Most cases consistent with Lyme disease are not tested in non-endemic region
A study published in the July issue of Clinical Infectious Diseases examines whether or not positive Lyme disease tests are of diagnostic value in regions, such as North Carolina, that are not considered endemic for the disease. Upon review of the data presented, the reader can better understand the frequency of Lyme disease testing in regions considered to have a low incidence of the illness.
by Daniel J. Cameron, MD MPH
Researchers from Duke University Health System in North Carolina reviewed the medical records of 1,621 patients, who had a clinical history consistent with Lyme disease and sought treatment at the facility between 2005 and 2010.  The authors, who were examining the predictive value of Lyme disease tests, discuss their findings in the July 20, 2015 issue of Clinical Infectious Diseases.
Upon review of the data presented, the reader can better understand the pattern of Lyme disease testing in a non-endemic region. Only 297 patients (18%) of the 1,621 individuals with a “clinical history consistent with Lyme disease” were tested for the disease.
The 297 cases consisted of: 110 patients with arthritis of a large joint; 98 patients with cranial nerve palsy; 75 patients with meningitis; 11 patients with both meningitis and cranial neuropathy; 1 patient with arthritis plus cranial nerve palsy; 1 patient with atrioventricular block alone; 1 patient with atrioventricular block plus cranial nerve palsy. 
The authors conceded that their study focused on patients who exhibited conditions most frequently attributable to Lyme disease (LD) and not those who presented with the full clinical spectrum of disseminated Lyme disease. The study did not include patients with well described manifestations of Lyme disease, such as chronic neurologic Lyme disease,  Lyme encephalopathy, [3,4] neuropsychiatric Lyme disease  and post-treatment Lyme disease. 
Although the patients exhibited symptoms “most frequently attributable to Lyme disease,” 82% of them were not tested for the disease. The study neglected to examine why these patients did not receive testing. Nor did the authors address where the patients were subsequently diagnosed with LD.
Reports of diagnostic delays remind us of the need to assess patients with clinical history consistent with LD. Treatment delays averaging 1.8 to 2 years have been reported in a case series  and Lyme encephalopathy.  In the case series, the majority (60%) of cases with delayed treatment met the CDC surveillance case definition with a rash, Bell’s palsy, or arthritis. 
This study should serve as a reminder of the need for clinicians to examine patients with a clinical history consistent with Lyme disease to determine if they do have the illness even in areas not considered endemic.
- Lantos PM, Branda JA, Boggan JC et al. Poor positive predictive value of Lyme disease serologic testing in an area of low disease incidence. Clin Infect Dis, (2015).
- Logigian EL, Kaplan RF, Steere AC. Chronic neurologic manifestations of Lyme disease. N Engl J Med, 323(21), 1438-1444 (1990).
- Logigian EL, Kaplan RF, Steere AC. Successful treatment of Lyme encephalopathy with intravenous ceftriaxone. J Infect Dis, 180(2), 377-383 (1999).
- Fallon BA, Keilp JG, Corbera KM et al. A randomized, placebo-controlled trial of repeated IV antibiotic therapy for Lyme encephalopathy. Neurology, 70(13), 992-1003 (2008).
- Fallon BA, Nields JA. Lyme disease: a neuropsychiatric illness. Am J Psychiatry, 151(11), 1571-1583 (1994).
- Aucott JN, Rebman AW, Crowder LA, Kortte KB. Post-treatment Lyme disease syndrome symptomatology and the impact on life functioning: is there something here? Qual Life Res, 22(1), 75-84 (2013).
- Cameron DJ. Consequences of treatment delay in Lyme disease. J Eval Clin Pract, 13(3), 470-472 (2007).