Recurrent Third Nerve Paresis with Migraine: A Case Report and Review of the Literature.

Ophthalmoplegic migraine (OM), first described by Charcot in 1870, is a disorder characterised by recurrent episodes of migraine associated with ophthalmoplegia. It has been extensively described in children and is rarer in adults. Commonly, the third nerve is affected with pupillary involvement and, more rarely, the fourth or the sixth nerve. OM is now believed to be an inflammatory demyelinating neuropathy. However, in the largest series of OM so far, by Lal et al. it most commonly involved the sixth nerve, started with a crescendo migraine and was accompanied by no enhancement of the cranial nerves. This has led to a rethink about the role of migraine, in the pathogenesis of OM. We describe a 14-year-old boy, with a 10-year history of intermittent headache followed by drooping of right eyelid and diplopia. The current episode started with a migrainous headache, which increased in severity over 3 days, followed by right third nerve paresis with pupillary involvement. Contrast-enhanced magnetic resonance imaging (MRI) of the brain with contrast showed nodular thickening at the root entry zone of the right oculomotor nerve with bright enhancement. The child responded to oral prednisolone, which was tapered over a month. Migraine prophylaxis with propranolol was concurrently added. His repeat MRI brain showed complete disappearance of enhancement of the lesion at 1 year.

Spontaneous Intracranial Hypotension: A Review of Neuroimaging and Current Concepts.

Spontaneous intracranial hypotension (SICH) is the emerging cause of orthostatic headache as it has been better recognized in recent years. SICH happens due to spinal cerebrospinal fluid (CSF) leak; however, the manifestations are predominantly cranial and hence imaging in SICH includes brain and spine. There are few characteristic brain imaging features to be concerned about to diagnose SICH in patients with vague symptoms or low clinical suspicion. Spine screening is recommended in these patients to assess spinal CSF leaks. While neuroradiologists play a significant role from the time of diagnosis to treatment of SICH, there is a need for all the general radiologists to be aware of the condition. Computed tomography myelogram and digital subtraction myelogram are performed for diagnostic and therapeutic management of SICH. There is a known risk for SICH recurrence in patients with sagittal longitudinal epidural collection and hence, targeted blood patch should be used instead of blind patch. Most importantly, slow mobilization is recommended following the patch to avoid recurrence.

Wernicke's encephalopathy: Is visual loss a red herring?

Predominantly visual loss, is very rare in Wernicke's encephalopathy. A 22 year old lady, in her 28th week of gestation, presented with a confused mental state, bilateral papilloedema with retinal hemorrhages, ophthalmoparesis, and cerebellar signs. Her MRI brain was suggestive of Wernicke's encephalopathy and she recovered with intravenous thiamine.

Role of imaging in CNS infections.

Neuroinfections are seen in both adults and children. These can result in serious morbidity and if left untreated and/or associated with comorbidities can be life threatening. Cross-sectional imaging like computed tomography (CT) and magnetic resonance imaging (MRI) are advised by the clinicians for the diagnosing, confirmation of the diagnosis, assess any complications of the infection, and also for follow up. Though CT is the initial imaging investigation commonly asked by the clinician, due to its lesser soft tissue resolution, early brain changes may not be seen on CT. MRI has better soft tissue resolution with no ionizing radiation to the patient and helps in detecting the early signs of infection. Appropriate MRI, not only helps the radiologist to reduce the number of possibilities of the causative organism but also differentiates tumors from infection. However, CT is useful to assess the bony changes and also easily available and affordable cross-sectional imaging modality worldwide. The review summarizes the approach of the radiologist to central nervous system (CNS) infections and their typical imaging characteristic features.

Optic Nerve Canal Relation to Posterior Paranasal Sinuses in Indian Ethnics: Review and Objective Classification.

INTRODUCTION: Posterior paranasal sinuses consisting of posterior ethmoid and sphenoid sinuses show varying pneumatization and relationship to Optic Nerve Canal (ONC). Most commonly ONC is superolateral to sphenoid sinus, however varied protrusion of ONC into the sinuses may occur. Rarely it may pass completely through the sinus. Optic Nerve (ON) is covered by a thin bony layer or by periosteum and sinus mucosa without bone. Extensive pneumatization of sphenoid sinus and bony dehiscence predisposes to ON injury. The posterior ethmoid cell namely the Onodi cell is of great surgical importance when the ON is along its lateral wall and surrounds the nerve. These varied relations imply that a detailed knowledge of the intimate relationship of ONC with the posterior paranasal sinuses is necessary to avoid unintentional complications during the surgeries involving the ONC region. AIM: To assess relationship of ONC to the posterior paranasal sinuses in Indian Ethnic study group. MATERIALS AND METHODS: Retrospective review of 100 paranasal sinus Computed Tomography (CT) scans were done using 64 row Multi Detector Computed Tomography (MDCT). Multiplanar reformation images were assessed for ONC relation to posterior ethmoid and sphenoid sinuses, wall dehiscence, and Pneumatization of Anterior Clinoid Process (PACP). RESULTS: 200 optic nerve canals were assessed and grouped into four types based on the modification of Delano et al., classification. The most common OCN was Type-1 (60%), followed by Type-2 (15%), Type-3 (14%) and Type-4 (11%). Dehiscence was seen in 35(17.5%) mostly in Type-3 canals. PACP was seen in 30 (15%). CONCLUSION: Knowledge of ON relationship to posterior paranasal sinuses will reduce the devastating complications during sinus surgeries. Our modified ONC classification is based on the bony canal morphology and the degree of protrusion into sinuses. As with other reported studies worldwide, Type-1 ONC is the commonest among the Indians also. Type-2 and 3 ONC with sinus wall dehiscence and PACP are the most important anatomical variations which may potentially predispose to risk of surgical injury to the optic nerves.