Nervous System Infections

CNS infections indude a wide variety of clinical conditions and etiologies meningitis, meningoencephalitis, encephalitis, brain and meningeal abscesses, and shunt infections. The focus of this chapter is meningitis. 

Infections are the result of hematogenous spread from a primary infection site, seeding from a parameningeal focus, reactivation from a latent site, trauma, or congenital defects in the CNS. 

Passive and active exposure to cigarette smoke and the presence of a cochlear implant that includes a positioner both increase the risk of bacterial meningitis. 

CNS infections may be caused by a variety of bacteria, fungi, viruses, and parasites. The most common causes of bacterial meningitis include Streptococcus pneumoniae. Neisseria meningitidis. Listeria monocytogenes, and Haemophilus influenzae. 

The critical first step in the acquisition of acute bacterial meningitis is nasopharyngeal colonization of the host by the bacterial pathogen. The bacteria first attach themselves to nasopharyngeal epithelial cells and are then phagocytized into the host s bloodstream. 

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Carpentier PA, Duncan DS, Miller SD (2008) GUal toU-hke receptor signaling in central nervous system infection and autoimmunity. Brain Behav Immun 22 140-147 Carr DJ, Serou M (1995) Exogenous and endogenous opioids as biological response modifiers. Immunopharmacology 31 59-71... 

Drug resistance 3.5 Central nervous system infections... 

Pulmonary disease, small-cell lung cancer, head trauma, stroke, central nervous system infections, pituitary surgery, prolactinoma, severe nausea, psychiatric disease, and postoperative state... 

For nearly 80% of patients with epilepsy, the underlying etiology is unknown.8 The most common recognized causes of epilepsy are head trauma and stroke. Developmental and genetic defects are the cause of about 5% of cases of epilepsy. Central nervous system (CNS) tumors, central nervous system infections, and neurodegen-erative diseases are other common causes. Other important causes of epilepsy are human immunodeficiency virus infection or neuro-cysticercosis infection, primarily occurring in Latin America. 

Isolated seizures that are not epilepsy can be caused by stroke, central nervous system trauma, central nervous system infections, metabolic disturbances (e.g., hyponatremia and hypoglycemia), and hypoxia. If these underlying causes of seizures are not corrected, they may lead to the development of recurrent seizures I or epilepsy. Medications can also cause seizures. Some drugs that are commonly associated with seizures include tramadol, bupropion, theophylline, some antidepressants, some antipsy-chotics, amphetamines, cocaine, imipenem, lithium, excessive doses of penicillins or cephalosporins, and sympathomimetics or stimulants. 

TABLE 67-3. Pathogen-Based Definitive Treatment for Central Nervous System Infections... 

Chap. 67 - Central Nervous System Infections Universal Program Number 014-999-07-082-H04... 

See Chap. 110, Central Nervous System Infections, authored by Isaac F. Mitroppoulos, Elizabeth D. Hermsen, Jeremy A Schafer, and John C. Rotscha-fer, for a more detailed discussion of this topic. 

Given a molecule such as sulfanilamide that is an active antibacterial, why go to all the trouble of modifying the stmcture to find other active molecules in the same stmctural class There are numerous answers to find safer molecules, more potent molecules, molecules active against a broader spectrum of bacteria, molecules active longer so that doses may be taken less frequently, molecules that may pass the blood-brain barrier and be effective against central nervous systems infections. 

Nausea and vomiting may be manifestations of a wide variety of conditions, including adverse effects from medications systemic disorders or infections pregnancy vestibular dysfunction central nervous system infection or increased pressure peritonitis hepatobiliary disorders radiation or chemotherapy and gastrointestinal obstruction, dysmotility, or infections. 

Blood-brain barrier Treatment of central nervous system infections, such as meningitis, depends on the ability of a drug to penetrate into the cerebrospinal fluid (CSF). The blood-brain barrier (see p. 8) ordinarily excludes many antibiotics. However, inflammation facilitates penetration and allows sufficient levels of many (but not all) antibiotics to enter the CSF. [Note For cure of meningitis, it is important that a bactericidal rather than a bacteriostatic effect is achieved in the CSF. Yet, this is not without its problems, since rapid bacteriolysis in the infected CSF will liberate high concentrations of bacterial cell walls and lipopolysaccharide that can exacerbate the inflammation. This has led to the use of adjunctive (simultaneous administration of) corticosteroids, which diminish the inflammatory process and neurologic sequelae.]... 

In addition, other possible causes of dementia also need to be excluded, especially the treatable forms of cognitive impairment, such as that due to depression, chronic drug intoxication, chronic central nervous system infection, thyroid disease, vitamin deficiencies (i.e.. Bn and thiamine), central nervous system angitis, and normal-pressure hydrocephalus (Bird, 2008). Individuals who do not meet these criteria but have short-term memory loss and have only minimal impairment in other cognitive abilities and are not functionally impaired at work or at home are considered to have mild cognitive impairment (Petersen et al., 2001). 

Hein A, Schuh H, Thiel S, Martin IP, Domes R (2003) Ramified feline microglia selects for distinct variants of feline immunodeficiency virus during early central nervous system infection. I Neurovirol 9 465 76. 

Rock RB, Gekker G, Hu S, Sheng WS, Cheeran M, Lokensgard JR, Peterson PK (2004) Role of microglia in central nervous system infections. Chn Microbiol Rev 17 942-964. 

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