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We read the article by Oksi et al 1 describing three patients withBorrelia burgdorferi infection and intracranial aneurysms with great interest.We encountered a patient with neuroborreliose and an aneurysm of the basilar artery, whom we describe.
A previously healthy 33 year old man presented with headache and progressive right hemiparesis. On neurological examination there was right facial weakness, moderate weakness of the right arm and leg (3/5), and brisk deep tendon reflexes. A right Babinski’s sign was present. Cerebral CT and MRI showed left anterior infarction, without enhancement with contrast. Examination of CSF disclosed 246 leucocytes/mm3; the protein content was 3.49 g/l. The IgG index was raised to 1.35. The CSF was xanthochromic, because of bilirubin. IgG antibodies against Borrelia burgdorferi in CSF were detected. A cerebral angiogram showed narrowing of the left anterior cerebral artery and an aneurysm of the basilar artery. Serum IgG antibodies againstBorrelia burgdorferi were detected. Investigations for other disorders were normal. We concluded that our patient had neuroborreliosis and he was treated with ceftriaxon intrvenously for 14 days. There was an almost complete recovery.
The diagnosis of neuroborreliosis in this patient is supported by the clinical presentation with right hemiparesis, positive serology forBorrelia burgdorferi, the presence of IgG antibodies against Borrelia burgdorferi in the CSF, and the response to antibiotic treatment. Based on the article by Oksi et al,1 it is very appealing to explain what happened in our patient by using their concept. Our patient had an aneurysm of the basilar artery. If vasculitis is one of the primary pathological mechanisms in neuroborreliosis, it can also lead to formation of aneurysms or vascular infarction.
However, we postulate that the presence of the aneurysm in our patient was a coincidence. There are two other explanations for the xanthochromia through bilirubin in his CSF. The first is the raised protein content of the CSF (in a patient with a meningitis due to neuroborreliosis). Or, our patient had a vasculitis (supported by the pleiocytosis of the CSF and by the narrowing of the left anterior cerebral artery on angiogram) which can lead to subarachnoid haemorrhage without the presence of an aneurysm, as was shown by Chehrenama et al.2
A causal relation between neuroborreliosis and the aneurysm is only based on circumstantial evidence. We do not agree that the reported cases of Oksi et al support this relation. Firstly, we think that only one of the three patients had neuroborreliosis. In the other two patients there was no pleiocytosis or raised protein content in the CSF, a finding that is considered to be a necessity for the diagnosis of neuroborreliosis.3-5Also, antibodies against Borrelia burgdorferi were not detected. Besides this, no evidence exists that in the one patient with neuroborreliosis and subarachnoid haemorrhage there is a causal relation with the aneurysm. He could indeed be one of those patients who happen to have an aneurysm.
For now, the answer to the question: “Intracranial aneurysms in three patients with disseminated Lyme borreliosis: cause or chance association?” should be chance association.
Oksi et al reply:
As a reply to the comments by Polet and Weinstein on our article “Intracranial aneurysms in three patients with disseminated Lyme borreliosis: cause or chance association?” we present the following comments.
Polet and Weinstein consider that only one of our three patients had neuroborreliosis. In our article1-1 we do not claim that all the patients had neuroborreliosis. However, all three patients had disseminated Lyme borreliosis based on the detection of Borrelia burgdorferi DNA in plasma samples of two patients, and an intrathecal production of antibodies against Borrelia burgdorferi in the third patient. It is also relevant to raise the question: what is neuroborreliosis? Does it require invasion of the spirochetes to none, one, or several of the following: cerebral tissue, meninges, CSF, or vessels in the central (or peripheral) nervous system. The authors state that an increased cell count or increased protein content is a necessity for neuroborreliosis, referring to the article by Garcia-Monco and Benach. However, this is not always the case as shown, for example in the studies by Luft and Coyle in which they describe patients with neuroborreliosis having DNA or antigens ofBorrelia burgdorferi in CSF despite normal routine CSF analysis and absence of antibodies againstBorrelia burgdorferi in CSF.1-2 1-3
Polet and Weinstein present a case of a patient with an intracranial aneurysm and suspected neuroborreliosis. They write that antibodies against Borrelia burgdorferi were detected in the CSF. However, the total IgG was increased, and they do not state whether the antibodies were intrathecally produced or not. If we understood correctly, the authors think that they, for some reason, could associate the focal narrowing of the left anterior cerebral artery with Borrelia burgdorferi but could not do the same with the aneurysm of the basilar artery. They do not have any evidence that excludes the possibility that the aneurysm could also have been caused by Borrelia burgdorferi. As we refer to in our article, high numbers of inflammatory cells have been found in aneurysms.1-4 We consider that it is possible that the aetiology of inflammatory changes in both instances may be the same—although probably seen at a different time point. We and others have found that disseminated Lyme borreliosis may be associated with cerebral vasculitis.1-5
Polet and Weinstein give a straightforward answer to the question presented in the title of our article. However, we think that it is not yet possible to give an answer to this question. The previously known association of another spirochetal infection, syphilis, to aneurysm formation, indicates that there might be a causal relation betweenBorrelia burgdorferi infection and aneurysm formation. This possible causal relation is a hypothesis that could be tested in the future in a larger number of patients with coexisting aneurysm and Lyme borreliosis. Definite answers would require analysis of a sufficient number of aneurysm samples using adequate techniques—for example, the polymerase chain reaction.
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