Fulminant myocarditis can be fatal or lead to chronic congestive heart failure. Most cases are self-limiting and are followed by full recovery The true incidence of myocarditis (inflammation of the heart) is unknown, because most cases are asymptomatic.
Central nervous system infections are fortunately rare, but they are extremely serious. The cerebral cortex and spinal cord are confined within the restricted boundaries of the skull and boney spinal canal. Inflammation and edema therefore have devastating consequences, often leading to tissue infarction that in turn results in permanent neurologic sequelae or death.
Bacterial meningitis remains one of the most feared and dangerous infectious diseases that a physician can encounter. This form of meningitis constitutes a true infectious disease emergency. It is important that the physician quickly make the appropriate diagnosis and initiate antibiotic therapy.
A 74-year-old white man with a history of chronic steroid use (10 mg prednisone daily) and stage I chronic lymphocytic leukemia presented at the emergency room with confusion and fever. Four days before admission, he complained of being increasingly tired. Two days before admission, he became increasingly lethargic, sleeping on floor.
Brain abscess is an uncommon disease, found in about 1 in 10,000 general hospital admissions. Infection of the cerebral cortex can result from the direct spread of bacteria from another focus of infection (accounts for 20% to 60% of cases) or from hematogenous seeding.
Intracranial epidural and subdural abscesses are rare. They usually result from spread of infection from a nidus of osteomyelitis after neurosurgery from an infected sinus (in particular the frontal sinus), or less commonly, from an infected middle ear or mastoid.
The Pneumonia Patient Outcome Research Team developed useful criteria called the pneumonia severity index for assessing pneumonia severity; however, that index proved to be complex and difficult to use. A simpler index called the CURB-65 (confusion, urea nitrogen, respiratory rate, blood pressure, age 65 years or older) has been shown to have sensitivity and specificity nearly equal to that of the pneumonia severity index. Both indexes can be used to guide decisions on admission to a hospital ward or intensive care unit. As shown in Figure 4.5, patients with a score of 0 or 1 can be treated as outpatients; those with a score of 2 or more warrant hospitalization.
Great overlap occurs among the clinical manifestations of the pathogens associated with acute community-acquired pneumonia. However, constellations of symptoms, signs, and laboratory findings serve to narrow the possibilities. By developing an ability to focus on a few pathogens or to identify a specific pathogen, clinicians can better predict the clinical course of pneumonia and can narrow antibiotic coverage. Pathogenic strains of S. pneumoniae have a thick capsule that prevents PMN binding and that blocks phagocytosis.
Despite dire warnings that we are approaching the end of the antibiotic era, the incidence of antibiotic-resistant bacteria continues to rise. The proportions of penicillin-resistant Streptococcus pneumoniae, hospital-acquired methicillin-resistant Staphylococcus aureus, and vancomycin-resistant Enterococcus strains continue to increase. Community-acquired methicillin-resistant Staphylococcus aureus is now common throughout the world.
To understand why antibiotics must be used judiciously, the physician needs to understand how bacteria are able to adapt to their environment. Point mutations can develop in the Deoxyribonucleic acid of bacteria as they replicate. These mutations occur in the natural environment, but are of no survival advantage unless the bacteria are placed under selective pressures.