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Interesting Case Rounds

Interesting Case Rounds. Shawn Dowling. Case. 35M. Engineer. Presents to emerg (MT area) Concerned that he has Listeriosis and that he’ll die Are you going t work this individual up? Counsel him?. In case anyone lives in a cave…. July; routine surveillance noted an  Listeriosis

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Interesting Case Rounds

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  1. Interesting Case Rounds Shawn Dowling

  2. Case • 35M. Engineer. Presents to emerg (MT area) • Concerned that he has Listeriosis and that he’ll die • Are you going t work this individual up? Counsel him?

  3. In case anyone lives in a cave… • July; routine surveillance noted an Listeriosis • Outbreak traced to Maple Lead factory in ON • 29 confirmed cases, 31 Suspected cases • 5 deaths confirmed to be from outbreak, 10 under investigation • AB - Cases for 2008 • Listeriosis cases as of August 26 • 9Cases/7 under investigation for link to outbreak • Results pending = 5 (including 2 deaths) • Results confirmed = 2 not linked outbreak • Cases linked to national outbreak = 0

  4. Objectives • Discuss Listeria monocytogenes in terms of • Microbiology • Pathophysiology • At risk populations • Clinical Presentations • Investigations • Management • Prevention

  5. Microbiology of Listeria monocytogenes • Only Listeria species that infects humans • Gram +ve rod, aerobic/facultative anaerobic • May resemble pneumococcus, diphtheria or haemophilus on gram stain

  6. Pathogenesis • Facultative intracellular parasite • Usu in soil and decaying vegetable matter • Infection usu from oral ingestion-> mucosal penetration->systemic infection • Immunity to Listeria primarily occurs via T-cell activation of macrophages • Listeria has a predilection for CNS and placental tissue

  7. Epidemiology • Baseline incidence 1.55/100,000 (likely under-estimated) Canada wide, in AB 1/100,000 • Sporadic illness • Outbreaks • <1% of FB illnesses but second highest mortality rate amongst foodborne illnesses (1st is Vibrio vulnificus), accts for 28% of all f.b. deaths

  8. What is an outbreak? • Increase in incidence beyond the expected in a defined geographic area, within a defined period of time • A statistically significant increase in the rate of adverse events above that noted in the past

  9. Steps to Outbreak Investigation • Verify diagnosis • Confirm outbreak • Identify and count cases • Develop epidemic curve • Take immediate control measures • Formulate and test hypotheses • Communicate findings • Implement interventions

  10. Listeria Outbreaks • Have been associated with a number of foods: MC are deli meats, soft cheeses(unpasteurized), smoked seafood, meat spreads and paté’s • Attack rate ranges from 50-100% • Incubation period • Mean = 3 wks, (range 3 to 90 days) • Reportable disease - call the MOH

  11. Predisposing Conditions • Most systemic listerial infections occur in individuals with one or more predisposing conditions • Pregnancy (esp 3rd trimester) • Immunocompromised state (i.e. steroid Tx, malignancy - esp lymphoma, ESRD, HIV, etc.) • Age: neonates and Elderly (>65 yoa) • (1995) Listeria was causative agent for bacterial meningitis - 22% in elderly, 23% in neonates, 4% in those b/w 2-60

  12. Case Definition • Confirmed Case • Symptomatic individuals[1] with laboratory confirmation of infection: • Isolation of Listeria monocytogenes from a normally sterile site (e.g., blood or cerebrospinal fluid [CSF] or, less commonly, joint, pleural, or pericardial fluid) OR • In the setting of miscarriage or stillbirth, isolation of L. monocytogenes from placental or fetal tissue (including amniotic fluid and meconium)

  13. Febrile gastroenteritis Focal Infections Infection in pregnancy Sepsis CNS infections Meningoencephalitis Cerebritis Rhomboencephalitis Mild Severe Clinical Manifestations

  14. Pt Assessment • Detailed food Hx • List of detailed recalled products • http://www.inspection.gc.ca/english/corpaffr/recarapp/2008/list97be.shtml • Recommend food cultures - ? necessary in times of an outbreak - speak to MOH

  15. Febrile Gastroenteritis • Usu occurs after ingestion of large inoculum, can occur in normal hosts • Sx: fever, watery diarrhea, N,V, HA, myalgias/arthralgias • Sx typically last 2 days • Usu self-limited, can progress to one of the other presentations if at-risk populations • Do not do stool cultures • Tx if: 1) persistent Sx, 2)high risk patients, 3)ingested food implicated in outbreak

  16. Usu in 3rd trimester Sx: fever, chills, back pain - nonspecific LOW Threshold to get b.c. in febrile preg patient w/o source(esp when an outbreak of listeria) Consequences Study of 11 pregnant pts; 2 fetal demises, 6 of 9 neonates had listerial infection, 3 not infected Granulomatosis infantiseptica: Disseminated abscess/granulomas Infection in Pregnancy

  17. Tx in Pregnant • Supportive Tx • Any pregnant patient with documented listeria infection should be treated: • Ampicillin IV 2 g Q4H • If allergic • TMP/SMX IV (do not use during 1st trimester or last month of pregnancy) - 5mg/kg of TMP • Alt: vancomycin if PCN allergic and CNS infection

  18. CNS Infection • Range of clinical presentation - fever + AMS to fulminant course + coma • Can present like classic meningitis or with focal CNS signs, ataxia, tremor, seizures

  19. Can also present like a cerebritis • Fever, HA, hemiplegia (resembling a stroke) • Can present like a rhomboencephalitis • Biphasic course of HA, fever, N/V followed by CN palsies, ataxia, tremor, decreased LOC, sz and hemiparesis

  20. CNS Investigations • CT if focal neuro signs, papilledema or AMS • LP • One of the nonTB causes of high lymphocyte counts (>25%) • Protein up • Glucose down (39%) • Gram stain - low sensitivity, low specificity • May need MRI - better than CT for cerebellar or brainstem lesions

  21. Tx with CNS infection • Ampicillin is drug of choice • Will likely be covering for other agents • Ceftriaxone does not cover Listeria • May consider adding synergistic gent dosing (1mg/kg Q8H) in CNS infection & sepsis

  22. Thoroughly cook/heat raw food from animal sources Beef, pork & poultry Additional recommendations for persons at high risk : avoiding unpasteurized cheeses. There is no need to avoid pasteurized cheeses, cream cheese, cottage cheese or yogurt), reheating leftovers of ready-to-eat foods such as hot dogs should be steaming hot before eating, and avoiding foods or thoroughly reheat cold cuts before eating from delicatessen counters especially pregnant women and immuno-suppressed persons although the risk is relatively low Prevention Measures

  23. Recommendations for patients with known exposure • ASx patients - reassure, discuss Sx • Sx patients + exposure • Febrile gastro + high risk; early blood cultures • Pregnant patient; Tx if Listeria +ve • CNS infection/sepsis - Tx as normal, consider adding Ampicillin (Vanco of PCN allergic) coverage +/- gent (synergistic dosing) in HIGH RISK patients

  24. More Sites • Health Canada • http://www.hc-sc.gc.ca/hl-vs/iyh-vsv/food-aliment/listeria-eng.php • AB Health and Wellness • http://www.health.alberta.ca/

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