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Meningitis, Encephalitis & Rabies

Meningitis, Encephalitis & Rabies. Overview. Meningitis The most board relevant topic Encephalitis A few brief words about Rabies. Definitions. Meningitis is an inflammation of the membranes that cover the brain and spinal cord. Encephalitis is an inflammation of the brain. Meningitis.

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Meningitis, Encephalitis & Rabies

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  1. Meningitis, Encephalitis & Rabies

  2. Overview • Meningitis • The most board relevant topic • Encephalitis • A few brief words about Rabies

  3. Definitions • Meningitis is an inflammation of the membranes that cover the brain and spinal cord. • Encephalitis is an inflammation of the brain

  4. Meningitis • Typical pathogens depend on the age of the host and the presence of comorbidities • Impaired cellular immunity (HIV, steroid use, transplant, cytotoxic chemotherapy) increases risk of Listeria monocytogenes • Impairedhumoral immunity (splenectomy, hypogammaglobulinemia, multiple myeloma) increase risk of S. pneumoniae • Differential diagnosis of acute meningitis includes infectious and noninfectious causes

  5. Viruses Nonpolio enteroviruses Arboviruses Herpesviruses (HSV, VZV, CMV, EBV and HHV-6) Lymphocytic choriomeningitis virus HIV Adenovirus Parainfluenza virus type 3 Influenza virus Measles virus Rickettsiae Rickettsia rickettsii Rickettsia conorii Rickettsia prowazekii Rickettsia typhi Orientia tsutsugamushi Ehrlichia and Anaplasma spp. Bacteria Haemophilus influenzae Neisseria meningitidis Streptococcus pneumoniae Listeria monocytogenes Escherichia coli Streptococcus agalactiae Propionibacterium acnes Staphylococcus aureus Staphylococcus epidermidis Bacteria continued Coxiella burnetii Mycoplasma pneumoniae Enterococcus spp. Klebsiella pneumoniae Pseudomonas aeruginosa Salmonella Acinetobacter Viridans streptococci Fusobacterium necrophorum Stenotrophomonas maltophilia Streptococcus pyogenes Pasteurella multocida Bacillus anthracis Capnocytophaga canimorsus Nocardia spp. Mycobacterium tuberculosis Spirochetes Treponema pallidum Borrelia burgdorferi Leptospira Protozoa and helminths Naegleria fowleri Angiostrongylus cantonensis Baylisascaris procynonis Strongyloides stercoralis Differential Diagnosis of Infectious Causes of Acute Meningitis Expanded from PPID 7th ed.

  6. Other infectious syndromes Parameningeal foci of infection Infective endocarditis Viral postinfectious syndromes Postvaccination (mumps, measles, polio, pertussis, rabies, vaccinia) Noninfectious etiologies and diseases of unknown etiology Intracranial tumors and cysts Craniopharyngioma Dermoid/epidermoid cyst Teratoma Systemic illness Systemic lupus erythematosus Vogt-Koyanagi-Harada syndrome Procedure-related Postneurosurgery Spinal anesthesia Intrathecal injections Chymopapain injection Medications Antimicrobials Trimethoprim Sulfamethoxazole Ciprofloxacin Penicillin Isoniazid Metronidazole Cephalosporins Pyrazinamide NSAIDs Muromonab-CD3 (OKT3) Azathioprine Cytosine arabinoside (high dose) Carbamazepine Immune globulin Ranitidine Phenazopyridine Miscellaneous Seizures Migraine or migraine-like syndromes Mollaret’s meningitis Noninfectious Etiologies of Acute Meningitis

  7. PPID 7th ed

  8. Acute Bacterial Meningitis PPID 7th edition

  9. Clinical Presentation • Headache (>90%) • Fever (>90%) • Meningismus (>85%) • Altered sensorium (>80%) • Vomiting (35%) • Seizures (30%) • Focal neurologic findings (10-20%) • Papilledema (<5%) ABM can be excluded in a patient with none of these symptoms JAMA 282 (2): 175-181, 1999 PPID 7th ed Chapter 84

  10. Kernig’s sign and Brudzinski’s sign both classically described but poor diagnostic sensitivity Clinical Presentation JAMA 282 (2): 175-181, 1999

  11. Pop Quiz • Which physical exam maneuver has the highest sensitivity for meningitis?

  12. Jolt Accentuation of Headache • Asking the patient to move their head side to side at a rate of 2-3x/min • Sensitivity of 97% and Specificity of 60% • Very High negative predictive value Uchihara, T. Headache. 1991

  13. N. meningitidis is present in 73% of patients with ABM who have a rash (petechial) Differential diagnosis includes RMSF, echovirus type 9, S. pneumoniae, H. influenzae, Acinetobacter and Staphylococcus aureus meningitis with sepsis Clinical Presentation

  14. Diagnosis & Treatment

  15. Who needs a head CT prior to lumbar puncture?

  16. Characteristics of Cerebrospinal Fluid Analysis in Meningitis Normal CSF Bloody Tap Viral Meningitis Bacterial meningitis Opening pressure (cm H2O) 5-20 Normal Normal to mildly elevated >18 WBC count (cells/mm3) <10 monocytes WBC:RBC 1:700 10-1000 lymphocyte 1000-5000 PMN < 1 PMN predominance predominance RBC count (cells/mm3) < 2WBC:RBC 1:700 Normal Normal Protein (mg/dl) <45 15-45 Normal 100-500 Glucose (mg/dl) >50% serum levels Normal Normal <40 10% of ABM presents with lymphocyte predominance Up to 50% of West Nile virus patients have neutrophil predominance Modified from Bartlett JG, Pocket book of infectious disease therapy, 10th ed, Baltimore, 1999

  17. CSF Gram staining • Sensitivity correlates with bacterial load • 25% of pts with < 103 CFUs/ml have + gs • 97% of pts with > 105 CFUs/ml have + gs • Sensitivity also correlates with pathogen • S. pneumoniae 90% • H. flu 86% • N. meningitidis 75% • GNR 50% • Listeria 30% PPID 7th ed. Ch 84

  18. Gram positive lancet-shaped diplococci ofStreptococcus pneumoniae

  19. Listeria monocytogenes Infections. Cerebrospinal fluid shows characteristic gram-positive rods (Gram stain). Listeriosis is much more common among patients with human immunodeficiency virus infection or acquired immunodeficiency syndrome compared with the general population.

  20. Neisseria meningitidis: Gram negative diplococci on CSF Gram stain

  21. CSF culture • Positive in 70-85% of patients who have not received prior antimicrobial therapy • Cultures may take up to 48 hrs for identification

  22. Steroids in Adults with Bacterial Meningitis • Routine use of dexamethasone is warranted in most adults with suspected pneumococcal meningitis • If the meningitis is found not to be caused by S. pneumoniae, dexamethasone should be discontinued • Should be given before or with first dose of abx • If the strain is highly resistant to PCN or cephalosporins “careful observation and follow-up are critical”

  23. MKSAP 14 Item 16 Gram Positive Diplococci

  24. MKSAP 14 Item 14

  25. Nonpolio enteroviruses Echoviruses Coxsackieviruses Enterovirus-71 Herpesviruses HSV, VZV, CMV, EBV and HHV-6 Lymphocytic choriomeningitis virus Mumps virus HIV Adenovirus Parainfluenza virus type 3 Influenza virus Measles virus Arboviruses Mosquito-borne California St. Louis Eastern equine Western equine Venezuelan equine West Nile virus Tick-borne Colorado tick fever Powassan Viral Meningitis/Encephalitis

  26. Enteroviruses • Leading recognizable cause of aseptic meningitis • 30,000 – 75,000 U.S. meningitis cases/yr • Marked summer/fall seasonality in temperate climates • Periods of warm weather and wearing sparse clothing facilitate fecal-oral spread • PCR on CSF and supportive therapy • Newly described Enterovirus-71 can cause anterior myelitis

  27. Arboviruses • California (La Crosse) • St. Louis • Eastern Equine -- 50-70% mortality • Western Equine • Venezuelan Equine • West Nile • Colorado tick fever

  28. West Nile Neuroinvasive Disease • WNV is now the most common cause of epidemic viral encephalitis in U.S. • WNV infection • Asymptomatic 80% • West Nile Fever 20% • Neuroinvasive disease <1% • Meningitis 40% • Encephalitis 60% • Acute flaccid paralysis/poliomyelitis • 5-10% of all patients with neuroinvasive disease • 4 cases/100,000 population during a WNV epidemic Ann Neurol 2006; 60:286-300

  29. www.cdc.gov

  30. www.cdc.gov

  31. West Nile Virus Screening of Blood Donations and Transfusion-Associated Transmission --- United States, 2003 • In 2002, transfusion-associated transmission of WNV recognized • In June 2003, nucleic acid amplification tests (NATs) for WNV applied to screen all blood donations • 6 million units screened • 818 positive viremia • 6 cases negative screen by NAT that transmitted WNV MMWRApril 9, 2004 / 53(13);281-2

  32. Distinguishing WNV, Enterovirus-71, Poliomyelitis and Guillain-Barre Syndrome

  33. Coastal marshes June, July, August Age <10, >55 yrs Unique clinical features CSF WBC >1000 Mortality 50-70% Sequelae 80% (esp children <10yrs)

  34. West, midwest Infants and adults >50 years old 5-15% mortality Sequelae: moderate in infants and low in others

  35. Mostly LaCrosse Virus Woodlands; June-September Children <20 Unique clinical feature: seizures Mortality <1% Sequelae rare <2%

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