A case of meningo-vascular syphilis associated with bilateral anterior cerebral artery aneurysms
Syphilis is a sexually transmitted disease caused by Treponema pallidum, a bacterium of the order of spirochetes, with human beings as the only host. Recently, the drastic increase in the incidence of syphilis worldwide, especially in urban areas, led clinicians to heighten their degree of suspicion, with special regard to the presence of this infection within the HIV populations, intravenous drugs users and homosexuals. New studies may be helpful in diagnosing and managing syphilis in both its early and delayed clinical manifestations.
We report the case of a 41 years old African man who came under our observation because of the worsening of an initially undertreated headache, whose first appearance was traced by the patient about 10 years ago. Clinical examination showed the presence of mildly depressed mood, left temporal region pain and tinnitus. Brain CT/MRI showed an ambiguous left frontal lesion (Fig. 1., A-B) and a MR-angiography (MRA) revealed two aneurysms occurring at both anterior cerebral arteries (ACAs) (Fig. 1., C-D). Microbiological and histopathological data proved consistent with the hypothesis of meningovascular syphilis (Fig. 2., A-F). The patient was treated with antibiotic therapy. Follow-up at 4 months did show a stable clinical picture.
Treponema pallidum typically invades the central nervous system in secondary and later stages of syphilitic infection. Neurosyphilis can manifest through a broad spectrum of clinical features; among those, meningovascular (arteritic) syphilis represents a reasonable hypothesis in our case: it occurs, on average, 7 years after the initial infection and its pathological features consist of endarteritis with perivascular inflammation of both medium and small-calibre vessels (Heubner and Nissl-Alzheimer-type, respectively). The subsequent luminal narrowing predisposes to cerebrovascular thrombosis, ischemia, vessel occlusion and infarction. This explains why the most common presentation of meningovascular syphilis is a stroke syndrome involving the middle cerebral artery (most common) or the branches of the basilar artery (second most common). A subacute encephalitic prodrome is present, characterized by the presence of headaches, vertigo, insomnia, and psychological abnormalities such as personality change, emotional lability, insomnia, decreased memory.
Syphilis-associated aneurysms are a relatively rare finding, mostly occurring in the carotid artery, the middle cerebral artery, the anterior cerebral artery, the anterior and posterior communicating arteries and the basilar artery. To our knowledge, this the first report of 2 mycotic aneurysms involving both ACAs. Although many cases remain asymptomatic, the majority of symptomatic mycotic brain aneurysms manifest themselves through symptoms related to their rupture, such as: severe unremitting localized headaches, dizziness, seizures, altered mental status and focal neurological deficits related to subarachnoid hemorrhage. The diagnosis of brain mycotic aneurysms is based on the use of neuroimaging (non-contrast CT scans, contrast-enhanced CT angiography, MRI and conventional angiography), in the presence of predisposing infectious conditions, eventually highlighted by positive cultures of peripheral blood or the infected aneurysm wall and cerebrospinal fluid (CSF) examination.Treponemal tests such as the fluorescent treponemal antibody absorption (FTA-ABS) and the Treponema pallidum hemagglutination assay (TPHA), highly sensitive and specific in advanced-stage syphilis, can produce persistently positive results, known as ”serological scar”, that should be followed up longer due to the possible existence of other treponema reservoirs.
The treatment of intracranial infectious aneurysms remains controversial and highly individualized, because of the lack of clear standards to guide clinical decision making. The conservative management (that we opted for) is indicated for patients with unruptured aneurysms and/or with high surgical risk and consists of a 4-6 weeks lasting antimicrobial therapy.Then, the patient must be followed with serial angiography to monitor the stability of the aneurysms. Alternatively, the definitive treatment of ruptured aneurysms relies on surgical clipping (young, symptomatic patients with accessible aneurysms), endovascular coiling (surgically inaccessible or multiple aneurysms, at high surgical risk), trapping via either modalities.
A Singular Case of Neurosyphilis Manifesting Through a Meningovascular Chronic Inflammatory Process in Association with the Occurrence of Two Aneurysms Involving the Distal A2 Segment of Both Anterior Cerebral Arteries: A Case Report and Review of the Literature.
Bagatti D, Mazibrada J, Ligarotti GK, Nazzi V, Franzini A.
World Neurosurg. 2015 Nov 5