Can pontine trigeminal T2-hyperintensity suggest herpetic etiology of trigeminal neuralgia?

Abstract

Background: Trigeminal neuralgia (TN) is usually classified into two different categories: idiopathic and secondary. We have investigated the frequency of brainstem pontine lesions in patients with idiopathic TN without multiple sclerosis (MS) or stroke, and their association with herpes zoster (HZ) infection.Methods: Brain magnetic resonance imaging (MRI) studies of 28 patients with TN were retrospectively reviewed. Results:We found seven patients with clinical suspicion of HZ infection and pontine T2 hyperintense lesions, associated with nerve atrophy in one case. Fifteen patients had a neurovascular conflict (NVC) without brainstem involvement, two of them associated with trigeminal atrophy, while four patients had only volumetric reduction of the nerve. In all patients MRI findings were ipsilateral to the side of TN.Conclusions: Pontine T2 hyperintensities could be considered as a MRI sign of TN in patients without NVCs. This "trigeminal pontine sign" (TPS) is frequently found in association with herpetic infections. Methods MRI brain scans of twenty-eight patients (18F, 10M; mean age 52.8±14 years; range of age 26-80 years) with TN without MS or brainstem infarction were retrospectively reviewed by two neuroradiologists with 20 and 24 years of experience, respectively.Eighteen patients (12F, 6M; mean age 50 years; range of age 26-77 years) had idiopathic TN while ten patients (6F, 4M; mean age 50 years; range of age 34-63 years) had a clinical suspicion of a herpes zoster (HZ) infection; only four of these ten patients performed lumbar puncture that confirmed the diagnosis.In all cases a brain MRI was performed (Gyroscan Intera, 1.5 T, Philips Medical System, Best, The Netherlands), including FLAIR (TR: 8,005 ms, TE: 100 ms, TI: 2,200 ms, matrix: 256×192, slice thickness: 5 mm), Fast Spin-Echo (FSE) T1-and T2-weighted (TR: 583-4,454 ms, TE: 15-100 ms, matrix: 244×194−384×288, slice thickness: 5 mm, respectively) sequences; axial three-dimensional (3D) FSE T2 with a driven equilibrium pulse (DRIVE) sequence (TE: 250; TR: 1,500; flip angle: 90°; matrix: 256×256; slice thickness: 1×1×1 mm; FOV: 130×130) and magnetic resonance angiography (MRA) were performed to depict NVC and nerve atrophy. MRA was performed without contrast medium injection by using a 3-dimensional time-of-flight sequence (3D TOF, TE: 65 ms; TR: 6.9 ms; flip angle: 20°; matrix: 160×160; slice thickness: 1.40 mm; FOV: 175×200 mm). Multi planar reformation (MPR) and maximum intensity projection (MIP) reconstructions were subsequently analyzed.We evaluated the presence of brainstem lesions and their correlation with the side of the pain and the TN category. ResultsSeven patients with HZ infection showed hyperintense pontine areas on turbo spin echo (TSE) T2-weighted and FLAIR images, which we called "trigeminal pontine sign" (TPS), all of them without a NVC. Their data were summarized in Table 1. MRI was always consistent with the side of the pain. These lesions had a linear appearance, involving the pathway from the trigeminal root entry zone (...

MRI Findings in Varicella Zoster Trigeminal Neuritis Without Rash

“…1 Linear trigeminal REZ hyperintensity, called "trigeminal pontine sign," was described in small case series of trigeminal neuralgia associated with herpes zoster infection. 2 Such lesion seen on MRI, especially if associated with contrast enhancement like in our case, can suggest VZV etiology. Clinicians should be aware that VZV reactivation can occur even in the absence of skin changes and that MRI can be of crucial importance in the early diagnosis of this condition.…”

“…Unrecognized and untreated trigeminal VZV infection may lead to potentially severe conditions . Linear trigeminal REZ hyperintensity, called “trigeminal pontine sign,” was described in small case series of trigeminal neuralgia associated with herpes zoster infection . Such lesion seen on MRI, especially if associated with contrast enhancement like in our case, can suggest VZV etiology.…”

Nonpainful Trigeminal Neuropathy Associated with a Solitary Pontine Lesion: A Case Series

“…Two major studies on SPL associated with TN have been published. A gender dominancy varied between the two studies [2, 3]. Therefore, it is not possible to state the dominancy of a gender in SPL patients with or without neuralgia.…”

“…A solitary pontine lesion (SPL) is a single brainstem lesion on the trigeminal nerve pathway without any other supratentorial or infratentorial lesion. The centripetal migration of the herpes zoster virus is responsible for the lesion [2]. SPLs are mostly found in patients with trigeminal neuralgia (TN) [2, 3].…”

“…The centripetal migration of the herpes zoster virus is responsible for the lesion [2]. SPLs are mostly found in patients with trigeminal neuralgia (TN) [2, 3]. Indeed, TN associated with an SPL has been identified as a new syndrome [3].…”