Our study revealed that 79 % of those referred for lumbar puncture upon suspicion of Lyme neuroborreliosis did not have typical symptoms of the disease – they were referred because of non-specific neurological symptoms such as prolonged tiredness, non-specific paraesthesias, difficulties with concentration, and myalgias. Patients in this group were unlikely to be diagnosed with Lyme neuroborreliosis.
Many of those who were diagnosed with definite or possible Lyme neuroborreliosis had had symptoms for less than three months, and none had had symptoms for more than six months. This may indicate that prolonged non-specific symptoms render a diagnosis of Lyme neuroborreliosis less likely. The symptoms of the disease are often such that patients seek medical assistance relatively quickly. A large percentage of the patients with non-typical symptoms had had them for more than a year, and none received a diagnosis of Lyme neuroborreliosis.
Whether lumbar puncture is necessary to diagnose Lyme neuroborreliosis is subject to international debate. Lumbar puncture is not required in the USA, whereas positive CSF results are required in Europe (7, 10, 20, 21). Certain doctors and patients argue that Lyme neuroborreliosis can be diagnosed on the basis of symptoms alone, including non-specific symptoms such as tiredness, myalgias and headache, and with the use of non-validated tests (15, 22). However, non-specific symptoms are common in the general population and there is little evidence that these are necessarily caused by Lyme neuroborreliosis; such diagnostic criteria are therefore not accepted by the major international academic communities (8, 14) – (16, 23, 24). An increased focus on the possible under-diagnosis of Lyme neuroborreliosis in persons with medically unexplained symptoms may have led to the increased use of lumbar puncture observed in recent years.
In our dataset, we found that all patients with definite Lyme neuroborreliosis had relatively high titres of Borrelia IgG antibodies in serum. Similar values were seen in 27 % of those who did not receive the diagnosis. In Sogn og Fjordane county, 10 % of healthy blood donors are Borrelia-IgG-seropositive – without this being associated with health problems (24, 25). In Vest-Agder county, 18 % of the population have serum antibodies (26). Exposure to Borrelia can lead to seropositive status for several years, for both IgM and IgG (27). A number of those with non-specific neurological symptoms may have been referred for evaluation for Lyme neuroborreliosis after testing positive for Borrelia antibodies at their GP surgery. The detection of anti-Borrelia antibodies in serum does not necessarily mean that a patient’s health problems are caused by Lyme neuroborreliosis, but a positive result may support the diagnosis in those who do have symptoms of the disease (24).
Peripheral facial nerve palsy was present in 63 % of patients with possible or definite Lyme neuroborreliosis, and 24 % of those assessed for peripheral facial nerve palsy received a diagnosis of either possible or definite Lyme neuroborreliosis. None of the eight patients with definite or possible Lyme neuroborreliosis had had a rash suspected of being erythema migrans, and only two recalled a tick bite within the last three months. It is known that about half of patients with Lyme neuroborreliosis do not recall either a tick bite or erythema migrans (7, 28).
Lyme neuroborreliosis is thus an important differential diagnosis in cases of new-onset peripheral facial nerve palsy, irrespective of whether the patient can recall a tick bite or erythema migrans. Sørlandet Hospital has introduced lumbar puncture for all patients with peripheral facial nerve palsy, and our results support this practice in an area highly endemic for Borrelia. None of those who received a diagnosis of possible or definite Lyme neuroborreliosis had symptoms of meningitis (headache with hypersensitivity to light and sound, and nausea or vomiting). The symptoms of Borrelia meningitis may be pronounced but often resemble those of viral meningitis – headache of varying severity and fluctuating fever, but with no other signs of meningitis (29).
One limitation of this study is that it is based on a review of medical records and not on direct discussions with, and examination of, patients. The dataset is relatively small, with only six patients with definite Lyme neuroborreliosis. Most of the records and referrals provided a good picture of symptoms and medical history, but it was not possible to resolve any ambiguities in the self-reported medical history and clinical results. We assumed that if a symptom was not described in the referral or medical records, then the patient had not had that symptom – however, this cannot be ruled out for certain. The individual who recorded symptoms was not formally blinded with respect to the results of the CSF analysis.