"In the Clinic": Lyme disease (7 Aug 2012)

Topics with information and discussion about published studies related to Lyme disease and other tick-borne diseases.
Post Reply
Posts: 2768
Joined: Thu 1 Jul 2010 8:33

"In the Clinic": Lyme disease (7 Aug 2012)

Post by RitaA » Wed 8 Aug 2012 21:02

I was going to post this extract yesterday, but it was a bit too brief:

In the Clinic | 7 August 2012

Lyme Disease

Linden T. Hu, MD
Ann Intern Med. 7 August 2012;157(3):ITC2-1

Today, Lyme disease is the most common vector-borne disease in the US, with over 22 500 confirmed cases in 2010. Borrelia burgdorferi, a spirochete, is transmitted by the bite of infected Ixodes ticks. These ticks have a 3-stage lifecycle (larvae, nymph, and adult) and take 1 blood meal at each stage. They become infected by feeding on an infected wild animal—typically white-footed mice, voles, chipmunks, or birds—during the larval feeding. The infection is maintained during the tick molting process to the nymphal stage and can be transmitted to other animals to maintain the cycle of infection in the wild. Both nymphal and adult Ixodes ticks can transmit infection to humans.
The author of the blog "Relative Risk" has access to the full article, and here are his notes:

http://relative-risk.blogspot.com/2012/ ... linic.html
08 August 2012

"In the Clinic"

Notes From:
Lyme disease. Hu LT. Ann Intern Med. 2012 Aug 7;157(3):ITC2-1.

What is “chronic Lyme disease,” and how should it be treated?

Chronic Lyme disease most commonly refers to continuation of such symptoms as fatigue, myalgia, arthralgia, memory loss, and headache after antibiotic therapy for Lyme disease. Whether chronic Lyme disease is a legitimate clinical entity has become highly controversial. Chronic Lyme disease as it is commonly applied should be distinguished from well-accepted sequelae of Lyme disease. There is little disagreement that some manifestations of Lyme disease, such as arthritis, neuropathy, and radiculopathy, can persist after antibiotic therapy and can be documented objectively through medical testing. The mechanism behind persistence of these types of symptoms in some patients is unknown but has been suggested to be due to preexisting damage from the inflammatory response to infection, from persistent low-level infection, or to an autoimmune response.

Persistent arthritis after antibiotic therapy often responds to anti-inflammatory or immunomodulatory agents, such as methotrexate or tumor-necrosis factor inhibitors. Although fatigue persisting for several months to a year after treatment for Lyme disease is not uncommon, a small percentage of patients may continue for years to have symptoms that are similar to those seen in fibromyalgia or the chronic fatigue syndrome. The relationship of these symptoms to Lyme disease is controversial because some studies have suggested that they occur in patients with Lyme disease at the same rate as in the general population. A longitudinal case–control study of Connecticut residents reported to the Connecticut Department of Health with Lyme disease and age-matched controls showed that although many patients reported increased symptoms and difficulty with activities of daily living 1–11 years after the diagnosis of Lyme disease, the frequency of these reports was similar to that of age-matched controls. However, other studies have suggested an increase in patient reports of joint pain or memory impairment without objective evidence of dysfunction. Complicating interpretation, anecdotal reports suggest that a significant proportion of patients diagnosed with chronic Lyme disease are either seronegative or have been diagnosed by serologic tests using nonstandard criteria. Most of these patients have nonspecific symptoms that do not allow clinical diagnosis of Lyme disease.

There have been 3 randomized, controlled trials to study the effect of repeated antibiotic treatment using longer courses on symptoms in patients with chronic Lyme disease. None have shown significant sustained benefit on fatigue, pain, or neurocognitive function. As such, current recommendations for management of chronic Lyme disease are for supportive care only. The largest placebo-controlled trial of antibiotics for patients with persistent symptoms after Lyme disease enrolled 78 seropositive and 51 seronegative patients that were assigned to ceftriaxone 2 g/d for 30 d followed by oral doxycyline 200 mg/d for 60 d or placebo. Although baseline assessments showed significant impairment in health-related quality of life, there was no significant difference between patients receiving antibiotics or placebo on physical and mental health component scores of the Medical Outcomes Study Short- Form-36 or on neuropsychiatric testing.

What other tools are available to help clinicians manage Lyme disease?

The Centers for Disease Controland Prevention (CDC) maintain up-to-date information on prevention, diagnosis, and treatment ofLyme disease as well as state-by-state statistics for Lyme transmission at http://www.CDC.gov/lyme. Information on practical aspects of patient management, including instructions on tick removal, and fact sheets for patients are also available at the CDC Web site. Another excellent resource for providing patient information is the American Lyme Disease Foundation (http://www.ALDF.com). Connecticut has put together an excellent handbook on management of tick exposure risk for homeowners, available for free at
http://www.ct.gov/caes/lib/caes/documen ... /b1010.pdf

Post Reply