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Biomedical subjects

B Chandra-Sekar

Publications and source records attributed to B Chandra-Sekar.

7 recordsLinked to original sources

Cavernous hemangiomas of the internal auditory canal.

Cavernous hemangiomas are vascular malformations that are seldom found in the central nervous system. Four cavernous hemangiomas of the internal auditory canal and one of the cerebellopontine angle have been reported previously. We present a series of seven (six of which have never been reported) cavernous hemangiomas limited primarily to the internal auditory canal. Whereas all cases but one had marked unilateral sensorineural hearing loss, only two had preoperative facial nerve dysfunction. There are no specific symptoms or physical or audiometric findings to differentiate cavernous hemangiomas from acoustic neuromas. However, a hemangioma should be suspected when facial paralysis is present in conjunction with a small intracanalicular tumor as demonstrated by computed tomography or magnetic resonance imaging. The former reveals calcium stippling in the lesions, whereas magnetic resonance imaging reveals a high signal intensity on both T1- and T2-weighted images.

Adult↗

Brain tumors presenting as a seizure disorder in infants.

Seizures occur in 25% to 40% of children with supratentorial tumors and are the presenting complaint in 10% to 15%. However, when divided by age, only 2% of children with seizures as the presenting complaint of brain tumors were less than 1 year of age. Three children, ranging in age from 20 days to 7 months and seen within the past 2 years, form the basis of this report. The presenting complaint in all children was seizures. Computed tomographic (CT) scan was indicated in all children because of intractability to anticonvulsant drug therapy (one patient) and focal electroencephalographic (EEG) abnormality with clinical evidence of complex partial seizure activity (two patients). CT scan showed a contrast-enhancing mass in the medial temporal lobe in all patients. At surgery, a temporal lobe tumor was found and resected in all children. Histopathologic examination revealed a ganglioglioma, a fibrillary astrocytoma, and an anaplastic astrocytoma. All children did well postoperatively and are seizure free to date. Our experience suggests that supratentorial tumors should be considered as a cause of intractable and/or focal seizures in children under 1 year of age, and that such tumors should be attacked aggressively neurosurgically. Our experience is also in agreement with that of Tadmor et al, who have suggested that with the advent of CT scanning supratentorial tumors in this age group have been found to be more common than previously realized.

Astrocytoma↗

Brachiocephalic artery dilation by percutaneous transluminal angioplasty.

Percutaneous transluminal angioplasty (PTA) was used to dilate stenotic lesions in 38 brachiocephalic arteries in 36 patient. Complete evaluation of the central nervous system blood supply is a prerequisite for the brachiocephalic PTA when cerebral symptoms are present. The femoral artery is the best vascular entry site; use of digital subtraction angiography equipment for arterial mapping is helpful. Balloon diameter should be the same as or slightly wider than the diameter of the normal artery adjacent to the stenotic segment. Spasm was successfully treated with intraarterial injection of nitroglycerin. The only drug therapy consistently used with PTA was aspirin. Complete dilation of the stenosis is the best prevention of thrombotic or embolic complications. In properly selected cases, proximal subclavian artery stenoses can be safely dilated, and the balloon can eventually be placed across the origin of the vertebral artery. Because of potential complications associated with brachiocephalic PTA, indications must be well established, and interventions should not be performed on marginal or asymptomatic stenoses.

Aged↗

Aneurysmal compression of the anterior visual pathways.

Ten patients with aneurysmal compression of the anterior visual pathways had visual loss, unilateral in 4 and bilateral in 6. There was no typical clinical presentation. Visual loss was acute or gradual, acuity sometimes fluctuated, and visual field testing was highly variable. The aneurysms were supraclinoid (four patients), carotid-ophthalmic (two), anterior communicating-anterior cerebral (three), and intracavernous carotid (one). Nine patients had successful clipping of their aneurysm, and in one, ipsilateral common carotid ligation was performed. Postoperatively, visual acuity was improved in six cases, unchanged in three, and worse in one.

Adult↗

Progressive multifocal leukoencephalopathy: three patients diagnosed by brain biopsy, with prolonged survival in two.

Since 1980, three immunocompromised patients have been proved to have progressive multifocal leukoencephalopathy (PML) by brain biopsy at the University of Alabama at Birmingham. Two patients presented with focal neurological findings, and the third presented with dementia. Computed tomography (CT) revealed white matter low density lesions in areas appropriate to the neurological abnormalities. Brain biopsy of areas that were abnormal on CT produced diagnostic tissue in all three patients. No patient suffered ill effects from the biopsy. Neuropathological findings on light microscopy were compatible with PML in each case, although there was diversity within the group. Involvement of gray and white matter was present in all biopsy specimens; oligodendrocytes, astrocytes, and neurons were affected. Electron microscopic demonstration of particles compatible with polyoma virus confirmed the diagnosis in each case. Immunosuppressive medication was discontinued in two of the patients; these two have survived more than 2 years after diagnosis. One of these two has gradually improved and is independent in simple activities of daily life. Brain stem and cerebellar involvement and seizure disorders have been present in all reported cases. PML can be accurately and rapidly diagnosed by brain biopsy, enabling therapeutic manipulations that may prolong survival.

Adult↗

Pitfalls in computed tomographic evaluation of the cavernous sinus.

Computed tomography (CT) is the diagnostic procedure of choice in cavernous sinus evaluation. Two patients are reported with painful ophthalmoplegia due to metastatic carcinoma to the cavernous sinus in which initial CT scanning was considered to be normal. These cases illustrate the necessity of thin tomographic sections (5 mm or less), multiple projections (axial, coronal) and large doses of intravenous contrast medium (bolus and drip infusion). Careful technique is essential in order to thoroughly evaluate the parasellar region and avoid a false-negative CT examination.

Adult↗