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     1  Meningitis
     2  Bacterial Viral ( aseptic) TB Fungal Chemical Parasitic ? Carcinomatous
     3  Meningitis Definition Bacterial meningitis is an inflammatory response to bacterial infection of the pia-arachnoid and CSF of the subarachnoid space Epidemiology Incidence is between 3-5 per 100,000 More than 2,000 deaths annually in the U.S. Relative frequency of bacterial species varies with age.
     4  Meningitis Epidemiology Neonates (< 1 Month) Gm (-) bacilli 50-60% Grp B Strep 20-40% Listeria sp. 2-10% H. influenza 0-3% S. pneumo 0-5%
     5  Meningitis Epidemiology Children (1 month to 15 years) H. influenzae 40-60% Declining dramatically in many geographic regions N. meningitidis 25-40% S. pneumo 10-20%
     6  Meningitis Epidemiology Adults (> 15 years) S. pneumo 30-50% N. Meningitidis 10-35% Major cause in epidemics Gm (-) Bacilli 1-10% Elderly S. aureus 5-15% H. influenzae 1-3% >60 include Listeria, E. coli, Pseudomonas
     7  Meningitis Pathogenesis Majority of cases are hematogenous in origin Organisms have virulence factors that allow bypassing of normal defenses Proteases Polysaccharidases
     8  Meningitis Pathology and Pathogenesis Sequential steps allow the pathogen into the CSF Nasopharyngeal colonization Nasopharyngeal epithelial cell invasion Bloodstream invasion Bacteremia with intravascular survival Crossing of the BBB and entry into the CSF Survival and replication in the subarachnoid space
     9  Meningitis Pathology Hallmark Exudate in the subarachnoid space Accumulation of exudate in the dependent areas of the brain Large numbers of PMN’s Within 2-3 days inflammation in the walls of the small and medium-sized blood vessels Blockage of normal CSF pathways and blockage of the normal absorption may lead to obstructive hydrocephalus
     10  Meningitis Clinical Manifestations HA Fever Meningismus Cerebral dysfunction Confusion, delirium, decreased level of consciousness N/V Photophobia
     11  Meningitis Clinical Manifestations – Nuchal rigidity Kernig’s Pt supine with flexed knee has increased pain with passive extension of the same leg Brudzinski’s Supine pt with neck flexed will raise knees to take pressure off of the meninges Present in 50% of acute bacterial meningitis cases Cranial Nerve Palsies IV, VI, VII Seizures
     12  Meningitis Clinical Manifestations - Meningococcemia Prominent rash Diffuse purpuric lesions principally involving the extremities Fever, hypotension, DIC History of terminal complement deficiency Classic findings often absent Neonates Elderly
     13  Meningitis
     14  Meningitis Diagnosis Assess for increased ICP Papilledema Focal neurologic findings Defer LP until CT scan or MRI obtained if any of above present If suspect meningitis and awaiting neuroimaging Obtain BC’s and start empiric Abx
     15  Meningitis Papilledema
     16  Obtain CT scan before lumbar puncture in patients with: Immunucompromised state History of CNS disease New onset seizures Papilledema Altered level of consciousness Focal neurologic signs
     17  Obtain blood cultures and give empiric antibiotics if LP is delayed
     18  LP-CSF Tube # 1 Protein & Glucose Tube # 2 Gram stain & Culture Tube # 3 Cell count & differential Tube # 4 Store ( PCR, viral studies etc)
     19  Meningitis Diagnosis CSF Findings : Opening pressure Appearance Cell count & differential Glucose Protein Gram stain & culture
     20  Opening pressure: high, > 200 mmH20 Cloudy 1000-5000 cells/mm3 with a neutrophil predominance of about 80-95% <40mg/dl and less than 2/3 of the serum glucose Protein elevated
     22  Meningitis Diagnosis Rapid Tests CIE (Counter immunoelectrophoresis/ latex agglut.) PCR CT/MRI Little role in DIAGNOSIS of menigitis Obtain if suspect increased ICP
     23  Meningitis Diagnosis Additional Tests CBC w/ diff Blood cultures CXR Electrolytes and renal function
     24  Meningitis Differential Diagnosis CNS infections (abscess, encephalitis) Viral/ Tb/ Lyme meningitis Ricketsial infections Cerebral vasculitis Subarachnoid hemorrhage Neurosyphilis
     25  Meningitis Treatment Emergent empirical antimicrobial therapy Based on age and underlying disease status Empiric antibiotic regimines Neonates (<3 months) Ampicillin plus a third generation cephalosporin Children Third generation cephalosporin ( alternative -ampicillin and chloramphenicol) Young adults Third generation cephalosporin (Ceftriaxone) + Vancomycin
     26  Meningitis Treatment Empiric Antibiotic Regimines Older adults Ampicillin in combination with third generation ceph. Postneurosurgical Pt’s Vancomycin plus ceftazidime until cultures are available
     28  Meningitis Treatment N. Meningitidis High dose Pen G S. pneumoniae Ceftriaxone For areas with high level resistance Vancomycin plus third generation cephalosporin or rifampin
     29  Meningitis Treatment Gm (-) Enterics Third generation cephalosporins L. monocytogenes Ampicillin S. aureus Vancomycin or Nafcillin S. epidermidis Vancomycin
     30  Meningitis Treatment Duration of Treatment Dependent on infecting organism Average of 10-14 days Gm (-) bacilli for 3 weeks
     31  Meningitis Treatment Steroids Shortly before or along with antibiotics. Do not give steroids after antibiotic treatment. de Gans J, van de Beek D. Dexamethasone in adults with bacterial meningitis. N Engl J Med. 2002;347:1549-56.
     32  Meningitis Prognosis Pneumococcal Meningitis Associated with the highest mortality rate 20-30% Permanent neurologic sequelae 1/3 of pts Hearing loss Mental retardation Seizures Cerebral Palsy
     33  Meningitis Vaccinations Asplenic pts should have had a pneumoccocal vaccine prior to their splenectomy Vaccines available for H. influenza Prophylaxis for N. meningitidis contacts Rifampin
     34  Meningitis Conclusion Meningitis is an infectious disease emergency Mortality is often high but can be prevented with appropriate medical therapy If you consider meningitis in your differential, you are committed to an LP and empiric antibiotics