North American tick-borne diseases

Magnetic resonance imaging of infectious meningitis and ventriculitis in adults

Magnetic resonance imaging findings of meningitis are usually nonspecific with respect to the causative pathogen because the brain response to these insults is similar in most cases. In this article, we will use a few representative cases to describe the characteristic magnetic resonance findings of meningitis and its complications, including ventriculitis.

Tularemia and Q fever

The zoonotic infections caused by Francisella tularensis and Coxiella burnetii, tularemia and Q fever, respectively, are two less commonly encountered clinical illnesses that are becoming increasingly recognized as epidemiologically important human diseases. The prevalence of tularemia and Q fever can be positively impacted by increased awareness of the clinical entities that arise from infection by these arthropod-borne organisms. Improved recognition of these clinical syndromes will lead to greater diagnostic accuracy in recognizing these diseases in patients. Ultimately, more stringent measures to prevent infection may be required, through raising public awareness, since current therapeutic regimens for these two diseases are limited, and knowledge of the pathogenesis of these two organisms are still in developing stages.

Cardiovascular manifestations of Lyme disease

Although the cardiac manifestations of Lyme disease may be diverse, in general they are treatable with currently available therapies. A high index of suspicion is required to make a diagnosis, especially for patients who may lack a suggestive history of tick exposure or residence in an endemic region. Lyme disease-related heart block may require pacemaker insertion and supportive care. The efficacy of antibiotics in the therapy of acute and chronic cardiac Lyme disease will require further study. Serologic testing and cardiac histopathology are the most precise methods of diagnosis. There is a need to develop more sensitive and specific diagnostic tests for Lyme disease and for Lyme carditis in particular.