Textbook of Hyperbaric Medicine

14 HBO Therapy in Chronic Lyme Disease (S. 149-150)

Introduction

Lyme disease and its longer-term sequitur, chronic Lyme disease, is one of the most challenging arthropod-borne infectious diseases to diagnose, study, and treat. Although named after the town in Southwest Connecticut in the United States where epidemiological cluster investigations were performed in the mid 1970s, the European medical literature predating this period suggests there was considerable knowledge of this disease prior to this date. In Europe and the United States, the disease is caused by the spirochete Borrelia burgdorferi, although several other Borrelia species have been identified as causative organisms in various parts of the world (Krupka et al 2007).

The spirochete is primarily tick-borne, the most common vector being the Ixodes genus, although its presence in mosquito genera has also been reported (Halouzka et al 1999, Zakovská et al 2002). In the United States, 23,000 individuals were bitten by Borrelia-infected Ixodes ticks in 2005, which makes Lyme disease the most common arthropod-borne infectious disease in that country (Centers for Disease Control and Prevention [CDC], 2007).

Following the tick bite, an erythema migrans or “bull’seye” rash typically develops several days or weeks later, which is capable of expanding until it can measure 30 cm across. An array of flu-like symptoms appears weeks to months thereafter, the most common of which are joint swellings akin to arthritis. Unfortunately, as many as half of bitten individuals do not notice the bite, and the rash itself may not appear bull’s-eye-shaped, nor appear at all in many cases (Edlow 2002, Stricker &amp, Phillips 2003). Although diagnostic tests are very specific (99%–100%), and thus good for surveillance, they have relatively poor sensitivity (50%–75%) (Stricker 2007), thus, diagnosis is made clinically.

CDC recommends a 2-tiered approach of ELISA or immunofluorescence as a screening test, followed by Western blotting for confirmation if the test is positive. Prompt treatment with 14 to 30-day courses of antibiotics cures the infection in80%-90%of infected individuals(Marques 2008, Smith et al 2002). The most appropriate choices are doxycycline or ceftriaxone for adults and amoxicillin for children, although it should be stressed that other antibiotics may be better suited to different Borrelia species.Our knowledge of the efficacy of antibiotic treatment is far from adequate (Dinser et al 2005, Smith et al 2002).

Chronic Lyme Disease Despite antibiotic therapy, a minority of patients do not respond or continue to report ongoing symptoms, such as fatigue, myalgia, arthralgias, sleep disturbances, cognitive disorders, and depression (Marques 2008), and herein lies a controversy. One school of thought, endorsed by the Infectious Diseases Society of America (IDSA) (Wormser et al 2006), maintains that in patients properly treated with antibiotics, such symptoms are not caused by the persistence of the organism, but are due to the presence of preexisting conditions, such as fibromyalgia or chronic fatigue syndrome, or the presence of chronic inflammatory states induced by the Borrelia species.