Invasive meningococcal disease (IMD) is a major public health issue due to its global distribution, potential of epidemic spread, predominant disease burden in children and adolescents, high case-fatality rates and substantial morbidity [1][2][3] . This disease presents a broad spectrum of manifestations and it is a neurological and clinical emergency that requires prompt recognition and initiation of therapy. In this article, we present a review on the epidemiology, pathophysiology, diagnosis, treatment and prevention of IMD, with focus on its neurological issues.
MicrobiologyNeisseria meningitidis (N. meningitidis) is an exclusively human gram-negative diplococcus that has a great genetic variety 1 . Its genetic plasticity and phenotypic diversity are hallmarks of the meningococcus evolution, as this bacteria acquired various genes from other species of Neisseria and also from other bacterias, like Haemophilus spp. The microorganism is a frequent colonizer of the human nasopharynx and oropharynx, but can also be found in other places, like the oral mucosa, the rectum and the urogenital tract . Meningococcal virulence is related to the major outer membrane components: capsular polysaccharide, outer membrane proteins (pili, porins, Opa, Opc, meningococcal iron-acquiring proteins), and lipo-oligosaccharide (endotoxin) [4][5][6] . There are 13 serogroups of N. meningitidis based on different capsular polysaccharide structures, but only six serogroups (A, B, C, W-135, Y and more recently X) cause most life-threatening disease 2,6,7 .Instituto de Infectologia Emílio Ribas, São Paulo SP, Brazil.Correpondence: José Eduardo Vidal; Rua Capote Valente 688 / apto. 78; 05409-002 São Paulo SP, Brasil; E-mail: josevibe@gmail.com ABStrACt Invasive meningococcal disease (IMD) is a major public health and continues to cause substantial mortality and morbidity. Serotype C is the most frequent in Brazil. The clinical spectrum of IMD is broad (meningitis, meningococcemia or both) and the clinical evolution may be unpredictable. Main features associated with mortality are: age higher than 50 years old, seizures, shock, and meningococcemia without meningitis. Blood cultures should be obtained immediately. Lumbar puncture can be performed without previous computed tomography scan (CT) in most cases. Clinical features can be useful to predic patients where an abnormal CT scan is likely. Cerebrospinal fluid (CSF) culture and Gram stain should always be required. Latex agglutination sensitivity is highly variable. Polymerase chain reaction is specially useful when other methods are negative or delayed. Usually ceftriaxone should not be delayed while awaiting CSF study or CT. Dexamethasone can be used in meningococcal meningitis. Early suspicion of IMD and antibiotic in primary care before hospitalization, rapid transportation to a hospital, and stabilization in an intensive-care unit has substantially reduced the case-fatality rate. Vaccines against serotypes A, C, W-135, and Y are available while vaccines against serotype B are expecte...