A host of symptoms including skin rash, joint symptoms, "sciatica" and other painful conditions make Lyme disease, a tick-born disease caused by spirochetes of the genus Borrelia, the chameleon among the infectious diseases.
Ticks can transmit Borrelia and should be removed. Photo: www.zecken.de
Patients with Lyme disease often consult their GP", relates Professor Peter Herzer, a rheumatologist practising in Munich. "However, they are also seen by neurologists, dermatologists, internists and orthopaedists." At the MEDICA Congress held in Düsseldorf parallel to the MEDICA, the world's largest medical trade fair, Herzer will be talking about the diagnostic conundrum of Lyme disease.
The range of symptoms reported by patients with Lyme borreliosis is as diversified as the spectrum of medical practitioners they consult. The classic bull's eye rash or target lesion which heralds the onset of the disease - erythema migrans (EM) - is generally recognised immediately. Typically, EM appears between several days and several weeks after the tick bite as an erythematous macule or papule at the site of the bite which then expands concentrically to form a large red blotch. In some cases, however, EM may be overlooked or entirely absent.
The symptoms of joint involvement are much less specific and hence frequently misinterpreted. "A patient who presents with a largely painless knee-joint effusion should set off warning lights for Lyme disease", says Herzer. A Borrelia infection can also cause cardiac symptoms, such as dysrthymias and reduced heart pumping function. Doctors should become especially suspicious when the ECG reveals a "brief, fluctuating atrioventricular block".
According to Herzer, correct interpretation of the early neurologic symptoms of Lyme disease is crucial. At the early stages of the disease, a wrong diagnosis can lead to unnecessary invasive procedures which cause stress to the patient without conferring any benefits. For example, patients with Lyme disease are frequently treated - and even undergo surgery - for intervertebral disc lesions. This is totally unnecessary, according to Herzer, since "the neurological symptoms of Lyme disease are relatively typical and can be elicited by a few targeted questions". Although the severe back pain radiating into the arms and legs experienced by some patients with Lyme disease resembles the pain of prolapsed disc, its tendency to migrate is a telltale difference. This pain typically occurs at night and is accompanied by sensory losses or distortions which also vary. If the patient then experiences paralysis of the facial muscles, i.e. Bell's palsy, prolapsed disc should be thrown out once and for all as a differential diagnosis.
In patients presenting with this constellation, the physician should entertain a strong suspicion of Lyme disease even if the patient has not reported a tick bite. The diagnosis is finally confirmed by serological demonstration of Borrelia antibodies. "In patients with neuroborreliosis", adds Herzer, "a spinal tap is always indicated to confirm infection of the central nervous system". Once the diagnosis of Lyme disease has been made, antibiotic treatment can be instituted. At the early stages of the disease at least the chances of complete recovery are very high.
Even if - or precisely because - Lyme disease can play "hide and seek" behind myriad symptoms, says Herzer, it is a mistake to test for Borrelia antibodies in every patient with unclear symptoms. Herzer describes a paradoxical situation in which "Lyme disease is often overlooked on the one hand and diagnosed too frequently on the other". In particular, many physicians are led astray by the demonstration of Borrelia antibodies. A positive serology result alone can mean many things: between two and five percent of the general population and up to 20 percent of individuals at risk - such as forest rangers and forestry workers - are seropositive for Borrelia because of previous contact to the microorganism. This does not however mean they have Lyme disease. To complicate matters further, the tests now available for Lyme disease vary greatly in quality and are insufficiently standardised. According to Herzer, some of the methods currently used "have simply never been validated".
In this situation Herzer's credo is: "No laboratory diagnostics without typical clinical symptoms". Going one step further, he laments the high prevalence of what he calls "an iatrogenic Borrelia anxiety disorder." By this he means: too many doctors ordering too many serology tests and, after reading the test results which are all too often positive for Borrelia, overhastily writing too many prescriptions for antibiotics. It is this situation which has allowed what is in fact a rare disease to become a household word.
As a consequence, Lyme disease, like many other generalised infectious diseases before it, is often associated with any number of non-specific symptoms for which it is not responsible. The message Herzer wants to bring across to the medical audience at the MEDICA is: "Don't overlook Lyme disease by any means but at the same time don't diagnose it in patients without the typical clinical symptoms!"
"Die Lyme-Borreliose, ein interdisziplinärer Imitator"
13.15 bis 14 Uhr
CCD-Süd Raum 2
Leitung: Professor Peter Herzer, München