathematical modeling, researchers have theorized that person-to-person spread was more common.

References: https://www.washingtonpost.com/news/speaking-of-science/wp/2016/05/24/broken-pottery-reveals-the-sheer-devastation-caused-by-the-black-death/

Podcast #295: UTI

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Author: Sam Killian, M.D.

Educational Pearls

  • Traditionally, UTI diagnosis has been dependent on urine culture, urinalysis and clinical symptoms. But a recent study casts some doubt on the utility of urine cultures.
  • A study in the Journal of Clinical Microbiology did urine cultures and E. coli PCR in 220 women with UTI symptoms and 86 women without UTI symptoms.
  • In the symptomatic women, 67% had positive E. Coli PCR and 98% had a pathogenic bacteria in their urine culture.
  • In the asymptomatic women, 10% had positive E. coli PCR and/or urine culture.
  • Therefore, this study suggests that urine culture may be of limited utility, since symptoms alone seemed to predict bacteriuria.

References: Burd EM, Kehl KS. A Critical Appraisal of the Role of the Clinical Microbiology Laboratory in the Diagnosis of Urinary Tract Infections. Journal of Clinical Microbiology. 2011;49(9 Supplement). doi:10.1128/jcm.00788-11.

Podcast #287: Sepsis Bundles

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Author: Aaron Lessen, M.D.

Educational Pearls

  • Treatment “bundles” are a popular approach to the rapid resuscitation of septic patients. A recent study in New York, where sepsis bundles are mandatory, sought to figure out which aspects of the bundle had impacts on mortality.
  • In a study of 40,000 septic patients, the study found that early antibiotics were associated with better outcomes, while early IV fluids were not associated with better outcomes.
  • This study affirms the important role of early antibiotics in sepsis. IV fluids may play an important role in the treatment of sepsis in some patients, but its role is less clear than antibiotics.

References:  Time to Treatment and Mortality during Mandated Emergency Care for Sepsis Christopher W. Seymour, M.D., Foster Gesten, M.D., Hallie C. Prescott, M.D., Marcus E. Friedrich, M.D., Theodore J. Iwashyna, M.D., Ph.D., Gary S. Phillips, M.A.S., Stanley Lemeshow, Ph.D., Tiffany Osborn, M.D., M.P.H., Kathleen M. Terry, Ph.D., and Mitchell M. Levy, M.D. N Engl J Med 2017; 376:2235-2244 June 8, 2017 DOI: 10.1056/NEJMoa170305

Podcast #285: C Diff

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Author: Aaron Lessen, M.D. 

Educational Pearls

  • While C. difficile infections are generally thought of as nosocomial, there is a subset of patients who acquire the infection in the community.
  • One recent study showed that about 10% of patients presenting to the ED with diarrhea and without vomiting had a C. diff infection.
  • Another study found risk factors for community-acquired C. diff included recent ED/Urgent care visits and antibiotic use. However, 36% of the patients in that study had no identifiable risk factors.

References:  Gupta A, Khanna S. Community-acquired Clostridium difficile infection: an increasing public health threat. Infection and Drug Resistance. 2014;7:63-72. doi:10.2147/IDR.S46780.

Podcast #277: Mucor

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Author: Don Stader, M.D.

Educational Pearls

  • Mucor/Rhizopus fungal infections usually present in diabetic or immunocompromised patients as a black, necrotic lesion on the face.
  • The fungus invades the vasculature of the face, causing tissue ischemia and necrosis.
  • The infection is more common in the diabetic population because the fungus prefers more acidic and glucose-rich environments.
  • This is a surgical emergency since it is cured only with excision of the affected tissue

References: Vijayabala GS, Annigeri RG, Sudarshan R. Mucormycosis in a diabetic ketoacidosis patient. Asian Pacific Journal of Tropical Biomedicine. 2013;3(10):830-833. doi:10.1016/S2221-1691(13)60164-1.