Biomedical subjects

M T Osuna

Publications and source records attributed to M T Osuna.

3 recordsLinked to original sources

PubMedDate not supplied

[False negative diffusion in acute ischemic stroke].

INTRODUCTION: The new techniques of magnetic resonance imaging have produced a important advance in the early diagnosis of acute ischemic stroke. The diffusion weighted imaging (DWI) has a high sensitivity and specificity in the acute ischemia. CASE REPORT: 70 years old woman with previous history of hypertension and dyslipemia. The patient presented sudden vertigo with cervical neck pain and gaze problems. The physical exploration revealed right miosis, nistagmus, IX and X cranial nerve affection and ataxia. The clinical diagnosis was Wallenberg s syndrome and a medulla lateral infarction. However DWI was normal (10 hours). The neurological deficit was persistent and a repeated study disclosed a lateral infarction of the medulla. CONCLUSIONS: The sensitivity of DWI is reduced during the first 24 hours. There are false negative diagnosis mainly in small infarctions of posterior territory.

Aged↗

PubMedDate not supplied

[Infiltration of the optic nerve by lymphoma. Diagnosis by magnetic resonance imaging].

INTRODUCTION: Systemic lymphoma with meningeal involvement is frequent and diagnosis is based on the clinical features, the study of the cerebrospinal fluid and evaluation by magnetic resonance imaging (MRI). Lymphoma with involvement of the orbitary region is more frequent in the optic nerve (ON) than of the eye itself. CLINICAL CASE: We report the case of a patient with diffuse non Hodgkin gastric lymphoma of the large B cell type, which coursed with amaurosis, exophthalmus and signs of tumorous meningeal involvement. The ophthalmologic study revealed a thrombosis in the central retinal vein. The MRI exploration only showed an infiltration of the ON with no pathological meningeal enhancement. ON involvement consisted in a peripheral enhancement of the sheath with obliteration of the subarachnoid space. This pattern accounts for the existence of an ischemic neuropathy by direct compression over the central retinal vein and artery. There are different anatomopathologic or ophthalmologic studies of neuropathy of the ON by lymphoma in the literature, but there is only one case of diagnosis by MRI. CONCLUSIONS: ON involvement can be the only radiological sign in cases of neoplastic tumours with meningeal involvement. The radiological pattern consists in a peripheral infiltration of the sheath of the ON.

Humans↗

PubMedDate not supplied

[Hyperammonemic encephalopathy associated with valproate acid].

We report 4 clinical cases of hyperammonemic encephalopathy (HE) associated with valproate acid (VPA) and review the literature on its pathophysiology. In all four cases, hepatic function was normal and valproic levels were within the therapeutic range. Elevated ammonium levels were found as the only biochemical abnormality. Patients showed decreased level of consciousness, confusion, ataxia and seizures. In 1 case the EEG showed diffused triphasic waves with frontal predominance. After suppression of treatment with VPA there was remission of clinical manifestations, and ammonium levels returned to normal. In order to obtain the correct diagnosis of HE, in all patients treated with either VPA mono or polytherapy, ammonium levels should be considered.

Adult↗