Snapshot An 18-year-old man presents to the emergency department for an intractable headache and generalized malaise. His symptoms began 3 days ago and have progressively worsened. Physical examination is significant for nuchal rigidity, diffuse petechia, and an inability to extend at the knee while the hips are flexed at 90°. A lumbar puncture is performed and cerebral spinal fluid studies demonstrate an elevated opening pressure, elevated protein, decreased glucose, and a leukocytosis. Gram stain of the cerebral spinal fluid demonstrates gram-negative diplococci. Introduction Classification a gram-negative diplococcus Epidemiology risk factors college students military infants and the elderly no meningococcus vaccine Transmission respiratory and oral secretions Microbiology properties metabolizes glucose produces IgA proteases contains lipooligosaccharides (has strong endotoxin activity) aerobic or facultatively anaerobic maltose fermenter reservoir nasopharynx penetrates mucosal epithelium and enters circulation pharynx → hematogenous spread (blood) → choroid plexus → meninges molecular biology virulence factors polysaccharide capsule an important virulence factor provides resistance against phagocytosis IgA protease allows oropharynx colonization endotoxin (lipooligosaccharide) analogous to LPS from other gram-negative bacteria causes hemorrhage and sepsis responsible for petechial rash small red dots of hemorrhage pili enables attachment to the nasopharynx antigenic variation avoids the immune system attack Pathogenesis begins as asymptomatic colonization in the nasopharynx in healthy patients in rare cases, the bacteria invade through the mucosa, resulting in bacteremia, which can allow seeding of the microbe to the meninges an inflammatory response against the microbe (due to its endotoxin) ensues, leading to tissue injury procoagulant pathways can also be activated, causing intravascular thrombosis (e.g., purpura and petechiae) Patients deficient in components of the alternative and terminal complement (C5b-C9 - membrane attack complex) pathways have increased susceptibility to recurrent Neisseria bacteremia Prevention meningococcal vaccine indication all patients 11-18 years of age ≤ 10 years of age and ≥ 19 years of age who are high risk for invasive meningococcal disease Associated conditions meningitis meningococcemia purpural fulminans Waterhouse-Friderichsen syndrome adrenal infarction leading to adrenal insufficiency Prognosis poor prognosis include shock, young and old age, coma, purpura fulminans, and disseminated intravascular coagulation Presentation Symptoms headache fever neck stiffness nausea and vomiting myalgias Physical petechial rash nuchal rigidity Brudzinki sign spontaneous flexion of the hips during passive neck flexion Kernig sign inability to extend the knees while the hips are flexed at 90° Studies Culture perform a Gram stain of the cerebral spinal fluid or blood gold standard for the diagnosis Differential Meningitis caused by other organisms Streptococcus pneumoniae Listeria monocytogenes differentiating factors different organisms are isolated with microbiologic testing Treatment Medical empiric antibiotic therapy indication preferably given after cerebral spinal fluid cultures and blood cultures are obtained given antibiotics first will impair diagnostic testing regimen third-generation cephalosporin e.g., ceftriaxone or cefotaxime antimicrobial chemoprophylaxis indication ideally given within 24 hours household members roommates or intimate contacts direct exposure to oral or respiratory secretions (e.g., kissing and endotracheal intubation) sitting next to the infectious person for ≥ 8 hours patients who work in a childcare center medication rifampin ciprofloxacin ceftriaxone Complications Sepsis Hypovolemic shock Cerebral edema and hydrocephalus Cognitive impairment